Merge branch 'main' into v2.17.x

20 files changed, 179 insertions, 48 deletions

diff --git a/cscript b/cscript
index af1db69a6..cee888420 100644
--- a/cscript
+++ b/cscript
@@ -38,6 +38,9 @@ for v in ['22.04']:
 for v in ['23.04', '23.10']:
     deb_build_depends[v] = copy.deepcopy(deb_build_depends_base)
     deb_build_depends[v].extend(['libssh-dev', 'python3.11'])
+for v in ['24.04']:
+    deb_build_depends[v] = copy.deepcopy(deb_build_depends_base)
+    deb_build_depends[v].extend(['libssh-dev', 'python3.12'])
 for v in ['9', '10']:
     deb_build_depends[v] = copy.deepcopy(deb_build_depends_base)
     deb_build_depends[v].extend(['libssh-gcrypt-dev', 'python'])
@@ -185,6 +188,30 @@ deb_depends['23.10'].extend(['libboost-filesystem1.74.0',
                              'libwxgtk3.2-1',
                              'libwxgtk-gl3.2-1'])
 
+def debs(boost, icu, x264):
+    output = copy.deepcopy(deb_depends_base)
+    output.extend(['libboost-filesystem' + boost,
+                   'libboost-thread' + boost,
+                   'libboost-regex' + boost,
+                   'libboost-date-time' + boost,
+                   'libcairomm-1.0-1v5',
+                   'libpangomm-1.4-1v5',
+                   'libxml++2.6-2v5',
+                   'libzip4',
+                   'libicu' + icu,
+                   'libnettle8',
+                   'libssh-4',
+                   'libx264-' + x264,
+                   'libcurl4',
+                   'libpulse0',
+                   'libxerces-c3.2',
+                   'libnanomsg5',
+                   'libwxgtk3.2-1',
+                   'libwxgtk-gl3.2-1'])
+    return output
+
+deb_depends['24.04'] = debs(boost='1.83.0', icu='74', x264='164')
+
 deb_depends['9'] = copy.deepcopy(deb_depends_base)
 deb_depends['9'].extend(['libboost-filesystem1.62.0',
                          'libboost-thread1.62.0',
@@ -731,7 +758,7 @@ def package_debian(target, cpu, version, options):
 
     target.set('CDIST_CONFIGURE', '"' + configure_options(target, options, for_package=True) + '"')
     target.set('CDIST_PACKAGE', f'dcpomatic{suffix}')
-    target.set('CDIST_WX_VERSION', "3.2" if target.version in ("23.04", "23.10") else "3.1")
+    target.set('CDIST_WX_VERSION', "3.2" if target.version in ("23.04", "23.10", "24.04") else "3.1")
     if not target.debug:
         target.set('CDIST_DEBUG_PACKAGE_FLAG', '--no-ddebs')
 
diff --git a/src/lib/dcp_content.cc b/src/lib/dcp_content.cc
index 378ba1882..c459a9ece 100644
--- a/src/lib/dcp_content.cc
+++ b/src/lib/dcp_content.cc
@@ -723,6 +723,14 @@ DCPContent::can_reference_audio (shared_ptr<const Film> film, string& why_not) c
 		return false;
 	}
 
+	if (audio && audio->stream()) {
+		auto const channels = audio->stream()->channels();
+		if (channels != film->audio_channels()) {
+			why_not = String::compose(_("it has a different number of audio channels than the project; set the project to have %1 channels."), channels);
+			return false;
+		}
+	}
+
 	auto part = [](shared_ptr<const Content> c) {
 		return static_cast<bool>(c->audio) && !c->audio->mapping().mapped_output_channels().empty();
 	};
diff --git a/src/lib/emailer.cc b/src/lib/email.cc
index f580e3c56..8557b40e0 100644
--- a/src/lib/emailer.cc
+++ b/src/lib/email.cc
@@ -21,7 +21,7 @@
 
 #include "compose.hpp"
 #include "config.h"
-#include "emailer.h"
+#include "email.h"
 #include "exceptions.h"
 #include <curl/curl.h>
 #include <boost/algorithm/string.hpp>
@@ -39,7 +39,7 @@ using std::vector;
 using dcp::ArrayData;
 
