1 files changed, 535 insertions, 0 deletions
diff --git a/src/decoder/plugins/OpusDecoderPlugin.cxx b/src/decoder/plugins/OpusDecoderPlugin.cxx
new file mode 100644
index 000000000..e14827e38
--- /dev/null
+++ b/src/decoder/plugins/OpusDecoderPlugin.cxx
@@ -0,0 +1,535 @@
+/*
+ * Copyright (C) 2003-2014 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 "OpusDomain.hxx"
+#include "OpusHead.hxx"
+#include "OpusTags.hxx"
+#include "OggFind.hxx"
+#include "OggSyncState.hxx"
+#include "../DecoderAPI.hxx"
+#include "OggCodec.hxx"
+#include "tag/TagHandler.hxx"
+#include "tag/TagBuilder.hxx"
+#include "input/InputStream.hxx"
+#include "util/Error.hxx"
+#include "Log.hxx"
+
+#include <opus.h>
+#include <ogg/ogg.h>
+
+#include <string.h>
+#include <stdio.h>
+
+static constexpr opus_int32 opus_sample_rate = 48000;
+
+/**
+ * Allocate an output buffer for 16 bit PCM samples big enough to hold
+ * a quarter second, larger than 120ms required by libopus.
+ */
+static constexpr unsigned opus_output_buffer_frames = opus_sample_rate / 4;
+
+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(gcc_unused const config_param &param)
+{
+	LogDebug(opus_domain, opus_get_version_string());
+
+	return true;
+}
+
+class MPDOpusDecoder {
+	Decoder &decoder;
+	InputStream &input_stream;
+
+	ogg_stream_state os;
+
+	OpusDecoder *opus_decoder;
+	opus_int16 *output_buffer;
+
+	/**
+	 * If non-zero, then a previous Opus stream has been found
+	 * already with this number of channels.  If opus_decoder is
+	 * nullptr, then its end-of-stream packet has been found
+	 * already.
+	 */
+	unsigned previous_channels;
+
+	bool os_initialized;
+
+	int opus_serialno;
+
+	ogg_int64_t eos_granulepos;
+
+	size_t frame_size;
+
+public:
+	MPDOpusDecoder(Decoder &_decoder,
+		       InputStream &_input_stream)
+		:decoder(_decoder), input_stream(_input_stream),
+		 opus_decoder(nullptr),
+		 output_buffer(nullptr),
+		 previous_channels(0),
+		 os_initialized(false) {}
+	~MPDOpusDecoder();
+
+	bool ReadFirstPage(OggSyncState &oy);
+	bool ReadNextPage(OggSyncState &oy);
+
+	DecoderCommand HandlePackets();
+	DecoderCommand HandlePacket(const ogg_packet &packet);
+	DecoderCommand HandleBOS(const ogg_packet &packet);
+	DecoderCommand HandleEOS();
+	DecoderCommand HandleTags(const ogg_packet &packet);
+	DecoderCommand HandleAudio(const ogg_packet &packet);
+
+	bool Seek(OggSyncState &oy, uint64_t where_frame);
+};
+
+MPDOpusDecoder::~MPDOpusDecoder()
+{
+	delete[] output_buffer;
+
+	if (opus_decoder != nullptr)
+		opus_decoder_destroy(opus_decoder);
+
+	if (os_initialized)
+		ogg_stream_clear(&os);
+}
+
+inline bool
+MPDOpusDecoder::ReadFirstPage(OggSyncState &oy)
+{
+	assert(!os_initialized);
+
+	if (!oy.ExpectFirstPage(os))
+		return false;
+
+	os_initialized = true;
+	return true;
+}
+
+inline bool
+MPDOpusDecoder::ReadNextPage(OggSyncState &oy)
+{
+	assert(os_initialized);
+
+	ogg_page page;
+	if (!oy.ExpectPage(page))
+		return false;
+
+	const auto page_serialno = ogg_page_serialno(&page);
+	if (page_serialno != os.serialno)
+		ogg_stream_reset_serialno(&os, page_serialno);
+
+	ogg_stream_pagein(&os, &page);
+	return true;
+}
+
+inline DecoderCommand
+MPDOpusDecoder::HandlePackets()
+{
+	ogg_packet packet;
+	while (ogg_stream_packetout(&os, &packet) == 1) {
+		auto cmd = HandlePacket(packet);
+		if (cmd != DecoderCommand::NONE)
+			return cmd;
+	}
+
+	return DecoderCommand::NONE;
+}
+
+inline DecoderCommand
+MPDOpusDecoder::HandlePacket(const ogg_packet &packet)
+{
+	if (packet.e_o_s)
+		return HandleEOS();
+
+	if (packet.b_o_s)
+		return HandleBOS(packet);
+	else if (opus_decoder == nullptr) {
+		LogDebug(opus_domain, "BOS packet expected");
+		return DecoderCommand::STOP;
+	}
+
+	if (IsOpusTags(packet))
+		return HandleTags(packet);
+
+	return HandleAudio(packet);
+}
+
+/**
+ * Load the end-of-stream packet and restore the previous file
+ * position.
