mpd/src/DecoderAPI.cxx

/*
 * Copyright (C) 2003-2013 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"
#include "DecoderAPI.hxx"
#include "DecoderError.hxx"
#include "AudioConfig.hxx"
#include "ReplayGainConfig.hxx"
#include "MusicChunk.hxx"
#include "MusicBuffer.hxx"
#include "MusicPipe.hxx"
#include "DecoderControl.hxx"
#include "DecoderInternal.hxx"
#include "Song.hxx"
#include "InputStream.hxx"
#include "util/Error.hxx"
#include "Log.hxx"

#include <assert.h>
#include <stdlib.h>
#include <string.h>

void
decoder_initialized(Decoder &decoder,
		    const AudioFormat audio_format,
		    bool seekable, float total_time)
{
	decoder_control &dc = decoder.dc;
	struct audio_format_string af_string;

	assert(dc.state == DecoderState::START);
	assert(dc.pipe != nullptr);
	assert(decoder.stream_tag == nullptr);
	assert(decoder.decoder_tag == nullptr);
	assert(!decoder.seeking);
	assert(audio_format.IsDefined());
	assert(audio_format.IsValid());

	dc.in_audio_format = audio_format;
	dc.out_audio_format = getOutputAudioFormat(audio_format);

	dc.seekable = seekable;
	dc.total_time = total_time;

	dc.Lock();
	dc.state = DecoderState::DECODE;
	dc.client_cond.signal();
	dc.Unlock();

	FormatDebug(decoder_domain, "audio_format=%s, seekable=%s",
		    audio_format_to_string(dc.in_audio_format, &af_string),
		    seekable ? "true" : "false");

	if (dc.in_audio_format != dc.out_audio_format)
		FormatDebug(decoder_domain, "converting to %s",
			    audio_format_to_string(dc.out_audio_format,
						   &af_string));
}

/**
 * Checks if we need an "initial seek".  If so, then the initial seek
 * is prepared, and the function returns true.
 */
gcc_pure
static bool
decoder_prepare_initial_seek(Decoder &decoder)
{
	const decoder_control &dc = decoder.dc;
	assert(dc.pipe != nullptr);

	if (dc.state != DecoderState::DECODE)
		/* wait until the decoder has finished initialisation
		   (reading file headers etc.) before emitting the
		   virtual "SEEK" command */
		return false;

	if (decoder.initial_seek_running)
		/* initial seek has already begun - override any other
		   command */
		return true;

	if (decoder.initial_seek_pending) {
		if (!dc.seekable) {
			/* seeking is not possible */
			decoder.initial_seek_pending = false;
			return false;
		}

		if (dc.command == DecoderCommand::NONE) {
			/* begin initial seek */

			decoder.initial_seek_pending = false;
			decoder.initial_seek_running = true;
			return true;
		}

		/* skip initial seek when there's another command
		   (e.g. STOP) */

		decoder.initial_seek_pending = false;
	}

	return false;
}

/**
 * Returns the current decoder command.  May return a "virtual"
 * synthesized command, e.g. to seek to the beginning of the CUE
 * track.
 */
gcc_pure
static DecoderCommand
decoder_get_virtual_command(Decoder &decoder)
{
	const decoder_control &dc = decoder.dc;
	assert(dc.pipe != nullptr);

	if (decoder_prepare_initial_seek(decoder))
		return DecoderCommand::SEEK;

	return dc.command;
}

DecoderCommand
decoder_get_command(Decoder &decoder)
{
	return decoder_get_virtual_command(decoder);
}

void
decoder_command_finished(Decoder &decoder)
{
	decoder_control &dc = decoder.dc;

	dc.Lock();

	assert(dc.command != DecoderCommand::NONE ||
	       decoder.initial_seek_running);
	assert(dc.command != DecoderCommand::SEEK ||
	       decoder.initial_seek_running ||
	       dc.seek_error || decoder.seeking);
	assert(dc.pipe != nullptr);

	if (decoder.initial_seek_running) {
		assert(!decoder.seeking);
		assert(decoder.chunk == nullptr);
		assert(dc.pipe->IsEmpty());

		decoder.initial_seek_running = false;
		decoder.timestamp = dc.start_ms / 1000.;
		dc.Unlock();
		return;
	}

	if (decoder.seeking) {
		decoder.seeking = false;