 
-Emailer::Emailer(string from, vector<string> to, string subject, string body)
+Email::Email(string from, vector<string> to, string subject, string body)
 	: _from (from)
 	, _to (to)
 	, _subject (subject)
@@ -51,7 +51,7 @@ Emailer::Emailer(string from, vector<string> to, string subject, string body)
 
 
 string
-Emailer::fix (string s) const
+Email::fix(string s) const
 {
 	boost::algorithm::replace_all (s, "\n", "\r\n");
 	boost::algorithm::replace_all (s, "\0", " ");
@@ -60,24 +60,24 @@ Emailer::fix (string s) const
 
 
 void
-Emailer::add_cc (string cc)
+Email::add_cc(string cc)
 {
 	_cc.push_back (cc);
 }
 
 
 void
-Emailer::add_bcc (string bcc)
+Email::add_bcc(string bcc)
 {
 	_bcc.push_back (bcc);
 }
 
 
 void
-Emailer::add_attachment (boost::filesystem::path file, string name, string mime_type)
+Email::add_attachment(boost::filesystem::path file, string name, string mime_type)
 {
 	Attachment a;
-	a.file = file;
+	a.file = dcp::ArrayData(file);
 	a.name = name;
 	a.mime_type = mime_type;
 	_attachments.push_back (a);
@@ -87,19 +87,19 @@ Emailer::add_attachment (boost::filesystem::path file, string name, string mime_
 static size_t
 curl_data_shim (void* ptr, size_t size, size_t nmemb, void* userp)
 {
-	return reinterpret_cast<Emailer*>(userp)->get_data (ptr, size, nmemb);
+	return reinterpret_cast<Email*>(userp)->get_data (ptr, size, nmemb);
 }
 
 
 static int
 curl_debug_shim (CURL* curl, curl_infotype type, char* data, size_t size, void* userp)
 {
-	return reinterpret_cast<Emailer*>(userp)->debug (curl, type, data, size);
+	return reinterpret_cast<Email*>(userp)->debug (curl, type, data, size);
 }
 
 
 size_t
-Emailer::get_data (void* ptr, size_t size, size_t nmemb)
+Email::get_data(void* ptr, size_t size, size_t nmemb)
 {
 	size_t const t = min (_email.length() - _offset, size * nmemb);
 	memcpy (ptr, _email.substr (_offset, t).c_str(), t);
@@ -109,7 +109,7 @@ Emailer::get_data (void* ptr, size_t size, size_t nmemb)
 
 
 void
-Emailer::send (string server, int port, EmailProtocol protocol, string user, string password)
+Email::send(string server, int port, EmailProtocol protocol, string user, string password)
 {
 	char date_buffer[128];
 	time_t now = time (0);
@@ -171,8 +171,7 @@ Emailer::send (string server, int port, EmailProtocol protocol, string user, str
 		}
 		bio = BIO_push (b64, bio);
 
-		ArrayData data (i.file);
-		BIO_write (bio, data.data(), data.size());
+		BIO_write(bio, i.file.data(), i.file.size());
 		(void) BIO_flush (bio);
 
 		char* out;
@@ -247,7 +246,7 @@ Emailer::send (string server, int port, EmailProtocol protocol, string user, str
 
 
 string
-Emailer::address_list(vector<string> addresses)
+Email::address_list(vector<string> addresses)
 {
 	string o;
 	for (auto i: addresses) {
@@ -259,7 +258,7 @@ Emailer::address_list(vector<string> addresses)
 
 
 int
-Emailer::debug (CURL *, curl_infotype type, char* data, size_t size)
+Email::debug(CURL *, curl_infotype type, char* data, size_t size)
 {
 	if (type == CURLINFO_TEXT) {
 		_notes += string (data, size);
@@ -273,7 +272,7 @@ Emailer::debug (CURL *, curl_infotype type, char* data, size_t size)
 
 
 string
-Emailer::encode_rfc1342 (string subject)
+Email::encode_rfc1342(string subject)
 {
 	auto b64 = BIO_new(BIO_f_base64());
 	if (!b64) {
diff --git a/src/lib/emailer.h b/src/lib/email.h
index 78942ad1e..36398bfd8 100644
--- a/src/lib/emailer.h
+++ b/src/lib/email.h
@@ -23,13 +23,14 @@
 #include <boost/scoped_array.hpp>
 
