From 211ff64e7dbb09f1395c879b294721b12bc9525a Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Mon, 5 Dec 2022 23:43:34 +0100
Subject: [PATCH] Prepare for ogg/opus encoding

---
 libs/ardour/ardour/export_format_base.h |  1 +
 libs/ardour/ardour/export_formats.h     | 26 +++++++++++++++++
 libs/ardour/enums.cc                    |  1 +
 libs/ardour/export_format_manager.cc    |  5 ++++
 libs/ardour/export_formats.cc           | 37 +++++++++++++++++++++++++
 libs/ardour/export_graph_builder.cc     |  3 +-
 6 files changed, 72 insertions(+), 1 deletion(-)

diff --git a/libs/ardour/ardour/export_format_base.h b/libs/ardour/ardour/export_format_base.h
index 517b3d1ff0..54380c4859 100644
--- a/libs/ardour/ardour/export_format_base.h
+++ b/libs/ardour/ardour/export_format_base.h
@@ -80,6 +80,7 @@ class LIBARDOUR_API ExportFormatBase {
 		SF_Float = SF_FORMAT_FLOAT,
 		SF_Double = SF_FORMAT_DOUBLE,
 		SF_Vorbis = SF_FORMAT_VORBIS,
+		SF_Opus = 0x0064, /* SF_FORMAT_OPUS */
 		SF_MPEG_LAYER_III = 0x0082  /* SF_FORMAT_MPEG_LAYER_III */
 	};
 
diff --git a/libs/ardour/ardour/export_formats.h b/libs/ardour/ardour/export_formats.h
index 625e1646ea..97cebc10c9 100644
--- a/libs/ardour/ardour/export_formats.h
+++ b/libs/ardour/ardour/export_formats.h
@@ -355,6 +355,32 @@ public:
 	}
 };
 
+class LIBARDOUR_API ExportFormatOggOpus : public ExportFormat, public HasSampleFormat, public HasCodecQuality
+{
+public:
+	ExportFormatOggOpus ();
+	~ExportFormatOggOpus (){};
+
+	bool set_compatibility_state (ExportFormatCompatibility const& compatibility);
+
+	Type get_type () const
+	{
+		return T_Sndfile;
+	}
+	SampleFormat get_explicit_sample_format () const
+	{
+		return SF_Opus;
+	}
+	int default_codec_quality () const
+	{
+		return 40;
+	}
+	virtual bool supports_tagging () const
+	{
+		return true;
+	}
+};
+
 class LIBARDOUR_API ExportFormatMPEG : public ExportFormat, public HasSampleFormat, public HasCodecQuality
 {
 public:
diff --git a/libs/ardour/enums.cc b/libs/ardour/enums.cc
index eda53fada6..7d56fbc3a3 100644
--- a/libs/ardour/enums.cc
+++ b/libs/ardour/enums.cc
@@ -652,6 +652,7 @@ setup_enum_writer ()
 	REGISTER_CLASS_ENUM (ExportFormatBase, SF_Float);
 	REGISTER_CLASS_ENUM (ExportFormatBase, SF_Double);
 	REGISTER_CLASS_ENUM (ExportFormatBase, SF_Vorbis);
+	REGISTER_CLASS_ENUM (ExportFormatBase, SF_Opus);
 	REGISTER_CLASS_ENUM (ExportFormatBase, SF_MPEG_LAYER_III);
 	REGISTER (_ExportFormatBase_SampleFormat);
 
diff --git a/libs/ardour/export_format_manager.cc b/libs/ardour/export_format_manager.cc
index 3ddde3ad78..cc295f06c2 100644
--- a/libs/ardour/export_format_manager.cc
+++ b/libs/ardour/export_format_manager.cc
@@ -204,6 +204,11 @@ ExportFormatManager::init_formats ()
 	fl_ptr->set_extension ("raw");
 	add_format (f_ptr);
 