+ */
+static bool
+LoadEOSPacket(InputStream &is, Decoder *decoder, int serialno,
+	      ogg_packet &packet)
+{
+	if (!is.CheapSeeking())
+		/* we do this for local files only, because seeking
+		   around remote files is expensive and not worth the
+		   troubl */
+		return false;
+
+	const auto old_offset = is.GetOffset();
+
+	/* create temporary Ogg objects for seeking and parsing the
+	   EOS packet */
+	OggSyncState oy(is, decoder);
+	ogg_stream_state os;
+	ogg_stream_init(&os, serialno);
+
+	bool result = OggSeekFindEOS(oy, os, packet, is);
+	ogg_stream_clear(&os);
+
+	/* restore the previous file position */
+	is.LockSeek(old_offset, IgnoreError());
+
+	return result;
+}
+
+/**
+ * Load the end-of-stream granulepos and restore the previous file
+ * position.
+ *
+ * @return -1 on error
+ */
+gcc_pure
+static ogg_int64_t
+LoadEOSGranulePos(InputStream &is, Decoder *decoder, int serialno)
+{
+	ogg_packet packet;
+	if (!LoadEOSPacket(is, decoder, serialno, packet))
+		return -1;
+
+	return packet.granulepos;
+}
+
+inline DecoderCommand
+MPDOpusDecoder::HandleBOS(const ogg_packet &packet)
+{
+	assert(packet.b_o_s);
+
+	if (opus_decoder != nullptr || !IsOpusHead(packet)) {
+		LogDebug(opus_domain, "BOS packet must be OpusHead");
+		return DecoderCommand::STOP;
+	}
+
+	unsigned channels;
+	if (!ScanOpusHeader(packet.packet, packet.bytes, channels) ||
+	    !audio_valid_channel_count(channels)) {
+		LogDebug(opus_domain, "Malformed BOS packet");
+		return DecoderCommand::STOP;
+	}
+
+	assert(opus_decoder == nullptr);
+	assert((previous_channels == 0) == (output_buffer == nullptr));
+
+	if (previous_channels != 0 && channels != previous_channels) {
+		FormatWarning(opus_domain,
+			      "Next stream has different channels (%u -> %u)",
+			      previous_channels, channels);
+		return DecoderCommand::STOP;
+	}
+
+	opus_serialno = os.serialno;
+
+	/* 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) {
+		FormatError(opus_domain, "libopus error: %s",
+			    opus_strerror(opus_error));
+		return DecoderCommand::STOP;
+	}
+
+	if (previous_channels != 0) {
+		/* decoder was already initialized by the previous
+		   stream; skip the rest of this method */
+		LogDebug(opus_domain, "Found another stream");
+		return decoder_get_command(decoder);
+	}
+
+	eos_granulepos = LoadEOSGranulePos(input_stream, &decoder,
+					   opus_serialno);
+	const auto duration = eos_granulepos >= 0
+		? SignedSongTime::FromScale<uint64_t>(eos_granulepos,
+						      opus_sample_rate)
+		: SignedSongTime::Negative();
+
+	previous_channels = channels;
+	const AudioFormat audio_format(opus_sample_rate,
+				       SampleFormat::S16, channels);
+	decoder_initialized(decoder, audio_format,
+			    eos_granulepos > 0, duration);
+	frame_size = audio_format.GetFrameSize();
+
+	output_buffer = new opus_int16[opus_output_buffer_frames
+				       * audio_format.channels];
+
+	return decoder_get_command(decoder);
+}
+
+inline DecoderCommand
+MPDOpusDecoder::HandleEOS()
+{
+	if (eos_granulepos < 0 && previous_channels != 0) {
+		/* allow chaining of (unseekable) streams */
+		assert(opus_decoder != nullptr);
+		assert(output_buffer != nullptr);
+
+		opus_decoder_destroy(opus_decoder);
+		opus_decoder = nullptr;
+
+		return decoder_get_command(decoder);
+	}
+
+	return DecoderCommand::STOP;
+}
+
+inline DecoderCommand
+MPDOpusDecoder::HandleTags(const ogg_packet &packet)
+{
+	ReplayGainInfo rgi;
+	rgi.Clear();
+
+	TagBuilder tag_builder;
+
+	DecoderCommand cmd;