 
-class Emailer
+class Email
 {
 public:
-	Emailer(std::string from, std::vector<std::string> to, std::string subject, std::string body);
+	Email(std::string from, std::vector<std::string> to, std::string subject, std::string body);
 
 	void add_cc (std::string cc);
 	void add_bcc (std::string bcc);
+	/** Add attachment, copying the contents of the file into memory */
 	void add_attachment (boost::filesystem::path file, std::string name, std::string mime_type);
 
 	void send (std::string server, int port, EmailProtocol protocol, std::string user = "", std::string password = "");
@@ -61,7 +62,7 @@ private:
 	std::vector<std::string> _bcc;
 
 	struct Attachment {
-		boost::filesystem::path file;
+		dcp::ArrayData file;
 		std::string name;
 		std::string mime_type;
 	};
diff --git a/src/lib/kdm_cli.cc b/src/lib/kdm_cli.cc
index 4e3f9ccb7..e4fabe1a6 100644
--- a/src/lib/kdm_cli.cc
+++ b/src/lib/kdm_cli.cc
@@ -27,7 +27,7 @@
 #include "cinema.h"
 #include "config.h"
 #include "dkdm_wrapper.h"
-#include "emailer.h"
+#include "email.h"
 #include "exceptions.h"
 #include "film.h"
 #include "kdm_with_metadata.h"
@@ -609,7 +609,7 @@ try
 	if (list_cinemas) {
 		auto cinemas = Config::instance()->cinemas ();
 		for (auto i: cinemas) {
-			out (String::compose("%1 (%2)", i->name, Emailer::address_list (i->emails)));
+			out (String::compose("%1 (%2)", i->name, Email::address_list(i->emails)));
 		}
 		return {};
 	}
diff --git a/src/lib/kdm_with_metadata.cc b/src/lib/kdm_with_metadata.cc
index 10054f01e..f7ff84435 100644
--- a/src/lib/kdm_with_metadata.cc
+++ b/src/lib/kdm_with_metadata.cc
@@ -23,7 +23,7 @@
 #include "config.h"
 #include "cross.h"
 #include "dcpomatic_log.h"
-#include "emailer.h"
+#include "email.h"
 #include "kdm_with_metadata.h"
 #include "screen.h"
 #include "util.h"
@@ -238,14 +238,13 @@ send_emails (
 		auto subject = substitute_variables(config->kdm_subject());
 		auto body = substitute_variables(config->kdm_email());
 
-		string screens;
+		vector<string> screens;
 		for (auto kdm: kdms_for_cinema) {
-			auto screen_name = kdm->get('s');
-			if (screen_name) {
-				screens += *screen_name + ", ";
+			if (auto screen_name = kdm->get('s')) {
+				screens.push_back(*screen_name);
 			}
 		}
-		boost::algorithm::replace_all (body, "$SCREENS", screens.substr (0, screens.length() - 2));
+		boost::algorithm::replace_all(body, "$SCREENS", screen_names_to_string(screens));
 
 		auto emails = first->emails();
 		std::copy(extra_addresses.begin(), extra_addresses.end(), std::back_inserter(emails));
@@ -253,7 +252,7 @@ send_emails (
 			continue;
 		}
 
-		Emailer email (config->kdm_from(), { emails.front() }, subject, body);
+		Email email(config->kdm_from(), { emails.front() }, subject, body);
 
 		/* Use CC for the second and subsequent email addresses, so we seem less spammy (#2310) */
 		for (auto cc = std::next(emails.begin()); cc != emails.end(); ++cc) {
@@ -268,8 +267,9 @@ send_emails (
 		}
 
 		email.add_attachment (zip_file, container_name_format.get(first->name_values(), ".zip"), "application/zip");
+		dcp::filesystem::remove(zip_file);
 
