Use dcp::compose rather than our own.compose

118 files changed, 395 insertions, 787 deletions

diff --git a/src/lib/analyse_audio_job.cc b/src/lib/analyse_audio_job.cc
index ca0f49f57..e71230683 100644
--- a/src/lib/analyse_audio_job.cc
+++ b/src/lib/analyse_audio_job.cc
@@ -21,13 +21,13 @@
 
 #include "analyse_audio_job.h"
 #include "audio_analysis.h"
-#include "compose.hpp"
 #include "dcpomatic_log.h"
 #include "film.h"
 #include "filter.h"
 #include "player.h"
 #include "playlist.h"
 #include "config.h"
+#include <dcp/compose.h>
 #include <iostream>
 
 #include "i18n.h"
diff --git a/src/lib/analytics.cc b/src/lib/analytics.cc
index ac0abc222..697e8f0e4 100644
--- a/src/lib/analytics.cc
+++ b/src/lib/analytics.cc
@@ -20,9 +20,9 @@
 
 
 #include "analytics.h"
-#include "compose.hpp"
 #include "exceptions.h"
 #include "warnings.h"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 #include <libcxml/cxml.h>
 DCPOMATIC_DISABLE_WARNINGS
@@ -60,7 +60,7 @@ Analytics::successful_dcp_encode ()
 			boost::bind(
 				boost::ref(Message),
 				_("Congratulations!"),
-				String::compose (_(
+				dcp::compose (_(
 					"<h2>You have made %1 DCPs with DCP-o-matic!</h2>"
 					"<img width=\"20%%\" src=\"memory:me.jpg\" align=\"center\">"
                                         "<p>Hello. I'm Carl and I'm the "
diff --git a/src/lib/atmos_mxf_content.cc b/src/lib/atmos_mxf_content.cc
index 82c20e88f..d833bc416 100644
--- a/src/lib/atmos_mxf_content.cc
+++ b/src/lib/atmos_mxf_content.cc
@@ -21,11 +21,11 @@
 
 #include "atmos_content.h"
 #include "atmos_mxf_content.h"
-#include "compose.hpp"
 #include "film.h"
 #include "job.h"
 #include <asdcp/KM_log.h>
 #include <dcp/atmos_asset.h>
+#include <dcp/compose.h>
 #include <dcp/exceptions.h>
 #include <dcp/raw_convert.h>
 #include <libxml++/libxml++.h>
@@ -93,7 +93,7 @@ AtmosMXFContent::examine (shared_ptr<const Film> film, shared_ptr<Job> job)
 string
 AtmosMXFContent::summary () const
 {
-	return String::compose (_("%1 [Atmos]"), path_summary());
+	return dcp::compose (_("%1 [Atmos]"), path_summary());
 }
 
 
diff --git a/src/lib/audio_content.cc b/src/lib/audio_content.cc
index 748cbb7d0..d0c08e480 100644
--- a/src/lib/audio_content.cc
+++ b/src/lib/audio_content.cc
@@ -20,11 +20,11 @@
 
 
 #include "audio_content.h"
-#include "compose.hpp"
 #include "config.h"
 #include "exceptions.h"
 #include "film.h"
 #include "frame_rate_change.h"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 #include <libcxml/cxml.h>
 #include <libxml++/libxml++.h>
@@ -148,7 +148,7 @@ AudioContent::technical_summary () const
 {
 	string s = "audio: ";
 	for (auto i: streams()) {
-		s += String::compose ("stream channels %1 rate %2 ", i->channels(), i->frame_rate());
+		s += dcp::compose ("stream channels %1 rate %2 ", i->channels(), i->frame_rate());
 	}
 
 	return s;
@@ -263,14 +263,14 @@ AudioContent::processing_description (shared_ptr<const Film> film) const
 	}
 
 	if (not_resampled && resampled) {
-		return String::compose (_("Some audio will be resampled to %1Hz"), resampled_frame_rate(film));
+		return dcp::compose (_("Some audio will be resampled to %1Hz"), resampled_frame_rate(film));
 	}
 
 	if (!not_resampled && resampled) {
 		if (same) {
-			return String::compose (_("Audio will be resampled from %1Hz to %2Hz"), common_frame_rate.get(), resampled_frame_rate(film));
+			return dcp::compose (_("Audio will be resampled from %1Hz to %2Hz"), common_frame_rate.get(), resampled_frame_rate(film));
 		} else {
-			return String::compose (_("Audio will be resampled to %1Hz"), resampled_frame_rate(film));
+			return dcp::compose (_("Audio will be resampled to %1Hz"), resampled_frame_rate(film));
 		}
 	}
 
@@ -288,7 +288,7 @@ AudioContent::channel_names () const
 	int stream = 1;
 	for (auto i: streams()) {
 		for (int j = 0; j < i->channels(); ++j) {
-			n.push_back (NamedChannel(String::compose ("%1:%2", stream, j + 1), index++));
+			n.push_back (NamedChannel(dcp::compose ("%1:%2", stream, j + 1), index++));
 		}
 		++stream;
 	}
diff --git a/src/lib/audio_decoder.cc b/src/lib/audio_decoder.cc
index 77c9b0695..7cc0621b3 100644
--- a/src/lib/audio_decoder.cc
+++ b/src/lib/audio_decoder.cc
@@ -25,7 +25,7 @@
 #include "dcpomatic_log.h"
 #include "log.h"
 #include "resampler.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 #include <iostream>
 
 #include "i18n.h"
diff --git a/src/lib/audio_filter_graph.cc b/src/lib/audio_filter_graph.cc
index fc43b5a34..e99434069 100644
--- a/src/lib/audio_filter_graph.cc
+++ b/src/lib/audio_filter_graph.cc
@@ -20,7 +20,7 @@
 
 #include "audio_filter_graph.h"
 #include "audio_buffers.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 extern "C" {
 #include <libavfilter/buffersink.h>
 #include <libavfilter/buffersrc.h>
@@ -149,7 +149,7 @@ AudioFilterGraph::process (shared_ptr<const AudioBuffers> buffers)
 	if (r < 0) {
 		char buffer[256];
 		av_strerror (r, buffer, sizeof(buffer));
-		throw DecodeError (String::compose (N_("could not push buffer into filter chain (%1)"), &buffer[0]));
+		throw DecodeError (dcp::compose (N_("could not push buffer into filter chain (%1)"), &buffer[0]));
 	}
 
 	while (true) {
diff --git a/src/lib/butler.cc b/src/lib/butler.cc
index 5a8e646aa..3edad6978 100644
--- a/src/lib/butler.cc
+++ b/src/lib/butler.cc
@@ -25,9 +25,9 @@
 #include "log.h"
 #include "dcpomatic_log.h"
 #include "cross.h"
-#include "compose.hpp"
 #include "exceptions.h"
 #include "video_content.h"
+#include <dcp/compose.h>
 
 
 using std::cout;
@@ -138,10 +138,10 @@ Butler::should_run () const
 		optional<DCPTime> pos = _audio.peek();
 		if (pos) {
 			throw ProgrammingError
-				(__FILE__, __LINE__, String::compose ("Butler video buffers reached %1 frames (audio is %2 at %3)", _video.size(), _audio.size(), pos->get()));
+				(__FILE__, __LINE__, dcp::compose ("Butler video buffers reached %1 frames (audio is %2 at %3)", _video.size(), _audio.size(), pos->get()));
 		} else {
 			throw ProgrammingError
-				(__FILE__, __LINE__, String::compose ("Butler video buffers reached %1 frames (audio is %2)", _video.size(), _audio.size()));
+				(__FILE__, __LINE__, dcp::compose ("Butler video buffers reached %1 frames (audio is %2)", _video.size(), _audio.size()));
 		}
 	}
 
@@ -150,10 +150,10 @@ Butler::should_run () const
 		optional<DCPTime> pos = _audio.peek();
 		if (pos) {
 			throw ProgrammingError
-				(__FILE__, __LINE__, String::compose ("Butler audio buffers reached %1 frames at %2 (video is %3)", _audio.size(), pos->get(), _video.size()));
+				(__FILE__, __LINE__, dcp::compose ("Butler audio buffers reached %1 frames at %2 (video is %3)", _audio.size(), pos->get(), _video.size()));
 		} else {
 			throw ProgrammingError
-				(__FILE__, __LINE__, String::compose ("Butler audio buffers reached %1 frames (video is %3)", _audio.size(), _video.size()));
+				(__FILE__, __LINE__, dcp::compose ("Butler audio buffers reached %1 frames (video is %3)", _audio.size(), _video.size()));
 		}
 	}
 
@@ -470,7 +470,7 @@ Butler::Error::summary () const
 		case Error::AGAIN:
 			return "Butler not ready";
 		case Error::DIED:
-			return String::compose("Butler died (%1)", message);
+			return dcp::compose("Butler died (%1)", message);
 		case Error::FINISHED:
 			return "Butler finished";
 	}
diff --git a/src/lib/combine_dcp_job.cc b/src/lib/combine_dcp_job.cc
index 5c299492b..0f548ec8b 100644
--- a/src/lib/combine_dcp_job.cc
+++ b/src/lib/combine_dcp_job.cc
@@ -20,9 +20,9 @@
 
 
 #include "combine_dcp_job.h"
-#include "compose.hpp"
 #include "config.h"
 #include <dcp/combine.h>
+#include <dcp/compose.h>
 #include <dcp/exceptions.h>
 
 #include "i18n.h"
@@ -64,8 +64,8 @@ CombineDCPJob::run ()
 		dcp::combine (
 			_inputs,
 			_output,
-			String::compose("libdcp %1", dcp::version),
-			String::compose("libdcp %1", dcp::version),
+			dcp::compose("libdcp %1", dcp::version),
+			dcp::compose("libdcp %1", dcp::version),
 			dcp::LocalTime().as_string(),
 			_annotation_text,
 			Config::instance()->signer_chain()
diff --git a/src/lib/compose.hpp b/src/lib/compose.hpp
deleted file mode 100644
index 479493f14..000000000
--- a/src/lib/compose.hpp
+++ /dev/null
@@ -1,392 +0,0 @@
-/* -*- c-basic-offset: 2 -*-
- * Defines String::compose(fmt, arg...) for easy, i18n-friendly
- * composition of strings.
- *
- * Version 1.0.
- *
- * Copyright (c) 2002 Ole Laursen <olau@hardworking.dk>.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public License
- * as published by the Free Software Foundation; either version 2.1 of
- * the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
- * USA.
- */
-
-//
-// Basic usage is like
-//
-//   std::cout << String::compose("This is a %1x%2 matrix.", rows, cols);
-//
-// See http://www.cs.aau.dk/~olau/compose/ or the included README.compose for
-// more details.
-//
-
-#ifndef DCPOMATIC_STRING_COMPOSE_H
-#define DCPOMATIC_STRING_COMPOSE_H
-
-#include <dcp/locale_convert.h>
-#include <boost/filesystem.hpp>
-#include <string>
-#include <list>
-#include <map>
-#include <inttypes.h>
-#include <cstdio>
-
-namespace StringPrivate
-{
-  // the actual composition class - using string::compose is cleaner, so we
-  // hide it here
-  class Composition
-  {
-  public:
-    // initialize and prepare format string on the form "text %1 text %2 etc."
-    explicit Composition(std::string fmt);
-
-    // supply an replacement argument starting from %1
-    template <typename T>
-    Composition &arg(const T &obj);
-
-    // compose and return string
-    std::string str() const;
-
-  private:
-    std::string os;
-    int arg_no;
-
-    // we store the output as a list - when the output string is requested, the
-    // list is concatenated to a string; this way we can keep iterators into
-    // the list instead of into a string where they're possibly invalidated on
-    // inserting a specification string
-    typedef std::list<std::string> output_list;
-    output_list output;
-
-    // the initial parse of the format string fills in the specification map
-    // with positions for each of the various %?s
-    typedef std::multimap<int, output_list::iterator> specification_map;
-    specification_map specs;
-  };
-
-  // helper for converting spec string numbers
-  inline int char_to_int(char c)
-  {
-    switch (c) {
-    case '0': return 0;
-    case '1': return 1;
-    case '2': return 2;
-    case '3': return 3;
-    case '4': return 4;
-    case '5': return 5;
-    case '6': return 6;
-    case '7': return 7;
-    case '8': return 8;
-    case '9': return 9;
-    default: return -1000;
-    }
-  }
-
-  inline bool is_number(int n)
-  {
-    switch (n) {
-    case '0':
-    case '1':
-    case '2':
-    case '3':
-    case '4':
-    case '5':
-    case '6':
-    case '7':
-    case '8':
-    case '9':
-      return true;
-
-    default:
-      return false;
-    }
-  }
-
-  // implementation of class Composition
-  template <typename T>
-  inline Composition &Composition::arg(const T &obj)
-  {
-    os += dcp::locale_convert<std::string>(obj);
-
-    if (!os.empty()) {		// manipulators don't produce output
-      for (specification_map::const_iterator i = specs.lower_bound(arg_no), end = specs.upper_bound(arg_no); i != end; ++i) {
-	output_list::iterator pos = i->second;
-	++pos;
-
-	output.insert(pos, os);
-      }
-
-      os = "";
-      ++arg_no;
-    }
-
-    return *this;
-  }
-
-  inline Composition::Composition(std::string fmt)
-    : arg_no(1)
-  {
-    std::string::size_type b = 0, i = 0;
-
-    // fill in output with the strings between the %1 %2 %3 etc. and
-    // fill in specs with the positions
-    while (i < fmt.length()) {
-      if (fmt[i] == '%' && i + 1 < fmt.length()) {
-	if (fmt[i + 1] == '%') {	// catch %%
-	  fmt.replace(i, 2, "%");
-	  ++i;
-	}
-	else if (is_number(fmt[i + 1])) { // aha! a spec!
-	  // save string
-	  output.push_back(fmt.substr(b, i - b));
-
-	  int n = 1;		// number of digits
-	  int spec_no = 0;
-
-	  do {
-	    spec_no += char_to_int(fmt[i + n]);
-	    spec_no *= 10;
-	    ++n;
-	  } while (i + n < fmt.length() && is_number(fmt[i + n]));
-
-	  spec_no /= 10;
-	  output_list::iterator pos = output.end();
-	  --pos;		// safe since we have just inserted a string>
-
-	  specs.insert(specification_map::value_type(spec_no, pos));
-
-	  // jump over spec string
-	  i += n;
-	  b = i;
-	}
-	else
-	  ++i;
-      }
-      else
-	++i;
-    }
-
-    if (i - b > 0)		// add the rest of the string
-      output.push_back(fmt.substr(b, i - b));
-  }
-
-  inline std::string Composition::str() const
-  {
-    // assemble string
-    std::string str;
-
-    for (output_list::const_iterator i = output.begin(), end = output.end();
-	 i != end; ++i)
-      str += *i;
-
-    return str;
-  }
-}
-
-// now for the real thing(s)
-namespace String
-{
-  // a series of functions which accept a format string on the form "text %1
-  // more %2 less %3" and a number of templated parameters and spits out the
-  // composited string
-  template <typename T1>
-  inline std::string compose(const std::string &fmt, const T1 &o1)
-  {
-    StringPrivate::Composition c(fmt);
-    c.arg(o1);
-    return c.str();
-  }
-
-  template <typename T1, typename T2>
-  inline std::string compose(const std::string &fmt,
-			     const T1 &o1, const T2 &o2)
-  {
-    StringPrivate::Composition c(fmt);
-    c.arg(o1).arg(o2);
-    return c.str();
-  }
-
-  template <typename T1, typename T2, typename T3>
-  inline std::string compose(const std::string &fmt,
-			     const T1 &o1, const T2 &o2, const T3 &o3)
-  {
-    StringPrivate::Composition c(fmt);
-    c.arg(o1).arg(o2).arg(o3);
-    return c.str();
-  }
-
-  template <typename T1, typename T2, typename T3, typename T4>
-  inline std::string compose(const std::string &fmt,
-			     const T1 &o1, const T2 &o2, const T3 &o3,
-			     const T4 &o4)
-  {
-    StringPrivate::Composition c(fmt);
-    c.arg(o1).arg(o2).arg(o3).arg(o4);
-    return c.str();
-  }
-
-  template <typename T1, typename T2, typename T3, typename T4, typename T5>
-  inline std::string compose(const std::string &fmt,
-			     const T1 &o1, const T2 &o2, const T3 &o3,
-			     const T4 &o4, const T5 &o5)
-  {
-    StringPrivate::Composition c(fmt);
-    c.arg(o1).arg(o2).arg(o3).arg(o4).arg(o5);
-    return c.str();
-  }
-
-  template <typename T1, typename T2, typename T3, typename T4, typename T5,
-	    typename T6>
-  inline std::string compose(const std::string &fmt,
-			     const T1 &o1, const T2 &o2, const T3 &o3,
-			     const T4 &o4, const T5 &o5, const T6 &o6)
-  {
-    StringPrivate::Composition c(fmt);
-    c.arg(o1).arg(o2).arg(o3).arg(o4).arg(o5).arg(o6);
-    return c.str();
-  }
-
-  template <typename T1, typename T2, typename T3, typename T4, typename T5,
-	    typename T6, typename T7>
-  inline std::string compose(const std::string &fmt,
-			     const T1 &o1, const T2 &o2, const T3 &o3,
-			     const T4 &o4, const T5 &o5, const T6 &o6,
-			     const T7 &o7)
-  {
-    StringPrivate::Composition c(fmt);
-    c.arg(o1).arg(o2).arg(o3).arg(o4).arg(o5).arg(o6).arg(o7);
-    return c.str();
-  }
-
-  template <typename T1, typename T2, typename T3, typename T4, typename T5,
-	    typename T6, typename T7, typename T8>
-  inline std::string compose(const std::string &fmt,
-			     const T1 &o1, const T2 &o2, const T3 &o3,
-			     const T4 &o4, const T5 &o5, const T6 &o6,
-			     const T7 &o7, const T8 &o8)
-  {
-    StringPrivate::Composition c(fmt);
-    c.arg(o1).arg(o2).arg(o3).arg(o4).arg(o5).arg(o6).arg(o7).arg(o8);
-    return c.str();
-  }
-
-  template <typename T1, typename T2, typename T3, typename T4, typename T5,
-	    typename T6, typename T7, typename T8, typename T9>
-  inline std::string compose(const std::string &fmt,
-			     const T1 &o1, const T2 &o2, const T3 &o3,
-			     const T4 &o4, const T5 &o5, const T6 &o6,
-			     const T7 &o7, const T8 &o8, const T9 &o9)
-  {
-    StringPrivate::Composition c(fmt);
-    c.arg(o1).arg(o2).arg(o3).arg(o4).arg(o5).arg(o6).arg(o7).arg(o8).arg(o9);
-    return c.str();
-  }
-
-  template <typename T1, typename T2, typename T3, typename T4, typename T5,
-	    typename T6, typename T7, typename T8, typename T9, typename T10>
-  inline std::string compose(const std::string &fmt,
-			     const T1 &o1, const T2 &o2, const T3 &o3,
-			     const T4 &o4, const T5 &o5, const T6 &o6,
-			     const T7 &o7, const T8 &o8, const T9 &o9,
-			     const T10 &o10)
-  {
-    StringPrivate::Composition c(fmt);
-    c.arg(o1).arg(o2).arg(o3).arg(o4).arg(o5).arg(o6).arg(o7).arg(o8).arg(o9)
-      .arg(o10);
-    return c.str();
-  }
-
-  template <typename T1, typename T2, typename T3, typename T4, typename T5,
-	    typename T6, typename T7, typename T8, typename T9, typename T10,
-	    typename T11>
-  inline std::string compose(const std::string &fmt,
-			     const T1 &o1, const T2 &o2, const T3 &o3,
-			     const T4 &o4, const T5 &o5, const T6 &o6,
-			     const T7 &o7, const T8 &o8, const T9 &o9,
-			     const T10 &o10, const T11 &o11)
-  {
-    StringPrivate::Composition c(fmt);
-    c.arg(o1).arg(o2).arg(o3).arg(o4).arg(o5).arg(o6).arg(o7).arg(o8).arg(o9)
-      .arg(o10).arg(o11);
-    return c.str();
-  }
-
-  template <typename T1, typename T2, typename T3, typename T4, typename T5,
-	    typename T6, typename T7, typename T8, typename T9, typename T10,
-	    typename T11, typename T12>
-  inline std::string compose(const std::string &fmt,
-			     const T1 &o1, const T2 &o2, const T3 &o3,
-			     const T4 &o4, const T5 &o5, const T6 &o6,
-			     const T7 &o7, const T8 &o8, const T9 &o9,
-			     const T10 &o10, const T11 &o11, const T12 &o12)
-  {
-    StringPrivate::Composition c(fmt);
-    c.arg(o1).arg(o2).arg(o3).arg(o4).arg(o5).arg(o6).arg(o7).arg(o8).arg(o9)
-      .arg(o10).arg(o11).arg(o12);
-    return c.str();
-  }
-
-  template <typename T1, typename T2, typename T3, typename T4, typename T5,
-	    typename T6, typename T7, typename T8, typename T9, typename T10,
-	    typename T11, typename T12, typename T13>
-  inline std::string compose(const std::string &fmt,
-			     const T1 &o1, const T2 &o2, const T3 &o3,
-			     const T4 &o4, const T5 &o5, const T6 &o6,
-			     const T7 &o7, const T8 &o8, const T9 &o9,
-			     const T10 &o10, const T11 &o11, const T12 &o12,
-			     const T13 &o13)
-  {
-    StringPrivate::Composition c(fmt);
-    c.arg(o1).arg(o2).arg(o3).arg(o4).arg(o5).arg(o6).arg(o7).arg(o8).arg(o9)
-      .arg(o10).arg(o11).arg(o12).arg(o13);
-    return c.str();
-  }
-
-  template <typename T1, typename T2, typename T3, typename T4, typename T5,
-	    typename T6, typename T7, typename T8, typename T9, typename T10,
-	    typename T11, typename T12, typename T13, typename T14>
-  inline std::string compose(const std::string &fmt,
-			     const T1 &o1, const T2 &o2, const T3 &o3,
-			     const T4 &o4, const T5 &o5, const T6 &o6,
-			     const T7 &o7, const T8 &o8, const T9 &o9,
-			     const T10 &o10, const T11 &o11, const T12 &o12,
-			     const T13 &o13, const T14 &o14)
-  {
-    StringPrivate::Composition c(fmt);
-    c.arg(o1).arg(o2).arg(o3).arg(o4).arg(o5).arg(o6).arg(o7).arg(o8).arg(o9)
-      .arg(o10).arg(o11).arg(o12).arg(o13).arg(o14);
-    return c.str();
-  }
-
-  template <typename T1, typename T2, typename T3, typename T4, typename T5,
-	    typename T6, typename T7, typename T8, typename T9, typename T10,
-	    typename T11, typename T12, typename T13, typename T14,
-	    typename T15>
-  inline std::string compose(const std::string &fmt,
-			     const T1 &o1, const T2 &o2, const T3 &o3,
-			     const T4 &o4, const T5 &o5, const T6 &o6,
-			     const T7 &o7, const T8 &o8, const T9 &o9,
-			     const T10 &o10, const T11 &o11, const T12 &o12,
-			     const T13 &o13, const T14 &o14, const T15 &o15)
-  {
-    StringPrivate::Composition c(fmt);
-    c.arg(o1).arg(o2).arg(o3).arg(o4).arg(o5).arg(o6).arg(o7).arg(o8).arg(o9)
-      .arg(o10).arg(o11).arg(o12).arg(o13).arg(o14).arg(o15);
-    return c.str();
-  }
-}
-
-
-#endif // STRING_COMPOSE_H
diff --git a/src/lib/config.cc b/src/lib/config.cc
index a8653a10c..ce7651ea8 100644
--- a/src/lib/config.cc
+++ b/src/lib/config.cc
@@ -30,9 +30,9 @@
 #include "cross.h"
 #include "film.h"
 #include "dkdm_wrapper.h"
-#include "compose.hpp"
 #include "crypto.h"
 #include "dkdm_recipient.h"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 #include <dcp/name_format.h>
 #include <dcp/certificate_chain.h>
@@ -217,13 +217,13 @@ Config::backup ()
 	/* Make a copy of the configuration */
 	try {
 		int n = 1;
-		while (n < 100 && boost::filesystem::exists(path(String::compose("config.xml.%1", n)))) {
+		while (n < 100 && boost::filesystem::exists(path(dcp::compose("config.xml.%1", n)))) {
 			++n;
 		}
 
