src/decoder/opus: new decoder plugin for the Opus codec

Using libopus and libogg.

1 files changed, 366 insertions, 0 deletions

diff --git a/src/decoder/OpusDecoderPlugin.cxx b/src/decoder/OpusDecoderPlugin.cxx
new file mode 100644
index 000000000..35e368ca9
--- /dev/null
+++ b/src/decoder/OpusDecoderPlugin.cxx
@@ -0,0 +1,366 @@
+/*
+ * Copyright (C) 2003-2012 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * 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
+ * the Free Software Foundation; either version 2 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h" /* must be first for large file support */
+#include "OpusDecoderPlugin.h"
+#include "OpusHead.hxx"
+#include "OpusTags.hxx"
+#include "OggUtil.hxx"
+
+extern "C" {
+#include "ogg_codec.h"
+#include "decoder_api.h"
+}
+
+#include "audio_check.h"
+#include "tag_handler.h"
+
+#include <opus.h>
+#include <ogg/ogg.h>
+
+#include <glib.h>
+
+#include <stdio.h>
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "opus"
+
+static const opus_int32 opus_sample_rate = 48000;
+
+gcc_pure
+static bool
+IsOpusHead(const ogg_packet &packet)
+{
+	return packet.bytes >= 8 && memcmp(packet.packet, "OpusHead", 8) == 0;
+}
+
+gcc_pure
+static bool
+IsOpusTags(const ogg_packet &packet)
+{
+	return packet.bytes >= 8 && memcmp(packet.packet, "OpusTags", 8) == 0;
+}
+
+static bool
+mpd_opus_init(G_GNUC_UNUSED const struct config_param *param)
+{
+	g_debug("%s", opus_get_version_string());
+
+	return true;
+}
+
+class MPDOpusDecoder {
+	struct decoder *decoder;
+	struct input_stream *input_stream;
+
+	ogg_stream_state os;
+
+	OpusDecoder *opus_decoder = nullptr;
+	opus_int16 *output_buffer = nullptr;
+	unsigned output_size = 0;
+
+	bool os_initialized = false;
+	bool found_opus = false;
+
+	int opus_serialno;
+
+	size_t frame_size;
+
+public:
+	MPDOpusDecoder(struct decoder *_decoder,
+		       struct input_stream *_input_stream)
+		:decoder(_decoder), input_stream(_input_stream) {}
+	~MPDOpusDecoder();
+
+	enum decoder_command HandlePage(ogg_page &page);
+	enum decoder_command HandlePacket(const ogg_packet &packet);
+	enum decoder_command HandleBOS(const ogg_packet &packet);
+	enum decoder_command HandleTags(const ogg_packet &packet);
+	enum decoder_command HandleAudio(const ogg_packet &packet);
+};
+
+MPDOpusDecoder::~MPDOpusDecoder()
+{
+	g_free(output_buffer);
+
+	if (opus_decoder != nullptr)
+		opus_decoder_destroy(opus_decoder);
+
+	if (os_initialized)
+		ogg_stream_clear(&os);
+}
+
+enum decoder_command
+MPDOpusDecoder::HandlePage(ogg_page &page)
+{
+	const auto page_serialno = ogg_page_serialno(&page);
+	if (!os_initialized) {
+		os_initialized = true;
+		ogg_stream_init(&os, page_serialno);
+	} else if (page_serialno != os.serialno)
+		ogg_stream_reset_serialno(&os, page_serialno);
+
+	ogg_stream_pagein(&os, &page);
+
+	ogg_packet packet;
+	while (ogg_stream_packetout(&os, &packet) == 1) {
+		enum decoder_command cmd = HandlePacket(packet);
+		if (cmd != DECODE_COMMAND_NONE)
+			return cmd;
+	}
+
+	return DECODE_COMMAND_NONE;
+}
+
+enum decoder_command
+MPDOpusDecoder::HandlePacket(const ogg_packet &packet)
+{
+	if (packet.e_o_s)
+		return DECODE_COMMAND_STOP;
+
+	if (packet.b_o_s)
+		return HandleBOS(packet);
+	else if (!found_opus)
+		return DECODE_COMMAND_STOP;
+
+	if (IsOpusTags(packet))
+		return HandleTags(packet);
+
+	return HandleAudio(packet);
+}
+
+enum decoder_command
+MPDOpusDecoder::HandleBOS(const ogg_packet &packet)
+{
+	assert(packet.b_o_s);
+
+	if (found_opus || !IsOpusHead(packet))
+		return DECODE_COMMAND_STOP;
+
+	unsigned channels;
+	if (!ScanOpusHeader(packet.packet, packet.bytes, channels) ||
+	    !audio_valid_channel_count(channels))
+		return DECODE_COMMAND_STOP;
+
+	assert(opus_decoder == nullptr);
+	assert(output_buffer == nullptr);
+
+	opus_serialno = os.serialno;
+	found_opus = true;
+
+	/* TODO: parse attributes from the OpusHead (sample rate,
+	   channels, ...) */
+
+	int opus_error;
+	opus_decoder = opus_decoder_create(opus_sample_rate, channels,
+					   &opus_error);
+	if (opus_decoder == nullptr) {
+		g_warning("libopus error: %s",