-		auto log_details = [](Emailer& email) {
+		auto log_details = [](Email& email) {
 			dcpomatic_log->log("Email content follows", LogEntry::TYPE_DEBUG_EMAIL);
 			dcpomatic_log->log(email.email(), LogEntry::TYPE_DEBUG_EMAIL);
 			dcpomatic_log->log("Email session follows", LogEntry::TYPE_DEBUG_EMAIL);
@@ -279,13 +279,10 @@ send_emails (
 		try {
 			email.send (config->mail_server(), config->mail_port(), config->mail_protocol(), config->mail_user(), config->mail_password());
 		} catch (...) {
-			dcp::filesystem::remove(zip_file);
 			log_details (email);
 			throw;
 		}
 
 		log_details (email);
-
-		dcp::filesystem::remove(zip_file);
 	}
 }
diff --git a/src/lib/send_notification_email_job.cc b/src/lib/send_notification_email_job.cc
index f40e8fefa..a2f3016f9 100644
--- a/src/lib/send_notification_email_job.cc
+++ b/src/lib/send_notification_email_job.cc
@@ -22,7 +22,7 @@
 #include "send_notification_email_job.h"
 #include "exceptions.h"
 #include "config.h"
-#include "emailer.h"
+#include "email.h"
 #include "compose.hpp"
 
 #include "i18n.h"
@@ -71,7 +71,7 @@ SendNotificationEmailJob::run ()
 	}
 
 	set_progress_unknown ();
-	Emailer email (config->notification_from(), { config->notification_to() }, config->notification_subject(), _body);
+	Email email(config->notification_from(), { config->notification_to() }, config->notification_subject(), _body);
 	for (auto i: config->notification_cc()) {
 		email.add_cc (i);
 	}
diff --git a/src/lib/send_problem_report_job.cc b/src/lib/send_problem_report_job.cc
index 34822b156..9569aca3b 100644
--- a/src/lib/send_problem_report_job.cc
+++ b/src/lib/send_problem_report_job.cc
@@ -26,7 +26,7 @@
 #include "film.h"
 #include "log.h"
 #include "version.h"
-#include "emailer.h"
+#include "email.h"
 #include "environment_info.h"
 #include <libxml++/libxml++.h>
 
@@ -108,8 +108,8 @@ SendProblemReportJob::run ()
 		body += "---<8----\n";
 	}
 
-	Emailer emailer (_from, {"carl@dcpomatic.com"}, "DCP-o-matic problem report", body);
-	emailer.send ("main.carlh.net", 2525, EmailProtocol::STARTTLS);
+	Email email(_from, {"carl@dcpomatic.com"}, "DCP-o-matic problem report", body);
+	email.send("main.carlh.net", 2525, EmailProtocol::STARTTLS);
 
 	set_progress (1);
 	set_state (FINISHED_OK);
diff --git a/src/lib/util.cc b/src/lib/util.cc
index 01a7f0248..ef15b90e5 100644
--- a/src/lib/util.cc
+++ b/src/lib/util.cc
@@ -1120,7 +1120,6 @@ word_wrap(string input, int columns)
 }
 
 
-
 #ifdef DCPOMATIC_GROK
 void
 setup_grok_library_path()
@@ -1147,3 +1146,31 @@ setup_grok_library_path()
 	setenv("LD_LIBRARY_PATH", new_path.c_str(), 1);
 }
 #endif
+
+string
+screen_names_to_string(vector<string> names)
+{
+	if (names.empty()) {
+		return {};
+	}
+
+	auto number = [](string const& s) {
+		return s.find_first_not_of("0123456789") == string::npos;
+	};
+
+	if (std::find_if(names.begin(), names.end(), [number](string const& s) { return !number(s); }) == names.end()) {
+		std::sort(names.begin(), names.end(), [](string const& a, string const& b) {
+			return dcp::raw_convert<int>(a) < dcp::raw_convert<int>(b);
+		});
+	} else {
+		std::sort(names.begin(), names.end());
+	}
+
+	string result;
+	for (auto const& name: names) {
+		result += name + ", ";
+	}
+
+	return result.substr(0, result.length() - 2);
+}
+
diff --git a/src/lib/util.h b/src/lib/util.h
index b85cf0a33..4f64369d3 100644
--- a/src/lib/util.h
+++ b/src/lib/util.h
@@ -114,4 +114,6 @@ number_attribute(cxml::ConstNodePtr node, std::string name1, std::string name2)
 	return *value;
 }
 