-		boost::filesystem::copy_file(path("config.xml", false), path(String::compose("config.xml.%1", n), false));
-		boost::filesystem::copy_file(path("cinemas.xml", false), path(String::compose("cinemas.xml.%1", n), false));
-		boost::filesystem::copy_file(path("dkdm_recipients.xml", false), path(String::compose("dkdm_recipients.xml.%1", n), false));
+		boost::filesystem::copy_file(path("config.xml", false), path(dcp::compose("config.xml.%1", n), false));
+		boost::filesystem::copy_file(path("cinemas.xml", false), path(dcp::compose("cinemas.xml.%1", n), false));
+		boost::filesystem::copy_file(path("dkdm_recipients.xml", false), path(dcp::compose("dkdm_recipients.xml.%1", n), false));
 	} catch (...) {}
 }
 
diff --git a/src/lib/content.cc b/src/lib/content.cc
index 49ab944be..d2d8208de 100644
--- a/src/lib/content.cc
+++ b/src/lib/content.cc
@@ -34,7 +34,7 @@
 #include "exceptions.h"
 #include "film.h"
 #include "job.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 #include <dcp/locale_convert.h>
 #include <dcp/raw_convert.h>
 #include <libcxml/cxml.h>
@@ -304,9 +304,9 @@ Content::clone () const
 string
 Content::technical_summary () const
 {
-	auto s = String::compose ("%1 %2 %3", path_summary(), digest(), position().seconds());
+	auto s = dcp::compose ("%1 %2 %3", path_summary(), digest(), position().seconds());
 	if (_video_frame_rate) {
-		s += String::compose(" %1", *_video_frame_rate);
+		s += dcp::compose(" %1", *_video_frame_rate);
 	}
 	return s;
 }
diff --git a/src/lib/content_factory.cc b/src/lib/content_factory.cc
index e912589fc..6531986fb 100644
--- a/src/lib/content_factory.cc
+++ b/src/lib/content_factory.cc
@@ -38,7 +38,7 @@
 #include "log_entry.h"
 #include "dcpomatic_log.h"
 #include "log.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 #include <libcxml/cxml.h>
 #include <dcp/smpte_subtitle_asset.h>
 #include <boost/algorithm/string.hpp>
diff --git a/src/lib/copy_to_drive_job.cc b/src/lib/copy_to_drive_job.cc
index 9ddedfe62..539afb61f 100644
--- a/src/lib/copy_to_drive_job.cc
+++ b/src/lib/copy_to_drive_job.cc
@@ -20,9 +20,9 @@
 
 #include "disk_writer_messages.h"
 #include "copy_to_drive_job.h"
-#include "compose.hpp"
 #include "exceptions.h"
 #include "dcpomatic_log.h"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 #include <nanomsg/nn.h>
 #include <unistd.h>
@@ -53,7 +53,7 @@ CopyToDriveJob::CopyToDriveJob (boost::filesystem::path dcp, Drive drive, Nanoms
 string
 CopyToDriveJob::name () const
 {
-	return String::compose (_("Copying %1\nto %2"), _dcp.filename().string(), _drive.description());
+	return dcp::compose (_("Copying %1\nto %2"), _dcp.filename().string(), _drive.description());
 }
 
 string
@@ -66,7 +66,7 @@ void
 CopyToDriveJob::run ()
 {
 	LOG_DISK("Sending write request to disk writer for %1 %2", _dcp.string(), _drive.device());
-	if (!_nanomsg.send(String::compose(DISK_WRITER_WRITE "\n%1\n%2\n", _dcp.string(), _drive.device()), 2000)) {
+	if (!_nanomsg.send(dcp::compose(DISK_WRITER_WRITE "\n%1\n%2\n", _dcp.string(), _drive.device()), 2000)) {
 		LOG_DISK_NC("Failed to send write request.");
 		throw CommunicationFailedError ();
 	}
diff --git a/src/lib/create_cli.cc b/src/lib/create_cli.cc
index 2258f8a2e..e311f74cf 100644
--- a/src/lib/create_cli.cc
+++ b/src/lib/create_cli.cc
@@ -19,11 +19,11 @@
 */
 
 
-#include "compose.hpp"
 #include "config.h"
 #include "create_cli.h"
 #include "dcp_content_type.h"
 #include "ratio.h"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 #include <iostream>
 #include <string>
@@ -67,7 +67,7 @@ argument_option (int& n, int argc, char* argv[], string short_name, string long_
 	}
 
 	if ((n + 1) >= argc) {
-		**error = String::compose("%1: option %2 requires an argument", argv[0], long_name);
+		**error = dcp::compose("%1: option %2 requires an argument", argv[0], long_name);
 		return;
 	}
 
@@ -108,7 +108,7 @@ CreateCLI::CreateCLI (int argc, char* argv[])
 		} else if (a == "-h" || a == "--help") {
 			error = "Create a film directory (ready for making a DCP) or metadata file from some content files.\n"
 				"A film directory will be created if -o or --output is specified, otherwise a metadata file\n"
-				"will be written to stdout.\n" + String::compose(_help, argv[0]);
+				"will be written to stdout.\n" + dcp::compose(_help, argv[0]);
 			return;
 		}
 
@@ -142,7 +142,7 @@ CreateCLI::CreateCLI (int argc, char* argv[])
 
 		if (!claimed) {
 			if (a.length() > 2 && a.substr(0, 2) == "--") {
-				error = String::compose("%1: unrecognised option '%2'", argv[0], a) + String::compose(_help, argv[0]);
+				error = dcp::compose("%1: unrecognised option '%2'", argv[0], a) + dcp::compose(_help, argv[0]);
 				return;
 			} else {
 				Content c;
@@ -178,20 +178,20 @@ CreateCLI::CreateCLI (int argc, char* argv[])
 
 	dcp_content_type = DCPContentType::from_isdcf_name(dcp_content_type_string);
 	if (!dcp_content_type) {
-		error = String::compose("%1: unrecognised DCP content type '%2'", argv[0], dcp_content_type_string);
+		error = dcp::compose("%1: unrecognised DCP content type '%2'", argv[0], dcp_content_type_string);
 		return;
 	}
 
 	if (!container_ratio_string.empty()) {
 		container_ratio = Ratio::from_id (container_ratio_string);
 		if (!container_ratio) {
-			error = String::compose("%1: unrecognised container ratio %2", argv[0], container_ratio_string);
+			error = dcp::compose("%1: unrecognised container ratio %2", argv[0], container_ratio_string);
 			return;
 		}
 	}
 
 	if (standard_string != "SMPTE" && standard_string != "interop") {
-		error = String::compose("%1: standard must be SMPTE or interop", argv[0]);
+		error = dcp::compose("%1: standard must be SMPTE or interop", argv[0]);
 		return;
 	}
 
@@ -200,7 +200,7 @@ CreateCLI::CreateCLI (int argc, char* argv[])
 	}
 
 	if (content.empty()) {
-		error = String::compose("%1: no content specified", argv[0]);
+		error = dcp::compose("%1: no content specified", argv[0]);
 		return;
 	}
 
@@ -209,7 +209,7 @@ CreateCLI::CreateCLI (int argc, char* argv[])
 	}
 
 	if (j2k_bandwidth && (*j2k_bandwidth < 10000000 || *j2k_bandwidth > Config::instance()->maximum_j2k_bandwidth())) {
-		error = String::compose("%1: j2k-bandwidth must be between 10 and %2 Mbit/s", argv[0], (Config::instance()->maximum_j2k_bandwidth() / 1000000));
+		error = dcp::compose("%1: j2k-bandwidth must be between 10 and %2 Mbit/s", argv[0], (Config::instance()->maximum_j2k_bandwidth() / 1000000));
 		return;
 	}
 }
diff --git a/src/lib/cross_common.cc b/src/lib/cross_common.cc
index 2e48bf3e0..0a5451ff1 100644
--- a/src/lib/cross_common.cc
+++ b/src/lib/cross_common.cc
@@ -20,9 +20,9 @@
 
 
 #include "cross.h"
-#include "compose.hpp"
 #include "dcpomatic_log.h"
 #include "warnings.h"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 DCPOMATIC_DISABLE_WARNINGS
 #include <libxml++/libxml++.h>
@@ -91,7 +91,7 @@ Drive::description () const
 		name = _("Unknown");
 	}
 
-	return String::compose(_("%1 (%2 GB) [%3]"), name, gb, _device);
+	return dcp::compose(_("%1 (%2 GB) [%3]"), name, gb, _device);
 }
 
 
@@ -108,7 +108,7 @@ Drive::log_summary () const
 		mp = mp.substr (0, mp.length() - 1);
 	}
 
-	return String::compose(
+	return dcp::compose(
 		"Device %1 mounted on %2 size %3 vendor %4 model %5",
 		_device, mp, _size, _vendor.get_value_or("[none]"), _model.get_value_or("[none]")
 			);
diff --git a/src/lib/cross_linux.cc b/src/lib/cross_linux.cc
index 65151791c..f2faa6a2a 100644
--- a/src/lib/cross_linux.cc
+++ b/src/lib/cross_linux.cc
@@ -19,7 +19,6 @@
 */
 
 
-#include "compose.hpp"
 #include "config.h"
 #include "cross.h"
 #include "dcpomatic_log.h"
@@ -27,6 +26,7 @@
 #include "exceptions.h"
 #include "log.h"
 #include "warnings.h"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 #include <glib.h>
 DCPOMATIC_DISABLE_WARNINGS
diff --git a/src/lib/cross_osx.cc b/src/lib/cross_osx.cc
index b9b7796a2..d7ca778f4 100644
--- a/src/lib/cross_osx.cc
+++ b/src/lib/cross_osx.cc
@@ -20,12 +20,12 @@
 
 
 #include "cross.h"
-#include "compose.hpp"
 #include "log.h"
 #include "dcpomatic_log.h"
 #include "config.h"
 #include "exceptions.h"
 #include "warnings.h"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 #include <glib.h>
 extern "C" {
diff --git a/src/lib/cross_windows.cc b/src/lib/cross_windows.cc
index ac92aa7eb..43dc87cc3 100644
--- a/src/lib/cross_windows.cc
+++ b/src/lib/cross_windows.cc
@@ -20,13 +20,13 @@
 
 
 #include "cross.h"
-#include "compose.hpp"
 #include "log.h"
 #include "dcpomatic_log.h"
 #include "config.h"
 #include "exceptions.h"
 #include "dcpomatic_assert.h"
 #include "util.h"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 #include <glib.h>
 extern "C" {
@@ -599,7 +599,7 @@ Drive::get ()
 			continue;
 		}
 
-		string const physical_drive = String::compose("\\\\.\\PHYSICALDRIVE%1", *device_number);
+		string const physical_drive = dcp::compose("\\\\.\\PHYSICALDRIVE%1", *device_number);
 
 		HANDLE device = CreateFileA (
 				physical_drive.c_str(), 0,
@@ -645,7 +645,7 @@ Drive::unmount ()
 {
 	LOG_DISK("Unmounting %1 with %2 mount points", _device, _mount_points.size());
 	DCPOMATIC_ASSERT (_mount_points.size() == 1);
-	string const device_name = String::compose ("\\\\.\\%1", _mount_points.front());
+	string const device_name = dcp::compose ("\\\\.\\%1", _mount_points.front());
 	string const truncated = device_name.substr (0, device_name.length() - 1);
 	//LOG_DISK("Actually opening %1", _device);
 	//HANDLE device = CreateFileA (_device.c_str(), (GENERIC_READ | GENERIC_WRITE), FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING, 0, 0);
diff --git a/src/lib/curl_uploader.cc b/src/lib/curl_uploader.cc
index 60835bea7..0b08227f0 100644
--- a/src/lib/curl_uploader.cc
+++ b/src/lib/curl_uploader.cc
@@ -23,7 +23,7 @@
 #include "exceptions.h"
 #include "config.h"
 #include "cross.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 #include <iostream>
 
 #include "i18n.h"
@@ -82,19 +82,19 @@ CurlUploader::upload_file (boost::filesystem::path from, boost::filesystem::path
 	curl_easy_setopt (
 		_curl, CURLOPT_URL,
 		/* Use generic_string so that we get forward-slashes in the path, even on Windows */
-		String::compose ("ftp://%1/%2/%3", Config::instance()->tms_ip(), Config::instance()->tms_path(), to.generic_string ()).c_str ()
+		dcp::compose ("ftp://%1/%2/%3", Config::instance()->tms_ip(), Config::instance()->tms_path(), to.generic_string ()).c_str ()
 		);
 
 	_file = fopen_boost (from, "rb");
 	if (!_file) {
-		throw NetworkError (String::compose (_("Could not open %1 to send"), from));
+		throw NetworkError (dcp::compose (_("Could not open %1 to send"), from));
 	}
 	_transferred = &transferred;
 	_total_size = total_size;
 
 	auto const r = curl_easy_perform (_curl);
 	if (r != CURLE_OK) {
-		throw NetworkError (String::compose (_("Could not write to remote file (%1)"), curl_easy_strerror (r)));
+		throw NetworkError (dcp::compose (_("Could not write to remote file (%1)"), curl_easy_strerror (r)));
 	}
 
 	fclose (_file);
diff --git a/src/lib/dcp.cc b/src/lib/dcp.cc
index abdfc7f9e..ee7b92ca5 100644
--- a/src/lib/dcp.cc
+++ b/src/lib/dcp.cc
@@ -19,12 +19,12 @@
 */
 
 
-#include "compose.hpp"
 #include "dcp.h"
 #include "dcp_content.h"
 #include "dcpomatic_log.h"
 #include "log.h"
 #include "util.h"
+#include <dcp/compose.h>
 #include <dcp/dcp.h>
 #include <dcp/decrypted_kdm.h>
 #include <dcp/exceptions.h>
diff --git a/src/lib/dcp_content.cc b/src/lib/dcp_content.cc
index c380e6f84..26ed49819 100644
--- a/src/lib/dcp_content.cc
+++ b/src/lib/dcp_content.cc
@@ -27,11 +27,11 @@
 #include "film.h"
 #include "config.h"
 #include "overlaps.h"
-#include "compose.hpp"
 #include "dcp_decoder.h"
 #include "log.h"
 #include "dcpomatic_log.h"
 #include "text_content.h"
+#include <dcp/compose.h>
 #include <dcp/dcp.h>
 #include <dcp/raw_convert.h>
 #include <dcp/exceptions.h>
@@ -315,7 +315,7 @@ string
 DCPContent::summary () const
 {
 	boost::mutex::scoped_lock lm (_mutex);
-	return String::compose (_("%1 [DCP]"), _name);
+	return dcp::compose (_("%1 [DCP]"), _name);
 }
 
 string
diff --git a/src/lib/dcp_encoder.cc b/src/lib/dcp_encoder.cc
index f1c412539..e0e2f39cf 100644
--- a/src/lib/dcp_encoder.cc
+++ b/src/lib/dcp_encoder.cc
@@ -33,10 +33,10 @@
 #include "player.h"
 #include "job.h"
 #include "writer.h"
-#include "compose.hpp"
 #include "referenced_reel_asset.h"
 #include "text_content.h"
 #include "player_video.h"
+#include <dcp/compose.h>
 #include <boost/signals2.hpp>
 #include <iostream>
 
diff --git a/src/lib/dcp_subtitle.cc b/src/lib/dcp_subtitle.cc
index 0943a6b08..21180dc2a 100644
--- a/src/lib/dcp_subtitle.cc
+++ b/src/lib/dcp_subtitle.cc
@@ -21,7 +21,7 @@
 
 #include "dcp_subtitle.h"
 #include "exceptions.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 #include <dcp/interop_subtitle_asset.h>
 #include <dcp/smpte_subtitle_asset.h>
 
@@ -56,7 +56,7 @@ DCPSubtitle::load (boost::filesystem::path file) const
 	}
 
 	if (!sc) {
-		throw FileError(String::compose(_("Could not read subtitles (%1 / %2)"), interop_error, smpte_error), file);
+		throw FileError(dcp::compose(_("Could not read subtitles (%1 / %2)"), interop_error, smpte_error), file);
 	}
 
 	return sc;
diff --git a/src/lib/dcp_text_track.cc b/src/lib/dcp_text_track.cc
index 0bd751275..749129c35 100644
--- a/src/lib/dcp_text_track.cc
+++ b/src/lib/dcp_text_track.cc
@@ -20,7 +20,7 @@
 
 
 #include "dcp_text_track.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 #include <string>
 
 #include "i18n.h"
@@ -50,7 +50,7 @@ DCPTextTrack::DCPTextTrack (string name_, optional<dcp::LanguageTag> language_)
 string
 DCPTextTrack::summary () const
 {
-	return String::compose("%1 (%2)", name, language ? language->to_string() : _("Unknown"));
+	return dcp::compose("%1 (%2)", name, language ? language->to_string() : _("Unknown"));
 }
 
 void
diff --git a/src/lib/dcp_video.cc b/src/lib/dcp_video.cc
index 4a505a7e1..895e39dd7 100644
--- a/src/lib/dcp_video.cc
+++ b/src/lib/dcp_video.cc
@@ -30,7 +30,6 @@
  */
 
 
-#include "compose.hpp"
 #include "config.h"
 #include "cross.h"
 #include "dcp_video.h"
@@ -44,6 +43,7 @@
 #include "rng.h"
 #include "warnings.h"
 #include <libcxml/cxml.h>
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 #include <dcp/openjpeg_image.h>
 #include <dcp/rgb_xyz.h>
diff --git a/src/lib/dcpomatic_log.h b/src/lib/dcpomatic_log.h
index 6a1c3a6ec..5eb8f2833 100644
--- a/src/lib/dcpomatic_log.h
+++ b/src/lib/dcpomatic_log.h
@@ -20,28 +20,28 @@
 
 
 #include "log.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 
 
 /** The current log; set up by the front-ends when they have a Film to log into */
 extern std::shared_ptr<Log> dcpomatic_log;
 
 
-#define LOG_GENERAL(...)      dcpomatic_log->log(String::compose(__VA_ARGS__), LogEntry::TYPE_GENERAL);
+#define LOG_GENERAL(...)      dcpomatic_log->log(dcp::compose(__VA_ARGS__), LogEntry::TYPE_GENERAL);
 #define LOG_GENERAL_NC(...)   dcpomatic_log->log(__VA_ARGS__, LogEntry::TYPE_GENERAL);
-#define LOG_ERROR(...)        dcpomatic_log->log(String::compose(__VA_ARGS__), LogEntry::TYPE_ERROR);
+#define LOG_ERROR(...)        dcpomatic_log->log(dcp::compose(__VA_ARGS__), LogEntry::TYPE_ERROR);
 #define LOG_ERROR_NC(...)     dcpomatic_log->log(__VA_ARGS__, LogEntry::TYPE_ERROR);
-#define LOG_WARNING(...)      dcpomatic_log->log(String::compose(__VA_ARGS__), LogEntry::TYPE_WARNING);
+#define LOG_WARNING(...)      dcpomatic_log->log(dcp::compose(__VA_ARGS__), LogEntry::TYPE_WARNING);
 #define LOG_WARNING_NC(...)   dcpomatic_log->log(__VA_ARGS__, LogEntry::TYPE_WARNING);
-#define LOG_TIMING(...)       dcpomatic_log->log(String::compose(__VA_ARGS__), LogEntry::TYPE_TIMING);
-#define LOG_DEBUG_ENCODE(...) dcpomatic_log->log(String::compose(__VA_ARGS__), LogEntry::TYPE_DEBUG_ENCODE);
-#define LOG_DEBUG_VIDEO_VIEW(...) dcpomatic_log->log(String::compose(__VA_ARGS__), LogEntry::TYPE_DEBUG_VIDEO_VIEW);
-#define LOG_DEBUG_THREE_D(...) dcpomatic_log->log(String::compose(__VA_ARGS__), LogEntry::TYPE_DEBUG_THREE_D);
+#define LOG_TIMING(...)       dcpomatic_log->log(dcp::compose(__VA_ARGS__), LogEntry::TYPE_TIMING);
+#define LOG_DEBUG_ENCODE(...) dcpomatic_log->log(dcp::compose(__VA_ARGS__), LogEntry::TYPE_DEBUG_ENCODE);
+#define LOG_DEBUG_VIDEO_VIEW(...) dcpomatic_log->log(dcp::compose(__VA_ARGS__), LogEntry::TYPE_DEBUG_VIDEO_VIEW);
+#define LOG_DEBUG_THREE_D(...) dcpomatic_log->log(dcp::compose(__VA_ARGS__), LogEntry::TYPE_DEBUG_THREE_D);
 #define LOG_DEBUG_THREE_D_NC(...) dcpomatic_log->log(__VA_ARGS__, LogEntry::TYPE_DEBUG_THREE_D);
-#define LOG_DISK(...)         dcpomatic_log->log(String::compose(__VA_ARGS__), LogEntry::TYPE_DISK);
+#define LOG_DISK(...)         dcpomatic_log->log(dcp::compose(__VA_ARGS__), LogEntry::TYPE_DISK);
 #define LOG_DISK_NC(...)      dcpomatic_log->log(__VA_ARGS__, LogEntry::TYPE_DISK);
-#define LOG_DEBUG_PLAYER(...)    dcpomatic_log->log(String::compose(__VA_ARGS__), LogEntry::TYPE_DEBUG_PLAYER);
+#define LOG_DEBUG_PLAYER(...)    dcpomatic_log->log(dcp::compose(__VA_ARGS__), LogEntry::TYPE_DEBUG_PLAYER);
 #define LOG_DEBUG_PLAYER_NC(...) dcpomatic_log->log(__VA_ARGS__, LogEntry::TYPE_DEBUG_PLAYER);
-#define LOG_DEBUG_AUDIO_ANALYSIS(...)    dcpomatic_log->log(String::compose(__VA_ARGS__), LogEntry::TYPE_DEBUG_AUDIO_ANALYSIS);
+#define LOG_DEBUG_AUDIO_ANALYSIS(...)    dcpomatic_log->log(dcp::compose(__VA_ARGS__), LogEntry::TYPE_DEBUG_AUDIO_ANALYSIS);
 #define LOG_DEBUG_AUDIO_ANALYSIS_NC(...) dcpomatic_log->log(__VA_ARGS__, LogEntry::TYPE_DEBUG_AUDIO_ANALYSIS);
 
diff --git a/src/lib/dcpomatic_socket.cc b/src/lib/dcpomatic_socket.cc
index a92a294e6..a1670de55 100644
--- a/src/lib/dcpomatic_socket.cc
+++ b/src/lib/dcpomatic_socket.cc
@@ -19,9 +19,9 @@
 */
 
 #include "dcpomatic_socket.h"
-#include "compose.hpp"
 #include "exceptions.h"
 #include "dcpomatic_assert.h"
+#include <dcp/compose.h>
 #include <boost/bind/bind.hpp>
 #include <boost/lambda/lambda.hpp>
 #include <iostream>
@@ -66,7 +66,7 @@ Socket::connect (boost::asio::ip::tcp::endpoint endpoint)
 	} while (ec == boost::asio::error::would_block);
 
 	if (ec) {
-		throw NetworkError (String::compose (_("error during async_connect (%1)"), ec.value ()));
+		throw NetworkError (dcp::compose (_("error during async_connect (%1)"), ec.value ()));
 	}
 
 	if (!_socket.is_open ()) {
@@ -91,7 +91,7 @@ Socket::write (uint8_t const * data, int size)
 	} while (ec == boost::asio::error::would_block);
 
 	if (ec) {
-		throw NetworkError (String::compose (_("error during async_write (%1)"), ec.value ()));
+		throw NetworkError (dcp::compose (_("error during async_write (%1)"), ec.value ()));
 	}
 
 	if (_write_digester) {
@@ -123,7 +123,7 @@ Socket::read (uint8_t* data, int size)
 	} while (ec == boost::asio::error::would_block);
 
 	if (ec) {
-		throw NetworkError (String::compose (_("error during async_read (%1)"), ec.value ()));
+		throw NetworkError (dcp::compose (_("error during async_read (%1)"), ec.value ()));
 	}
 
 	if (_read_digester) {
diff --git a/src/lib/dkdm_wrapper.cc b/src/lib/dkdm_wrapper.cc
index 4698c159d..ceba6582c 100644
--- a/src/lib/dkdm_wrapper.cc
+++ b/src/lib/dkdm_wrapper.cc
@@ -19,10 +19,10 @@
 */
 
