Hand-apply bbfb370d7de28ec1e8f307865cc6253bb5d4366e from master; quicker digest calculation.

27 files changed, 103 insertions, 111 deletions

diff --git a/src/lib/audio_content.cc b/src/lib/audio_content.cc
index 61357c60f..9909e3a08 100644
--- a/src/lib/audio_content.cc
+++ b/src/lib/audio_content.cc
@@ -181,7 +181,7 @@ AudioContent::audio_analysis_path () const
 	}
 
 	boost::filesystem::path p = film->audio_analysis_dir ();
-	p /= digest().get_value_or ("X") + "_" + audio_mapping().digest();
+	p /= digest() + "_" + audio_mapping().digest();
 	return p;
 }
 
diff --git a/src/lib/content.cc b/src/lib/content.cc
index a8d058cc1..550a8cd05 100644
--- a/src/lib/content.cc
+++ b/src/lib/content.cc
@@ -88,7 +88,7 @@ Content::Content (shared_ptr<const Film> f, cxml::ConstNodePtr node)
 	for (list<cxml::NodePtr>::const_iterator i = path_children.begin(); i != path_children.end(); ++i) {
 		_paths.push_back ((*i)->content ());
 	}
-	_digest = node->optional_string_child ("Digest");
+	_digest = node->optional_string_child ("Digest").get_value_or ("X");
 	_position = DCPTime (node->number_child<double> ("Position"));
 	_trim_start = DCPTime (node->number_child<double> ("TrimStart"));
 	_trim_end = DCPTime (node->number_child<double> ("TrimEnd"));
@@ -124,21 +124,15 @@ Content::as_xml (xmlpp::Node* node) const
 	for (vector<boost::filesystem::path>::const_iterator i = _paths.begin(); i != _paths.end(); ++i) {
 		node->add_child("Path")->add_child_text (i->string ());
 	}
-	if (_digest) {
-		node->add_child("Digest")->add_child_text (_digest.get ());
-	}
+	node->add_child("Digest")->add_child_text (_digest);
 	node->add_child("Position")->add_child_text (raw_convert<string> (_position.get ()));
 	node->add_child("TrimStart")->add_child_text (raw_convert<string> (_trim_start.get ()));
 	node->add_child("TrimEnd")->add_child_text (raw_convert<string> (_trim_end.get ()));
 }
 
 void
-Content::examine (shared_ptr<Job> job, bool calculate_digest)
+Content::examine (shared_ptr<Job> job)
 {
-	if (!calculate_digest) {
-		return;
-	}
-
 	if (job) {
 		job->sub (_("Computing digest"));
 	}
@@ -146,8 +140,12 @@ Content::examine (shared_ptr<Job> job, bool calculate_digest)
 	boost::mutex::scoped_lock lm (_mutex);
 	vector<boost::filesystem::path> p = _paths;
 	lm.unlock ();
-	
-	string const d = md5_digest (p, job);
+
+	/* Some content files are very big, so we use a poor's
+	   digest here: a MD5 of the first and last 1e6 bytes with the
+	   size of the first file tacked on the end as a string.
+	*/
+	string const d = md5_digest_head_tail (p, 1000000) + dcp::raw_convert<string> (boost::filesystem::file_size (p.front ()));
 
 	lm.lock ();
 	_digest = d;
@@ -220,7 +218,7 @@ Content::clone () const
 string
 Content::technical_summary () const
 {
-	return String::compose ("%1 %2 %3", path_summary(), digest().get_value_or("X"), position().seconds());
+	return String::compose ("%1 %2 %3", path_summary(), digest(), position().seconds());
 }
 
 DCPTime
@@ -237,7 +235,7 @@ Content::identifier () const
 {
 	SafeStringStream s;
 	
-	s << Content::digest().get_value_or("X")
+	s << Content::digest()
 	  << "_" << position().get()
 	  << "_" << trim_start().get()
 	  << "_" << trim_end().get();
diff --git a/src/lib/content.h b/src/lib/content.h
index a3e6da988..c6cede5fa 100644
--- a/src/lib/content.h
+++ b/src/lib/content.h
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2013-2014 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2013-2015 Carl Hetherington <cth@carlh.net>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -66,9 +66,8 @@ public:
 	/** Examine the content to establish digest, frame rates and any other
 	 *  useful metadata.
 	 *  @param job Job to use to report progress, or 0.
-	 *  @param calculate_digest True to calculate a digest for the content's file(s).
 	 */
-	virtual void examine (boost::shared_ptr<Job> job, bool calculate_digest);
+	virtual void examine (boost::shared_ptr<Job> job);
 	