+extern std::string screen_names_to_string(std::vector<std::string> names);
+
 #endif
diff --git a/src/lib/wscript b/src/lib/wscript
index 5bae3e0d1..878b503a8 100644
--- a/src/lib/wscript
+++ b/src/lib/wscript
@@ -87,7 +87,7 @@ sources = """
           dkdm_recipient.cc
           dkdm_wrapper.cc
           dolby_cp750.cc
-          emailer.cc
+          email.cc
           empty.cc
           encoder.cc
           encode_server.cc
diff --git a/src/tools/dcpomatic.cc b/src/tools/dcpomatic.cc
index f65037c2f..d516c6f5b 100644
--- a/src/tools/dcpomatic.cc
+++ b/src/tools/dcpomatic.cc
@@ -72,7 +72,7 @@
 #include "lib/dcpomatic_log.h"
 #include "lib/dcpomatic_socket.h"
 #include "lib/dkdm_wrapper.h"
-#include "lib/emailer.h"
+#include "lib/email.h"
 #include "lib/encode_server_finder.h"
 #include "lib/exceptions.h"
 #include "lib/ffmpeg_encoder.h"
@@ -1146,9 +1146,9 @@ private:
 			error_dialog (this, _("You must enter a valid email address when sending translations, "
 					      "otherwise the DCP-o-matic maintainers cannot credit you or contact you with questions."));
 		} else {
-			Emailer emailer(dialog.email(), { "carl@dcpomatic.com" }, "DCP-o-matic translations", body);
+			Email email(dialog.email(), { "carl@dcpomatic.com" }, "DCP-o-matic translations", body);
 			try {
-				emailer.send ("main.carlh.net", 2525, EmailProtocol::STARTTLS);
+				email.send("main.carlh.net", 2525, EmailProtocol::STARTTLS);
 			} catch (NetworkError& e) {
 				error_dialog (this, _("Could not send translations"), std_to_wx(e.what()));
 			}
diff --git a/src/wx/audio_panel.cc b/src/wx/audio_panel.cc
index d7deeec41..34923fb02 100644
--- a/src/wx/audio_panel.cc
+++ b/src/wx/audio_panel.cc
@@ -196,6 +196,7 @@ AudioPanel::film_changed (FilmProperty property)
 	case FilmProperty::AUDIO_PROCESSOR:
 		_mapping->set_output_channels (_parent->film()->audio_output_names ());
 		setup_peak ();
+		setup_sensitivity();
 		break;
 	case FilmProperty::VIDEO_FRAME_RATE:
 		setup_description ();
diff --git a/src/wx/dkdm_dialog.cc b/src/wx/dkdm_dialog.cc
index 8da3090c5..82c2e3598 100644
--- a/src/wx/dkdm_dialog.cc
+++ b/src/wx/dkdm_dialog.cc
@@ -178,7 +178,7 @@ DKDMDialog::make_clicked ()
 		return;
 	}
 
-	auto result = _output->make (kdms, film->name(), bind(&DKDMDialog::confirm_overwrite, this, _1));
+	auto result = _output->make(kdms, film->dcp_name(), bind(&DKDMDialog::confirm_overwrite, this, _1));
 	if (result.first) {
 		JobManager::instance()->add (result.first);
 	}
diff --git a/src/wx/dolby_doremi_certificate_panel.cc b/src/wx/dolby_doremi_certificate_panel.cc
index d290535c2..4d8845402 100644
--- a/src/wx/dolby_doremi_certificate_panel.cc
+++ b/src/wx/dolby_doremi_certificate_panel.cc
@@ -117,11 +117,21 @@ static void
 try_ims(vector<Location>& locations, string prefix, string serial)
 {
 	locations.push_back({
+		String::compose("%1%2xxx/Dolby-IMS1000-%3.dcicerts.zip", prefix, serial.substr(0, 3), serial),
+		String::compose("Dolby-IMS1000-%1.cert.sha256.pem", serial)
+	});
+
+	locations.push_back({
 		String::compose("%1%2xxx/Dolby-IMS2000-%3.dcicerts.zip", prefix, serial.substr(0, 3), serial),
 		String::compose("Dolby-IMS2000-%1.cert.sha256.pem", serial)
 	});
 