 
-#include "compose.hpp"
 #include "dkdm_wrapper.h"
 #include "dcpomatic_assert.h"
 #include "warnings.h"
+#include <dcp/compose.h>
 DCPOMATIC_DISABLE_WARNINGS
 #include <libxml++/libxml++.h>
 DCPOMATIC_ENABLE_WARNINGS
@@ -57,7 +57,7 @@ DKDMBase::read (cxml::ConstNodePtr node)
 string
 DKDM::name () const
 {
-	return String::compose ("%1 (%2)", _dkdm.content_title_text(), _dkdm.cpl_id());
+	return dcp::compose ("%1 (%2)", _dkdm.content_title_text(), _dkdm.cpl_id());
 }
 
 
diff --git a/src/lib/emailer.cc b/src/lib/emailer.cc
index 6ef23c3e0..4933b9953 100644
--- a/src/lib/emailer.cc
+++ b/src/lib/emailer.cc
@@ -19,10 +19,10 @@
 */
 
 
-#include "compose.hpp"
 #include "config.h"
 #include "emailer.h"
 #include "exceptions.h"
+#include <dcp/compose.h>
 #include <curl/curl.h>
 #include <boost/algorithm/string.hpp>
 #include <boost/date_time/c_local_time_adjustor.hpp>
@@ -189,9 +189,9 @@ Emailer::send (string server, int port, EmailProtocol protocol, string user, str
 
 	if ((protocol == EmailProtocol::AUTO && port == 465) || protocol == EmailProtocol::SSL) {
 		/* "SSL" or "Implicit TLS"; I think curl wants us to use smtps here */
-		curl_easy_setopt (curl, CURLOPT_URL, String::compose("smtps://%1:%2", server, port).c_str());
+		curl_easy_setopt (curl, CURLOPT_URL, dcp::compose("smtps://%1:%2", server, port).c_str());
 	} else {
-		curl_easy_setopt (curl, CURLOPT_URL, String::compose("smtp://%1:%2", server, port).c_str());
+		curl_easy_setopt (curl, CURLOPT_URL, dcp::compose("smtp://%1:%2", server, port).c_str());
 	}
 
 	if (!user.empty ()) {
diff --git a/src/lib/encode_server.cc b/src/lib/encode_server.cc
index 24ba5bc45..739903c8b 100644
--- a/src/lib/encode_server.cc
+++ b/src/lib/encode_server.cc
@@ -33,12 +33,12 @@
 #include "config.h"
 #include "cross.h"
 #include "player_video.h"
-#include "compose.hpp"
 #include "log.h"
 #include "dcpomatic_log.h"
 #include "encoded_log_entry.h"
 #include "version.h"
 #include "warnings.h"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 #include <libcxml/cxml.h>
 DCPOMATIC_DISABLE_WARNINGS
diff --git a/src/lib/environment_info.cc b/src/lib/environment_info.cc
index 2a6d47a00..d7ac75ccb 100644
--- a/src/lib/environment_info.cc
+++ b/src/lib/environment_info.cc
@@ -19,11 +19,11 @@
 */
 
 
-#include "compose.hpp"
 #include "cross.h"
 #include "log.h"
 #include "version.h"
 #include "warnings.h"
+#include <dcp/compose.h>
 #include <dcp/version.h>
 #include <libssh/libssh.h>
 DCPOMATIC_DISABLE_WARNINGS
@@ -85,12 +85,12 @@ environment_info ()
 {
 	list<string> info;
 
-	info.push_back (String::compose ("DCP-o-matic %1 git %2 using %3", dcpomatic_version, dcpomatic_git_commit, dependency_version_summary()));
+	info.push_back (dcp::compose ("DCP-o-matic %1 git %2 using %3", dcpomatic_version, dcpomatic_git_commit, dependency_version_summary()));
 
 	{
 		char buffer[128];
 		gethostname (buffer, sizeof (buffer));
-		info.push_back (String::compose ("Host name %1", &buffer[0]));
+		info.push_back (dcp::compose ("Host name %1", &buffer[0]));
 	}
 
 #ifdef DCPOMATIC_DEBUG
@@ -109,7 +109,7 @@ environment_info ()
 	os_info.dwOSVersionInfoSize = sizeof (os_info);
 	GetVersionEx (&os_info);
 	info.push_back (
-		String::compose (
+		dcp::compose (
 			"Windows version %1.%2.%3",
 			(int) os_info.dwMajorVersion, (int) os_info.dwMinorVersion, (int) os_info.dwBuildNumber
 			)
@@ -141,9 +141,9 @@ environment_info ()
 #endif
 #endif
 
-	info.push_back (String::compose ("CPU: %1, %2 processors", cpu_info(), boost::thread::hardware_concurrency()));
+	info.push_back (dcp::compose ("CPU: %1, %2 processors", cpu_info(), boost::thread::hardware_concurrency()));
 	for (auto const& i: mount_info()) {
-		info.push_back (String::compose("Mount: %1 %2", i.first, i.second));
+		info.push_back (dcp::compose("Mount: %1 %2", i.first, i.second));
 	}
 
 	return info;
diff --git a/src/lib/exceptions.cc b/src/lib/exceptions.cc
index 9350430f9..119963d90 100644
--- a/src/lib/exceptions.cc
+++ b/src/lib/exceptions.cc
@@ -20,7 +20,7 @@
 
 
 #include "exceptions.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 
 #include "i18n.h"
 
@@ -33,7 +33,7 @@ using boost::optional;
 /** @param f File that we were trying to open */
 OpenFileError::OpenFileError (boost::filesystem::path f, int error, Mode mode)
 	: FileError (
-		String::compose (
+		dcp::compose (
 			mode == READ_WRITE ? _("could not open file %1 for read/write (%2)") :
 			(mode == READ ? _("could not open file %1 for read (%2)") : _("could not open file %1 for write (%2)")),
 			f.string(),
@@ -46,7 +46,7 @@ OpenFileError::OpenFileError (boost::filesystem::path f, int error, Mode mode)
 
 
 FileNotFoundError::FileNotFoundError (boost::filesystem::path f)
-	: runtime_error(String::compose("File %1 not found", f.string()))
+	: runtime_error(dcp::compose("File %1 not found", f.string()))
 	, _file (f)
 {
 
@@ -54,35 +54,35 @@ FileNotFoundError::FileNotFoundError (boost::filesystem::path f)
 
 
 ReadFileError::ReadFileError (boost::filesystem::path f, int e)
-	: FileError (String::compose(_("could not read from file %1 (%2)"), f.string(), strerror(e)), f)
+	: FileError (dcp::compose(_("could not read from file %1 (%2)"), f.string(), strerror(e)), f)
 {
 
 }
 
 
 WriteFileError::WriteFileError (boost::filesystem::path f, int e)
-	: FileError (String::compose(_("could not write to file %1 (%2)"), f.string(), strerror(e)), f)
+	: FileError (dcp::compose(_("could not write to file %1 (%2)"), f.string(), strerror(e)), f)
 {
 
 }
 
 
 MissingSettingError::MissingSettingError (string s)
-	: SettingError (s, String::compose(_("Missing required setting %1"), s))
+	: SettingError (s, dcp::compose(_("Missing required setting %1"), s))
 {
 
 }
 
 
 PixelFormatError::PixelFormatError (string o, AVPixelFormat f)
-	: runtime_error (String::compose(_("Cannot handle pixel format %1 during %2"), (int) f, o))
+	: runtime_error (dcp::compose(_("Cannot handle pixel format %1 during %2"), (int) f, o))
 {
 
 }
 
 
 TextSubtitleError::TextSubtitleError (string saw, string expecting, boost::filesystem::path f)
-	: FileError (String::compose(_("Error in subtitle file: saw %1 while expecting %2"), saw.empty() ? "[nothing]" : saw, expecting), f)
+	: FileError (dcp::compose(_("Error in subtitle file: saw %1 while expecting %2"), saw.empty() ? "[nothing]" : saw, expecting), f)
 {
 
 }
@@ -96,14 +96,14 @@ InvalidSignerError::InvalidSignerError ()
 
 
 InvalidSignerError::InvalidSignerError (string reason)
-	: runtime_error (String::compose(_("The certificate chain for signing is invalid (%1)"), reason))
+	: runtime_error (dcp::compose(_("The certificate chain for signing is invalid (%1)"), reason))
 {
 
 }
 
 
 ProgrammingError::ProgrammingError (string file, int line, string message)
-	: runtime_error (String::compose(_("Programming error at %1:%2 %3"), file, line, message))
+	: runtime_error (dcp::compose(_("Programming error at %1:%2 %3"), file, line, message))
 {
 
 }
@@ -117,7 +117,7 @@ KDMAsContentError::KDMAsContentError ()
 
 
 KDMError::KDMError (string s, string d)
-	: runtime_error (String::compose("%1 (%2)", s, d))
+	: runtime_error (dcp::compose("%1 (%2)", s, d))
 	, _summary (s)
 	, _detail (d)
 {
@@ -126,14 +126,14 @@ KDMError::KDMError (string s, string d)
 
 
 GLError::GLError (char const * last, int e)
-	: runtime_error (String::compose("%1 failed %2", last, e))
+	: runtime_error (dcp::compose("%1 failed %2", last, e))
 {
 
 }
 
 
 CopyError::CopyError (string m, optional<int> n)
-	: runtime_error (String::compose("%1%2", m, n ? String::compose(" (%1)", *n) : ""))
+	: runtime_error (dcp::compose("%1%2", m, n ? dcp::compose(" (%1)", *n) : ""))
 	, _message (m)
 	, _number (n)
 {
@@ -149,7 +149,7 @@ CommunicationFailedError::CommunicationFailedError ()
 
 
 VerifyError::VerifyError (string m, int n)
-	: runtime_error (String::compose("%1 (%2)", m, n))
+	: runtime_error (dcp::compose("%1 (%2)", m, n))
 	, _message (m)
 	, _number (n)
 {
diff --git a/src/lib/exceptions.h b/src/lib/exceptions.h
index 5cbf69941..d6a0055c3 100644
--- a/src/lib/exceptions.h
+++ b/src/lib/exceptions.h
@@ -28,7 +28,7 @@
 #define DCPOMATIC_EXCEPTIONS_H
 
 
-#include "compose.hpp"
+#include <dcp/compose.h>
 extern "C" {
 #include <libavutil/pixfmt.h>
 }
@@ -50,19 +50,19 @@ public:
 	{}
 
 	DecodeError (std::string function, std::string caller)
-		: std::runtime_error (String::compose("%1 failed [%2]", function, caller))
+		: std::runtime_error (dcp::compose("%1 failed [%2]", function, caller))
 	{}
 
 	DecodeError (std::string function, std::string caller, int error)
-		: std::runtime_error (String::compose("%1 failed [%2] (%3)", function, caller, error))
+		: std::runtime_error (dcp::compose("%1 failed [%2] (%3)", function, caller, error))
 	{}
 
 	DecodeError (std::string function, std::string caller, boost::filesystem::path file)
-		: std::runtime_error (String::compose("%1 failed [%2] (%3)", function, caller, file.string()))
+		: std::runtime_error (dcp::compose("%1 failed [%2] (%3)", function, caller, file.string()))
 	{}
 
 	DecodeError (std::string function, std::string caller, int error, boost::filesystem::path file)
-		: std::runtime_error (String::compose("%1 failed [%2] (%3) (%4)", function, caller, error, file.string()))
+		: std::runtime_error (dcp::compose("%1 failed [%2] (%3) (%4)", function, caller, error, file.string()))
 	{}
 };
 
@@ -87,11 +87,11 @@ public:
 	{}
 
 	explicit EncodeError (std::string function, std::string caller)
-		: std::runtime_error (String::compose("%1 failed [%2]", function, caller))
+		: std::runtime_error (dcp::compose("%1 failed [%2]", function, caller))
 	{}
 
 	explicit EncodeError (std::string function, std::string caller, int error)
-		: std::runtime_error (String::compose("%1 failed [%2] (%3)", function, caller, error))
+		: std::runtime_error (dcp::compose("%1 failed [%2] (%3)", function, caller, error))
 	{}
 };
 
@@ -106,7 +106,7 @@ public:
 	 *  @param f Name of the file that this exception concerns.
 	 */
 	FileError (std::string m, boost::filesystem::path f)
-		: std::runtime_error (String::compose("%1 with %2", m, f.string()))
+		: std::runtime_error (dcp::compose("%1 with %2", m, f.string()))
 		, _file (f)
 	{}
 
diff --git a/src/lib/ext.cc b/src/lib/ext.cc
index feba68c1f..d8df7609e 100644
--- a/src/lib/ext.cc
+++ b/src/lib/ext.cc
@@ -19,7 +19,6 @@
 */
 
 
-#include "compose.hpp"
 #include "cross.h"
 #include "dcpomatic_log.h"
 #include "digester.h"
@@ -27,6 +26,7 @@
 #include "exceptions.h"
 #include "ext.h"
 #include "nanomsg.h"
+#include <dcp/compose.h>
 
 #ifdef DCPOMATIC_LINUX
 #include <linux/fs.h>
@@ -97,13 +97,13 @@ write (boost::filesystem::path from, boost::filesystem::path to, uint64_t& total
 	ext4_file out;
 	int r = ext4_fopen(&out, to.generic_string().c_str(), "wb");
 	if (r != EOK) {
-		throw CopyError (String::compose("Failed to open file %1", to.generic_string()), r);
+		throw CopyError (dcp::compose("Failed to open file %1", to.generic_string()), r);
 	}
 
 	FILE* in = fopen_boost (from, "rb");
 	if (!in) {
 		ext4_fclose (&out);
-		throw CopyError (String::compose("Failed to open file %1", from.string()), 0);
+		throw CopyError (dcp::compose("Failed to open file %1", from.string()), 0);
 	}
 
 	uint8_t* buffer = new uint8_t[block_size];
@@ -119,7 +119,7 @@ write (boost::filesystem::path from, boost::filesystem::path to, uint64_t& total
 			fclose (in);
 			ext4_fclose (&out);
 			delete[] buffer;
-			throw CopyError (String::compose("Short read; expected %1 but read %2", this_time, read), 0);
+			throw CopyError (dcp::compose("Short read; expected %1 but read %2", this_time, read), 0);
 		}
 
 		digester.add (buffer, this_time);
@@ -136,14 +136,14 @@ write (boost::filesystem::path from, boost::filesystem::path to, uint64_t& total
 			fclose (in);
 			ext4_fclose (&out);
 			delete[] buffer;
-			throw CopyError (String::compose("Short write; expected %1 but wrote %2", this_time, written), 0);
+			throw CopyError (dcp::compose("Short write; expected %1 but wrote %2", this_time, written), 0);
 		}
 		remaining -= this_time;
 		total_remaining -= this_time;
 
 		++progress_count;
 		if ((progress_count % progress_frequency) == 0 && nanomsg) {
-			nanomsg->send(String::compose(DISK_WRITER_COPY_PROGRESS "\n%1\n", (1 - float(total_remaining) / total)), SHORT_TIMEOUT);
+			nanomsg->send(dcp::compose(DISK_WRITER_COPY_PROGRESS "\n%1\n", (1 - float(total_remaining) / total)), SHORT_TIMEOUT);
 		}
 	}
 
@@ -163,7 +163,7 @@ read (boost::filesystem::path from, boost::filesystem::path to, uint64_t& total_
 	LOG_DISK("Opening %1 for read", to.generic_string());
 	int r = ext4_fopen(&in, to.generic_string().c_str(), "rb");
 	if (r != EOK) {
-		throw VerifyError (String::compose("Failed to open file %1", to.generic_string()), r);
+		throw VerifyError (dcp::compose("Failed to open file %1", to.generic_string()), r);
 	}
 	LOG_DISK("Opened %1 for read", to.generic_string());
 
@@ -178,14 +178,14 @@ read (boost::filesystem::path from, boost::filesystem::path to, uint64_t& total_
 		if (read != this_time) {
 			ext4_fclose (&in);
 			delete[] buffer;
-			throw VerifyError (String::compose("Short read; expected %1 but read %2", this_time, read), 0);
+			throw VerifyError (dcp::compose("Short read; expected %1 but read %2", this_time, read), 0);
 		}
 
 		digester.add (buffer, this_time);
 		remaining -= this_time;
 		total_remaining -= this_time;
 		if (nanomsg) {
-			nanomsg->send(String::compose(DISK_WRITER_VERIFY_PROGRESS "\n%1\n", (1 - float(total_remaining) / total)), SHORT_TIMEOUT);
+			nanomsg->send(dcp::compose(DISK_WRITER_VERIFY_PROGRESS "\n%1\n", (1 - float(total_remaining) / total)), SHORT_TIMEOUT);
 		}
 	}
 
@@ -229,7 +229,7 @@ copy (boost::filesystem::path from, boost::filesystem::path to, uint64_t& total_
 	if (is_directory(from)) {
 		int r = ext4_dir_mk (cr.generic_string().c_str());
 		if (r != EOK) {
-			throw CopyError (String::compose("Failed to create directory %1", cr.generic_string()), r);
+			throw CopyError (dcp::compose("Failed to create directory %1", cr.generic_string()), r);
 		}
 
 		for (directory_iterator i = directory_iterator(from); i != directory_iterator(); ++i) {
@@ -263,7 +263,7 @@ void
 format_progress (void* context, float progress)
 {
 	if (context) {
-		reinterpret_cast<Nanomsg*>(context)->send(String::compose(DISK_WRITER_FORMAT_PROGRESS "\n%1\n", progress), SHORT_TIMEOUT);
+		reinterpret_cast<Nanomsg*>(context)->send(dcp::compose(DISK_WRITER_FORMAT_PROGRESS "\n%1\n", progress), SHORT_TIMEOUT);
 	}
 }
 
@@ -402,17 +402,17 @@ try
 } catch (CopyError& e) {
 	LOG_DISK("CopyError (from write): %1 %2", e.message(), e.number().get_value_or(0));
 	if (nanomsg) {
-		nanomsg->send(String::compose(DISK_WRITER_ERROR "\n%1\n%2\n", e.message(), e.number().get_value_or(0)), LONG_TIMEOUT);
+		nanomsg->send(dcp::compose(DISK_WRITER_ERROR "\n%1\n%2\n", e.message(), e.number().get_value_or(0)), LONG_TIMEOUT);
 	}
 } catch (VerifyError& e) {
 	LOG_DISK("VerifyError (from write): %1 %2", e.message(), e.number());
 	if (nanomsg) {
-		nanomsg->send(String::compose(DISK_WRITER_ERROR "\n%1\n%2\n", e.message(), e.number()), LONG_TIMEOUT);
+		nanomsg->send(dcp::compose(DISK_WRITER_ERROR "\n%1\n%2\n", e.message(), e.number()), LONG_TIMEOUT);
 	}
 } catch (exception& e) {
 	LOG_DISK("Exception (from write): %1", e.what());
 	if (nanomsg) {
-		nanomsg->send(String::compose(DISK_WRITER_ERROR "\n%1\n0\n", e.what()), LONG_TIMEOUT);
+		nanomsg->send(dcp::compose(DISK_WRITER_ERROR "\n%1\n0\n", e.what()), LONG_TIMEOUT);
 	}
 }
 
diff --git a/src/lib/ffmpeg.cc b/src/lib/ffmpeg.cc
index d476b4c29..9d07a8109 100644
--- a/src/lib/ffmpeg.cc
+++ b/src/lib/ffmpeg.cc
@@ -29,8 +29,8 @@
 #include "ffmpeg_subtitle_stream.h"
 #include "ffmpeg_audio_stream.h"
 #include "digester.h"
-#include "compose.hpp"
 #include "config.h"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 extern "C" {
 #include <libavcodec/avcodec.h>
@@ -103,7 +103,7 @@ FFmpeg::ffmpeg_log_callback (void* ptr, int level, const char* fmt, va_list vl)
 	av_log_format_line (ptr, level, fmt, vl, line, sizeof (line), &prefix);
 	string str (line);
 	boost::algorithm::trim (str);
-	dcpomatic_log->log (String::compose ("FFmpeg: %1", str), LogEntry::TYPE_GENERAL);
+	dcpomatic_log->log (dcp::compose ("FFmpeg: %1", str), LogEntry::TYPE_GENERAL);
 }
 
 
@@ -236,7 +236,7 @@ FFmpeg::setup_decoders ()
 				throw DecodeError (N_("avcodec_open2"), N_("FFmpeg::setup_decoders"), r);
 			}
 		} else {
-			dcpomatic_log->log (String::compose ("No codec found for stream %1", i), LogEntry::TYPE_WARNING);
+			dcpomatic_log->log (dcp::compose ("No codec found for stream %1", i), LogEntry::TYPE_WARNING);
 		}
 	}
 }
diff --git a/src/lib/ffmpeg_content.cc b/src/lib/ffmpeg_content.cc
index 516962936..8e8d43282 100644
--- a/src/lib/ffmpeg_content.cc
+++ b/src/lib/ffmpeg_content.cc
@@ -25,7 +25,6 @@
 #include "ffmpeg_examiner.h"
 #include "ffmpeg_subtitle_stream.h"
 #include "ffmpeg_audio_stream.h"
-#include "compose.hpp"
 #include "job.h"
 #include "util.h"
 #include "filter.h"
@@ -35,6 +34,7 @@
 #include "exceptions.h"
 #include "frame_rate_change.h"
 #include "text_content.h"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 #include <libcxml/cxml.h>
 extern "C" {
@@ -115,7 +115,7 @@ FFmpegContent::FFmpegContent (cxml::ConstNodePtr node, int version, list<string>
 		if (f) {
 			_filters.push_back (f);
 		} else {
-			notes.push_back (String::compose (_("DCP-o-matic no longer supports the `%1' filter, so it has been turned off."), i->content()));
+			notes.push_back (dcp::compose (_("DCP-o-matic no longer supports the `%1' filter, so it has been turned off."), i->content()));
 		}
 	}
 
@@ -338,11 +338,11 @@ string
 FFmpegContent::summary () const
 {
 	if (video && audio) {
-		return String::compose (_("%1 [movie]"), path_summary());
+		return dcp::compose (_("%1 [movie]"), path_summary());
 	} else if (video) {
-		return String::compose (_("%1 [video]"), path_summary());
+		return dcp::compose (_("%1 [video]"), path_summary());
 	} else if (audio) {
-		return String::compose (_("%1 [audio]"), path_summary());
+		return dcp::compose (_("%1 [audio]"), path_summary());
 	}
 
 	return path_summary ();
@@ -378,7 +378,7 @@ FFmpegContent::technical_summary () const
 		s += " - " + audio->technical_summary ();
 	}
 
-	return s + String::compose (
+	return s + dcp::compose (
 		"ffmpeg: audio %1 subtitle %2 filters %3", as, ss, filt
 		);
 }
@@ -550,14 +550,14 @@ FFmpegContent::add_properties (shared_ptr<const Film> film, list<UserProperty>&
 				/// file is limited, so that not all possible values are valid.
 				p.push_back (
 					UserProperty (
-						UserProperty::VIDEO, _("Colour range"), String::compose(_("Limited (%1-%2)"), lim_start, lim_end)
+						UserProperty::VIDEO, _("Colour range"), dcp::compose(_("Limited (%1-%2)"), lim_start, lim_end)
 						)
 					);
 				break;
 			case AVCOL_RANGE_JPEG:
 				/// TRANSLATORS: this means that the range of pixel values used in this
 				/// file is full, so that all possible pixel values are valid.
-				p.push_back (UserProperty (UserProperty::VIDEO, _("Colour range"), String::compose (_("Full (0-%1)"), total)));
+				p.push_back (UserProperty (UserProperty::VIDEO, _("Colour range"), dcp::compose (_("Full (0-%1)"), total)));
 				break;
 			default:
 				DCPOMATIC_ASSERT (false);
diff --git a/src/lib/ffmpeg_decoder.cc b/src/lib/ffmpeg_decoder.cc
index 31fbde773..a1b44624e 100644
--- a/src/lib/ffmpeg_decoder.cc
+++ b/src/lib/ffmpeg_decoder.cc
@@ -39,10 +39,10 @@
 #include "video_decoder.h"
 #include "film.h"
 #include "audio_decoder.h"
-#include "compose.hpp"
 #include "text_content.h"
 #include "audio_content.h"
 #include "frame_interval_checker.h"
+#include <dcp/compose.h>
 #include <dcp/subtitle_string.h>
 #include <sub/ssa_reader.h>
 #include <sub/subtitle.h>
@@ -340,7 +340,7 @@ FFmpegDecoder::deinterleave_audio (AVFrame* frame)
 	break;
 
 	default:
-		throw DecodeError (String::compose(_("Unrecognised audio sample format (%1)"), static_cast<int>(format)));
+		throw DecodeError (dcp::compose(_("Unrecognised audio sample format (%1)"), static_cast<int>(format)));
 	}
 
 	return audio;
diff --git a/src/lib/ffmpeg_encoder.cc b/src/lib/ffmpeg_encoder.cc
index 1ce375594..bd4f29c78 100644
--- a/src/lib/ffmpeg_encoder.cc
+++ b/src/lib/ffmpeg_encoder.cc
@@ -27,7 +27,7 @@
 #include "image.h"
 #include "cross.h"
 #include "butler.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 #include <iostream>
 