 	/** @return Quick one-line summary of the content, as will be presented in the
 	 *  film editor.
@@ -107,8 +106,11 @@ public:
 	
 	bool paths_valid () const;
 
-	/** @return MD5 digest of the content's file(s) */
-	boost::optional<std::string> digest () const {
+       /** @return Digest of the content's file(s).  Note: this is
+        *  not a complete MD5-or-whatever hash, but a sort of poor
+        *  man' version (see comments in ::examine).
+        */
+	std::string digest () const {
 		boost::mutex::scoped_lock lm (_mutex);
 		return _digest;
 	}
@@ -167,7 +169,7 @@ protected:
 	std::vector<boost::filesystem::path> _paths;
 	
 private:
-	boost::optional<std::string> _digest;
+	std::string _digest;
 	DCPTime _position;
 	DCPTime _trim_start;
 	DCPTime _trim_end;
diff --git a/src/lib/dcp_content.cc b/src/lib/dcp_content.cc
index 2bf14dcff..d1a658001 100644
--- a/src/lib/dcp_content.cc
+++ b/src/lib/dcp_content.cc
@@ -77,12 +77,12 @@ DCPContent::read_directory (boost::filesystem::path p)
 }
 
 void
-DCPContent::examine (shared_ptr<Job> job, bool calculate_digest)
+DCPContent::examine (shared_ptr<Job> job)
 {
 	bool const could_be_played = can_be_played ();
 		
 	job->set_progress_unknown ();
-	Content::examine (job, calculate_digest);
+	Content::examine (job);
 	
 	shared_ptr<DCPExaminer> examiner (new DCPExaminer (shared_from_this ()));
 	take_from_video_examiner (examiner);
diff --git a/src/lib/dcp_content.h b/src/lib/dcp_content.h
index 82f5a8089..aa53d76a9 100644
--- a/src/lib/dcp_content.h
+++ b/src/lib/dcp_content.h
@@ -52,7 +52,7 @@ public:
 
 	DCPTime full_length () const;
 	
-	void examine (boost::shared_ptr<Job>, bool calculate_digest);
+	void examine (boost::shared_ptr<Job>);
 	std::string summary () const;
 	std::string technical_summary () const;
 	void as_xml (xmlpp::Node *) const;
diff --git a/src/lib/dcp_subtitle_content.cc b/src/lib/dcp_subtitle_content.cc
index 45c4be9b2..9f2ff61c5 100644
--- a/src/lib/dcp_subtitle_content.cc
+++ b/src/lib/dcp_subtitle_content.cc
@@ -47,9 +47,9 @@ DCPSubtitleContent::DCPSubtitleContent (shared_ptr<const Film> film, cxml::Const
 }
 
 void
-DCPSubtitleContent::examine (shared_ptr<Job> job, bool calculate_digest)
+DCPSubtitleContent::examine (shared_ptr<Job> job)
 {
-	Content::examine (job, calculate_digest);
+	Content::examine (job);
 
 	shared_ptr<dcp::SubtitleContent> sc = load (path (0));
 	
diff --git a/src/lib/dcp_subtitle_content.h b/src/lib/dcp_subtitle_content.h
index 4b5f1fa05..05af71690 100644
--- a/src/lib/dcp_subtitle_content.h
+++ b/src/lib/dcp_subtitle_content.h
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2014 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2014-2015 Carl Hetherington <cth@carlh.net>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -27,7 +27,7 @@ public:
 	DCPSubtitleContent (boost::shared_ptr<const Film>, cxml::ConstNodePtr, int);
 