		/* delete frames from the old song position */

		if (decoder.chunk != nullptr) {
			dc.buffer->Return(decoder.chunk);
			decoder.chunk = nullptr;
		}

		dc.pipe->Clear(*dc.buffer);

		decoder.timestamp = dc.seek_where;
	}

	dc.command = DecoderCommand::NONE;
	dc.client_cond.signal();
	dc.Unlock();
}

double decoder_seek_where(gcc_unused Decoder & decoder)
{
	const decoder_control &dc = decoder.dc;

	assert(dc.pipe != nullptr);

	if (decoder.initial_seek_running)
		return dc.start_ms / 1000.;

	assert(dc.command == DecoderCommand::SEEK);

	decoder.seeking = true;

	return dc.seek_where;
}

void decoder_seek_error(Decoder & decoder)
{
	decoder_control &dc = decoder.dc;

	assert(dc.pipe != nullptr);

	if (decoder.initial_seek_running) {
		/* d'oh, we can't seek to the sub-song start position,
		   what now? - no idea, ignoring the problem for now. */
		decoder.initial_seek_running = false;
		return;
	}

	assert(dc.command == DecoderCommand::SEEK);

	dc.seek_error = true;
	decoder.seeking = false;

	decoder_command_finished(decoder);
}

/**
 * Should be read operation be cancelled?  That is the case when the
 * player thread has sent a command such as "STOP".
 */
gcc_pure
static inline bool
decoder_check_cancel_read(const Decoder *decoder)
{
	if (decoder == nullptr)
		return false;

	const decoder_control &dc = decoder->dc;
	if (dc.command == DecoderCommand::NONE)
		return false;

	/* ignore the SEEK command during initialization, the plugin
	   should handle that after it has initialized successfully */
	if (dc.command == DecoderCommand::SEEK &&
	    (dc.state == DecoderState::START || decoder->seeking))
		return false;

	return true;
}

size_t
decoder_read(Decoder *decoder,
	     InputStream &is,
	     void *buffer, size_t length)
{
	/* XXX don't allow decoder==nullptr */

	assert(decoder == nullptr ||
	       decoder->dc.state == DecoderState::START ||
	       decoder->dc.state == DecoderState::DECODE);
	assert(buffer != nullptr);

	if (length == 0)
		return 0;

	is.Lock();

	while (true) {
		if (decoder_check_cancel_read(decoder)) {
			is.Unlock();
			return 0;
		}

		if (is.IsAvailable())
			break;

		is.cond.wait(is.mutex);
	}

	Error error;
	size_t nbytes = is.Read(buffer, length, error);
	assert(nbytes == 0 || !error.IsDefined());
	assert(nbytes > 0 || error.IsDefined() || is.IsEOF());

	if (gcc_unlikely(nbytes == 0 && error.IsDefined()))
		LogError(error);

	is.Unlock();

	return nbytes;
}

void
decoder_timestamp(Decoder &decoder, double t)
{
	assert(t >= 0);

	decoder.timestamp = t;
}

/**
 * Sends a #tag as-is to the music pipe.  Flushes the current chunk
 * (decoder.chunk) if there is one.
 */
static DecoderCommand
do_send_tag(Decoder &decoder, const Tag &tag)
{
	struct music_chunk *chunk;

	if (decoder.chunk != nullptr) {
		/* there is a partial chunk - flush it, we want the
		   tag in a new chunk */
		decoder_flush_chunk(decoder);
		decoder.dc.client_cond.signal();
	}

	assert(decoder.chunk == nullptr);

	chunk = decoder_get_chunk(decoder);
	if (chunk == nullptr) {
		assert(decoder.dc.command != DecoderCommand::NONE);
		return decoder.dc.command;
	}

	chunk->tag = new Tag(tag);
	return DecoderCommand::NONE;
}

static bool
update_stream_tag(Decoder &decoder, InputStream *is)
{
	Tag *tag;

	tag = is != nullptr
		? is->LockReadTag()
		: nullptr;
	if (tag == nullptr) {
		tag = decoder.song_tag;
		if (tag == nullptr)
			return false;

		/* no stream tag present - submit the song tag
		   instead */
		decoder.song_tag = nullptr;
	}

	delete decoder.stream_tag;
	decoder.stream_tag = tag;
	return true;
}

DecoderCommand
decoder_data(Decoder &decoder,
	     InputStream *is,
	     const void *data, size_t length,
	     uint16_t kbit_rate)
{
	decoder_control &dc = decoder.dc;
	DecoderCommand cmd;

	assert(dc.state == DecoderState::DECODE);
	assert(dc.pipe != nullptr);
	assert(length % dc.in_audio_format.GetFrameSize() == 0);

	dc.Lock();
	cmd = decoder_get_virtual_command(decoder);
	dc.Unlock();

	if (cmd == DecoderCommand::STOP || cmd == DecoderCommand::SEEK ||
	    length == 0)
		return cmd;