 #include "i18n.h"
@@ -136,7 +136,7 @@ FFmpegEncoder::go ()
 		if (files > 1) {
 			/// TRANSLATORS: _reel%1 here is to be added to an export filename to indicate
 			/// which reel it is.  Preserve the %1; it will be replaced with the reel number.
-			filename = filename.string() + String::compose(_("_reel%1"), i + 1);
+			filename = filename.string() + dcp::compose(_("_reel%1"), i + 1);
 		}
 
 		file_encoders.push_back (
@@ -179,7 +179,7 @@ FFmpegEncoder::go ()
 			auto v = _butler->get_video (true, &e);
 			_butler->rethrow ();
 			if (!v.first) {
-				throw DecodeError(String::compose("Error during decoding: %1", e.summary()));
+				throw DecodeError(dcp::compose("Error during decoding: %1", e.summary()));
 			}
 			auto fe = encoder->get (v.first->eyes());
 			if (fe) {
@@ -248,17 +248,17 @@ FFmpegEncoder::FileEncoderSet::FileEncoderSet (
 		/// TRANSLATORS: L here is an abbreviation for "left", to indicate the left-eye part of a 3D export
 		_encoders[Eyes::LEFT] = make_shared<FFmpegFileEncoder>(
 			video_frame_size, video_frame_rate, audio_frame_rate, channels, format,
-			audio_stream_per_channel, x264_crf, String::compose("%1_%2%3", output.string(), _("L"), extension)
+			audio_stream_per_channel, x264_crf, dcp::compose("%1_%2%3", output.string(), _("L"), extension)
 			);
 		/// TRANSLATORS: R here is an abbreviation for "right", to indicate the right-eye part of a 3D export
 		_encoders[Eyes::RIGHT] = make_shared<FFmpegFileEncoder>(
 			video_frame_size, video_frame_rate, audio_frame_rate, channels, format,
-			audio_stream_per_channel, x264_crf, String::compose("%1_%2%3", output.string(), _("R"), extension)
+			audio_stream_per_channel, x264_crf, dcp::compose("%1_%2%3", output.string(), _("R"), extension)
 			);
 	} else {
 		_encoders[Eyes::BOTH] = make_shared<FFmpegFileEncoder>(
 			video_frame_size, video_frame_rate, audio_frame_rate, channels, format,
-			audio_stream_per_channel, x264_crf, String::compose("%1%2", output.string(), extension)
+			audio_stream_per_channel, x264_crf, dcp::compose("%1%2", output.string(), extension)
 			);
 	}
 }
diff --git a/src/lib/ffmpeg_file_encoder.cc b/src/lib/ffmpeg_file_encoder.cc
index 29ee7455b..080f3ade9 100644
--- a/src/lib/ffmpeg_file_encoder.cc
+++ b/src/lib/ffmpeg_file_encoder.cc
@@ -28,7 +28,7 @@
 #include "log.h"
 #include "image.h"
 #include "cross.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 #include <iostream>
 
 #include "i18n.h"
@@ -62,7 +62,7 @@ public:
 	{
 		_codec = avcodec_find_encoder_by_name (codec_name.c_str());
 		if (!_codec) {
-			throw EncodeError (String::compose("avcodec_find_encoder_by_name failed for %1", codec_name));
+			throw EncodeError (dcp::compose("avcodec_find_encoder_by_name failed for %1", codec_name));
 		}
 
 		_codec_context = avcodec_alloc_context3 (_codec);
@@ -263,7 +263,7 @@ FFmpegFileEncoder::FFmpegFileEncoder (
 
 	r = avio_open_boost (&_format_context->pb, _output, AVIO_FLAG_WRITE);
 	if (r < 0) {
-		throw EncodeError (String::compose(_("Could not open output file %1 (%2)"), _output.string(), r));
+		throw EncodeError (dcp::compose(_("Could not open output file %1 (%2)"), _output.string(), r));
 	}
 
 	AVDictionary* options = nullptr;
@@ -307,7 +307,7 @@ FFmpegFileEncoder::setup_video ()
 {
 	_video_codec = avcodec_find_encoder_by_name (_video_codec_name.c_str());
 	if (!_video_codec) {
-		throw EncodeError (String::compose("avcodec_find_encoder_by_name failed for %1", _video_codec_name));
+		throw EncodeError (dcp::compose("avcodec_find_encoder_by_name failed for %1", _video_codec_name));
 	}
 
 	_video_codec_context = avcodec_alloc_context3 (_video_codec);
diff --git a/src/lib/ffmpeg_image_proxy.cc b/src/lib/ffmpeg_image_proxy.cc
index 54fb1c468..e26f4b040 100644
--- a/src/lib/ffmpeg_image_proxy.cc
+++ b/src/lib/ffmpeg_image_proxy.cc
@@ -19,7 +19,6 @@
 */
 
 
-#include "compose.hpp"
 #include "cross.h"
 #include "dcpomatic_socket.h"
 #include "exceptions.h"
@@ -27,6 +26,7 @@
 #include "image.h"
 #include "util.h"
 #include "warnings.h"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 DCPOMATIC_DISABLE_WARNINGS
 extern "C" {
@@ -160,7 +160,7 @@ FFmpegImageProxy::image (optional<dcp::Size>) const
 		if (_path) {
 			throw OpenFileError (_path->string(), e, OpenFileError::READ);
 		} else {
-			boost::throw_exception(DecodeError(String::compose(_("Could not decode image (%1)"), e)));
+			boost::throw_exception(DecodeError(dcp::compose(_("Could not decode image (%1)"), e)));
 		}
 	}
 
diff --git a/src/lib/file_group.cc b/src/lib/file_group.cc
index 7dae1da92..c5f6aa0cb 100644
--- a/src/lib/file_group.cc
+++ b/src/lib/file_group.cc
@@ -24,11 +24,11 @@
  */
 
 
-#include "compose.hpp"
 #include "cross.h"
 #include "dcpomatic_assert.h"
 #include "exceptions.h"
 #include "file_group.h"
+#include <dcp/compose.h>
 #include <sndfile.h>
 #include <cstdio>
 
@@ -182,7 +182,7 @@ FileGroup::read (uint8_t* buffer, int amount) const
 		}
 
 		if (ferror(_current_file)) {
-			throw FileError (String::compose("fread error %1", errno), _paths[_current_path]);
+			throw FileError (dcp::compose("fread error %1", errno), _paths[_current_path]);
 		}
 
 		if (eof) {
diff --git a/src/lib/film.cc b/src/lib/film.cc
index 44c49220b..3fe92c7cd 100644
--- a/src/lib/film.cc
+++ b/src/lib/film.cc
@@ -44,7 +44,6 @@
 #include "environment_info.h"
 #include "audio_processor.h"
 #include "digester.h"
-#include "compose.hpp"
 #include "screen.h"
 #include "audio_content.h"
 #include "video_content.h"
@@ -58,6 +57,7 @@
 #include "ffmpeg_subtitle_stream.h"
 #include "font.h"
 #include <libcxml/cxml.h>
+#include <dcp/compose.h>
 #include <dcp/cpl.h>
 #include <dcp/certificate_chain.h>
 #include <dcp/util.h>
@@ -564,7 +564,7 @@ Film::read_metadata (optional<boost::filesystem::path> path)
 		throw runtime_error (_("This film was created with a newer version of DCP-o-matic, and it cannot be loaded into this version.  Sorry!"));
 	} else if (_state_version < current_state_version) {
 		/* This is an older version; save a copy (if we haven't already) */
-		auto const older = path->parent_path() / String::compose("metadata.%1.xml", _state_version);
+		auto const older = path->parent_path() / dcp::compose("metadata.%1.xml", _state_version);
 		if (!boost::filesystem::is_regular_file(older)) {
 			try {
 				boost::filesystem::copy_file(*path, older);
@@ -887,7 +887,7 @@ Film::isdcf_name (bool if_created_now) const
 		auto fl = _luminance->value_in_foot_lamberts();
 		char buffer[64];
 		snprintf (buffer, sizeof(buffer), "%.1f", fl);
-		d += String::compose("-%1fl", buffer);
+		d += dcp::compose("-%1fl", buffer);
 	}
 
 	if (video_frame_rate() != 24) {
@@ -969,7 +969,7 @@ Film::isdcf_name (bool if_created_now) const
 	if (!ch.first && !ch.second) {
 		d += "_MOS";
 	} else if (ch.first) {
-		d += String::compose("_%1%2", ch.first, ch.second);
+		d += dcp::compose("_%1%2", ch.first, ch.second);
 	}
 
 	if (audio_channels() > static_cast<int>(dcp::Channel::HI) && find(mapped.begin(), mapped.end(), static_cast<int>(dcp::Channel::HI)) != mapped.end()) {
diff --git a/src/lib/filter_graph.cc b/src/lib/filter_graph.cc
index fc6b9033a..1984604ce 100644
--- a/src/lib/filter_graph.cc
+++ b/src/lib/filter_graph.cc
@@ -28,7 +28,7 @@
 #include "filter.h"
 #include "exceptions.h"
 #include "image.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 extern "C" {
 #include <libavfilter/buffersrc.h>
 #include <libavfilter/buffersink.h>
@@ -104,7 +104,7 @@ FilterGraph::setup (vector<Filter const *> filters)
 
 	int e = avfilter_graph_config (_graph, 0);
 	if (e < 0) {
-		throw DecodeError (String::compose(N_("could not configure filter graph (%1)"), e));
+		throw DecodeError (dcp::compose(N_("could not configure filter graph (%1)"), e));
 	}
 }
 
diff --git a/src/lib/frame_rate_change.cc b/src/lib/frame_rate_change.cc
index a1ff2ae65..0ee4a492e 100644
--- a/src/lib/frame_rate_change.cc
+++ b/src/lib/frame_rate_change.cc
@@ -23,7 +23,7 @@
 #include "types.h"
 #include "content.h"
 #include "film.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 #include <cmath>
 
 #include "i18n.h"
@@ -94,7 +94,7 @@ FrameRateChange::description () const
 		} else if (repeat == 2) {
 			description = _("Each content frame will be doubled in the DCP.\n");
 		} else if (repeat > 2) {
-			description = String::compose (_("Each content frame will be repeated %1 more times in the DCP.\n"), repeat - 1);
+			description = dcp::compose (_("Each content frame will be repeated %1 more times in the DCP.\n"), repeat - 1);
 		}
 
 		if (change_speed) {
diff --git a/src/lib/hints.cc b/src/lib/hints.cc
index 64122db8d..7653638fd 100644
--- a/src/lib/hints.cc
+++ b/src/lib/hints.cc
@@ -22,7 +22,6 @@
 #include "audio_analysis.h"
 #include "audio_content.h"
 #include "audio_processor.h"
-#include "compose.hpp"
 #include "content.h"
 #include "cross.h"
 #include "dcp_content_type.h"
@@ -37,6 +36,7 @@
 #include "util.h"
 #include "video_content.h"
 #include "writer.h"
+#include <dcp/compose.h>
 #include <dcp/cpl.h>
 #include <dcp/raw_convert.h>
 #include <dcp/reel.h>
@@ -182,7 +182,7 @@ Hints::check_frame_rate ()
 	case 25:
 	{
 		/* You might want to go to 24 */
-		string base = String::compose(_("You are set up for a DCP at a frame rate of %1 fps.  This frame rate is not supported by all projectors.  You may want to consider changing your frame rate to %2 fps."), 25, 24);
+		string base = dcp::compose(_("You are set up for a DCP at a frame rate of %1 fps.  This frame rate is not supported by all projectors.  You may want to consider changing your frame rate to %2 fps."), 25, 24);
 		if (f->interop()) {
 			base += "  ";
 			base += _("If you do use 25fps you should change your DCP standard to SMPTE.");
@@ -198,7 +198,7 @@ Hints::check_frame_rate ()
 	case 50:
 	case 60:
 		/* You almost certainly want to go to half frame rate */
-		hint (String::compose(_("You are set up for a DCP at a frame rate of %1 fps.  This frame rate is not supported by all projectors.  You are advised to change the DCP frame rate to %2 fps."), f->video_frame_rate(), f->video_frame_rate() / 2));
+		hint (dcp::compose(_("You are set up for a DCP at a frame rate of %1 fps.  This frame rate is not supported by all projectors.  You are advised to change the DCP frame rate to %2 fps."), f->video_frame_rate(), f->video_frame_rate() / 2));
 		break;
 	}
 }
@@ -287,7 +287,7 @@ Hints::check_vob ()
 	}
 
 	if (vob > 1) {
-		hint (String::compose (_("You have %1 files that look like they are VOB files from DVD. You should join them to ensure smooth joins between the files."), vob));
+		hint (dcp::compose (_("You have %1 files that look like they are VOB files from DVD. You should join them to ensure smooth joins between the files."), vob));
 	}
 }
 
@@ -336,7 +336,7 @@ Hints::check_loudness ()
 		ch = ch.substr (0, ch.length() - 2);
 
 		if (!ch.empty()) {
-			hint(String::compose(
+			hint(dcp::compose(
 					_("Your audio level is very high (on %1).  You should reduce the gain of your audio content."),
 					ch
 					)
@@ -540,7 +540,7 @@ Hints::closed_caption (PlayerText text, DCPTimePeriod period)
 			if (!_long_ccap) {
 				_long_ccap = true;
 				hint (
-					String::compose(
+					dcp::compose(
 						"At least one of your closed caption lines has more than %1 characters.  "
 						"It is advisable to make each line %1 characters at most in length.",
 						MAX_CLOSED_CAPTION_LENGTH,
@@ -551,7 +551,7 @@ Hints::closed_caption (PlayerText text, DCPTimePeriod period)
 	}
 
 	if (!_too_many_ccap_lines && lines > MAX_CLOSED_CAPTION_LINES) {
-		hint (String::compose(_("Some of your closed captions span more than %1 lines, so they will be truncated."), MAX_CLOSED_CAPTION_LINES));
+		hint (dcp::compose(_("Some of your closed captions span more than %1 lines, so they will be truncated."), MAX_CLOSED_CAPTION_LINES));
 		_too_many_ccap_lines = true;
 	}
 
diff --git a/src/lib/image.cc b/src/lib/image.cc
index 8e6c5717b..591727ba5 100644
--- a/src/lib/image.cc
+++ b/src/lib/image.cc
@@ -24,7 +24,6 @@
  */
 
 
-#include "compose.hpp"
 #include "dcpomatic_socket.h"
 #include "exceptions.h"
 #include "image.h"
@@ -32,6 +31,7 @@
 #include "timer.h"
 #include "util.h"
 #include "warnings.h"
+#include <dcp/compose.h>
 #include <dcp/rgb_xyz.h>
 #include <dcp/transfer_function.h>
 DCPOMATIC_DISABLE_WARNINGS
@@ -1384,7 +1384,7 @@ png_error_fn (png_structp png_ptr, char const * message)
 void
 Image::png_error (char const * message)
 {
-	throw EncodeError (String::compose ("Error during PNG write: %1", message));
+	throw EncodeError (dcp::compose ("Error during PNG write: %1", message));
 }
 
 dcp::ArrayData
diff --git a/src/lib/image_content.cc b/src/lib/image_content.cc
index 517d6792f..b0d253624 100644
--- a/src/lib/image_content.cc
+++ b/src/lib/image_content.cc
@@ -21,12 +21,12 @@
 #include "image_content.h"
 #include "video_content.h"
 #include "image_examiner.h"
-#include "compose.hpp"
 #include "film.h"
 #include "job.h"
 #include "frame_rate_change.h"
 #include "exceptions.h"
 #include "image_filename_sorter.h"
+#include <dcp/compose.h>
 #include <libcxml/cxml.h>
 #include <libxml++/libxml++.h>
 #include <iostream>
diff --git a/src/lib/image_examiner.cc b/src/lib/image_examiner.cc
index 89d1517ce..d94891c6e 100644
--- a/src/lib/image_examiner.cc
+++ b/src/lib/image_examiner.cc
@@ -26,9 +26,9 @@
 #include "exceptions.h"
 #include "config.h"
 #include "cross.h"
-#include "compose.hpp"
 #include "ffmpeg_image_proxy.h"
 #include "image.h"
+#include <dcp/compose.h>
 #include <dcp/openjpeg_image.h>
 #include <dcp/exceptions.h>
 #include <dcp/j2k_transcode.h>
@@ -62,7 +62,7 @@ ImageExaminer::ImageExaminer (shared_ptr<const Film> film, shared_ptr<const Imag
 			_video_size = dcp::decompress_j2k (buffer, size, 0)->size ();
 		} catch (dcp::ReadError& e) {
 			delete[] buffer;
-			throw DecodeError (String::compose (_("Could not decode JPEG2000 file %1 (%2)"), path, e.what ()));
+			throw DecodeError (dcp::compose (_("Could not decode JPEG2000 file %1 (%2)"), path, e.what ()));
 		}
 		delete[] buffer;
 	} else {
diff --git a/src/lib/internet.cc b/src/lib/internet.cc
index ca72399f3..648e4b1a9 100644
--- a/src/lib/internet.cc
+++ b/src/lib/internet.cc
@@ -20,10 +20,10 @@
 
 
 #include "scoped_temporary.h"
-#include "compose.hpp"
 #include "exceptions.h"
 #include "cross.h"
 #include "util.h"
+#include <dcp/compose.h>
 #include <curl/curl.h>
 #include <zip.h>
 #include <boost/optional.hpp>
@@ -118,7 +118,7 @@ get_from_url (string url, bool pasv, bool skip_pasv_ip, ScopedTemporary& temp)
 	temp.close ();
 	curl_easy_cleanup (curl);
 	if (cr != CURLE_OK) {
-		return String::compose (_("Download failed (%1 error %2)"), url, (int) cr);
+		return dcp::compose (_("Download failed (%1 error %2)"), url, (int) cr);
 	}
 
 	return optional<string>();
@@ -173,7 +173,7 @@ get_from_zip_url (string url, string file, bool pasv, bool skip_pasv_ip, functio
 	zip_error_init (&error);
 	auto zip = zip_open_from_source (zip_source, ZIP_RDONLY, &error);
 	if (!zip) {
-		return String::compose (_("Could not open downloaded ZIP file (%1:%2: %3)"), error.zip_err, error.sys_err, error.str ? error.str : "");
+		return dcp::compose (_("Could not open downloaded ZIP file (%1:%2: %3)"), error.zip_err, error.sys_err, error.str ? error.str : "");
 	}
 
 #else
diff --git a/src/lib/j2k_encoder.cc b/src/lib/j2k_encoder.cc
index 5dee5ca35..c3f308508 100644
--- a/src/lib/j2k_encoder.cc
+++ b/src/lib/j2k_encoder.cc
@@ -37,7 +37,7 @@
 #include "player.h"
 #include "player_video.h"
 #include "encode_server_description.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 #include <libcxml/cxml.h>
 #include <iostream>
 
diff --git a/src/lib/job.cc b/src/lib/job.cc
index 52558046a..9aeaf800a 100644
--- a/src/lib/job.cc
+++ b/src/lib/job.cc
@@ -29,7 +29,7 @@
 #include "film.h"
 #include "log.h"
 #include "dcpomatic_log.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 #include <dcp/exceptions.h>
 #include <sub/exceptions.h>
 #include <boost/thread.hpp>
@@ -95,7 +95,7 @@ Job::start ()
 void
 Job::run_wrapper ()
 {
-	start_of_thread (String::compose("Job-%1", json_name()));
+	start_of_thread (dcp::compose("Job-%1", json_name()));
 
 	try {
 
@@ -103,7 +103,7 @@ Job::run_wrapper ()
 
 	} catch (dcp::FileError& e) {
 
-		string m = String::compose (_("An error occurred whilst handling the file %1."), boost::filesystem::path (e.filename()).leaf());
+		string m = dcp::compose (_("An error occurred whilst handling the file %1."), boost::filesystem::path (e.filename()).leaf());
 
 		try {
 			auto const s = boost::filesystem::space (e.filename());
@@ -158,8 +158,8 @@ Job::run_wrapper ()
 	} catch (OpenFileError& e) {
 
 		set_error (
-			String::compose (_("Could not open %1"), e.file().string()),
-			String::compose (
+			dcp::compose (_("Could not open %1"), e.file().string()),
+			dcp::compose (
 				_("DCP-o-matic could not open the file %1 (%2).  Perhaps it does not exist or is in an unexpected format."),
 				boost::filesystem::absolute (e.file()).string(),
 				e.what()
@@ -173,8 +173,8 @@ Job::run_wrapper ()
 
 		if (e.code() == boost::system::errc::no_such_file_or_directory) {
 			set_error (
-				String::compose (_("Could not open %1"), e.path1().string ()),
-				String::compose (
+				dcp::compose (_("Could not open %1"), e.path1().string ()),
+				dcp::compose (
 					_("DCP-o-matic could not open the file %1 (%2).  Perhaps it does not exist or is in an unexpected format."),
 					boost::filesystem::absolute (e.path1()).string(),
 					e.what()
@@ -443,7 +443,7 @@ void
 Job::set_error (string s, string d)
 {
 	if (_film) {
-		_film->log()->log (String::compose ("Error in job: %1 (%2)", s, d), LogEntry::TYPE_ERROR);
+		_film->log()->log (dcp::compose ("Error in job: %1 (%2)", s, d), LogEntry::TYPE_ERROR);
 	}
 
 	boost::mutex::scoped_lock lm (_state_mutex);
@@ -488,19 +488,19 @@ Job::status () const
 			if (now.date() != finish.date()) {
 				/// TRANSLATORS: the %1 in this string will be filled in with a day of the week
 				/// to say what day a job will finish.
-				day = String::compose (_(" on %1"), day_of_week_to_string(finish.date().day_of_week()));
+				day = dcp::compose (_(" on %1"), day_of_week_to_string(finish.date().day_of_week()));
 			}
 			/// TRANSLATORS: "remaining; finishing at" here follows an amount of time that is remaining
 			/// on an operation; after it is an estimated wall-clock completion time.
-			s += String::compose(
+			s += dcp::compose(
 				_("; %1 remaining; finishing at %2%3"),
 				seconds_to_approximate_hms(r), finish_string, day
 				);
 		}
 	} else if (finished_ok ()) {
-		s = String::compose (_("OK (ran for %1)"), seconds_to_hms (_ran_for));
+		s = dcp::compose (_("OK (ran for %1)"), seconds_to_hms (_ran_for));
 	} else if (finished_in_error ()) {
-		s = String::compose (_("Error: %1"), error_summary ());
+		s = dcp::compose (_("Error: %1"), error_summary ());
 	} else if (finished_cancelled ()) {
 		s = _("Cancelled");
 	}
diff --git a/src/lib/nanomsg.cc b/src/lib/nanomsg.cc
index 61e6c08ce..24b54f93f 100644
--- a/src/lib/nanomsg.cc
+++ b/src/lib/nanomsg.cc
@@ -44,11 +44,11 @@ Nanomsg::Nanomsg (bool server)
 	}
 	if (server) {
 		if ((_endpoint = nn_bind(_socket, NANOMSG_URL)) < 0) {
-			throw runtime_error(String::compose("Could not bind nanomsg socket (%1)", errno));
+			throw runtime_error(dcp::compose("Could not bind nanomsg socket (%1)", errno));
 		}
 	} else {
 		if ((_endpoint = nn_connect(_socket, NANOMSG_URL)) < 0) {
-			throw runtime_error(String::compose("Could not connect nanomsg socket (%1)", errno));
+			throw runtime_error(dcp::compose("Could not connect nanomsg socket (%1)", errno));
 		}
 	}
 }
@@ -73,7 +73,7 @@ Nanomsg::send (string s, int timeout)
 		if (errno == ETIMEDOUT || errno == EAGAIN) {
 			return false;
 		}
-		throw runtime_error(String::compose("Could not send to nanomsg socket (%1)", errno));
+		throw runtime_error(dcp::compose("Could not send to nanomsg socket (%1)", errno));
 	} else if (r != int(s.length())) {
 		throw runtime_error("Could not send to nanomsg socket (message too big)");
 	}
diff --git a/src/lib/player.cc b/src/lib/player.cc
index 5de089ba9..3080fccd8 100644
--- a/src/lib/player.cc
+++ b/src/lib/player.cc
@@ -49,9 +49,9 @@
 #include "audio_content.h"
 #include "dcp_decoder.h"
 #include "image_decoder.h"
-#include "compose.hpp"
 #include "shuffler.h"
 #include "timer.h"
+#include <dcp/compose.h>
 #include <dcp/reel.h>
 #include <dcp/reel_sound_asset.h>
 #include <dcp/reel_subtitle_asset.h>
@@ -723,7 +723,7 @@ Player::pass ()
 			/* Let's not worry about less than a frame at 24fps */
 			int64_t const too_much_error = DCPTime::from_frames(1, 24).get();
 			if (error >= too_much_error) {
-				_film->log()->log(String::compose("Silence starting before or after last audio by %1", error), LogEntry::TYPE_ERROR);
+				_film->log()->log(dcp::compose("Silence starting before or after last audio by %1", error), LogEntry::TYPE_ERROR);
 			}
 			DCPOMATIC_ASSERT (error < too_much_error);
 			period.from = *_last_audio_time;
@@ -1265,7 +1265,7 @@ Player::emit_audio (shared_ptr<AudioBuffers> data, DCPTime time)
 {
 	/* Log if the assert below is about to fail */
 	if (_last_audio_time && labs(time.get() - _last_audio_time->get()) > 1) {
-		_film->log()->log(String::compose("Out-of-sequence emit %1 vs %2", to_string(time), to_string(*_last_audio_time)), LogEntry::TYPE_WARNING);
+		_film->log()->log(dcp::compose("Out-of-sequence emit %1 vs %2", to_string(time), to_string(*_last_audio_time)), LogEntry::TYPE_WARNING);
 	}
 