 	/* Content */
-	void examine (boost::shared_ptr<Job>, bool calculate_digest);
+	void examine (boost::shared_ptr<Job>);
 	std::string summary () const;
 	std::string technical_summary () const;
 	void as_xml (xmlpp::Node *) const;
diff --git a/src/lib/examine_content_job.cc b/src/lib/examine_content_job.cc
index ee887271f..2b8f118f8 100644
--- a/src/lib/examine_content_job.cc
+++ b/src/lib/examine_content_job.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2012 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2012-2015 Carl Hetherington <cth@carlh.net>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -29,10 +29,9 @@ using std::string;
 using std::cout;
 using boost::shared_ptr;
 
-ExamineContentJob::ExamineContentJob (shared_ptr<const Film> f, shared_ptr<Content> c, bool calculate_digest)
+ExamineContentJob::ExamineContentJob (shared_ptr<const Film> f, shared_ptr<Content> c)
 	: Job (f)
 	, _content (c)
-	, _calculate_digest (calculate_digest)
 {
 
 }
@@ -50,7 +49,7 @@ ExamineContentJob::name () const
 void
 ExamineContentJob::run ()
 {
-	_content->examine (shared_from_this (), _calculate_digest);
+	_content->examine (shared_from_this ());
 	set_progress (1);
 	set_state (FINISHED_OK);
 }
diff --git a/src/lib/examine_content_job.h b/src/lib/examine_content_job.h
index e59dba0b8..016a56371 100644
--- a/src/lib/examine_content_job.h
+++ b/src/lib/examine_content_job.h
@@ -26,7 +26,7 @@ class Log;
 class ExamineContentJob : public Job
 {
 public:
-	ExamineContentJob (boost::shared_ptr<const Film>, boost::shared_ptr<Content>, bool calculate_digest);
+	ExamineContentJob (boost::shared_ptr<const Film>, boost::shared_ptr<Content>);
 	~ExamineContentJob ();
 
 	std::string name () const;
@@ -34,6 +34,5 @@ public:
 
 private:
 	boost::shared_ptr<Content> _content;
-	bool _calculate_digest;
 };
 
diff --git a/src/lib/ffmpeg_content.cc b/src/lib/ffmpeg_content.cc
index d5fd592d6..9e9473935 100644
--- a/src/lib/ffmpeg_content.cc
+++ b/src/lib/ffmpeg_content.cc
@@ -163,11 +163,11 @@ FFmpegContent::as_xml (xmlpp::Node* node) const
 }
 
 void
-FFmpegContent::examine (shared_ptr<Job> job, bool calculate_digest)
+FFmpegContent::examine (shared_ptr<Job> job)
 {
 	job->set_progress_unknown ();
 
-	Content::examine (job, calculate_digest);
+	Content::examine (job);
 
 	shared_ptr<FFmpegExaminer> examiner (new FFmpegExaminer (shared_from_this (), job));
 	take_from_video_examiner (examiner);
@@ -367,7 +367,7 @@ FFmpegContent::audio_analysis_path () const
 	*/
 
 	boost::filesystem::path p = film->audio_analysis_dir ();
-	string name = digest().get_value_or ("X");
+	string name = digest();
 	if (audio_stream ()) {
 		name += "_" + audio_stream()->identifier ();
 	}
diff --git a/src/lib/ffmpeg_content.h b/src/lib/ffmpeg_content.h
index 2831c2acf..76ba43567 100644
--- a/src/lib/ffmpeg_content.h
+++ b/src/lib/ffmpeg_content.h
@@ -56,7 +56,7 @@ public:
 		return boost::dynamic_pointer_cast<FFmpegContent> (Content::shared_from_this ());
 	}
 	
-	void examine (boost::shared_ptr<Job>, bool calculate_digest);
+	void examine (boost::shared_ptr<Job>);
 	std::string summary () const;
 	std::string technical_summary () const;
 	void as_xml (xmlpp::Node *) const;
diff --git a/src/lib/film.cc b/src/lib/film.cc
index 82add67c5..ecc98d7dc 100644
--- a/src/lib/film.cc
+++ b/src/lib/film.cc
@@ -952,20 +952,20 @@ Film::content () const
 }
 
 void
-Film::examine_content (shared_ptr<Content> c, bool calculate_digest)
+Film::examine_content (shared_ptr<Content> c)
 {
-	shared_ptr<Job> j (new ExamineContentJob (shared_from_this(), c, calculate_digest));
+	shared_ptr<Job> j (new ExamineContentJob (shared_from_this(), c));
 	JobManager::instance()->add (j);
 }
 
 void
-Film::examine_and_add_content (shared_ptr<Content> c, bool calculate_digest)
+Film::examine_and_add_content (shared_ptr<Content> c)
 {
 	if (dynamic_pointer_cast<FFmpegContent> (c)) {
 		run_ffprobe (c->path(0), file ("ffprobe.log"), _log);
 	}
 			
