Added support for exporting mp4 chapter marks

The mp4 file format supports chapter marks using the so called
mp4chaps format to enable chapter wise navigation in an mp4 file. The
format is like

hh:mm:ss.sss Chapter Title

This commit adds the ability to export those kind of chapter marks
along with TOC and CUE marks. The filename extension for the chapter
mark file is "chapters.txt". The format specification description is
"MP4ch".

7 files changed, 82 insertions, 8 deletions

diff --git a/libs/ardour/ardour/export_format_manager.h b/libs/ardour/ardour/export_format_manager.h
index dad7d84b72..fff97299e5 100644
--- a/libs/ardour/ardour/export_format_manager.h
+++ b/libs/ardour/ardour/export_format_manager.h
@@ -100,6 +100,7 @@ class LIBARDOUR_API ExportFormatManager : public PBD::ScopedConnectionList
 
 	void select_with_cue (bool);
 	void select_with_toc (bool);
+	void select_with_mp4chaps (bool);
 	void select_upload (bool);
 	void set_command (std::string);
 	void select_src_quality (ExportFormatBase::SRCQuality value);
diff --git a/libs/ardour/ardour/export_format_specification.h b/libs/ardour/ardour/export_format_specification.h
index 2a62d792f0..ed6e259644 100644
--- a/libs/ardour/ardour/export_format_specification.h
+++ b/libs/ardour/ardour/export_format_specification.h
@@ -96,6 +96,7 @@ class LIBARDOUR_API ExportFormatSpecification : public ExportFormatBase {
 	void set_tag (bool tag_it) { _tag = tag_it; }
 	void set_with_cue (bool yn) { _with_cue = yn; }
 	void set_with_toc (bool yn) { _with_toc = yn; }
+	void set_with_mp4chaps (bool yn) { _with_mp4chaps = yn; }
 	void set_soundcloud_upload (bool yn) { _soundcloud_upload = yn; }
 	void set_command (std::string command) { _command = command; }
 
@@ -127,6 +128,8 @@ class LIBARDOUR_API ExportFormatSpecification : public ExportFormatBase {
 	float normalize_target () const { return _normalize_target; }
 	bool with_toc() const { return _with_toc; }
 	bool with_cue() const { return _with_cue; }
+	bool with_mp4chaps() const { return _with_mp4chaps; }
+
 	bool soundcloud_upload() const { return _soundcloud_upload; }
 	std::string command() const { return _command; }
 
@@ -178,6 +181,7 @@ class LIBARDOUR_API ExportFormatSpecification : public ExportFormatBase {
 	float           _normalize_target;
 	bool            _with_toc;
 	bool            _with_cue;
+	bool            _with_mp4chaps;
 	bool            _soundcloud_upload;
 	std::string	_command;
 
diff --git a/libs/ardour/ardour/export_handler.h b/libs/ardour/ardour/export_handler.h
index 8336cea732..526d32b4c6 100644
--- a/libs/ardour/ardour/export_handler.h
+++ b/libs/ardour/ardour/export_handler.h
@@ -185,14 +185,19 @@ class LIBARDOUR_API ExportHandler : public ExportElementFactory, public sigc::tr
 
 	void write_cue_header (CDMarkerStatus & status);
 	void write_toc_header (CDMarkerStatus & status);
+	void write_mp4ch_header (CDMarkerStatus & status);
 
 	void write_track_info_cue (CDMarkerStatus & status);
 	void write_track_info_toc (CDMarkerStatus & status);
+	void write_track_info_mp4ch (CDMarkerStatus & status);
 
 	void write_index_info_cue (CDMarkerStatus & status);
 	void write_index_info_toc (CDMarkerStatus & status);
+	void write_index_info_mp4ch (CDMarkerStatus & status);
 