 	/* This audio must follow on from the previous, allowing for half a sample (at 48kHz) leeway */
diff --git a/src/lib/playlist.cc b/src/lib/playlist.cc
index e8714e9d6..bf2f3d734 100644
--- a/src/lib/playlist.cc
+++ b/src/lib/playlist.cc
@@ -32,7 +32,7 @@
 #include "config.h"
 #include "util.h"
 #include "digester.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 #include <libcxml/cxml.h>
 #include <libxml++/libxml++.h>
 #include <boost/bind/placeholders.hpp>
@@ -219,12 +219,12 @@ Playlist::set_from_xml (shared_ptr<const Film> film, cxml::ConstNodePtr node, in
 			string note = _("Your project contains video content that was not aligned to a frame boundary.");
 			note += "  ";
 			if (old_pos < content->position()) {
-				note += String::compose(
+				note += dcp::compose(
 					_("The file %1 has been moved %2 milliseconds later."),
 					content->path_summary(), DCPTime(content->position() - old_pos).seconds() * 1000
 					);
 			} else {
-				note += String::compose(
+				note += dcp::compose(
 					_("The file %1 has been moved %2 milliseconds earlier."),
 					content->path_summary(), DCPTime(content->position() - old_pos).seconds() * 1000
 					);
@@ -239,12 +239,12 @@ Playlist::set_from_xml (shared_ptr<const Film> film, cxml::ConstNodePtr node, in
 			string note = _("Your project contains video content whose trim was not aligned to a frame boundary.");
 			note += "  ";
 			if (old_trim < content->trim_start()) {
-				note += String::compose(
+				note += dcp::compose(
 					_("The file %1 has been trimmed by %2 milliseconds more."),
 					content->path_summary(), ContentTime(content->trim_start() - old_trim).seconds() * 1000
 					);
 			} else {
-				note += String::compose(
+				note += dcp::compose(
 					_("The file %1 has been trimmed by %2 milliseconds less."),
 					content->path_summary(), ContentTime(old_trim - content->trim_start()).seconds() * 1000
 					);
diff --git a/src/lib/reel_writer.cc b/src/lib/reel_writer.cc
index 521ba55df..24d25b4fa 100644
--- a/src/lib/reel_writer.cc
+++ b/src/lib/reel_writer.cc
@@ -26,13 +26,13 @@
 #include "dcpomatic_log.h"
 #include "digester.h"
 #include "font_data.h"
-#include "compose.hpp"
 #include "config.h"
 #include "audio_buffers.h"
 #include "image.h"
 #include <dcp/atmos_asset.h>
 #include <dcp/atmos_asset_writer.h>
 #include <dcp/certificate_chain.h>
+#include <dcp/compose.h>
 #include <dcp/cpl.h>
 #include <dcp/dcp.h>
 #include <dcp/interop_subtitle_asset.h>
@@ -415,7 +415,7 @@ ReelWriter::finish (boost::filesystem::path output_dcp)
 		boost::filesystem::rename (film()->file(aaf), audio_to, ec);
 		if (ec) {
 			throw FileError (
-				String::compose (_("could not move audio asset into the DCP (%1)"), ec.value ()), aaf
+				dcp::compose (_("could not move audio asset into the DCP (%1)"), ec.value ()), aaf
 				);
 		}
 
@@ -432,7 +432,7 @@ ReelWriter::finish (boost::filesystem::path output_dcp)
 		boost::filesystem::rename (film()->file(aaf), atmos_to, ec);
 		if (ec) {
 			throw FileError (
-				String::compose (_("could not move atmos asset into the DCP (%1)"), ec.value ()), aaf
+				dcp::compose (_("could not move atmos asset into the DCP (%1)"), ec.value ()), aaf
 				);
 		}
 
@@ -511,7 +511,7 @@ maybe_add_text (
 		if (!text_only && reel_asset->actual_duration() != period_duration) {
 			throw ProgrammingError (
 				__FILE__, __LINE__,
-				String::compose ("%1 vs %2", reel_asset->actual_duration(), period_duration)
+				dcp::compose ("%1 vs %2", reel_asset->actual_duration(), period_duration)
 				);
 		}
 		reel->add (reel_asset);
@@ -557,7 +557,7 @@ ReelWriter::create_reel_picture (shared_ptr<dcp::Reel> reel, list<ReferencedReel
 	if (reel_asset->duration() != period_duration) {
 		throw ProgrammingError (
 			__FILE__, __LINE__,
-			String::compose ("%1 vs %2", reel_asset->actual_duration(), period_duration)
+			dcp::compose ("%1 vs %2", reel_asset->actual_duration(), period_duration)
 			);
 	}
 	reel->add (reel_asset);
@@ -609,7 +609,7 @@ ReelWriter::create_reel_sound (shared_ptr<dcp::Reel> reel, list<ReferencedReelAs
 		if (reel_asset->actual_duration() != period_duration) {
 			throw ProgrammingError (
 				__FILE__, __LINE__,
-				String::compose ("%1 vs %2", reel_asset->actual_duration(), period_duration)
+				dcp::compose ("%1 vs %2", reel_asset->actual_duration(), period_duration)
 				);
 		}
 
diff --git a/src/lib/resampler.cc b/src/lib/resampler.cc
index 056b2e1ee..30164ca21 100644
--- a/src/lib/resampler.cc
+++ b/src/lib/resampler.cc
@@ -22,8 +22,8 @@
 #include "resampler.h"
 #include "audio_buffers.h"
 #include "exceptions.h"
-#include "compose.hpp"
 #include "dcpomatic_assert.h"
+#include <dcp/compose.h>
 #include <samplerate.h>
 #include <iostream>
 #include <cmath>
@@ -51,7 +51,7 @@ Resampler::Resampler (int in, int out, int channels)
 	int error;
 	_src = src_new (SRC_SINC_BEST_QUALITY, _channels, &error);
 	if (!_src) {
-		throw runtime_error (String::compose(N_("could not create sample-rate converter (%1)"), error));
+		throw runtime_error (dcp::compose(N_("could not create sample-rate converter (%1)"), error));
 	}
 }
 
@@ -73,7 +73,7 @@ Resampler::set_fast ()
 	int error;
 	_src = src_new (SRC_LINEAR, _channels, &error);
 	if (!_src) {
-		throw runtime_error (String::compose(N_("could not create sample-rate converter (%1)"), error));
+		throw runtime_error (dcp::compose(N_("could not create sample-rate converter (%1)"), error));
 	}
 }
 
@@ -117,7 +117,7 @@ Resampler::run (shared_ptr<const AudioBuffers> in)
 		int const r = src_process (_src, &data);
 		if (r) {
 			throw EncodeError (
-				String::compose (
+				dcp::compose (
 					N_("could not run sample-rate converter (%1) [processing %2 to %3, %4 channels]"),
 					src_strerror (r),
 					in_frames,
@@ -173,7 +173,7 @@ Resampler::flush ()
 
 	int const r = src_process (_src, &data);
 	if (r) {
-		throw EncodeError (String::compose(N_("could not run sample-rate converter (%1)"), src_strerror(r)));
+		throw EncodeError (dcp::compose(N_("could not run sample-rate converter (%1)"), src_strerror(r)));
 	}
 
 	out->ensure_size (out_offset + data.output_frames_gen);
diff --git a/src/lib/scp_uploader.cc b/src/lib/scp_uploader.cc
index 9c349f233..9373346ef 100644
--- a/src/lib/scp_uploader.cc
+++ b/src/lib/scp_uploader.cc
@@ -24,8 +24,8 @@
 #include "job.h"
 #include "config.h"
 #include "cross.h"
-#include "compose.hpp"
 #include "warnings.h"
+#include <dcp/compose.h>
 #include <sys/stat.h>
 
 #include "i18n.h"
@@ -42,7 +42,7 @@ SCPUploader::SCPUploader (function<void (string)> set_status, function<void (flo
 {
 	_session = ssh_new ();
 	if (!_session) {
-		throw NetworkError (String::compose(_("SSH error [%1]"), "ssh_new"));
+		throw NetworkError (dcp::compose(_("SSH error [%1]"), "ssh_new"));
 	}
 
 	ssh_options_set (_session, SSH_OPTIONS_HOST, Config::instance()->tms_ip().c_str());
@@ -52,29 +52,29 @@ SCPUploader::SCPUploader (function<void (string)> set_status, function<void (flo
 
 	int r = ssh_connect (_session);
 	if (r != SSH_OK) {
-		throw NetworkError (String::compose(_("Could not connect to server %1 (%2)"), Config::instance()->tms_ip(), ssh_get_error(_session)));
+		throw NetworkError (dcp::compose(_("Could not connect to server %1 (%2)"), Config::instance()->tms_ip(), ssh_get_error(_session)));
 	}
 
 DCPOMATIC_DISABLE_WARNINGS
 	r = ssh_is_server_known (_session);
 	if (r == SSH_SERVER_ERROR) {
-		throw NetworkError (String::compose(_("SSH error [%1] (%2)"), "ssh_is_server_known", ssh_get_error(_session)));
+		throw NetworkError (dcp::compose(_("SSH error [%1] (%2)"), "ssh_is_server_known", ssh_get_error(_session)));
 	}
 DCPOMATIC_ENABLE_WARNINGS
 
 	r = ssh_userauth_password (_session, 0, Config::instance()->tms_password().c_str ());
 	if (r != SSH_AUTH_SUCCESS) {
-		throw NetworkError (String::compose(_("Failed to authenticate with server (%1)"), ssh_get_error(_session)));
+		throw NetworkError (dcp::compose(_("Failed to authenticate with server (%1)"), ssh_get_error(_session)));
 	}
 
 	_scp = ssh_scp_new (_session, SSH_SCP_WRITE | SSH_SCP_RECURSIVE, Config::instance()->tms_path().c_str());
 	if (!_scp) {
-		throw NetworkError (String::compose(_("SSH error [%1] (%2)"), "ssh_scp_new", ssh_get_error(_session)));
+		throw NetworkError (dcp::compose(_("SSH error [%1] (%2)"), "ssh_scp_new", ssh_get_error(_session)));
 	}
 
 	r = ssh_scp_init (_scp);
 	if (r != SSH_OK) {
-		throw NetworkError (String::compose(_("SSH error [%1] (%2)"), "ssh_scp_init", ssh_get_error(_session)));
+		throw NetworkError (dcp::compose(_("SSH error [%1] (%2)"), "ssh_scp_init", ssh_get_error(_session)));
 	}
 }
 
@@ -93,7 +93,7 @@ SCPUploader::create_directory (boost::filesystem::path directory)
 	/* Use generic_string so that we get forward-slashes in the path, even on Windows */
 	int const r = ssh_scp_push_directory (_scp, directory.generic_string().c_str(), S_IRWXU);
 	if (r != SSH_OK) {
-		throw NetworkError (String::compose(_("Could not create remote directory %1 (%2)"), directory, ssh_get_error(_session)));
+		throw NetworkError (dcp::compose(_("Could not create remote directory %1 (%2)"), directory, ssh_get_error(_session)));
 	}
 }
 
@@ -107,7 +107,7 @@ SCPUploader::upload_file (boost::filesystem::path from, boost::filesystem::path
 
 	auto f = fopen_boost (from, "rb");
 	if (f == nullptr) {
-		throw NetworkError (String::compose(_("Could not open %1 to send"), from));
+		throw NetworkError (dcp::compose(_("Could not open %1 to send"), from));
 	}
 
 	boost::uintmax_t buffer_size = 64 * 1024;
@@ -124,7 +124,7 @@ SCPUploader::upload_file (boost::filesystem::path from, boost::filesystem::path
 		int const r = ssh_scp_write (_scp, buffer, t);
 		if (r != SSH_OK) {
 			fclose (f);
-			throw NetworkError (String::compose(_("Could not write to remote file (%1)"), ssh_get_error(_session)));
+			throw NetworkError (dcp::compose(_("Could not write to remote file (%1)"), ssh_get_error(_session)));
 		}
 		to_do -= t;
 		transferred += t;
diff --git a/src/lib/send_kdm_email_job.cc b/src/lib/send_kdm_email_job.cc
index 67ddd0eef..1ed042130 100644
--- a/src/lib/send_kdm_email_job.cc
+++ b/src/lib/send_kdm_email_job.cc
@@ -20,9 +20,9 @@
 
 
 #include "send_kdm_email_job.h"
-#include "compose.hpp"
 #include "kdm_with_metadata.h"
 #include "film.h"
+#include <dcp/compose.h>
 #include <list>
 
 #include "i18n.h"
@@ -89,7 +89,7 @@ SendKDMEmailJob::name () const
 		return _("Email KDMs");
 	}
 
-	return String::compose (_("Email KDMs for %2"), *f);
+	return dcp::compose (_("Email KDMs for %2"), *f);
 }
 
 
diff --git a/src/lib/send_notification_email_job.cc b/src/lib/send_notification_email_job.cc
index c4d5a6518..2e272a454 100644
--- a/src/lib/send_notification_email_job.cc
+++ b/src/lib/send_notification_email_job.cc
@@ -23,7 +23,7 @@
 #include "exceptions.h"
 #include "config.h"
 #include "emailer.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 #include <list>
 
 #include "i18n.h"
diff --git a/src/lib/send_problem_report_job.cc b/src/lib/send_problem_report_job.cc
index 6ab83ee62..fc5028ae4 100644
--- a/src/lib/send_problem_report_job.cc
+++ b/src/lib/send_problem_report_job.cc
@@ -20,7 +20,6 @@
 
 
 #include "send_problem_report_job.h"
-#include "compose.hpp"
 #include "film.h"
 #include "cross.h"
 #include "film.h"
@@ -28,6 +27,7 @@
 #include "version.h"
 #include "emailer.h"
 #include "environment_info.h"
+#include <dcp/compose.h>
 #include <libxml++/libxml++.h>
 
 #include "i18n.h"
@@ -68,7 +68,7 @@ SendProblemReportJob::name () const
 		return _("Email problem report");
 	}
 
-	return String::compose (_("Email problem report for %1"), _film->name());
+	return dcp::compose (_("Email problem report for %1"), _film->name());
 }
 
 
diff --git a/src/lib/shuffler.cc b/src/lib/shuffler.cc
index 5a4faf4d1..16c9bb05b 100644
--- a/src/lib/shuffler.cc
+++ b/src/lib/shuffler.cc
@@ -84,8 +84,8 @@ Shuffler::video (weak_ptr<Piece> weak_piece, ContentVideo video)
 				);
 
 		if (!store_front_in_sequence) {
-			string const store = _store.empty() ? "store empty" : String::compose("store front frame=%1 eyes=%2", _store.front().second.frame, static_cast<int>(_store.front().second.eyes));
-			string const last = _last ? String::compose("last frame=%1 eyes=%2", _last->frame, static_cast<int>(_last->eyes)) : "no last";
+			string const store = _store.empty() ? "store empty" : dcp::compose("store front frame=%1 eyes=%2", _store.front().second.frame, static_cast<int>(_store.front().second.eyes));
+			string const last = _last ? dcp::compose("last frame=%1 eyes=%2", _last->frame, static_cast<int>(_last->eyes)) : "no last";
 			LOG_DEBUG_THREE_D("Shuffler not in sequence: %1 %2", store, last);
 		}
 
diff --git a/src/lib/subtitle_encoder.cc b/src/lib/subtitle_encoder.cc
index ba47e1231..531c9cdcb 100644
--- a/src/lib/subtitle_encoder.cc
+++ b/src/lib/subtitle_encoder.cc
@@ -19,11 +19,11 @@
 */
 
 
-#include "compose.hpp"
 #include "font_data.h"
 #include "job.h"
 #include "player.h"
 #include "subtitle_encoder.h"
+#include <dcp/compose.h>
 #include <dcp/interop_subtitle_asset.h>
 #include <dcp/raw_convert.h>
 #include <dcp/smpte_subtitle_asset.h>
@@ -72,7 +72,7 @@ SubtitleEncoder::SubtitleEncoder (shared_ptr<const Film> film, shared_ptr<Job> j
 			if (files > 1) {
 				/// TRANSLATORS: _reel%1 here is to be added to an export filename to indicate
 				/// which reel it is.  Preserve the %1; it will be replaced with the reel number.
-				filename /= String::compose("%1_reel%2", initial_name, i + 1);
+				filename /= dcp::compose("%1_reel%2", initial_name, i + 1);
 			} else {
 				filename /= initial_name;
 			}
diff --git a/src/lib/text_decoder.cc b/src/lib/text_decoder.cc
index 0a7bdf95d..3b28b7e12 100644
--- a/src/lib/text_decoder.cc
+++ b/src/lib/text_decoder.cc
@@ -23,7 +23,7 @@
 #include "text_content.h"
 #include "util.h"
 #include "log.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 #include <sub/subtitle.h>
 #include <boost/algorithm/string.hpp>
 #include <iostream>
diff --git a/src/lib/timer.cc b/src/lib/timer.cc
index caef89e0e..6f4072747 100644
--- a/src/lib/timer.cc
+++ b/src/lib/timer.cc
@@ -24,9 +24,9 @@
  */
 
 
-#include "compose.hpp"
 #include "timer.h"
 #include "util.h"
+#include <dcp/compose.h>
 #include <sys/time.h>
 #include <iostream>
 
@@ -130,7 +130,7 @@ StateTimer::~StateTimer ()
 		char buffer[64];
 		snprintf (buffer, 64, "%.4f", i.second.total_time);
 		string total_time (buffer);
-		sorted.push_back (make_pair(i.second.total_time, String::compose("\t%1%2 %3 %4", name, total_time, i.second.number, (i.second.total_time / i.second.number))));
+		sorted.push_back (make_pair(i.second.total_time, dcp::compose("\t%1%2 %3 %4", name, total_time, i.second.number, (i.second.total_time / i.second.number))));
 	}
 
 	sorted.sort ([](pair<double, string> const& a, pair<double, string> const& b) {
diff --git a/src/lib/transcode_job.cc b/src/lib/transcode_job.cc
index 3502c3346..463a3c7bd 100644
--- a/src/lib/transcode_job.cc
+++ b/src/lib/transcode_job.cc
@@ -25,7 +25,6 @@
 
 
 #include "analytics.h"
-#include "compose.hpp"
 #include "config.h"
 #include "dcp_encoder.h"
 #include "dcpomatic_log.h"
@@ -35,6 +34,7 @@
 #include "log.h"
 #include "transcode_job.h"
 #include "upload_job.h"
+#include <dcp/compose.h>
 #include <iomanip>
 #include <iostream>
 
@@ -68,7 +68,7 @@ TranscodeJob::~TranscodeJob ()
 string
 TranscodeJob::name () const
 {
-	return String::compose (_("Transcoding %1"), _film->name());
+	return dcp::compose (_("Transcoding %1"), _film->name());
 }
 
 
diff --git a/src/lib/types.cc b/src/lib/types.cc
index 228ebf28f..9e8748159 100644
--- a/src/lib/types.cc
+++ b/src/lib/types.cc
@@ -19,10 +19,10 @@
 */
 
 #include "types.h"
-#include "compose.hpp"
 #include "dcpomatic_assert.h"
 #include "warnings.h"
 #include <dcp/raw_convert.h>
+#include <dcp/compose.h>
 #include <dcp/cpl.h>
 #include <dcp/dcp.h>
 #include <dcp/reel_file_asset.h>
@@ -112,7 +112,7 @@ string_to_text_type (string s)
 	} else if (s == "closed-caption") {
 		return TextType::CLOSED_CAPTION;
 	} else {
-		throw MetadataError (String::compose ("Unknown text type %1", s));
+		throw MetadataError (dcp::compose ("Unknown text type %1", s));
 	}
 }
 
diff --git a/src/lib/upload_job.cc b/src/lib/upload_job.cc
index 113e3a7e8..e88b3aaf8 100644
--- a/src/lib/upload_job.cc
+++ b/src/lib/upload_job.cc
@@ -24,7 +24,6 @@
  */
 
 
-#include "compose.hpp"
 #include "config.h"
 #include "curl_uploader.h"
 #include "dcpomatic_log.h"
@@ -32,6 +31,7 @@
 #include "log.h"
 #include "scp_uploader.h"
 #include "upload_job.h"
+#include <dcp/compose.h>
 #include <iostream>
 
 #include "i18n.h"
diff --git a/src/lib/uploader.cc b/src/lib/uploader.cc
index c5448e469..11fb55f35 100644
--- a/src/lib/uploader.cc
+++ b/src/lib/uploader.cc
@@ -21,7 +21,7 @@
 
 #include "uploader.h"
 #include "dcpomatic_assert.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 
 #include "i18n.h"
 
@@ -76,7 +76,7 @@ Uploader::upload_directory (boost::filesystem::path base, boost::filesystem::pat
 		if (is_directory(i.path())) {
 			upload_directory (base, i.path(), transferred, total_size);
 		} else {
-			_set_status (String::compose(_("copying %1"), i.path().leaf()));
+			_set_status (dcp::compose(_("copying %1"), i.path().leaf()));
 			upload_file (i.path(), remove_prefix (base, i.path()), transferred, total_size);
 		}
 	}
diff --git a/src/lib/util.cc b/src/lib/util.cc
index a3c8c5082..8903eae1d 100644
--- a/src/lib/util.cc
+++ b/src/lib/util.cc
@@ -36,7 +36,6 @@
 #include "digester.h"
 #include "audio_processor.h"
 #include "crypto.h"
-#include "compose.hpp"
 #include "audio_buffers.h"
 #include "string_text.h"
 #include "font.h"
@@ -46,6 +45,7 @@
 #include "text_decoder.h"
 #include "job_manager.h"
 #include "warnings.h"
+#include <dcp/compose.h>
 #include <dcp/decrypted_kdm.h>
 #include <dcp/locale_convert.h>
 #include <dcp/util.h>
@@ -385,7 +385,7 @@ DCPOMATIC_ENABLE_WARNINGS
 
 #ifdef DCPOMATIC_WINDOWS
 	putenv ("PANGOCAIRO_BACKEND=fontconfig");
-	putenv (String::compose("FONTCONFIG_PATH=%1", resources_path().string()).c_str());
+	putenv (dcp::compose("FONTCONFIG_PATH=%1", resources_path().string()).c_str());
 #endif
 
 #ifdef DCPOMATIC_OSX
@@ -452,11 +452,11 @@ dcpomatic_setup_gettext_i18n (string lang)
 		/* Override our environment language.  Note that the caller must not
 		   free the string passed into putenv().
 		*/
-		string s = String::compose ("LANGUAGE=%1", lang);
+		string s = dcp::compose ("LANGUAGE=%1", lang);
 		putenv (strdup (s.c_str ()));
-		s = String::compose ("LANG=%1", lang);
+		s = dcp::compose ("LANG=%1", lang);
 		putenv (strdup (s.c_str ()));
-		s = String::compose ("LC_ALL=%1", lang);
+		s = dcp::compose ("LC_ALL=%1", lang);
 		putenv (strdup (s.c_str ()));
 	}
 