-	shared_ptr<Job> j (new ExamineContentJob (shared_from_this(), c, calculate_digest));
+	shared_ptr<Job> j (new ExamineContentJob (shared_from_this(), c));
 	j->Finished.connect (bind (&Film::maybe_add_content, this, boost::weak_ptr<Job> (j), boost::weak_ptr<Content> (c)));
 	JobManager::instance()->add (j);
 }
diff --git a/src/lib/film.h b/src/lib/film.h
index 43f7bae78..2de065159 100644
--- a/src/lib/film.h
+++ b/src/lib/film.h
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2012-2014 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2012-2015 Carl Hetherington <cth@carlh.net>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -252,8 +252,8 @@ public:
 	void set_directory (boost::filesystem::path);
 	void set_name (std::string);
 	void set_use_isdcf_name (bool);
-	void examine_content (boost::shared_ptr<Content>, bool calculate_digest);
-	void examine_and_add_content (boost::shared_ptr<Content>, bool calculate_digest);
+	void examine_content (boost::shared_ptr<Content>);
+	void examine_and_add_content (boost::shared_ptr<Content>);
 	void add_content (boost::shared_ptr<Content>);
 	void remove_content (boost::shared_ptr<Content>);
 	void move_content_earlier (boost::shared_ptr<Content>);
diff --git a/src/lib/image_content.cc b/src/lib/image_content.cc
index b8d2a6921..1dbd7871b 100644
--- a/src/lib/image_content.cc
+++ b/src/lib/image_content.cc
@@ -100,9 +100,9 @@ ImageContent::as_xml (xmlpp::Node* node) const
 }
 
 void
-ImageContent::examine (shared_ptr<Job> job, bool calculate_digest)
+ImageContent::examine (shared_ptr<Job> job)
 {
-	Content::examine (job, calculate_digest);
+	Content::examine (job);
 
 	shared_ptr<const Film> film = _film.lock ();
 	DCPOMATIC_ASSERT (film);
diff --git a/src/lib/image_content.h b/src/lib/image_content.h
index 8c50fd8a8..38aa77bf5 100644
--- a/src/lib/image_content.h
+++ b/src/lib/image_content.h
@@ -37,7 +37,7 @@ public:
 		return boost::dynamic_pointer_cast<ImageContent> (Content::shared_from_this ());
 	};
 
-	void examine (boost::shared_ptr<Job>, bool calculate_digest);
+	void examine (boost::shared_ptr<Job>);
 	std::string summary () const;
 	std::string technical_summary () const;
 	void as_xml (xmlpp::Node *) const;
diff --git a/src/lib/sndfile_content.cc b/src/lib/sndfile_content.cc
index e0b7cc10c..e757c77c5 100644
--- a/src/lib/sndfile_content.cc
+++ b/src/lib/sndfile_content.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2013-2014 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2013-2015 Carl Hetherington <cth@carlh.net>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -82,10 +82,10 @@ SndfileContent::valid_file (boost::filesystem::path f)
 }
 
 void
-SndfileContent::examine (shared_ptr<Job> job, bool calculate_digest)
+SndfileContent::examine (shared_ptr<Job> job)
 {
 	job->set_progress_unknown ();
-	Content::examine (job, calculate_digest);
+	Content::examine (job);
 	shared_ptr<AudioExaminer> dec (new SndfileDecoder (shared_from_this()));
 	take_from_audio_examiner (dec);
 }
diff --git a/src/lib/sndfile_content.h b/src/lib/sndfile_content.h
index 1fff01f60..1bac51167 100644
--- a/src/lib/sndfile_content.h
+++ b/src/lib/sndfile_content.h
@@ -41,7 +41,7 @@ public:
 	