 	void frames_to_cd_frames_string (char* buf, framepos_t when);
+	void frames_to_chapter_marks_string (char* buf, framepos_t when);
+
 	std::string toc_escape_cdtext (const std::string&);
 	std::string toc_escape_filename (const std::string&);
 	std::string cue_escape_cdtext (const std::string& txt);
diff --git a/libs/ardour/ardour/types.h b/libs/ardour/ardour/types.h
index 921cb3e39a..b0fb9faa9c 100644
--- a/libs/ardour/ardour/types.h
+++ b/libs/ardour/ardour/types.h
@@ -461,7 +461,8 @@ namespace ARDOUR {
 	enum CDMarkerFormat {
 		CDMarkerNone,
 		CDMarkerCUE,
-		CDMarkerTOC
+		CDMarkerTOC,
+		MP4Chaps
 	};
 
 	enum HeaderFormat {
diff --git a/libs/ardour/export_format_manager.cc b/libs/ardour/export_format_manager.cc
index 04cfa76677..f87a08686f 100644
--- a/libs/ardour/export_format_manager.cc
+++ b/libs/ardour/export_format_manager.cc
@@ -293,6 +293,12 @@ ExportFormatManager::select_with_toc (bool value)
 	check_for_description_change ();
 }
 
+void
+ExportFormatManager::select_with_mp4chaps (bool value)
+{
+	current_selection->set_with_mp4chaps (value);
+	check_for_description_change ();
+}
 
 void
 ExportFormatManager::set_command (std::string command)
diff --git a/libs/ardour/export_format_specification.cc b/libs/ardour/export_format_specification.cc
index 9a972da0bf..7e41b209a4 100644
--- a/libs/ardour/export_format_specification.cc
+++ b/libs/ardour/export_format_specification.cc
@@ -170,6 +170,7 @@ ExportFormatSpecification::ExportFormatSpecification (Session & s)
 	, _normalize_target (1.0)
 	, _with_toc (false)
 	, _with_cue (false)
+	, _with_mp4chaps (false)
 	, _soundcloud_upload (false)
 	, _command ("")
 {
@@ -248,6 +249,7 @@ ExportFormatSpecification::get_state ()
 	root->add_property ("id", _id.to_s());
 	root->add_property ("with-cue", _with_cue ? "true" : "false");
 	root->add_property ("with-toc", _with_toc ? "true" : "false");
+	root->add_property ("with-mp4chaps", _with_mp4chaps ? "true" : "false");
 	root->add_property ("command", _command);
 
 	node = root->add_child ("Encoding");
@@ -319,14 +321,19 @@ ExportFormatSpecification::set_state (const XMLNode & root)
 	} else {
 		_with_cue = false;
 	}
-	
+
 	if ((prop = root.property ("with-toc"))) {
 		_with_toc = string_is_affirmative (prop->value());
 	} else {
 		_with_toc = false;
 	}
-	
-	
+
+	if ((prop = root.property ("with-mp4chaps"))) {
+		_with_mp4chaps = string_is_affirmative (prop->value());
+	} else {
+		_with_mp4chaps = false;
+	}
+
 	if ((prop = root.property ("command"))) {
 		_command = prop->value();
 	} else {
@@ -602,6 +609,10 @@ ExportFormatSpecification::description (bool include_name)
 		components.push_back ("CUE");
 	}
 
+	if (_with_mp4chaps) {
+		components.push_back ("MP4ch");
+	}
+
 	if (!_command.empty()) {
 		components.push_back ("+");
 	}
diff --git a/libs/ardour/export_handler.cc b/libs/ardour/export_handler.cc
index b44c46e549..33e19d663f 100644
--- a/libs/ardour/export_handler.cc
+++ b/libs/ardour/export_handler.cc
@@ -305,6 +305,10 @@ ExportHandler::finish_timespan ()
 			export_cd_marker_file (current_timespan, fmt, filename, CDMarkerTOC);
 		}
 