	/* send stream tags */

	if (update_stream_tag(decoder, is)) {
		if (decoder.decoder_tag != nullptr) {
			/* merge with tag from decoder plugin */
			Tag *tag = Tag::Merge(*decoder.decoder_tag,
					      *decoder.stream_tag);
			cmd = do_send_tag(decoder, *tag);
			delete tag;
		} else
			/* send only the stream tag */
			cmd = do_send_tag(decoder, *decoder.stream_tag);

		if (cmd != DecoderCommand::NONE)
			return cmd;
	}

	if (dc.in_audio_format != dc.out_audio_format) {
		Error error;
		data = decoder.conv_state.Convert(dc.in_audio_format,
						   data, length,
						   dc.out_audio_format,
						   &length,
						   error);
		if (data == nullptr) {
			/* the PCM conversion has failed - stop
			   playback, since we have no better way to
			   bail out */
			LogError(error);
			return DecoderCommand::STOP;
		}
	}

	while (length > 0) {
		struct music_chunk *chunk;
		size_t nbytes;
		bool full;

		chunk = decoder_get_chunk(decoder);
		if (chunk == nullptr) {
			assert(dc.command != DecoderCommand::NONE);
			return dc.command;
		}

		void *dest = chunk->Write(dc.out_audio_format,
					  decoder.timestamp -
					  dc.song->start_ms / 1000.0,
					  kbit_rate, &nbytes);
		if (dest == nullptr) {
			/* the chunk is full, flush it */
			decoder_flush_chunk(decoder);
			dc.client_cond.signal();
			continue;
		}

		assert(nbytes > 0);

		if (nbytes > length)
			nbytes = length;

		/* copy the buffer */

		memcpy(dest, data, nbytes);

		/* expand the music pipe chunk */

		full = chunk->Expand(dc.out_audio_format, nbytes);
		if (full) {
			/* the chunk is full, flush it */
			decoder_flush_chunk(decoder);
			dc.client_cond.signal();
		}

		data = (const uint8_t *)data + nbytes;
		length -= nbytes;

		decoder.timestamp += (double)nbytes /
			dc.out_audio_format.GetTimeToSize();

		if (dc.end_ms > 0 &&
		    decoder.timestamp >= dc.end_ms / 1000.0)
			/* the end of this range has been reached:
			   stop decoding */
			return DecoderCommand::STOP;
	}

	return DecoderCommand::NONE;
}

DecoderCommand
decoder_tag(Decoder &decoder, InputStream *is,
	    Tag &&tag)
{
	gcc_unused const decoder_control &dc = decoder.dc;
	DecoderCommand cmd;

	assert(dc.state == DecoderState::DECODE);
	assert(dc.pipe != nullptr);

	/* save the tag */

	delete decoder.decoder_tag;
	decoder.decoder_tag = new Tag(tag);

	/* check for a new stream tag */

	update_stream_tag(decoder, is);

	/* check if we're seeking */

	if (decoder_prepare_initial_seek(decoder))
		/* during initial seek, no music chunk must be created
		   until seeking is finished; skip the rest of the
		   function here */
		return DecoderCommand::SEEK;

	/* send tag to music pipe */

	if (decoder.stream_tag != nullptr) {
		/* merge with tag from input stream */
		Tag *merged;

		merged = Tag::Merge(*decoder.stream_tag,
				    *decoder.decoder_tag);
		cmd = do_send_tag(decoder, *merged);
		delete merged;
	} else
		/* send only the decoder tag */
		cmd = do_send_tag(decoder, *decoder.decoder_tag);

	return cmd;
}

void
decoder_replay_gain(Decoder &decoder,
		    const ReplayGainInfo *replay_gain_info)
{
	if (replay_gain_info != nullptr) {
		static unsigned serial;
		if (++serial == 0)
			serial = 1;

		if (REPLAY_GAIN_OFF != replay_gain_mode) {
			ReplayGainMode rgm = replay_gain_mode;
			if (rgm != REPLAY_GAIN_ALBUM)
				rgm = REPLAY_GAIN_TRACK;

			const auto &tuple = replay_gain_info->tuples[rgm];
			const auto scale =
				tuple.CalculateScale(replay_gain_preamp,
						     replay_gain_missing_preamp,
						     replay_gain_limit);
			decoder.dc.replay_gain_db = 20.0 * log10f(scale);
		}

		decoder.replay_gain_info = *replay_gain_info;
		decoder.replay_gain_serial = serial;

		if (decoder.chunk != nullptr) {
			/* flush the current chunk because the new
			   replay gain values affect the following
			   samples */
			decoder_flush_chunk(decoder);
			decoder.dc.client_cond.signal();
		}
	} else
		decoder.replay_gain_serial = 0;
}

void
decoder_mixramp(Decoder &decoder, MixRampInfo &&mix_ramp)
{
	decoder_control &dc = decoder.dc;

	dc.SetMixRamp(std::move(mix_ramp));
}