 	DCPTime full_length () const;
 	
-	void examine (boost::shared_ptr<Job>, bool calculate_digest);
+	void examine (boost::shared_ptr<Job>);
 	std::string summary () const;
 	std::string technical_summary () const;
 	std::string information () const;
diff --git a/src/lib/subrip_content.cc b/src/lib/subrip_content.cc
index 819bca321..fc0637bfd 100644
--- a/src/lib/subrip_content.cc
+++ b/src/lib/subrip_content.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2014 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2014-2015 Carl Hetherington <cth@carlh.net>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -50,9 +50,9 @@ SubRipContent::SubRipContent (shared_ptr<const Film> film, cxml::ConstNodePtr no
 }
 
 void
-SubRipContent::examine (boost::shared_ptr<Job> job, bool calculate_digest)
+SubRipContent::examine (boost::shared_ptr<Job> job)
 {
-	Content::examine (job, calculate_digest);
+	Content::examine (job);
 	SubRip s (shared_from_this ());
 
 	shared_ptr<const Film> film = _film.lock ();
diff --git a/src/lib/subrip_content.h b/src/lib/subrip_content.h
index 4321ecb6a..e63526179 100644
--- a/src/lib/subrip_content.h
+++ b/src/lib/subrip_content.h
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2014 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2014-2015 Carl Hetherington <cth@carlh.net>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -30,7 +30,7 @@ public:
 	}
 	
 	/* Content */
-	void examine (boost::shared_ptr<Job>, bool calculate_digest);
+	void examine (boost::shared_ptr<Job>);
 	std::string summary () const;
 	std::string technical_summary () const;
 	void as_xml (xmlpp::Node *) const;
diff --git a/src/lib/util.cc b/src/lib/util.cc
index c0e32b778..0a6f381db 100644
--- a/src/lib/util.cc
+++ b/src/lib/util.cc
@@ -417,45 +417,53 @@ dcpomatic_setup_gettext_i18n (string lang)
 #endif
 }
 
-/** @param job Optional job for which to report progress */
+/** Compute a digest of the first and last `size' bytes of a set of files. */
 string
-md5_digest (vector<boost::filesystem::path> files, shared_ptr<Job> job)
+md5_digest_head_tail (vector<boost::filesystem::path> files, boost::uintmax_t size)
 {
-	boost::uintmax_t const buffer_size = 64 * 1024;
-	char buffer[buffer_size];
-
+	boost::scoped_array<char> buffer (new char[size]);
 	MD5Digester digester;
 
-	vector<int64_t> sizes;
-	for (size_t i = 0; i < files.size(); ++i) {
-		sizes.push_back (boost::filesystem::file_size (files[i]));
-	}
-
-	for (size_t i = 0; i < files.size(); ++i) {
+	/* Head */
+	boost::uintmax_t to_do = size;
+	char* p = buffer.get ();
+	int i = 0;
+	while (i < int64_t (files.size()) && to_do > 0) {
 		FILE* f = fopen_boost (files[i], "rb");
 		if (!f) {
 			throw OpenFileError (files[i].string());
 		}
 
-		boost::uintmax_t const bytes = boost::filesystem::file_size (files[i]);
-		boost::uintmax_t remaining = bytes;
-
-		while (remaining > 0) {
-			int const t = min (remaining, buffer_size);
-			int const r = fread (buffer, 1, t, f);
-			if (r != t) {
-				throw ReadFileError (files[i], errno);
-			}
-			digester.add (buffer, t);
-			remaining -= t;
-
-			if (job) {
-				job->set_progress ((float (i) + 1 - float(remaining) / bytes) / files.size ());
-			}
+		boost::uintmax_t this_time = min (to_do, boost::filesystem::file_size (files[i]));
+		fread (p, 1, this_time, f);
+		p += this_time;
+ 		to_do -= this_time;
+		fclose (f);
+
+		++i;
+	}
+	digester.add (buffer.get(), size - to_do);
+
+	/* Tail */
+	to_do = size;
+	p = buffer.get ();
+	i = files.size() - 1;
+	while (i >= 0 && to_do > 0) {
+		FILE* f = fopen_boost (files[i], "rb");
+		if (!f) {
+			throw OpenFileError (files[i].string());
 		}
 