@@ -881,7 +881,7 @@ checked_fwrite (void const * ptr, size_t size, FILE* stream, boost::filesystem::
 	if (N != size) {
 		if (ferror(stream)) {
 			fclose (stream);
-			throw FileError (String::compose("fwrite error %1", errno), path);
+			throw FileError (dcp::compose("fwrite error %1", errno), path);
 		} else {
 			fclose (stream);
 			throw FileError ("Unexpected short write", path);
@@ -896,7 +896,7 @@ checked_fread (void* ptr, size_t size, FILE* stream, boost::filesystem::path pat
 	if (N != size) {
 		if (ferror(stream)) {
 			fclose (stream);
-			throw FileError (String::compose("fread error %1", errno), path);
+			throw FileError (dcp::compose("fread error %1", errno), path);
 		} else {
 			fclose (stream);
 			throw FileError ("Unexpected short read", path);
diff --git a/src/lib/video_content.cc b/src/lib/video_content.cc
index 5686a0a6f..054c91873 100644
--- a/src/lib/video_content.cc
+++ b/src/lib/video_content.cc
@@ -21,7 +21,6 @@
 #include "video_content.h"
 #include "content.h"
 #include "video_examiner.h"
-#include "compose.hpp"
 #include "ratio.h"
 #include "config.h"
 #include "colour_conversion.h"
@@ -31,6 +30,7 @@
 #include "frame_rate_change.h"
 #include "log.h"
 #include "dcpomatic_log.h"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 #include <libcxml/cxml.h>
 #include <libxml++/libxml++.h>
@@ -354,7 +354,7 @@ VideoContent::identifier () const
 string
 VideoContent::technical_summary () const
 {
-	string s = String::compose (
+	string s = dcp::compose (
 		N_("video: length %1 frames, size %2x%3"),
 		length_after_3d_combine(),
 		size().width,
@@ -362,7 +362,7 @@ VideoContent::technical_summary () const
 		);
 
 	if (sample_aspect_ratio ()) {
-		s += String::compose (N_(", sample aspect ratio %1"), (sample_aspect_ratio().get ()));
+		s += dcp::compose (N_(", sample aspect ratio %1"), (sample_aspect_ratio().get ()));
 	}
 
 	return s;
@@ -426,7 +426,7 @@ VideoContent::processing_description (shared_ptr<const Film> film)
 	char buffer[256];
 
 	if (size().width && size().height) {
-		d += String::compose (
+		d += dcp::compose (
 			_("Content video is %1x%2"),
 			size_after_3d_split().width,
 			size_after_3d_split().height
@@ -447,7 +447,7 @@ VideoContent::processing_description (shared_ptr<const Film> film)
 
 	if ((crop().left || crop().right || crop().top || crop().bottom) && size() != dcp::Size (0, 0)) {
 		dcp::Size cropped = size_after_crop ();
-		d += String::compose (
+		d += dcp::compose (
 			_("\nCropped to %1x%2"),
 			cropped.width, cropped.height
 			);
@@ -460,7 +460,7 @@ VideoContent::processing_description (shared_ptr<const Film> film)
 	auto const scaled = scaled_size (container_size);
 
 	if (scaled != size_after_crop ()) {
-		d += String::compose (
+		d += dcp::compose (
 			_("\nScaled to %1x%2"),
 			scaled.width, scaled.height
 			);
@@ -470,7 +470,7 @@ VideoContent::processing_description (shared_ptr<const Film> film)
 	}
 
 	if (scaled != container_size) {
-		d += String::compose (
+		d += dcp::compose (
 			_("\nPadded with black to fit container %1 (%2x%3)"),
 			film->container()->container_nickname (),
 			container_size.width, container_size.height
@@ -497,7 +497,7 @@ void
 VideoContent::add_properties (list<UserProperty>& p) const
 {
 	p.push_back (UserProperty (UserProperty::VIDEO, _("Length"), length (), _("video frames")));
-	p.push_back (UserProperty (UserProperty::VIDEO, _("Size"), String::compose ("%1x%2", size().width, size().height)));
+	p.push_back (UserProperty (UserProperty::VIDEO, _("Size"), dcp::compose ("%1x%2", size().width, size().height)));
 }
 
 void
diff --git a/src/lib/video_decoder.cc b/src/lib/video_decoder.cc
index ce42f428f..a05c30f64 100644
--- a/src/lib/video_decoder.cc
+++ b/src/lib/video_decoder.cc
@@ -19,7 +19,6 @@
 */
 
 
-#include "compose.hpp"
 #include "film.h"
 #include "frame_interval_checker.h"
 #include "image.h"
@@ -27,6 +26,7 @@
 #include "log.h"
 #include "raw_image_proxy.h"
 #include "video_decoder.h"
+#include <dcp/compose.h>
 #include <iostream>
 
 #include "i18n.h"
@@ -82,7 +82,7 @@ VideoDecoder::emit (shared_ptr<const Film> film, shared_ptr<const ImageProxy> im
 		if (_frame_interval_checker->guess() == FrameIntervalChecker::PROBABLY_NOT_3D && vft == VideoFrameType::THREE_D) {
 			boost::throw_exception (
 				DecodeError(
-					String::compose(
+					dcp::compose(
 						_("The content file %1 is set as 3D but does not appear to contain 3D images.  Please set it to 2D.  "
 						  "You can still make a 3D DCP from this content by ticking the 3D option in the DCP video tab."),
 						_content->path(0)
diff --git a/src/lib/video_filter_graph.cc b/src/lib/video_filter_graph.cc
index a61da6773..87915fff7 100644
--- a/src/lib/video_filter_graph.cc
+++ b/src/lib/video_filter_graph.cc
@@ -19,10 +19,10 @@
 */
 
 
-#include "compose.hpp"
 #include "image.h"
 #include "video_filter_graph.h"
 #include "warnings.h"
+#include <dcp/compose.h>
 extern "C" {
 #include <libavfilter/buffersrc.h>
 #include <libavfilter/buffersink.h>
@@ -63,7 +63,7 @@ VideoFilterGraph::process (AVFrame* frame)
 	} else {
 		int r = av_buffersrc_write_frame (_buffer_src_context, frame);
 		if (r < 0) {
-			throw DecodeError (String::compose(N_("could not push buffer into filter chain (%1)."), r));
+			throw DecodeError (dcp::compose(N_("could not push buffer into filter chain (%1)."), r));
 		}
 
 		while (true) {
diff --git a/src/lib/video_mxf_content.cc b/src/lib/video_mxf_content.cc
index c7ee69d89..20ff3d3fc 100644
--- a/src/lib/video_mxf_content.cc
+++ b/src/lib/video_mxf_content.cc
@@ -24,8 +24,8 @@
 #include "video_content.h"
 #include "job.h"
 #include "film.h"
-#include "compose.hpp"
 #include <asdcp/KM_log.h>
+#include <dcp/compose.h>
 #include <dcp/mono_picture_asset.h>
 #include <dcp/stereo_picture_asset.h>
 #include <dcp/exceptions.h>
@@ -102,7 +102,7 @@ VideoMXFContent::examine (shared_ptr<const Film> film, shared_ptr<Job> job)
 string
 VideoMXFContent::summary () const
 {
-	return String::compose (_("%1 [video]"), path_summary());
+	return dcp::compose (_("%1 [video]"), path_summary());
 }
 
 
diff --git a/src/lib/video_ring_buffers.cc b/src/lib/video_ring_buffers.cc
index 63c52ee06..0ac097977 100644
--- a/src/lib/video_ring_buffers.cc
+++ b/src/lib/video_ring_buffers.cc
@@ -21,7 +21,7 @@
 
 #include "video_ring_buffers.h"
 #include "player_video.h"
-#include "compose.hpp"
+#include <dcp/compose.h>
 #include <list>
 #include <iostream>
 
@@ -89,7 +89,7 @@ VideoRingBuffers::memory_used () const
 	for (auto const& i: _data) {
 		m += i.first->memory_used();
 	}
-	return make_pair(m, String::compose("%1 frames", _data.size()));
+	return make_pair(m, dcp::compose("%1 frames", _data.size()));
 }
 
 
diff --git a/src/lib/writer.cc b/src/lib/writer.cc
index 6b8076875..6bb3afd0e 100644
--- a/src/lib/writer.cc
+++ b/src/lib/writer.cc
@@ -20,7 +20,6 @@
 
 
 #include "writer.h"
-#include "compose.hpp"
 #include "film.h"
 #include "ratio.h"
 #include "log.h"
@@ -37,6 +36,7 @@
 #include "util.h"
 #include "reel_writer.h"
 #include "text_content.h"
+#include <dcp/compose.h>
 #include <dcp/cpl.h>
 #include <dcp/locale_convert.h>
 #include <dcp/reel_file_asset.h>
@@ -616,12 +616,12 @@ Writer::finish (boost::filesystem::path output_dcp)
 
 	auto creator = Config::instance()->dcp_creator();
 	if (creator.empty()) {
-		creator = String::compose("DCP-o-matic %1 %2", dcpomatic_version, dcpomatic_git_commit);
+		creator = dcp::compose("DCP-o-matic %1 %2", dcpomatic_version, dcpomatic_git_commit);
 	}
 
 	auto issuer = Config::instance()->dcp_issuer();
 	if (issuer.empty()) {
-		issuer = String::compose("DCP-o-matic %1 %2", dcpomatic_version, dcpomatic_git_commit);
+		issuer = dcp::compose("DCP-o-matic %1 %2", dcpomatic_version, dcpomatic_git_commit);
 	}
 
 	cpl->set_creator (creator);
@@ -746,13 +746,13 @@ Writer::write_cover_sheet (boost::filesystem::path output_dcp)
 	}
 
 	if (size > (1000000000L)) {
-		boost::algorithm::replace_all (text, "$SIZE", String::compose("%1GB", dcp::locale_convert<string>(size / 1000000000.0, 1, true)));
+		boost::algorithm::replace_all (text, "$SIZE", dcp::compose("%1GB", dcp::locale_convert<string>(size / 1000000000.0, 1, true)));
 	} else {
-		boost::algorithm::replace_all (text, "$SIZE", String::compose("%1MB", dcp::locale_convert<string>(size / 1000000.0, 1, true)));
+		boost::algorithm::replace_all (text, "$SIZE", dcp::compose("%1MB", dcp::locale_convert<string>(size / 1000000.0, 1, true)));
 	}
 
 	auto ch = audio_channel_types (film()->mapped_audio_channels(), film()->audio_channels());
-	auto description = String::compose("%1.%2", ch.first, ch.second);
+	auto description = dcp::compose("%1.%2", ch.first, ch.second);
 
 	if (description == "0.0") {
 		description = _("None");
@@ -766,11 +766,11 @@ Writer::write_cover_sheet (boost::filesystem::path output_dcp)
 	auto const hmsf = film()->length().split(film()->video_frame_rate());
 	string length;
 	if (hmsf.h == 0 && hmsf.m == 0) {
-		length = String::compose("%1s", hmsf.s);
+		length = dcp::compose("%1s", hmsf.s);
 	} else if (hmsf.h == 0 && hmsf.m > 0) {
-		length = String::compose("%1m%2s", hmsf.m, hmsf.s);
+		length = dcp::compose("%1m%2s", hmsf.m, hmsf.s);
 	} else if (hmsf.h > 0 && hmsf.m > 0) {
-		length = String::compose("%1h%2m%3s", hmsf.h, hmsf.m, hmsf.s);
+		length = dcp::compose("%1h%2m%3s", hmsf.h, hmsf.m, hmsf.s);
 	}
 
 	boost::algorithm::replace_all (text, "$LENGTH", length);
diff --git a/src/tools/dcpomatic.cc b/src/tools/dcpomatic.cc
index 24c5bd5ec..99084c8d6 100644
--- a/src/tools/dcpomatic.cc
+++ b/src/tools/dcpomatic.cc
@@ -74,7 +74,6 @@
 #include "lib/update_checker.h"
 #include "lib/cross.h"
 #include "lib/content_factory.h"
-#include "lib/compose.hpp"
 #include "lib/dcpomatic_socket.h"
 #include "lib/hints.h"
 #include "lib/dcp_content.h"
@@ -87,6 +86,7 @@
 #include "lib/dcpomatic_log.h"
 #include "lib/subtitle_encoder.h"
 #include "lib/warnings.h"
+#include <dcp/compose.h>
 #include <dcp/exceptions.h>
 #include <dcp/raw_convert.h>
 DCPOMATIC_DISABLE_WARNINGS
@@ -1030,14 +1030,14 @@ private:
 #ifdef DCPOMATIC_LINUX
 		int r = system ("which nautilus");
 		if (WEXITSTATUS (r) == 0) {
-			r = system (String::compose("nautilus \"%1\"", _film->directory()->string()).c_str());
+			r = system (dcp::compose("nautilus \"%1\"", _film->directory()->string()).c_str());
 			if (WEXITSTATUS (r)) {
 				error_dialog (this, _("Could not show DCP."), _("Could not run nautilus"));
 			}
 		} else {
 			int r = system ("which konqueror");
 			if (WEXITSTATUS (r) == 0) {
-				r = system (String::compose ("konqueror \"%1\"", _film->directory()->string()).c_str());
+				r = system (dcp::compose ("konqueror \"%1\"", _film->directory()->string()).c_str());
 				if (WEXITSTATUS (r)) {
 					error_dialog (this, _("Could not show DCP"), _("Could not run konqueror"));
 				}
@@ -1046,7 +1046,7 @@ private:
 #endif
 
 #ifdef DCPOMATIC_OSX
-		int r = system (String::compose ("open -R \"%1\"", _film->dir (_film->dcp_name(false)).string()).c_str());
+		int r = system (dcp::compose ("open -R \"%1\"", _film->dir (_film->dcp_name(false)).string()).c_str());
 		if (WEXITSTATUS (r)) {
 			error_dialog (this, _("Could not show DCP"));
 		}
@@ -1444,7 +1444,7 @@ private:
 		for (size_t i = 0; i < history.size(); ++i) {
 			string s;
 			if (i < 9) {
-				s = String::compose ("&%1 %2", i + 1, history[i].string());
+				s = dcp::compose ("&%1 %2", i + 1, history[i].string());
 			} else {
 				s = history[i].string();
 			}
@@ -1638,7 +1638,7 @@ private:
 				try {
 					_frame->load_film (_film_to_load);
 				} catch (exception& e) {
-					error_dialog (nullptr, std_to_wx(String::compose(wx_to_std(_("Could not load film %1 (%2)")), _film_to_load)), std_to_wx(e.what()));
+					error_dialog (nullptr, std_to_wx(dcp::compose(wx_to_std(_("Could not load film %1 (%2)")), _film_to_load)), std_to_wx(e.what()));
 				}
 			}
 
diff --git a/src/tools/dcpomatic_batch.cc b/src/tools/dcpomatic_batch.cc
index 061470602..08cd7248b 100644
--- a/src/tools/dcpomatic_batch.cc
+++ b/src/tools/dcpomatic_batch.cc
@@ -26,7 +26,6 @@
 #include "wx/servers_list_dialog.h"
 #include "wx/wx_signal_manager.h"
 #include "wx/wx_util.h"
-#include "lib/compose.hpp"
 #include "lib/config.h"
 #include "lib/dcpomatic_socket.h"
 #include "lib/film.h"
@@ -35,6 +34,7 @@
 #include "lib/transcode_job.h"
 #include "lib/util.h"
 #include "lib/version.h"
+#include <dcp/compose.h>
 #include <wx/aboutdlg.h>
 #include <wx/cmdline.h>
 #include <wx/preferences.h>
@@ -454,7 +454,7 @@ class App : public wxApp
 				} catch (exception& e) {
 					error_dialog (
 						0,
-						std_to_wx(String::compose(wx_to_std(_("Could not load film %1")), i.string())),
+						std_to_wx(dcp::compose(wx_to_std(_("Could not load film %1")), i.string())),
 						std_to_wx(e.what())
 						);
 				}
diff --git a/src/tools/dcpomatic_combiner.cc b/src/tools/dcpomatic_combiner.cc
index 4a783d634..0f6004bd2 100644
--- a/src/tools/dcpomatic_combiner.cc
+++ b/src/tools/dcpomatic_combiner.cc
@@ -152,7 +152,7 @@ private:
 			if (!confirm_dialog (
 				    this,
 				    std_to_wx (
-					    String::compose(wx_to_std(_("The directory %1 already exists and is not empty.  "
+					    dcp::compose(wx_to_std(_("The directory %1 already exists and is not empty.  "
 									"Are you sure you want to use it?")),
 							    output.string())
 					    )
@@ -162,7 +162,7 @@ private:
 		} else if (is_regular_file(output)) {
 			error_dialog (
 				this,
-				String::compose (wx_to_std(_("%1 already exists as a file, so you cannot use it for a DCP.")), output.string())
+				dcp::compose (wx_to_std(_("%1 already exists as a file, so you cannot use it for a DCP.")), output.string())
 				);
 			return;
 		}
diff --git a/src/tools/dcpomatic_disk.cc b/src/tools/dcpomatic_disk.cc
index 7e43c0684..563620693 100644
--- a/src/tools/dcpomatic_disk.cc
+++ b/src/tools/dcpomatic_disk.cc
@@ -202,7 +202,7 @@ private:
 #ifdef DCPOMATIC_OSX
 	void uninstall()
 	{
-		system(String::compose("osascript \"%1/uninstall_disk.applescript\"", resources_path().string()).c_str());
+		system(dcp::compose("osascript \"%1/uninstall_disk.applescript\"", resources_path().string()).c_str());
 	}
 #endif
 
diff --git a/src/tools/dcpomatic_disk_writer.cc b/src/tools/dcpomatic_disk_writer.cc
index c638b72eb..ca6618125 100644
--- a/src/tools/dcpomatic_disk_writer.cc
+++ b/src/tools/dcpomatic_disk_writer.cc
@@ -19,7 +19,6 @@
 */
 
 
-#include "lib/compose.hpp"
 #include "lib/cross.h"
 #include "lib/dcpomatic_log.h"
 #include "lib/digester.h"
@@ -30,6 +29,7 @@
 #include "lib/nanomsg.h"
 #include "lib/version.h"
 #include "lib/warnings.h"
+#include <dcp/compose.h>
 
 #ifdef DCPOMATIC_POSIX
 #include <sys/ioctl.h>
diff --git a/src/tools/dcpomatic_kdm.cc b/src/tools/dcpomatic_kdm.cc
index 4d84f2f33..c83beec74 100644
--- a/src/tools/dcpomatic_kdm.cc
+++ b/src/tools/dcpomatic_kdm.cc
@@ -36,7 +36,6 @@
 #include "wx/wx_signal_manager.h"
 #include "wx/wx_util.h"
 #include "lib/cinema.h"
-#include "lib/compose.hpp"
 #include "lib/config.h"
 #include "lib/cross.h"
 #include "lib/dkdm_wrapper.h"
@@ -46,6 +45,7 @@
 #include "lib/screen.h"
 #include "lib/send_kdm_email_job.h"
 #include "lib/util.h"
+#include <dcp/compose.h>
 #include <dcp/encrypted_kdm.h>
 #include <dcp/decrypted_kdm.h>
 #include <dcp/exceptions.h>
diff --git a/src/tools/dcpomatic_player.cc b/src/tools/dcpomatic_player.cc
index 112f2c065..16847911c 100644
--- a/src/tools/dcpomatic_player.cc
+++ b/src/tools/dcpomatic_player.cc
@@ -38,7 +38,6 @@
 #include "lib/util.h"
 #include "lib/internet.h"
 #include "lib/update_checker.h"
-#include "lib/compose.hpp"
 #include "lib/dcp_content.h"
 #include "lib/job_manager.h"
 #include "lib/job.h"
@@ -56,6 +55,7 @@
 #include "lib/ffmpeg_content.h"
 #include "lib/dcpomatic_log.h"
 #include "lib/file_log.h"
+#include <dcp/compose.h>
 #include <dcp/cpl.h>
 #include <dcp/dcp.h>
 #include <dcp/raw_convert.h>
@@ -694,7 +694,7 @@ private:
 			try {
 				load_dcp (history[n]);
 			} catch (exception& e) {
-				error_dialog (0, std_to_wx(String::compose(wx_to_std(_("Could not load DCP %1.")), history[n])), std_to_wx(e.what()));
+				error_dialog (0, std_to_wx(dcp::compose(wx_to_std(_("Could not load DCP %1.")), history[n])), std_to_wx(e.what()));
 			}
 		}
 	}
@@ -955,7 +955,7 @@ private:
 		for (size_t i = 0; i < history.size(); ++i) {
 			string s;
 			if (i < 9) {
-				s = String::compose ("&%1 %2", i + 1, history[i].string());
+				s = dcp::compose ("&%1 %2", i + 1, history[i].string());
 			} else {
 				s = history[i].string();
 			}
@@ -1164,7 +1164,7 @@ private:
 				try {
 					_frame->load_dcp (_dcp_to_load);
 				} catch (exception& e) {
-					error_dialog (0, std_to_wx (String::compose (wx_to_std (_("Could not load DCP %1.")), _dcp_to_load)), std_to_wx(e.what()));
+					error_dialog (0, std_to_wx (dcp::compose (wx_to_std (_("Could not load DCP %1.")), _dcp_to_load)), std_to_wx(e.what()));
 				}
 			}
 
diff --git a/src/tools/dcpomatic_server.cc b/src/tools/dcpomatic_server.cc
index 401fb1077..825098e9b 100644
--- a/src/tools/dcpomatic_server.cc
+++ b/src/tools/dcpomatic_server.cc
@@ -241,7 +241,7 @@ public:
 #else
 		string const colour = gui_is_dark() ? "white" : "black";
 		wxBitmap bitmap (
-			bitmap_path(String::compose("dcpomatic_small_%1", colour)),
+			bitmap_path(dcp::compose("dcpomatic_small_%1", colour)),
 			wxBITMAP_TYPE_PNG
 			);
 		wxIcon icon;
diff --git a/src/wx/about_dialog.cc b/src/wx/about_dialog.cc
index 73c569282..3a2558f14 100644
--- a/src/wx/about_dialog.cc
+++ b/src/wx/about_dialog.cc
@@ -26,8 +26,8 @@
 #include "wx_util.h"
 #include "static_text.h"
 #include "lib/version.h"
-#include "lib/compose.hpp"
 #include "lib/warnings.h"
+#include <dcp/compose.h>
 DCPOMATIC_DISABLE_WARNINGS
 #include <wx/notebook.h>
 #include <wx/hyperlink.h>
@@ -57,9 +57,9 @@ AboutDialog::AboutDialog (wxWindow* parent)
 
 	wxString s;
 	if (strcmp (dcpomatic_git_commit, "release") == 0) {
-		t = new StaticText (this, std_to_wx(String::compose("Version %1", dcpomatic_version)));
+		t = new StaticText (this, std_to_wx(dcp::compose("Version %1", dcpomatic_version)));
 	} else {
-		t = new StaticText (this, std_to_wx(String::compose("Version %1 git %2", dcpomatic_version, dcpomatic_git_commit)));
+		t = new StaticText (this, std_to_wx(dcp::compose("Version %1 git %2", dcpomatic_version, dcpomatic_git_commit)));
 	}
 	t->SetFont (version_font);
 	sizer->Add (t, wxSizerFlags().Centre().Border(wxALL, 2));
diff --git a/src/wx/audio_plot.cc b/src/wx/audio_plot.cc
index 90a4aa91d..cfb08eb54 100644
--- a/src/wx/audio_plot.cc
+++ b/src/wx/audio_plot.cc
@@ -24,7 +24,7 @@
 #include "film_viewer.h"
 #include "lib/audio_decoder.h"
 #include "lib/audio_analysis.h"
-#include "lib/compose.hpp"
+#include <dcp/compose.h>
 #include <wx/graphics.h>
 #include <boost/bind/bind.hpp>
 #include <iostream>
@@ -190,7 +190,7 @@ AudioPlot::paint ()
 		int const y = (metrics.height - (i - _minimum) * metrics.y_scale) - metrics.y_origin;
 		h_grid.MoveToPoint (metrics.db_label_width - 4, y);
 		h_grid.AddLineToPoint (metrics.db_label_width + data_width, y);
-		gc->DrawText (std_to_wx (String::compose ("%1dB", i)), 0, y - (db_label_height / 2));
+		gc->DrawText (std_to_wx (dcp::compose ("%1dB", i)), 0, y - (db_label_height / 2));
 	}
 
 	gc->SetPen (wxPen (wxColour (200, 200, 200)));
diff --git a/src/wx/barco_alchemy_certificate_panel.cc b/src/wx/barco_alchemy_certificate_panel.cc
index a1d6167aa..25ec3511c 100644
--- a/src/wx/barco_alchemy_certificate_panel.cc
+++ b/src/wx/barco_alchemy_certificate_panel.cc
@@ -22,8 +22,8 @@
 #include "download_certificate_dialog.h"
 #include "wx_util.h"
 #include "lib/internet.h"
-#include "lib/compose.hpp"
 #include "lib/config.h"
+#include <dcp/compose.h>
 
 using std::string;
 using boost::optional;
@@ -55,7 +55,7 @@ void
 BarcoAlchemyCertificatePanel::do_download ()
 {
 	string const serial = wx_to_std (_serial->GetValue());
-	string const url = String::compose (
+	string const url = dcp::compose (
 		"ftp://%1:%2@certificates.barco.com/%3xxx/%4/Barco-ICMP.%5_cert.pem",
 		Config::instance()->barco_username().get(),
 		Config::instance()->barco_password().get(),
diff --git a/src/wx/christie_certificate_panel.cc b/src/wx/christie_certificate_panel.cc
index ab131e015..77a067fb5 100644
--- a/src/wx/christie_certificate_panel.cc
+++ b/src/wx/christie_certificate_panel.cc
@@ -22,8 +22,8 @@
 #include "download_certificate_dialog.h"
 #include "wx_util.h"
 #include "lib/internet.h"
-#include "lib/compose.hpp"
 #include "lib/config.h"
+#include <dcp/compose.h>
 
 using std::string;
 using boost::optional;
@@ -50,7 +50,7 @@ ChristieCertificatePanel::ChristieCertificatePanel (DownloadCertificateDialog* d
 void
 ChristieCertificatePanel::do_download ()
 {
-	string const prefix = String::compose(
+	string const prefix = dcp::compose(
 		"ftp://%1:%2@certificates.christiedigital.com/Certificates/",
 		Config::instance()->christie_username().get(),
 		Config::instance()->christie_password().get()
@@ -59,7 +59,7 @@ ChristieCertificatePanel::do_download ()
 	string serial = wx_to_std (_serial->GetValue());
 	serial.insert (0, 12 - serial.length(), '0');
 