+	if (ScanOpusTags(packet.packet, packet.bytes,
+			 &rgi,
+			 &add_tag_handler, &tag_builder) &&
+	    !tag_builder.IsEmpty()) {
+		decoder_replay_gain(decoder, &rgi);
+
+		Tag tag = tag_builder.Commit();
+		cmd = decoder_tag(decoder, input_stream, std::move(tag));
+	} else
+		cmd = decoder_get_command(decoder);
+
+	return cmd;
+}
+
+inline DecoderCommand
+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, opus_output_buffer_frames,
+				  0);
+	if (nframes < 0) {
+		FormatError(opus_domain, "libopus error: %s",
+			    opus_strerror(nframes));
+		return DecoderCommand::STOP;
+	}
+
+	if (nframes > 0) {
+		const size_t nbytes = nframes * frame_size;
+		auto cmd = decoder_data(decoder, input_stream,
+					output_buffer, nbytes,
+					0);
+		if (cmd != DecoderCommand::NONE)
+			return cmd;
+
+		if (packet.granulepos > 0)
+			decoder_timestamp(decoder,
+					  double(packet.granulepos)
+					  / opus_sample_rate);
+	}
+
+	return DecoderCommand::NONE;
+}
+
+bool
+MPDOpusDecoder::Seek(OggSyncState &oy, uint64_t where_frame)
+{
+	assert(eos_granulepos > 0);
+	assert(input_stream.IsSeekable());
+	assert(input_stream.KnownSize());
+
+	const ogg_int64_t where_granulepos(where_frame);
+
+	/* interpolate the file offset where we expect to find the
+	   given granule position */
+	/* TODO: implement binary search */
+	offset_type offset(where_granulepos * input_stream.GetSize()
+			   / eos_granulepos);
+
+	return OggSeekPageAtOffset(oy, os, input_stream, offset);
+}
+
+static void
+mpd_opus_stream_decode(Decoder &decoder,
+		       InputStream &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.LockRewind(IgnoreError());
+
+	MPDOpusDecoder d(decoder, input_stream);
+	OggSyncState oy(input_stream, &decoder);
+
+	if (!d.ReadFirstPage(oy))
+		return;
+
+	while (true) {
+		auto cmd = d.HandlePackets();
+		if (cmd == DecoderCommand::SEEK) {
+			if (d.Seek(oy, decoder_seek_where_frame(decoder)))
+				decoder_command_finished(decoder);
+			else
+				decoder_seek_error(decoder);
+
+			continue;
+		}
+
+		if (cmd != DecoderCommand::NONE)
+			break;
+
+		if (!d.ReadNextPage(oy))
+			break;
+	}
+}
+
+static bool
+mpd_opus_scan_stream(InputStream &is,
+		     const struct tag_handler *handler, void *handler_ctx)
+{
+	OggSyncState oy(is);
+
+	ogg_stream_state os;
+	if (!oy.ExpectFirstPage(os))
+		return false;
+
+	/* read at most two more pages */
+	unsigned remaining_pages = 2;
+
+	bool result = false;
+
+	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 (!oy.ExpectPageIn(os)) {
+				result = false;
+				break;
+			}
+
+			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,
+					  nullptr,
+					  handler, handler_ctx))
+				result = false;
+
+			break;
+		}
+	}
+
+	if (packet.e_o_s || OggSeekFindEOS(oy, os, packet, is)) {
+		const auto duration =
+			SongTime::FromScale<uint64_t>(packet.granulepos,
+						      opus_sample_rate);
+		tag_handler_invoke_duration(handler, handler_ctx, duration);
+	}
+
+	ogg_stream_clear(&os);
+
+	return result;
+}
+
+static const char *const opus_suffixes[] = {
+	"opus",
+	"ogg",
+	"oga",
+	nullptr
+};
+
+static const char *const opus_mime_types[] = {
+	/* the official MIME type (RFC 5334) */
+	"audio/ogg",
+
+	/* deprecated (RFC 5334) */
+	"application/ogg",
+
+	/* deprecated; from an early draft */
+	"audio/opus",
+	nullptr
+};
+
+const struct DecoderPlugin opus_decoder_plugin = {
+	"opus",
+	mpd_opus_init,
+	nullptr,
+	mpd_opus_stream_decode,
+	nullptr,
+	nullptr,
+	mpd_opus_scan_stream,
+	nullptr,
+	opus_suffixes,
+	opus_mime_types,
+};