+		boost::uintmax_t this_time = min (to_do, boost::filesystem::file_size (files[i]));
+		fseek (f, -this_time, SEEK_END);
+		fread (p, 1, this_time, f);
+		p += this_time;
+		to_do -= this_time;
 		fclose (f);
-	}
+
+		--i;
+	}		
+	digester.add (buffer.get(), size - to_do);
 
 	return digester.get ();
 }
diff --git a/src/lib/util.h b/src/lib/util.h
index b06c8a58b..ee2865e76 100644
--- a/src/lib/util.h
+++ b/src/lib/util.h
@@ -61,7 +61,7 @@ extern std::string dependency_version_summary ();
 extern double seconds (struct timeval);
 extern void dcpomatic_setup ();
 extern void dcpomatic_setup_gettext_i18n (std::string);
-extern std::string md5_digest (std::vector<boost::filesystem::path>, boost::shared_ptr<Job>);
+extern std::string md5_digest_head_tail (std::vector<boost::filesystem::path>, boost::uintmax_t size);
 extern void ensure_ui_thread ();
 extern std::string audio_channel_name (int);
 extern bool valid_image_file (boost::filesystem::path);
diff --git a/src/tools/dcpomatic.cc b/src/tools/dcpomatic.cc
index 614073947..e929f185d 100644
--- a/src/tools/dcpomatic.cc
+++ b/src/tools/dcpomatic.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2012-2014 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2012-2015 Carl Hetherington <cth@carlh.net>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -810,7 +810,7 @@ class App : public wxApp
 		if (!_film_to_create.empty ()) {
 			_frame->new_film (_film_to_create);
 			if (!_content_to_add.empty ()) {
-				_frame->film()->examine_and_add_content (content_factory (_frame->film(), _content_to_add), true);
+				_frame->film()->examine_and_add_content (content_factory (_frame->film(), _content_to_add));
 			}
 		}
 
@@ -903,7 +903,7 @@ class App : public wxApp
 			dialog->Destroy ();
 		} else if (uc->state() == UpdateChecker::FAILED) {
 			if (!UpdateChecker::instance()->last_emit_was_first ()) {
-				error_dialog (_frame, _("The DCP-o-matic download server could not be contaced."));
+				error_dialog (_frame, _("The DCP-o-matic download server could not be contacted."));
 			}
 		} else {
 			if (!UpdateChecker::instance()->last_emit_was_first ()) {
diff --git a/src/tools/dcpomatic_create.cc b/src/tools/dcpomatic_create.cc
index 6e8f16888..304f4f697 100644
--- a/src/tools/dcpomatic_create.cc
+++ b/src/tools/dcpomatic_create.cc
@@ -178,7 +178,7 @@ main (int argc, char* argv[])
 			if (vc) {
 				vc->set_scale (VideoContentScale (content_ratio));
 			}
-			film->examine_and_add_content (c, true);
+			film->examine_and_add_content (c);
 		}
 		
 		JobManager* jm = JobManager::instance ();
diff --git a/src/wx/content_menu.cc b/src/wx/content_menu.cc
index 15a234184..3bdaf2591 100644
--- a/src/wx/content_menu.cc
+++ b/src/wx/content_menu.cc
@@ -207,7 +207,7 @@ ContentMenu::find_missing ()
 		return;
 	}
 
-	shared_ptr<Job> j (new ExamineContentJob (film, content, true));
+	shared_ptr<Job> j (new ExamineContentJob (film, content));
 	
 	j->Finished.connect (
 		bind (
@@ -231,7 +231,7 @@ ContentMenu::re_examine ()
 	}
 
 	for (ContentList::iterator i = _content.begin(); i != _content.end(); ++i) {
-		film->examine_content (*i, true);
+		film->examine_content (*i);
 	}
 }
 