-	string const url = String::compose ("%1F-IMB/F-IMB_%2_sha256.pem", prefix, serial);
+	string const url = dcp::compose ("%1F-IMB/F-IMB_%2_sha256.pem", prefix, serial);
 
 	optional<string> all_errors;
 	bool ok = true;
@@ -68,7 +68,7 @@ ChristieCertificatePanel::do_download ()
 	if (error) {
 		all_errors = *error;
 
-		string const url = String::compose ("%1IMB-S2/IMB-S2_%2_sha256.pem", prefix, serial);
+		string const url = dcp::compose ("%1IMB-S2/IMB-S2_%2_sha256.pem", prefix, serial);
 
 		error = get_from_url (url, true, false, boost::bind(&DownloadCertificatePanel::load_certificate_from_chain, this, _1));
 		if (error) {
diff --git a/src/wx/closed_captions_dialog.cc b/src/wx/closed_captions_dialog.cc
index 7fcfc0808..73ad98a26 100644
--- a/src/wx/closed_captions_dialog.cc
+++ b/src/wx/closed_captions_dialog.cc
@@ -24,7 +24,7 @@
 #include "lib/string_text.h"
 #include "lib/butler.h"
 #include "lib/text_content.h"
-#include "lib/compose.hpp"
+#include <dcp/compose.h>
 #include <boost/bind/bind.hpp>
 
 using std::list;
@@ -249,7 +249,7 @@ ClosedCaptionsDialog::update_tracks (shared_ptr<const Film> film)
 
 	_track->Clear ();
 	for (auto const& i: _tracks) {
-		_track->Append (std_to_wx(String::compose("%1 (%2)", i.name, i.language ? i.language->to_string() : wx_to_std(_("Unknown")))));
+		_track->Append (std_to_wx(dcp::compose("%1 (%2)", i.name, i.language ? i.language->to_string() : wx_to_std(_("Unknown")))));
 	}
 
 	if (_track->GetCount() > 0) {
diff --git a/src/wx/content_panel.cc b/src/wx/content_panel.cc
index bcc699913..5c2b19f61 100644
--- a/src/wx/content_panel.cc
+++ b/src/wx/content_panel.cc
@@ -31,7 +31,6 @@
 #include "wx_util.h"
 #include "lib/audio_content.h"
 #include "lib/case_insensitive_sorter.h"
-#include "lib/compose.hpp"
 #include "lib/config.h"
 #include "lib/content_factory.h"
 #include "lib/cross.h"
@@ -45,6 +44,7 @@
 #include "lib/string_text_file_content.h"
 #include "lib/text_content.h"
 #include "lib/video_content.h"
+#include <dcp/compose.h>
 #include <wx/wx.h>
 #include <wx/notebook.h>
 #include <wx/listctrl.h>
diff --git a/src/wx/content_sub_panel.cc b/src/wx/content_sub_panel.cc
index 9c236abeb..a43a5fc94 100644
--- a/src/wx/content_sub_panel.cc
+++ b/src/wx/content_sub_panel.cc
@@ -22,8 +22,8 @@
 #include "content_panel.h"
 #include "wx_util.h"
 #include "lib/dcp_content.h"
-#include "lib/compose.hpp"
 #include "lib/log.h"
+#include <dcp/compose.h>
 #include <wx/notebook.h>
 
 using std::list;
diff --git a/src/wx/dolby_doremi_certificate_panel.cc b/src/wx/dolby_doremi_certificate_panel.cc
index 817867cc1..6049a6818 100644
--- a/src/wx/dolby_doremi_certificate_panel.cc
+++ b/src/wx/dolby_doremi_certificate_panel.cc
@@ -22,10 +22,10 @@
 #include "dolby_doremi_certificate_panel.h"
 #include "download_certificate_dialog.h"
 #include "wx_util.h"
-#include "lib/compose.hpp"
 #include "lib/internet.h"
 #include "lib/signal_manager.h"
 #include "lib/util.h"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 #include <curl/curl.h>
 #include <zip.h>
@@ -53,30 +53,30 @@ DolbyDoremiCertificatePanel::DolbyDoremiCertificatePanel (DownloadCertificateDia
 static void
 try_dcp2000 (list<string>& urls, list<string>& files, string prefix, string serial)
 {
-	urls.push_back (String::compose("%1%2xxx/dcp2000-%3.dcicerts.zip", prefix, serial.substr(0, 3), serial));
-	files.push_back (String::compose("dcp2000-%1.cert.sha256.pem", serial));
+	urls.push_back (dcp::compose("%1%2xxx/dcp2000-%3.dcicerts.zip", prefix, serial.substr(0, 3), serial));
+	files.push_back (dcp::compose("dcp2000-%1.cert.sha256.pem", serial));
 
-	urls.push_back (String::compose("%1%2xxx/dcp2000-%3.dcicerts.zip", prefix, serial.substr(0, 3), serial));
-	files.push_back (String::compose("dcp2000-%1.cert.sha256.pem", serial));
+	urls.push_back (dcp::compose("%1%2xxx/dcp2000-%3.dcicerts.zip", prefix, serial.substr(0, 3), serial));
+	files.push_back (dcp::compose("dcp2000-%1.cert.sha256.pem", serial));
 
-	urls.push_back (String::compose("%1%2xxx/dcp2000-%3.certs.zip", prefix, serial.substr(0, 3), serial));
-	files.push_back (String::compose("dcp2000-%1.cert.sha256.pem", serial));
+	urls.push_back (dcp::compose("%1%2xxx/dcp2000-%3.certs.zip", prefix, serial.substr(0, 3), serial));
+	files.push_back (dcp::compose("dcp2000-%1.cert.sha256.pem", serial));
 }
 
 
 static void
 try_imb (list<string>& urls, list<string>& files, string prefix, string serial)
 {
-	urls.push_back (String::compose("%1%2xxx/imb-%3.dcicerts.zip", prefix, serial.substr(0, 3), serial));
-	files.push_back (String::compose("imb-%1.cert.sha256.pem", serial));
+	urls.push_back (dcp::compose("%1%2xxx/imb-%3.dcicerts.zip", prefix, serial.substr(0, 3), serial));
+	files.push_back (dcp::compose("imb-%1.cert.sha256.pem", serial));
 }
 
 
 static void
 try_ims (list<string>& urls, list<string>& files, string prefix, string serial)
 {
-	urls.push_back (String::compose("%1%2xxx/ims-%3.dcicerts.zip", prefix, serial.substr(0, 3), serial));
-	files.push_back (String::compose("ims-%1.cert.sha256.pem", serial));
+	urls.push_back (dcp::compose("%1%2xxx/ims-%3.dcicerts.zip", prefix, serial.substr(0, 3), serial));
+	files.push_back (dcp::compose("ims-%1.cert.sha256.pem", serial));
 }
 
 
@@ -92,11 +92,11 @@ try_cat862 (list<string>& urls, list<string>& files, string prefix, string seria
 		cat862 = "CAT862_617000_and_higher";
 	} else {
 		int const lower = serial_int - (serial_int % 1000);
-		cat862 = String::compose ("CAT862_%1-%2", lower, lower + 999);
+		cat862 = dcp::compose ("CAT862_%1-%2", lower, lower + 999);
 	}
 
-	urls.push_back (String::compose("%1%2/cert_Dolby256-CAT862-%3.zip", prefix, cat862, serial_int));
-	files.push_back (String::compose("cert_Dolby256-CAT862-%1.pem.crt", serial_int));
+	urls.push_back (dcp::compose("%1%2/cert_Dolby256-CAT862-%3.zip", prefix, cat862, serial_int));
+	files.push_back (dcp::compose("cert_Dolby256-CAT862-%1.pem.crt", serial_int));
 }
 
 
@@ -112,11 +112,11 @@ try_dsp100 (list<string>& urls, list<string>& files, string prefix, string seria
 		dsp100 = "DSP100_3000_and_higher";
 	} else {
 		int const lower = serial_int - (serial_int % 1000);
-		dsp100 = String::compose ("DSP100_%1_thru_%2", lower, lower + 999);
+		dsp100 = dcp::compose ("DSP100_%1_thru_%2", lower, lower + 999);
 	}
 
-	urls.push_back (String::compose("%1%2/cert_Dolby256-DSP100-%3.zip", prefix, dsp100, serial_int));
-	files.push_back (String::compose("cert_Dolby256-DSP100-%1.pem.crt", serial_int));
+	urls.push_back (dcp::compose("%1%2/cert_Dolby256-DSP100-%3.zip", prefix, dsp100, serial_int));
+	files.push_back (dcp::compose("cert_Dolby256-DSP100-%1.pem.crt", serial_int));
 }
 
 
@@ -132,11 +132,11 @@ try_cat745 (list<string>& urls, list<string>& files, string prefix, string seria
 		cat745 = "CAT745_6000_and_higher";
 	} else {
 		int const lower = serial_int - (serial_int % 1000);
-		cat745 = String::compose("CAT745_%1_thru_%2", lower, lower + 999);
+		cat745 = dcp::compose("CAT745_%1_thru_%2", lower, lower + 999);
 	}
 
-	urls.push_back (String::compose("%1%2/cert_Dolby-CAT745-%3.zip", prefix, cat745, serial_int));
-	files.push_back (String::compose("cert_Dolby-CAT745-%1.pem.crt", serial_int));
+	urls.push_back (dcp::compose("%1%2/cert_Dolby-CAT745-%3.zip", prefix, cat745, serial_int));
+	files.push_back (dcp::compose("cert_Dolby-CAT745-%1.pem.crt", serial_int));
 }
 
 
@@ -146,16 +146,16 @@ try_cp850 (list<string>& urls, list<string>& files, string prefix, string serial
 	int const serial_int = raw_convert<int> (serial.substr (1));
 
 	int const lower = serial_int - (serial_int % 1000);
-	urls.push_back (String::compose ("%1CP850_CAT1600_F%2-F%3/cert_RMB_SPB_MDE_FMA.Dolby-CP850-F%4.zip", prefix, lower, lower + 999, serial_int));
-	files.push_back (String::compose ("cert_RMB_SPB_MDE_FMA.Dolby-CP850-F%1.pem.crt", serial_int));
+	urls.push_back (dcp::compose ("%1CP850_CAT1600_F%2-F%3/cert_RMB_SPB_MDE_FMA.Dolby-CP850-F%4.zip", prefix, lower, lower + 999, serial_int));
+	files.push_back (dcp::compose ("cert_RMB_SPB_MDE_FMA.Dolby-CP850-F%1.pem.crt", serial_int));
 }
 
 
 static void
 try_ims3000 (list<string>& urls, list<string>& files, string prefix, string serial)
 {
-	urls.push_back (String::compose ("%1%2xxx/cert_Dolby-IMS3000-%3-SMPTE.zip", prefix, serial.substr(0, 3), serial));
-	files.push_back (String::compose("cert_Dolby-IMS3000-%1-SMPTE.pem", serial));
+	urls.push_back (dcp::compose ("%1%2xxx/cert_Dolby-IMS3000-%3-SMPTE.zip", prefix, serial.substr(0, 3), serial));
+	files.push_back (dcp::compose("cert_Dolby-IMS3000-%1-SMPTE.pem", serial));
 }
 
 
diff --git a/src/wx/download_certificate_panel.cc b/src/wx/download_certificate_panel.cc
index c30b05008..b4bdd1ce4 100644
--- a/src/wx/download_certificate_panel.cc
+++ b/src/wx/download_certificate_panel.cc
@@ -22,9 +22,9 @@
 #include "download_certificate_dialog.h"
 #include "download_certificate_panel.h"
 #include "wx_util.h"
-#include "lib/compose.hpp"
 #include "lib/signal_manager.h"
 #include <dcp/certificate_chain.h>
+#include <dcp/compose.h>
 #include <dcp/exceptions.h>
 #include <dcp/util.h>
 #include <boost/bind/bind.hpp>
@@ -63,7 +63,7 @@ DownloadCertificatePanel::load_certificate (boost::filesystem::path file)
 	try {
 		_certificate = dcp::Certificate (dcp::file_to_string(file));
 	} catch (dcp::MiscError& e) {
-		return String::compose(wx_to_std(_("Could not read certificate file (%1)")), e.what());
+		return dcp::compose(wx_to_std(_("Could not read certificate file (%1)")), e.what());
 	}
 	return {};
 }
@@ -75,7 +75,7 @@ DownloadCertificatePanel::load_certificate_from_chain (boost::filesystem::path f
 	try {
 		_certificate = dcp::CertificateChain (dcp::file_to_string(file)).leaf();
 	} catch (dcp::MiscError& e) {
-		return String::compose(wx_to_std(_("Could not read certificate file (%1)")), e.what());
+		return dcp::compose(wx_to_std(_("Could not read certificate file (%1)")), e.what());
 	}
 	return {};
 }
diff --git a/src/wx/film_name_location_dialog.cc b/src/wx/film_name_location_dialog.cc
index 516ed86ae..55e5a534d 100644
--- a/src/wx/film_name_location_dialog.cc
+++ b/src/wx/film_name_location_dialog.cc
@@ -26,7 +26,7 @@
 #include "dir_picker_ctrl.h"
 #endif
 #include "lib/config.h"
-#include "lib/compose.hpp"
+#include <dcp/compose.h>
 #include <wx/stdpaths.h>
 #include <boost/filesystem.hpp>
 
@@ -139,7 +139,7 @@ FilmNameLocationDialog::check_path ()
 		if (!confirm_dialog (
 			    this,
 			    std_to_wx (
-				    String::compose(wx_to_std(_("The directory %1 already exists and is not empty.  "
+				    dcp::compose(wx_to_std(_("The directory %1 already exists and is not empty.  "
 								  "Are you sure you want to use it?")),
 						    path().string().c_str())
 				    )
@@ -149,7 +149,7 @@ FilmNameLocationDialog::check_path ()
 	} else if (boost::filesystem::is_regular_file(path())) {
 		error_dialog (
 			this,
-			String::compose (wx_to_std(_("%1 already exists as a file, so you cannot use it for a film.")), path().c_str())
+			dcp::compose (wx_to_std(_("%1 already exists as a file, so you cannot use it for a film.")), path().c_str())
 			);
 		return false;
 	}
diff --git a/src/wx/film_viewer.cc b/src/wx/film_viewer.cc
index 4ea2a8b00..031c00154 100644
--- a/src/wx/film_viewer.cc
+++ b/src/wx/film_viewer.cc
@@ -48,12 +48,12 @@
 #include "lib/butler.h"
 #include "lib/log.h"
 #include "lib/config.h"
-#include "lib/compose.hpp"
 #include "lib/dcpomatic_log.h"
 #include "lib/text_content.h"
 extern "C" {
 #include <libavutil/pixfmt.h>
 }
+#include <dcp/compose.h>
 #include <dcp/exceptions.h>
 #include <wx/tglbtn.h>
 #include <iostream>
diff --git a/src/wx/gdc_certificate_panel.cc b/src/wx/gdc_certificate_panel.cc
index f7f86895d..555c1b232 100644
--- a/src/wx/gdc_certificate_panel.cc
+++ b/src/wx/gdc_certificate_panel.cc
@@ -22,8 +22,8 @@
 #include "download_certificate_dialog.h"
 #include "wx_util.h"
 #include "lib/internet.h"
-#include "lib/compose.hpp"
 #include "lib/config.h"
+#include <dcp/compose.h>
 
 using std::string;
 using boost::optional;
@@ -54,7 +54,7 @@ GDCCertificatePanel::do_download ()
 		/* We're adding the A ourselves */
 		serial = serial.substr(1);
 	}
-	string const url = String::compose(
+	string const url = dcp::compose(
 		"ftp://%1:%2@ftp.gdc-tech.com/SHA256/A%3.crt.pem",
 		Config::instance()->gdc_username().get(),
 		Config::instance()->gdc_password().get(),
diff --git a/src/wx/job_manager_view.cc b/src/wx/job_manager_view.cc
index 19243393c..e49227ef1 100644
--- a/src/wx/job_manager_view.cc
+++ b/src/wx/job_manager_view.cc
@@ -33,7 +33,7 @@
 #include "lib/job.h"
 #include "lib/util.h"
 #include "lib/exceptions.h"
-#include "lib/compose.hpp"
+#include <dcp/compose.h>
 #include <iostream>
 
 
diff --git a/src/wx/job_view.cc b/src/wx/job_view.cc
index 231176e4f..cb1a9fcdd 100644
--- a/src/wx/job_view.cc
+++ b/src/wx/job_view.cc
@@ -27,11 +27,11 @@
 #include "dcpomatic_button.h"
 #include "lib/job.h"
 #include "lib/job_manager.h"
-#include "lib/compose.hpp"
 #include "lib/config.h"
 #include "lib/send_notification_email_job.h"
 #include "lib/transcode_job.h"
 #include "lib/analyse_audio_job.h"
+#include <dcp/compose.h>
 #include <wx/wx.h>
 #include <boost/algorithm/string.hpp>
 
diff --git a/src/wx/name_format_editor.cc b/src/wx/name_format_editor.cc
index b2c11b50c..969cd6076 100644
--- a/src/wx/name_format_editor.cc
+++ b/src/wx/name_format_editor.cc
@@ -44,7 +44,7 @@ NameFormatEditor::NameFormatEditor (wxWindow* parent, dcp::NameFormat name, dcp:
 	_panel->SetSizer (_sizer);
 
 	for (auto const& i: titles) {
-		auto t = new StaticText (_panel, std_to_wx (String::compose ("%%%1 %2", i.first, i.second)));
+		auto t = new StaticText (_panel, std_to_wx (dcp::compose ("%%%1 %2", i.first, i.second)));
 		_sizer->Add (t);
 		auto font = t->GetFont();
 		font.SetStyle (wxFONTSTYLE_ITALIC);
diff --git a/src/wx/name_format_editor.h b/src/wx/name_format_editor.h
index 596b42740..972f32655 100644
--- a/src/wx/name_format_editor.h
+++ b/src/wx/name_format_editor.h
@@ -23,8 +23,8 @@
 #define DCPOMATIC_NAME_FORMAT_EDITOR_H
 
 
-#include "lib/compose.hpp"
 #include "lib/warnings.h"
+#include <dcp/compose.h>
 #include <dcp/name_format.h>
 DCPOMATIC_DISABLE_WARNINGS
 #include <wx/wx.h>
diff --git a/src/wx/player_information.cc b/src/wx/player_information.cc
index f0eaa59bb..ae5ebe617 100644
--- a/src/wx/player_information.cc
+++ b/src/wx/player_information.cc
@@ -22,11 +22,11 @@
 #include "wx_util.h"
 #include "film_viewer.h"
 #include "lib/playlist.h"
-#include "lib/compose.hpp"
 #include "lib/video_content.h"
 #include "lib/audio_content.h"
 #include "lib/dcp_content.h"
 #include "lib/film.h"
+#include <dcp/compose.h>
 
 using std::cout;
 using std::string;
@@ -157,7 +157,7 @@ PlayerInformation::triggered_update ()
 	vfr = dcp->video_frame_rate ();
 	DCPOMATIC_ASSERT (vfr);
 
-	string const len = String::compose(
+	string const len = dcp::compose(
 		wx_to_std(_("Length: %1 (%2 frames)")),
 		time_to_hmsf(dcp->full_length(fv->film()), lrint(*vfr)),
 		dcp->full_length(fv->film()).frames_round(*vfr)
diff --git a/src/wx/playlist_controls.cc b/src/wx/playlist_controls.cc
index d65cb0fcc..b935b0ba2 100644
--- a/src/wx/playlist_controls.cc
+++ b/src/wx/playlist_controls.cc
@@ -30,7 +30,7 @@
 #include "lib/scoped_temporary.h"
 #include "lib/internet.h"
 #include "lib/ffmpeg_content.h"
-#include "lib/compose.hpp"
+#include <dcp/compose.h>
 #include <dcp/raw_convert.h>
 #include <dcp/exceptions.h>
 #include <wx/listctrl.h>
diff --git a/src/wx/qube_certificate_panel.cc b/src/wx/qube_certificate_panel.cc
index e1c6bfb41..403fff695 100644
--- a/src/wx/qube_certificate_panel.cc
+++ b/src/wx/qube_certificate_panel.cc
@@ -23,8 +23,8 @@
 #include "download_certificate_dialog.h"
 #include "wx_util.h"
 #include "lib/internet.h"
-#include "lib/compose.hpp"
 #include "lib/config.h"
+#include <dcp/compose.h>
 #include <boost/algorithm/string/predicate.hpp>
 
 
@@ -50,7 +50,7 @@ QubeCertificatePanel::QubeCertificatePanel (DownloadCertificateDialog* dialog, s
 void
 QubeCertificatePanel::do_download ()
 {
-	auto files = ls_url(String::compose("%1SMPTE-%2/", base, _type));
+	auto files = ls_url(dcp::compose("%1SMPTE-%2/", base, _type));
 	if (files.empty()) {
 		error_dialog (this, _("Could not read certificates from Qube server."));
 		return;
@@ -59,7 +59,7 @@ QubeCertificatePanel::do_download ()
 	auto const serial = wx_to_std(_serial->GetValue());
 	optional<string> name;
 	for (auto i: files) {
-		if (boost::algorithm::starts_with(i, String::compose("%1-%2-", _type, serial))) {
+		if (boost::algorithm::starts_with(i, dcp::compose("%1-%2-", _type, serial))) {
 			name = i;
 			break;
 		}
@@ -71,7 +71,7 @@ QubeCertificatePanel::do_download ()
 		return;
 	}
 
-	auto error = get_from_url (String::compose("%1SMPTE-%2/%3", base, _type, *name), true, false, boost::bind(&DownloadCertificatePanel::load_certificate, this, _1));
+	auto error = get_from_url (dcp::compose("%1SMPTE-%2/%3", base, _type, *name), true, false, boost::bind(&DownloadCertificatePanel::load_certificate, this, _1));
 
 	if (error) {
 		_dialog->message()->SetLabel(wxT(""));
diff --git a/src/wx/recipient_dialog.cc b/src/wx/recipient_dialog.cc
index d59226a96..b6638edd8 100644
--- a/src/wx/recipient_dialog.cc
+++ b/src/wx/recipient_dialog.cc
@@ -25,8 +25,8 @@
 #include "download_certificate_dialog.h"
 #include "table_dialog.h"
 #include "dcpomatic_button.h"
-#include "lib/compose.hpp"
 #include "lib/util.h"
+#include <dcp/compose.h>
 #include <dcp/exceptions.h>
 #include <dcp/certificate_chain.h>
 #include "lib/warnings.h"
diff --git a/src/wx/screen_dialog.cc b/src/wx/screen_dialog.cc
index 8da8f061e..e438ca87e 100644
--- a/src/wx/screen_dialog.cc
+++ b/src/wx/screen_dialog.cc
@@ -26,9 +26,9 @@
 #include "static_text.h"
 #include "table_dialog.h"
 #include "wx_util.h"
-#include "lib/compose.hpp"
 #include "lib/util.h"
 #include "lib/warnings.h"
+#include <dcp/compose.h>
 #include <dcp/exceptions.h>
 #include <dcp/certificate_chain.h>
 DCPOMATIC_DISABLE_WARNINGS
diff --git a/src/wx/timeline_dialog.cc b/src/wx/timeline_dialog.cc
index 975f7cd9d..8f4ea0cea 100644
--- a/src/wx/timeline_dialog.cc
+++ b/src/wx/timeline_dialog.cc
@@ -23,9 +23,9 @@
 #include "film_editor.h"
 #include "timeline_dialog.h"
 #include "wx_util.h"
-#include "lib/compose.hpp"
 #include "lib/cross.h"
 #include "lib/playlist.h"
+#include <dcp/compose.h>
 #include <wx/graphics.h>
 #include <iostream>
 #include <list>
diff --git a/src/wx/wx_util.cc b/src/wx/wx_util.cc
index a0beb8f72..b0ed81cc4 100644
--- a/src/wx/wx_util.cc
+++ b/src/wx/wx_util.cc
@@ -646,7 +646,7 @@ bitmap_path (string name)
 	base = resources_path();
 #endif
 