 	locations.push_back({
+		String::compose("%1%2xxx/cert_Dolby-IMS3000-%3-SMPTE.zip", prefix, serial.substr(0, 3), serial),
+		String::compose("cert_Dolby-IMS3000-%1-SMPTE.pem", serial)
+	});
+
+	locations.push_back({
 		String::compose("%1%2xxx/ims-%3.dcicerts.zip", prefix, serial.substr(0, 3), serial),
 		String::compose("ims-%1.cert.sha256.pem", serial)
 	});
diff --git a/src/wx/full_config_dialog.cc b/src/wx/full_config_dialog.cc
index 66dbae63e..e3ea91224 100644
--- a/src/wx/full_config_dialog.cc
+++ b/src/wx/full_config_dialog.cc
@@ -52,7 +52,7 @@
 #include "lib/config.h"
 #include "lib/cross.h"
 #include "lib/dcp_content_type.h"
-#include "lib/emailer.h"
+#include "lib/email.h"
 #include "lib/exceptions.h"
 #include "lib/filter.h"
 #include "lib/log.h"
@@ -983,7 +983,7 @@ private:
 			return;
 		}
 
-		Emailer emailer(
+		Email email(
 			wx_to_std(dialog.from()),
 			{ wx_to_std(dialog.to()) },
 			wx_to_std(_("DCP-o-matic test email")),
@@ -991,7 +991,7 @@ private:
 			);
 		auto config = Config::instance();
 		try {
-			emailer.send(config->mail_server(), config->mail_port(), config->mail_protocol(), config->mail_user(), config->mail_password());
+			email.send(config->mail_server(), config->mail_port(), config->mail_protocol(), config->mail_user(), config->mail_password());
 		} catch (NetworkError& e) {
 			error_dialog(_panel, std_to_wx(e.summary()), std_to_wx(e.detail().get_value_or("")));
 			return;
diff --git a/src/wx/kdm_dialog.cc b/src/wx/kdm_dialog.cc
index c88a1ac40..5ab13b4ce 100644
--- a/src/wx/kdm_dialog.cc
+++ b/src/wx/kdm_dialog.cc
@@ -227,7 +227,7 @@ KDMDialog::make_clicked ()
 		return;
 	}
 
-	auto result = _output->make (kdms, film->name(), bind (&KDMDialog::confirm_overwrite, this, _1));
+	auto result = _output->make(kdms, film->dcp_name(), bind (&KDMDialog::confirm_overwrite, this, _1));
 	if (result.first) {
 		JobManager::instance()->add (result.first);
 	}
diff --git a/src/wx/timeline.cc b/src/wx/timeline.cc
index 4683769d4..38e9de4ee 100644
--- a/src/wx/timeline.cc
+++ b/src/wx/timeline.cc
@@ -109,6 +109,7 @@ Timeline::Timeline(wxWindow* parent, ContentPanel* cp, shared_ptr<Film> film, Fi
 	_main_canvas->Bind   (wxEVT_RIGHT_DOWN, boost::bind (&Timeline::right_down,   this, _1));
 	_main_canvas->Bind   (wxEVT_MOTION,     boost::bind (&Timeline::mouse_moved,  this, _1));
 	_main_canvas->Bind   (wxEVT_SIZE,       boost::bind (&Timeline::resized,      this));
+	_main_canvas->Bind   (wxEVT_MOUSEWHEEL, boost::bind(&Timeline::mouse_wheel_turned, this, _1));
 	_main_canvas->Bind   (wxEVT_SCROLLWIN_TOP,        boost::bind (&Timeline::scrolled,     this, _1));
 	_main_canvas->Bind   (wxEVT_SCROLLWIN_BOTTOM,     boost::bind (&Timeline::scrolled,     this, _1));
 	_main_canvas->Bind   (wxEVT_SCROLLWIN_LINEUP,     boost::bind (&Timeline::scrolled,     this, _1));
@@ -133,6 +134,50 @@ Timeline::Timeline(wxWindow* parent, ContentPanel* cp, shared_ptr<Film> film, Fi
 