+		if (fmt->with_mp4chaps()) {
+			export_cd_marker_file (current_timespan, fmt, filename, MP4Chaps);
+		}
+
 		if (fmt->tag()) {
 			AudiofileTagger::tag_file(filename, *SessionMetadata::Metadata());
 		}
@@ -403,6 +407,11 @@ ExportHandler::export_cd_marker_file (ExportTimespanPtr timespan, ExportFormatSp
 			track_func = &ExportHandler::write_track_info_cue;
 			index_func = &ExportHandler::write_index_info_cue;
 			break;
+		case MP4Chaps:
+			header_func = &ExportHandler::write_mp4ch_header;
+			track_func = &ExportHandler::write_track_info_mp4ch;
+			index_func = &ExportHandler::write_index_info_mp4ch;
+			break;
 		default:
 			return;
 		}
@@ -500,17 +509,19 @@ ExportHandler::export_cd_marker_file (ExportTimespanPtr timespan, ExportFormatSp
 string
 ExportHandler::get_cd_marker_filename(std::string filename, CDMarkerFormat format)
 {
-	/* do not strip file suffix because there may be more than one format, 
+	/* do not strip file suffix because there may be more than one format,
 	   and we do not want the CD marker file from one format to overwrite
 	   another (e.g. foo.wav.cue > foo.aiff.cue)
 	*/
 
 	switch (format) {
-	  case CDMarkerTOC:
+	case CDMarkerTOC:
 		return filename + ".toc";
-	  case CDMarkerCUE:
+	case CDMarkerCUE:
 		return filename + ".cue";
-	  default:
+	case MP4Chaps:
+		return filename + ".chapters.txt";
+	default:
 		return filename + ".marker"; // Should not be reached when actually creating a file
 	}
 }
@@ -590,6 +601,11 @@ ExportHandler::write_toc_header (CDMarkerStatus & status)
 }
 
 void
+ExportHandler::write_mp4ch_header (CDMarkerStatus & status)
+{
+}
+
+void
 ExportHandler::write_track_info_cue (CDMarkerStatus & status)
 {
 	gchar buf[18];
@@ -693,6 +709,14 @@ ExportHandler::write_track_info_toc (CDMarkerStatus & status)
 	status.out << "START" << buf << endl;
 }
 
+void ExportHandler::write_track_info_mp4ch (CDMarkerStatus & status)
+{
+	gchar buf[18];
+
+	frames_to_chapter_marks_string(buf, status.track_start_frame);
+	status.out << buf << " " << status.marker->name() << endl;
+}
+
 void
 ExportHandler::write_index_info_cue (CDMarkerStatus & status)
 {
@@ -716,6 +740,11 @@ ExportHandler::write_index_info_toc (CDMarkerStatus & status)
 }
 
 void
+ExportHandler::write_index_info_mp4ch (CDMarkerStatus & status)
+{
+}
+
+void
 ExportHandler::frames_to_cd_frames_string (char* buf, framepos_t when)
 {
 	framecnt_t remainder;
@@ -730,6 +759,23 @@ ExportHandler::frames_to_cd_frames_string (char* buf, framepos_t when)
 	sprintf (buf, " %02d:%02d:%02d", mins, secs, frames);
 }
 
+void
+ExportHandler::frames_to_chapter_marks_string (char* buf, framepos_t when)
+{
+	framecnt_t remainder;
+	framecnt_t fr = session.nominal_frame_rate();
+	int hours, mins, secs, msecs;
+
+	hours = when / (3600 * fr);
+	remainder = when - (hours * 3600 * fr);
+	mins = remainder / (60 * fr);
+	remainder -= mins * 60 * fr;
+	secs = remainder / fr;
+	remainder -= secs * fr;
+	msecs = (remainder * 1000) / fr;
+	sprintf (buf, "%02d:%02d:%02d.%03d", hours, mins, secs, msecs);
+}
+
 std::string
 ExportHandler::toc_escape_cdtext (const std::string& txt)
 {