-	auto p = base / String::compose("%1.png", name);
+	auto p = base / dcp::compose("%1.png", name);
 	return std_to_wx (p.string());
 }
 
diff --git a/test/cpl_hash_test.cc b/test/cpl_hash_test.cc
index f34c29583..0e57d54e4 100644
--- a/test/cpl_hash_test.cc
+++ b/test/cpl_hash_test.cc
@@ -51,7 +51,7 @@ BOOST_AUTO_TEST_CASE (hash_added_to_imported_dcp_test)
 	make_and_verify_dcp (ov);
 
 	/* Remove <Hash> tags from the CPL */
-	for (auto i: directory_iterator(String::compose("build/test/%1/%2", ov_name, ov->dcp_name()))) {
+	for (auto i: directory_iterator(dcp::compose("build/test/%1/%2", ov_name, ov->dcp_name()))) {
 		if (boost::algorithm::starts_with(i.path().filename().string(), "cpl_")) {
 			auto in = fopen_boost(i.path(), "r");
 			BOOST_REQUIRE (in);
@@ -70,7 +70,7 @@ BOOST_AUTO_TEST_CASE (hash_added_to_imported_dcp_test)
 	}
 
 	string const vf_name = "hash_added_to_imported_dcp_test_vf";
-	auto ov_content = make_shared<DCPContent>(String::compose("build/test/%1/%2", ov_name, ov->dcp_name()));
+	auto ov_content = make_shared<DCPContent>(dcp::compose("build/test/%1/%2", ov_name, ov->dcp_name()));
 	auto vf = new_test_film2 (
 		vf_name, { ov_content }
 		);
@@ -80,7 +80,7 @@ BOOST_AUTO_TEST_CASE (hash_added_to_imported_dcp_test)
 
 	/* Check for Hash tags in the VF DCP */
 	int hashes = 0;
-	for (auto i: directory_iterator(String::compose("build/test/%1/%2", vf_name, vf->dcp_name()))) {
+	for (auto i: directory_iterator(dcp::compose("build/test/%1/%2", vf_name, vf->dcp_name()))) {
 		if (boost::algorithm::starts_with(i.path().filename().string(), "cpl_")) {
 			auto in = fopen_boost(i.path(), "r");
 			BOOST_REQUIRE (in);
diff --git a/test/digest_test.cc b/test/digest_test.cc
index 59a8cb7a7..0a155d8ba 100644
--- a/test/digest_test.cc
+++ b/test/digest_test.cc
@@ -28,9 +28,9 @@
 #include "lib/film.h"
 #include "lib/image_content.h"
 #include "lib/dcp_content_type.h"
-#include "lib/compose.hpp"
 #include "lib/config.h"
 #include "test.h"
+#include <dcp/compose.h>
 #include <dcp/cpl.h>
 #include <dcp/reel.h>
 #include <dcp/reel_picture_asset.h>
@@ -46,7 +46,7 @@ using std::make_shared;
 static string
 openssl_hash (boost::filesystem::path file)
 {
-	auto pipe = popen (String::compose ("openssl sha1 -binary %1 | openssl base64 -e", file.string()).c_str (), "r");
+	auto pipe = popen (dcp::compose ("openssl sha1 -binary %1 | openssl base64 -e", file.string()).c_str (), "r");
 	BOOST_REQUIRE (pipe);
 	char buffer[128];
 	string output;
diff --git a/test/ffmpeg_encoder_test.cc b/test/ffmpeg_encoder_test.cc
index d0bce0356..62c55e682 100644
--- a/test/ffmpeg_encoder_test.cc
+++ b/test/ffmpeg_encoder_test.cc
@@ -20,7 +20,6 @@
 
 
 #include "lib/audio_content.h"
-#include "lib/compose.hpp"
 #include "lib/content_factory.h"
 #include "lib/dcp_content.h"
 #include "lib/ffmpeg_content.h"
@@ -34,6 +33,7 @@
 #include "lib/transcode_job.h"
 #include "lib/video_content.h"
 #include "test.h"
+#include <dcp/compose.h>
 #include <boost/test/unit_test.hpp>
 
 
@@ -65,7 +65,7 @@ ffmpeg_content_test (int number, boost::filesystem::path content, ExportFormat f
 		BOOST_REQUIRE (false);
 	}
 
-	name = String::compose("%1_test%2", name, number);
+	name = dcp::compose("%1_test%2", name, number);
 
 	auto c = make_shared<FFmpegContent>(content);
 	shared_ptr<Film> film = new_test_film2 (name, {c}, &cl);
@@ -74,7 +74,7 @@ ffmpeg_content_test (int number, boost::filesystem::path content, ExportFormat f
 
 	film->write_metadata ();
 	auto job = make_shared<TranscodeJob>(film);
-	auto file = boost::filesystem::path("build") / "test" / String::compose("%1.%2", name, extension);
+	auto file = boost::filesystem::path("build") / "test" / dcp::compose("%1.%2", name, extension);
 	cl.add (file);
 	FFmpegEncoder encoder (film, job, file, format, false, false, false, 23);
 	encoder.go ();
diff --git a/test/hints_test.cc b/test/hints_test.cc
index 263f02435..827427222 100644
--- a/test/hints_test.cc
+++ b/test/hints_test.cc
@@ -90,7 +90,7 @@ BOOST_AUTO_TEST_CASE (hint_closed_caption_too_long)
 	check (
 		TextType::CLOSED_CAPTION,
 		"hint_closed_caption_too_long",
-		String::compose("At least one of your closed caption lines has more than %1 characters.  It is advisable to make each line %1 characters at most in length.", MAX_CLOSED_CAPTION_LENGTH, MAX_CLOSED_CAPTION_LENGTH)
+		dcp::compose("At least one of your closed caption lines has more than %1 characters.  It is advisable to make each line %1 characters at most in length.", MAX_CLOSED_CAPTION_LENGTH, MAX_CLOSED_CAPTION_LENGTH)
 	      );
 }
 
@@ -100,7 +100,7 @@ BOOST_AUTO_TEST_CASE (hint_many_closed_caption_lines)
 	check (
 		TextType::CLOSED_CAPTION,
 		"hint_many_closed_caption_lines",
-		String::compose("Some of your closed captions span more than %1 lines, so they will be truncated.", MAX_CLOSED_CAPTION_LINES)
+		dcp::compose("Some of your closed captions span more than %1 lines, so they will be truncated.", MAX_CLOSED_CAPTION_LINES)
 	      );
 }
 
@@ -174,7 +174,7 @@ BOOST_AUTO_TEST_CASE (hint_subtitle_mxf_too_big)
 	content->text.front()->set_type (TextType::OPEN_SUBTITLE);
 	content->text.front()->set_language (dcp::LanguageTag("en-US"));
 	for (int i = 1; i < 512; ++i) {
-		auto font = make_shared<dcpomatic::Font>(String::compose("font_%1", i));
+		auto font = make_shared<dcpomatic::Font>(dcp::compose("font_%1", i));
 		font->set_file ("test/data/LiberationSans-Regular.ttf");
 		content->text.front()->add_font(font);
 	}
@@ -197,7 +197,7 @@ BOOST_AUTO_TEST_CASE (hint_closed_caption_xml_too_big)
 
 	auto film = new_test_film2 (name);
 
-	auto ccap = fopen_boost (String::compose("build/test/%1.srt", name), "w");
+	auto ccap = fopen_boost (dcp::compose("build/test/%1.srt", name), "w");
 	BOOST_REQUIRE (ccap);
 	for (int i = 0; i < 2048; ++i) {
 		fprintf(ccap, "%d\n", i + 1);
diff --git a/test/image_filename_sorter_test.cc b/test/image_filename_sorter_test.cc
index eb662a120..b6d5a731a 100644
--- a/test/image_filename_sorter_test.cc
+++ b/test/image_filename_sorter_test.cc
@@ -26,7 +26,7 @@
 
 
 #include "lib/image_filename_sorter.h"
-#include "lib/compose.hpp"
+#include <dcp/compose.h>
 #include <boost/test/unit_test.hpp>
 
 
@@ -67,11 +67,11 @@ BOOST_AUTO_TEST_CASE (image_filename_sorter_test2)
 {
 	vector<boost::filesystem::path> paths;
 	for (int i = 0; i < 100000; ++i) {
-		paths.push_back(String::compose("some.filename.with.%1.number.tiff", i));
+		paths.push_back(dcp::compose("some.filename.with.%1.number.tiff", i));
 	}
 	random_shuffle (paths.begin(), paths.end());
 	sort (paths.begin(), paths.end(), ImageFilenameSorter());
 	for (int i = 0; i < 100000; ++i) {
-		BOOST_CHECK_EQUAL(paths[i].string(), String::compose("some.filename.with.%1.number.tiff", i));
+		BOOST_CHECK_EQUAL(paths[i].string(), dcp::compose("some.filename.with.%1.number.tiff", i));
 	}
 }
diff --git a/test/image_test.cc b/test/image_test.cc
index 3993b3efb..c461a93d3 100644
--- a/test/image_test.cc
+++ b/test/image_test.cc
@@ -26,12 +26,12 @@
  */
 
 
-#include "lib/compose.hpp"
 #include "lib/image.h"
 #include "lib/image_content.h"
 #include "lib/image_decoder.h"
 #include "lib/ffmpeg_image_proxy.h"
 #include "test.h"
+#include <dcp/compose.h>
 #include <boost/test/unit_test.hpp>
 #include <iostream>
 
@@ -364,7 +364,7 @@ BOOST_AUTO_TEST_CASE (crop_scale_window_test7)
 			true,
 			false
 			);
-		path file = String::compose("crop_scale_window_test7-%1.png", left_crop);
+		path file = dcp::compose("crop_scale_window_test7-%1.png", left_crop);
 		write_image(cropped, path("build") / "test" / file);
 		check_image(path("test") / "data" / file, path("build") / "test" / file, 10);
 	}
diff --git a/test/kdm_naming_test.cc b/test/kdm_naming_test.cc
index f692c165d..a78d0a12d 100644
--- a/test/kdm_naming_test.cc
+++ b/test/kdm_naming_test.cc
@@ -120,7 +120,7 @@ BOOST_AUTO_TEST_CASE (single_kdm_naming_test)
 	auto until_time = until.time_of_day (true, false);
 	boost::algorithm::replace_all (until_time, ":", "-");
 
-	auto const ref = String::compose("KDM_Cinema_A_-_Screen_1_-_my_great_film_-_%1_%2_-_%3_%4.xml", from.date(), from_time, until.date(), until_time);
+	auto const ref = dcp::compose("KDM_Cinema_A_-_Screen_1_-_my_great_film_-_%1_%2_-_%3_%4.xml", from.date(), from_time, until.date(), until_time);
 	BOOST_CHECK_MESSAGE (boost::filesystem::exists("build/test/single_kdm_naming_test/" + ref), "File " << ref << " not found");
 }
 
@@ -195,36 +195,36 @@ BOOST_AUTO_TEST_CASE (directory_kdm_naming_test, * boost::unit_test::depends_on(
 
 	path const base = "build/test/directory_kdm_naming_test";
 
-	path dir_a = String::compose("Cinema_A_-_%s_-_my_great_film_-_%1_%2_-_%3_%4", from.date(), from_time, until.date(), until_time);
+	path dir_a = dcp::compose("Cinema_A_-_%s_-_my_great_film_-_%1_%2_-_%3_%4", from.date(), from_time, until.date(), until_time);
 	BOOST_CHECK_MESSAGE (boost::filesystem::exists(base / dir_a), "Directory " << dir_a << " not found");
-	path dir_b = String::compose("Cinema_B_-_%s_-_my_great_film_-_%1_%2_-_%3_%4", from.date(), from_time, until.date(), until_time);
+	path dir_b = dcp::compose("Cinema_B_-_%s_-_my_great_film_-_%1_%2_-_%3_%4", from.date(), from_time, until.date(), until_time);
 	BOOST_CHECK_MESSAGE (boost::filesystem::exists(base / dir_b), "Directory " << dir_b << " not found");
 
 #ifdef DCPOMATIC_WINDOWS
-	path ref = String::compose("KDM_Cinema_A_-_Screen_2_-_my_great_film_-_%1_%2_-_%3_%4.xml", from.date(), from_time, until.date(), until_time);
+	path ref = dcp::compose("KDM_Cinema_A_-_Screen_2_-_my_great_film_-_%1_%2_-_%3_%4.xml", from.date(), from_time, until.date(), until_time);
 #else
-	path ref = String::compose("KDM_Cinema_A_-_Screen_2_-_my_great_film_-_%1_%2_-_%3_%4_-_%5.xml", from.date(), from_time, until.date(), until_time, cpl_id);
+	path ref = dcp::compose("KDM_Cinema_A_-_Screen_2_-_my_great_film_-_%1_%2_-_%3_%4_-_%5.xml", from.date(), from_time, until.date(), until_time, cpl_id);
 #endif
 	BOOST_CHECK_MESSAGE (boost::filesystem::exists(base / dir_a / ref), "File " << ref << " not found");
 
 #ifdef DCPOMATIC_WINDOWS
-	ref = String::compose("KDM_Cinema_B_-_Screen_X_-_my_great_film_-_%1_%2_-_%3_%4.xml", from.date(), from_time, until.date(), until_time);
+	ref = dcp::compose("KDM_Cinema_B_-_Screen_X_-_my_great_film_-_%1_%2_-_%3_%4.xml", from.date(), from_time, until.date(), until_time);
 #else
-	ref = String::compose("KDM_Cinema_B_-_Screen_X_-_my_great_film_-_%1_%2_-_%3_%4_-_%5.xml", from.date(), from_time, until.date(), until_time, cpl_id);
+	ref = dcp::compose("KDM_Cinema_B_-_Screen_X_-_my_great_film_-_%1_%2_-_%3_%4_-_%5.xml", from.date(), from_time, until.date(), until_time, cpl_id);
 #endif
 	BOOST_CHECK_MESSAGE (boost::filesystem::exists(base / dir_b / ref), "File " << ref << " not found");
 
 #ifdef DCPOMATIC_WINDOWS
-	ref = String::compose("KDM_Cinema_A_-_Screen_1_-_my_great_film_-_%1_%2_-_%3_%4.xml", from.date(), from_time, until.date(), until_time);
+	ref = dcp::compose("KDM_Cinema_A_-_Screen_1_-_my_great_film_-_%1_%2_-_%3_%4.xml", from.date(), from_time, until.date(), until_time);
 #else
-	ref = String::compose("KDM_Cinema_A_-_Screen_1_-_my_great_film_-_%1_%2_-_%3_%4_-_%5.xml", from.date(), from_time, until.date(), until_time, cpl_id);
+	ref = dcp::compose("KDM_Cinema_A_-_Screen_1_-_my_great_film_-_%1_%2_-_%3_%4_-_%5.xml", from.date(), from_time, until.date(), until_time, cpl_id);
 #endif
 	BOOST_CHECK_MESSAGE (boost::filesystem::exists(base / dir_a / ref), "File " << ref << " not found");
 
 #ifdef DCPOMATIC_WINDOWS
-	ref = String::compose("KDM_Cinema_B_-_Screen_Z_-_my_great_film_-_%1_%2_-_%3_%4.xml", from.date(), from_time, until.date(), until_time);
+	ref = dcp::compose("KDM_Cinema_B_-_Screen_Z_-_my_great_film_-_%1_%2_-_%3_%4.xml", from.date(), from_time, until.date(), until_time);
 #else
-	ref = String::compose("KDM_Cinema_B_-_Screen_Z_-_my_great_film_-_%1_%2_-_%3_%4_-_%5.xml", from.date(), from_time, until.date(), until_time, cpl_id);
+	ref = dcp::compose("KDM_Cinema_B_-_Screen_Z_-_my_great_film_-_%1_%2_-_%3_%4_-_%5.xml", from.date(), from_time, until.date(), until_time, cpl_id);
 #endif
 	BOOST_CHECK_MESSAGE (boost::filesystem::exists(base / dir_b / ref), "File " << ref << " not found");
 }
diff --git a/test/markers_test.cc b/test/markers_test.cc
index 844f25660..a2d581423 100644
--- a/test/markers_test.cc
+++ b/test/markers_test.cc
@@ -51,7 +51,7 @@ BOOST_AUTO_TEST_CASE (automatic_ffoc_lfoc_markers_test1)
 	film->set_interop (false);
 	make_and_verify_dcp (film);
 
-	dcp::DCP dcp (String::compose("build/test/%1/%2", name, film->dcp_name()));
+	dcp::DCP dcp (dcp::compose("build/test/%1/%2", name, film->dcp_name()));
 	dcp.read ();
 	BOOST_REQUIRE_EQUAL (dcp.cpls().size(), 1U);
 	auto cpl = dcp.cpls().front();
@@ -87,7 +87,7 @@ BOOST_AUTO_TEST_CASE (automatic_ffoc_lfoc_markers_test2)
 			dcp::VerificationNote::Code::INCORRECT_LFOC
 		});
 
-	dcp::DCP dcp (String::compose("build/test/%1/%2", name, film->dcp_name()));
+	dcp::DCP dcp (dcp::compose("build/test/%1/%2", name, film->dcp_name()));
 	dcp.read ();
 	BOOST_REQUIRE_EQUAL (dcp.cpls().size(), 1U);
 	auto cpl = dcp.cpls().front();
diff --git a/test/player_test.cc b/test/player_test.cc
index c325537fa..08fa5eb18 100644
--- a/test/player_test.cc
+++ b/test/player_test.cc
@@ -38,9 +38,9 @@
 #include "lib/dcp_content.h"
 #include "lib/text_content.h"
 #include "lib/butler.h"
-#include "lib/compose.hpp"
 #include "lib/cross.h"
 #include "test.h"
+#include <dcp/compose.h>
 #include <boost/test/unit_test.hpp>
 #include <boost/algorithm/string.hpp>
 #include <iostream>
@@ -242,12 +242,12 @@ BOOST_AUTO_TEST_CASE (player_seek_test)
 		butler->seek (t, true);
 		auto video = butler->get_video(true, 0);
 		BOOST_CHECK_EQUAL(video.second.get(), t.get());
-		write_image(video.first->image(bind(PlayerVideo::force, _1, AV_PIX_FMT_RGB24), VideoRange::FULL, false, true), String::compose("build/test/player_seek_test_%1.png", i));
+		write_image(video.first->image(bind(PlayerVideo::force, _1, AV_PIX_FMT_RGB24), VideoRange::FULL, false, true), dcp::compose("build/test/player_seek_test_%1.png", i));
 		/* This 14.08 is empirically chosen (hopefully) to accept changes in rendering between the reference and a test machine
 		   (17.10 and 16.04 seem to anti-alias a little differently) but to reject gross errors e.g. missing fonts or missing
 		   text altogether.
 		*/
-		check_image(TestPaths::private_data() / String::compose("player_seek_test_%1.png", i), String::compose("build/test/player_seek_test_%1.png", i), 14.08);
+		check_image(TestPaths::private_data() / dcp::compose("player_seek_test_%1.png", i), dcp::compose("build/test/player_seek_test_%1.png", i), 14.08);
 	}
 }
 
@@ -277,9 +277,9 @@ BOOST_AUTO_TEST_CASE (player_seek_test2)
 		auto video = butler->get_video(true, 0);
 		BOOST_CHECK_EQUAL(video.second.get(), t.get());
 		write_image(
-			video.first->image(bind(PlayerVideo::force, _1, AV_PIX_FMT_RGB24), VideoRange::FULL, false, true), String::compose("build/test/player_seek_test2_%1.png", i)
+			video.first->image(bind(PlayerVideo::force, _1, AV_PIX_FMT_RGB24), VideoRange::FULL, false, true), dcp::compose("build/test/player_seek_test2_%1.png", i)
 			);
-		check_image(TestPaths::private_data() / String::compose("player_seek_test2_%1.png", i), String::compose("build/test/player_seek_test2_%1.png", i), 14.08);
+		check_image(TestPaths::private_data() / dcp::compose("player_seek_test2_%1.png", i), dcp::compose("build/test/player_seek_test2_%1.png", i), 14.08);
 	}
 }
 
diff --git a/test/subtitle_language_test.cc b/test/subtitle_language_test.cc
index e198b78f9..2ee0da336 100644
--- a/test/subtitle_language_test.cc
+++ b/test/subtitle_language_test.cc
@@ -56,7 +56,7 @@ BOOST_AUTO_TEST_CASE (subtitle_language_interop_test)
 			dcp::VerificationNote::Code::INVALID_SUBTITLE_DURATION
 		});
 
-	check_dcp (String::compose("test/data/%1", name), String::compose("build/test/%1/%2", name, film->dcp_name()));
+	check_dcp (dcp::compose("test/data/%1", name), dcp::compose("build/test/%1/%2", name, film->dcp_name()));
 }
 
 
@@ -79,6 +79,6 @@ BOOST_AUTO_TEST_CASE (subtitle_language_smpte_test)
 			dcp::VerificationNote::Code::MISSING_CPL_METADATA
 		});
 
-	check_dcp (String::compose("test/data/%1", name), String::compose("build/test/%1/%2", name, film->dcp_name()));
+	check_dcp (dcp::compose("test/data/%1", name), dcp::compose("build/test/%1/%2", name, film->dcp_name()));
 }
 
diff --git a/test/test.cc b/test/test.cc
index 4dab0cff1..7720fa3b7 100644
--- a/test/test.cc
+++ b/test/test.cc
@@ -25,7 +25,6 @@
  */
 
 
-#include "lib/compose.hpp"
 #include "lib/config.h"
 #include "lib/cross.h"
 #include "lib/dcp_content_type.h"
@@ -42,6 +41,7 @@
 #include "lib/signal_manager.h"
 #include "lib/util.h"
 #include "test.h"
+#include <dcp/compose.h>
 #include <dcp/cpl.h>
 #include <dcp/dcp.h>
 #include <dcp/mono_picture_asset.h>
@@ -754,7 +754,7 @@ write_image (shared_ptr<const Image> image, boost::filesystem::path file)
 void
 check_ffmpeg (boost::filesystem::path ref, boost::filesystem::path check, int audio_tolerance)
 {
-	int const r = system (String::compose("ffcmp -t %1 %2 %3", audio_tolerance, ref.string(), check.string()).c_str());
+	int const r = system (dcp::compose("ffcmp -t %1 %2 %3", audio_tolerance, ref.string(), check.string()).c_str());
 	BOOST_REQUIRE_EQUAL (WEXITSTATUS(r), 0);
 }
 
diff --git a/test/threed_test.cc b/test/threed_test.cc
index f98464fb5..06d05c1d8 100644
--- a/test/threed_test.cc
+++ b/test/threed_test.cc
@@ -201,7 +201,7 @@ BOOST_AUTO_TEST_CASE (threed_test7)
 		}
 	}
 	BOOST_REQUIRE (failed);
-	BOOST_CHECK_EQUAL (failed->error_summary(), String::compose("The content file %1 is set as 3D but does not appear to contain 3D images.  Please set it to 2D.  You can still make a 3D DCP from this content by ticking the 3D option in the DCP video tab.", content_path.string()));
+	BOOST_CHECK_EQUAL (failed->error_summary(), dcp::compose("The content file %1 is set as 3D but does not appear to contain 3D images.  Please set it to 2D.  You can still make a 3D DCP from this content by ticking the 3D option in the DCP video tab.", content_path.string()));
 
 	while (signal_manager->ui_idle ()) {}