 
 void
+Timeline::mouse_wheel_turned(wxMouseEvent& event)
+{
+	auto const rotation = event.GetWheelRotation();
+
+	if (event.ControlDown()) {
+		/* On my mouse one click of the scroll wheel is 120, and it's -ve when
+		 * scrolling the wheel towards me.
+		 */
+		auto const scale = rotation > 0 ?
+			(1.0 / (rotation / 90.0)) :
+			(-rotation / 90.0);
+
+		int before_start_x;
+		int before_start_y;
+		_main_canvas->GetViewStart(&before_start_x, &before_start_y);
+
+		auto const before_pps = _pixels_per_second.get_value_or(1);
+		auto const before_pos = _last_mouse_wheel_x && *_last_mouse_wheel_x == event.GetX() ?
+			*_last_mouse_wheel_time :
+			(before_start_x * _x_scroll_rate + event.GetX()) / before_pps;
+
+		set_pixels_per_second(before_pps * scale);
+		setup_scrollbars();
+
+		auto after_left = std::max(0.0, before_pos * _pixels_per_second.get_value_or(1) - event.GetX());
+		_main_canvas->Scroll(after_left / _x_scroll_rate, before_start_y);
+		_labels_canvas->Scroll(0, before_start_y);
+		Refresh();
+
+		if (!_last_mouse_wheel_x || *_last_mouse_wheel_x != event.GetX()) {
+			_last_mouse_wheel_x = event.GetX();
+			_last_mouse_wheel_time = before_pos;
+		}
+	} else if (event.ShiftDown()) {
+		int before_start_x;
+		int before_start_y;
+		_main_canvas->GetViewStart(&before_start_x, &before_start_y);
+		auto const width = _main_canvas->GetSize().GetWidth();
+		_main_canvas->Scroll(std::max(0.0, before_start_x - rotation * 100.0 / width), before_start_y);
+	}
+}
+
+
+void
 Timeline::update_playhead ()
 {
 	Refresh ();
diff --git a/src/wx/timeline.h b/src/wx/timeline.h
index 2485e835f..621609fa7 100644
--- a/src/wx/timeline.h
+++ b/src/wx/timeline.h
@@ -110,6 +110,7 @@ private:
 	void set_pixels_per_track (int h);
 	void zoom_all ();
 	void update_playhead ();
+	void mouse_wheel_turned(wxMouseEvent& event);
 
 	std::shared_ptr<TimelineView> event_to_view (wxMouseEvent &);
 	TimelineContentViewList selected_views () const;
@@ -143,6 +144,8 @@ private:
 	int _pixels_per_track;
 	bool _first_resize;
 	wxTimer _timer;
+	boost::optional<int> _last_mouse_wheel_x;
+	boost::optional<double> _last_mouse_wheel_time;
 
 	static double const _minimum_pixels_per_second;
 	static int const _minimum_pixels_per_track;
diff --git a/test/util_test.cc b/test/util_test.cc
index 49d0b3bc2..afcc4cfc9 100644
--- a/test/util_test.cc
+++ b/test/util_test.cc
@@ -155,3 +155,14 @@ BOOST_AUTO_TEST_CASE(word_wrap_test)
 	BOOST_CHECK(word_wrap("hello this is a longer bit of text and it should be word-wrapped", 31) == string{"hello this is a longer bit of \ntext and it should be word-\nwrapped\n"});
 	BOOST_CHECK_EQUAL(word_wrap("hellocan'twrapthissadly", 5), "hello\ncan't\nwrapt\nhissa\ndly\n");
 }
+
+
+BOOST_AUTO_TEST_CASE(screen_names_to_string_test)
+{
+	BOOST_CHECK_EQUAL(screen_names_to_string({"1", "2", "3"}), "1, 2, 3");
+	BOOST_CHECK_EQUAL(screen_names_to_string({"3", "2", "1"}), "1, 2, 3");
+	BOOST_CHECK_EQUAL(screen_names_to_string({"39", "3", "10", "1", "2"}), "1, 2, 3, 10, 39");
+	BOOST_CHECK_EQUAL(screen_names_to_string({"Sheila", "Fred", "Jim"}), "Fred, Jim, Sheila");
+	BOOST_CHECK_EQUAL(screen_names_to_string({"Sheila", "Fred", "Jim", "1"}), "1, Fred, Jim, Sheila");
+}
+