@@ -269,7 +269,7 @@ ContentMenu::kdm ()
 		dcp->add_kdm (dcp::EncryptedKDM (dcp::file_to_string (wx_to_std (d->GetPath ()))));
 		shared_ptr<Film> film = _film.lock ();
 		DCPOMATIC_ASSERT (film);
-		film->examine_content (dcp, true);
+		film->examine_content (dcp);
 	}
 	
 	d->Destroy ();
diff --git a/src/wx/content_panel.cc b/src/wx/content_panel.cc
index 4d73a608d..8bcf46f5c 100644
--- a/src/wx/content_panel.cc
+++ b/src/wx/content_panel.cc
@@ -248,7 +248,7 @@ ContentPanel::add_file_clicked ()
 	/* XXX: check for lots of files here and do something */
 
 	for (unsigned int i = 0; i < paths.GetCount(); ++i) {
-		_film->examine_and_add_content (content_factory (_film, wx_to_std (paths[i])), true);
+		_film->examine_and_add_content (content_factory (_film, wx_to_std (paths[i])));
 	}
 
 	d->Destroy ();
@@ -281,7 +281,7 @@ ContentPanel::add_folder_clicked ()
 	if (is_dcp) {
 		try {
 			shared_ptr<DCPContent> content (new DCPContent (_film, path));
-			_film->examine_and_add_content (content, true);
+			_film->examine_and_add_content (content);
 		} catch (...) {
 			error_dialog (_panel, _("Could not find a DCP in that folder."));
 		}
@@ -290,7 +290,6 @@ ContentPanel::add_folder_clicked ()
 		ImageSequenceDialog* e = new ImageSequenceDialog (_panel);
 		r = e->ShowModal ();
 		float const frame_rate = e->frame_rate ();
-		bool const digest = e->digest ();
 		e->Destroy ();
 
 		if (r != wxID_OK) {
@@ -302,7 +301,7 @@ ContentPanel::add_folder_clicked ()
 		try {
 			shared_ptr<ImageContent> content (new ImageContent (_film, path));
 			content->set_video_frame_rate (frame_rate);
-			_film->examine_and_add_content (content, digest);
+			_film->examine_and_add_content (content);
 		} catch (...) {
 			error_dialog (_panel, _("Could not find any images in that folder"));
 			return;
@@ -491,6 +490,6 @@ ContentPanel::files_dropped (wxDropFilesEvent& event)
 	
 	wxString* paths = event.GetFiles ();
 	for (int i = 0; i < event.GetNumberOfFiles(); i++) {
-		_film->examine_and_add_content (content_factory (_film, wx_to_std (paths[i])), true);
+		_film->examine_and_add_content (content_factory (_film, wx_to_std (paths[i])));
 	}
 }
diff --git a/src/wx/image_sequence_dialog.cc b/src/wx/image_sequence_dialog.cc
index f4491bda3..02602267c 100644
--- a/src/wx/image_sequence_dialog.cc
+++ b/src/wx/image_sequence_dialog.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2014 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2014-2015 Carl Hetherington <cth@carlh.net>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -28,11 +28,6 @@ ImageSequenceDialog::ImageSequenceDialog (wxWindow* parent)
 {
 	add (_("Frame rate"), true);
 	_frame_rate = add (new wxTextCtrl (this, wxID_ANY, N_("24")));
-	_digest = new wxCheckBox (this, wxID_ANY, _("Calculate digests"));
-	_digest->SetValue (true);
-	_digest->SetToolTip (_("By default DCP-o-matic will calculate digests (hashes) of your image files so that it knows if they change.  Turning this off will speed up import but you must not alter the image files after import or strange things may happen."));
-	add (_digest);
-
 	layout ();
 }
 
@@ -47,9 +42,3 @@ ImageSequenceDialog::frame_rate () const
 
 	return 0;
 }
-
-bool
-ImageSequenceDialog::digest () const
-{
-	return _digest->GetValue ();
-}
diff --git a/src/wx/image_sequence_dialog.h b/src/wx/image_sequence_dialog.h
index d3658b7b8..536ae6680 100644
--- a/src/wx/image_sequence_dialog.h
+++ b/src/wx/image_sequence_dialog.h
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2014 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2014-2015 Carl Hetherington <cth@carlh.net>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -26,9 +26,7 @@ public:
 	ImageSequenceDialog (wxWindow* parent);
 
 	float frame_rate () const;
-	bool digest () const;
 
 private:
 	wxTextCtrl* _frame_rate;
-	wxCheckBox* _digest;
 };