+			  opus_strerror(opus_error));
+		return DECODE_COMMAND_STOP;
+	}
+
+	struct audio_format audio_format;
+	audio_format_init(&audio_format, opus_sample_rate,
+			  SAMPLE_FORMAT_S16, channels);
+	decoder_initialized(decoder, &audio_format, false, -1);
+	frame_size = audio_format_frame_size(&audio_format);
+
+	/* allocate an output buffer for 16 bit PCM samples big enough
+	   to hold a quarter second, larger than 120ms required by
+	   libopus */
+	output_size = audio_format.sample_rate / 4;
+	output_buffer = (opus_int16 *)
+		g_malloc(sizeof(*output_buffer) * output_size *
+			 audio_format.channels);
+
+	return decoder_get_command(decoder);
+}
+
+enum decoder_command
+MPDOpusDecoder::HandleTags(const ogg_packet &packet)
+{
+	struct tag *tag = tag_new();
+
+	enum decoder_command cmd;
+	if (ScanOpusTags(packet.packet, packet.bytes, &add_tag_handler, tag) &&
+	    !tag_is_empty(tag))
+		cmd = decoder_tag(decoder, input_stream, tag);
+	else
+		cmd = decoder_get_command(decoder);
+
+	tag_free(tag);
+	return cmd;
+}
+
+enum decoder_command
+MPDOpusDecoder::HandleAudio(const ogg_packet &packet)
+{
+	assert(opus_decoder != nullptr);
+
+	int nframes = opus_decode(opus_decoder,
+				  (const unsigned char*)packet.packet,
+				  packet.bytes,
+				  output_buffer, output_size,
+				  0);
+	if (nframes < 0) {
+		g_warning("%s", opus_strerror(nframes));
+		return DECODE_COMMAND_STOP;
+	}
+
+	if (nframes > 0) {
+		const size_t nbytes = nframes * frame_size;
+		enum decoder_command cmd =
+			decoder_data(decoder, input_stream,
+				     output_buffer, nbytes,
+				     0);
+		if (cmd != DECODE_COMMAND_NONE)
+			return cmd;
+	}
+
+	return DECODE_COMMAND_NONE;
+}
+
+static void
+mpd_opus_stream_decode(struct decoder *decoder,
+		       struct input_stream *input_stream)
+{
+	if (ogg_codec_detect(decoder, input_stream) != OGG_CODEC_OPUS)
+		return;
+
+	/* rewind the stream, because ogg_codec_detect() has
+	   moved it */
+	input_stream_lock_seek(input_stream, 0, SEEK_SET, nullptr);
+
+	MPDOpusDecoder d(decoder, input_stream);
+
+	ogg_sync_state oy;
+	ogg_sync_init(&oy);
+
+	while (true) {
+		if (!OggFeed(oy, decoder, input_stream, 1024))
+			break;
+
+		ogg_page page;
+		while (ogg_sync_pageout(&oy, &page) == 1) {
+			enum decoder_command cmd = d.HandlePage(page);
+			if (cmd != DECODE_COMMAND_NONE)
+				break;
+		}
+	}
+
+	ogg_sync_clear(&oy);
+}
+
+static bool
+mpd_opus_scan_stream(struct input_stream *is,
+		     const struct tag_handler *handler, void *handler_ctx)
+{
+	ogg_sync_state oy;
+	ogg_sync_init(&oy);
+
+	ogg_page page;
+	if (!OggExpectPage(oy, page, nullptr, is)) {
+		ogg_sync_clear(&oy);
+		return false;
+	}
+
+	/* read at most two more pages */
+	unsigned remaining_pages = 2;
+
+	bool result = false;
+
+	ogg_stream_state os;
+	ogg_stream_init(&os, ogg_page_serialno(&page));
+	ogg_stream_pagein(&os, &page);
+
+	ogg_packet packet;
+	while (true) {
+		int r = ogg_stream_packetout(&os, &packet);
+		if (r < 0) {
+			result = false;
+			break;
+		}
+
+		if (r == 0) {
+			if (remaining_pages-- == 0)
+				break;
+
+			if (!OggExpectPage(oy, page, nullptr, is)) {
+				result = false;
+				break;
+			}
+
+			ogg_stream_pagein(&os, &page);
+			continue;
+		}
+
+		if (packet.b_o_s) {
+			if (!IsOpusHead(packet))
+				break;
+
+			unsigned channels;
+			if (!ScanOpusHeader(packet.packet, packet.bytes, channels) ||
+			    !audio_valid_channel_count(channels)) {
+				result = false;
+				break;
+			}
+
+			result = true;
+		} else if (!result)
+			break;
+		else if (IsOpusTags(packet)) {
+			if (!ScanOpusTags(packet.packet, packet.bytes,
+					  handler, handler_ctx))
+				result = false;
+
+			break;
+		}
+	}
+
+	ogg_stream_clear(&os);
+	ogg_sync_clear(&oy);
+
+	return result;
+}
+
+static const char *const opus_suffixes[] = {
+	"opus",
+	"ogg",
+	"oga",
+	nullptr
+};
+
+static const char *const opus_mime_types[] = {
+	"audio/opus",
+	nullptr
+};
+
+const struct decoder_plugin opus_decoder_plugin = {
+	"opus",
+	mpd_opus_init,
+	nullptr,
+	mpd_opus_stream_decode,
+	nullptr,
+	nullptr,
+	mpd_opus_scan_stream,
+	nullptr,
+	opus_suffixes,
+	opus_mime_types,
+};