+	try {
+		f_ptr.reset (new ExportFormatOggOpus ());
+		add_format (f_ptr);
+	} catch (ExportFormatIncompatible & e) {}
+
 	try {
 		f_ptr.reset (new ExportFormatOggVorbis ());
 		add_format (f_ptr);
diff --git a/libs/ardour/export_formats.cc b/libs/ardour/export_formats.cc
index b6cbad0c3a..0c4ece2a68 100644
--- a/libs/ardour/export_formats.cc
+++ b/libs/ardour/export_formats.cc
@@ -179,6 +179,8 @@ HasSampleFormat::get_sample_format_name (ExportFormatBase::SampleFormat format)
 		return _("8-bit unsigned");
 	  case ExportFormatBase::SF_Vorbis:
 		return _("Vorbis sample format");
+	  case ExportFormatBase::SF_Opus:
+		return _("OPUS codec");
 	  case ExportFormatBase::SF_MPEG_LAYER_III:
 		return _("MPEG-2 Audio Layer III");
 	  case ExportFormatBase::SF_None:
@@ -382,6 +384,41 @@ ExportFormatBWF::set_compatibility_state (ExportFormatCompatibility const & comp
 }
 
 
+/*** OPUS ***/
+
+ExportFormatOggOpus::ExportFormatOggOpus ()
+	: HasSampleFormat (sample_formats)
+{
+	SF_INFO sf_info;
+	sf_info.channels = 2;
+	sf_info.samplerate = SR_44_1;
+	sf_info.format = F_Ogg | SF_Opus;
+	if (sf_format_check (&sf_info) != SF_TRUE) {
+		throw ExportFormatIncompatible();
+	}
+
+	set_name ("Ogg OPUS");
+	set_format_id (F_Ogg);
+	sample_formats.insert (SF_Opus);
+
+	// libsndfile doesn't expose direct quality control - use these coarse approximations
+	add_codec_quality ("Low (0%)",            0);
+	add_codec_quality ("Default (40%)",      40);
+	add_codec_quality ("High (60%)",         60);
+	add_codec_quality ("Very High (100%)",  100);
+
+	set_extension ("opus");
+	set_quality (Q_LossyCompression);
+}
+
+bool
+ExportFormatOggOpus::set_compatibility_state (ExportFormatCompatibility const& compatibility)
+{
+	bool compatible = compatibility.has_format (F_Ogg);
+	set_compatible (compatible);
+	return compatible;
+}
+
 /*** MPEG / MP3 ***/
 
 ExportFormatMPEG::ExportFormatMPEG (std::string const& name, std::string const& ext) :
diff --git a/libs/ardour/export_graph_builder.cc b/libs/ardour/export_graph_builder.cc
index a25fd39734..578432857c 100644
--- a/libs/ardour/export_graph_builder.cc
+++ b/libs/ardour/export_graph_builder.cc
@@ -345,7 +345,8 @@ ExportGraphBuilder::Encoder::init_writer (boost::shared_ptr<AudioGrapher::Sndfil
 	writer.reset (new AudioGrapher::SndfileWriter<T> (writer_filename, format, channels, config.format->sample_rate(), config.broadcast_info));
 	writer->FileWritten.connect_same_thread (copy_files_connection, boost::bind (&ExportGraphBuilder::Encoder::copy_files, this, _1));
 	if ((format & SF_FORMAT_SUBMASK) == ExportFormatBase::SF_Vorbis ||
-	    (format & SF_FORMAT_TYPEMASK) == ExportFormatBase::F_MPEG) {
+	    (format & SF_FORMAT_TYPEMASK) == ExportFormatBase::F_MPEG ||
+	    (format & SF_FORMAT_SUBMASK) == ExportFormatBase::SF_Opus) {
 		/* libsndfile uses range 0..1 (worst.. best) for
 		 * SFC_SET_VBR_ENCODING_QUALITY and maps
 		 * SFC_SET_COMPRESSION_LEVEL = 1.0 - VBR_ENCODING_QUALITY