Beispiel #1
0
/**
 * The decoder has acknowledged the "START" command (see
 * player_wait_for_decoder()).  This function checks if the decoder
 * initialization has completed yet.
 *
 * The player lock is not held.
 */
static bool
player_check_decoder_startup(struct player *player)
{
	struct player_control *pc = player->pc;
	struct decoder_control *dc = player->dc;

	assert(player->decoder_starting);

	decoder_lock(dc);

	GError *error = dc_get_error(dc);
	if (error != NULL) {
		/* the decoder failed */
		decoder_unlock(dc);

		player_lock(pc);
		pc_set_error(pc, PLAYER_ERROR_DECODER, error);
		player_unlock(pc);

		return false;
	} else if (!decoder_is_starting(dc)) {
		/* the decoder is ready and ok */

		decoder_unlock(dc);

		if (player->output_open &&
		    !audio_output_all_wait(pc, 1))
			/* the output devices havn't finished playing
			   all chunks yet - wait for that */
			return true;

		player_lock(pc);
		pc->total_time = real_song_duration(dc->song, dc->total_time);
		pc->audio_format = dc->in_audio_format;
		player_unlock(pc);

		player->play_audio_format = dc->out_audio_format;
		player->decoder_starting = false;

		if (!player->paused && !player_open_output(player)) {
			char *uri = song_get_uri(dc->song);
			g_warning("problems opening audio device "
				  "while playing \"%s\"", uri);
			g_free(uri);

			return true;
		}

		return true;
	} else {
		/* the decoder is not yet ready; wait
		   some more */
		player_wait_decoder(pc, dc);
		decoder_unlock(dc);

		return true;
	}
}
/*
 * The main loop of the player thread, during playback.  This is
 * basically a state machine, which multiplexes data between the
 * decoder thread and the output threads.
 */
static void do_play(struct player_control *pc, struct decoder_control *dc)
{
	struct player player = {
		.pc = pc,
		.dc = dc,
		.buffering = true,
		.decoder_starting = false,
		.paused = false,
		.queued = true,
		.song = NULL,
		.xfade = XFADE_UNKNOWN,
		.cross_fading = false,
		.cross_fade_chunks = 0,
		.cross_fade_tag = NULL,
		.elapsed_time = 0.0,
	};

	player_unlock(pc);

	player.pipe = music_pipe_new();

	player_dc_start(&player, player.pipe);
	if (!player_wait_for_decoder(&player)) {
		player_dc_stop(&player);
		player_command_finished(pc);
		music_pipe_free(player.pipe);
		event_pipe_emit(PIPE_EVENT_PLAYLIST);
		player_lock(pc);
		return;
	}

	player_lock(pc);
	pc->state = PLAYER_STATE_PLAY;
	player_command_finished_locked(pc);

	while (true) {
		player_process_command(&player);
		if (pc->command == PLAYER_COMMAND_STOP ||
		    pc->command == PLAYER_COMMAND_EXIT ||
		    pc->command == PLAYER_COMMAND_CLOSE_AUDIO) {
			player_unlock(pc);
			audio_output_all_cancel();
			break;
		}

		player_unlock(pc);

		if (player.buffering) {
			/* buffering at the start of the song - wait
			   until the buffer is large enough, to
			   prevent stuttering on slow machines */

			if (music_pipe_size(player.pipe) < pc->buffered_before_play &&
			    !decoder_lock_is_idle(dc)) {
				/* not enough decoded buffer space yet */

				if (!player.paused &&
				    audio_format_defined(&player.play_audio_format) &&
				    audio_output_all_check() < 4 &&
				    !player_send_silence(&player))
					break;

				decoder_lock(dc);
				/* XXX race condition: check decoder again */
				player_wait_decoder(pc, dc);
				decoder_unlock(dc);
				player_lock(pc);
				continue;
			} else {
				/* buffering is complete */
				player.buffering = false;
			}
		}

		if (player.decoder_starting) {
			/* wait until the decoder is initialized completely */

			if (!player_check_decoder_startup(&player))
				break;

			player_lock(pc);
			continue;
		}

#ifndef NDEBUG
		/*
		music_pipe_check_format(&play_audio_format,
					player.next_song_chunk,
					&dc->out_audio_format);
		*/
#endif

		if (decoder_lock_is_idle(dc) && player.queued &&
		    dc->pipe == player.pipe) {
			/* the decoder has finished the current song;
			   make it decode the next song */

			assert(dc->pipe == NULL || dc->pipe == player.pipe);

			player_dc_start(&player, music_pipe_new());
		}

		if (player_dc_at_next_song(&player) &&
		    player.xfade == XFADE_UNKNOWN &&
		    !decoder_lock_is_starting(dc)) {
			/* enable cross fading in this song?  if yes,
			   calculate how many chunks will be required
			   for it */
			player.cross_fade_chunks =
				cross_fade_calc(pc->cross_fade_seconds, dc->total_time,
						pc->mixramp_db,
						pc->mixramp_delay_seconds,
						dc->replay_gain_db,
						dc->replay_gain_prev_db,
						dc->mixramp_start,
						dc->mixramp_prev_end,
						&dc->out_audio_format,
						&player.play_audio_format,
						music_buffer_size(player_buffer) -
						pc->buffered_before_play);
			if (player.cross_fade_chunks > 0) {
				player.xfade = XFADE_ENABLED;
				player.cross_fading = false;
			} else
				/* cross fading is disabled or the
				   next song is too short */
				player.xfade = XFADE_DISABLED;
		}

		if (player.paused) {
			player_lock(pc);

			if (pc->command == PLAYER_COMMAND_NONE)
				player_wait(pc);
			continue;
		} else if (!music_pipe_empty(player.pipe)) {
			/* at least one music chunk is ready - send it
			   to the audio output */

			play_next_chunk(&player);
		} else if (audio_output_all_check() > 0) {
			/* not enough data from decoder, but the
			   output thread is still busy, so it's
			   okay */

			/* XXX synchronize in a better way */
			g_usleep(10000);
		} else if (player_dc_at_next_song(&player)) {
			/* at the beginning of a new song */

			if (!player_song_border(&player))
				break;
		} else if (decoder_lock_is_idle(dc)) {
			/* check the size of the pipe again, because
			   the decoder thread may have added something
			   since we last checked */
			if (music_pipe_empty(player.pipe)) {
				/* wait for the hardware to finish
				   playback */
				audio_output_all_drain();
				break;
			}
		} else {
			/* the decoder is too busy and hasn't provided
			   new PCM data in time: send silence (if the
			   output pipe is empty) */
			if (!player_send_silence(&player))
				break;
		}

		player_lock(pc);
	}

	player_dc_stop(&player);

	music_pipe_clear(player.pipe, player_buffer);
	music_pipe_free(player.pipe);

	if (player.cross_fade_tag != NULL)
		tag_free(player.cross_fade_tag);

	player_lock(pc);

	if (player.queued) {
		assert(pc->next_song != NULL);
		pc->next_song = NULL;
	}

	pc->state = PLAYER_STATE_STOP;

	player_unlock(pc);

	event_pipe_emit(PIPE_EVENT_PLAYLIST);

	player_lock(pc);
}

static gpointer
player_task(gpointer arg)
{
	struct player_control *pc = arg;

	struct decoder_control *dc = dc_new(pc->cond);
	decoder_thread_start(dc);

	player_buffer = music_buffer_new(pc->buffer_chunks);

	player_lock(pc);

	while (1) {
		switch (pc->command) {
		case PLAYER_COMMAND_QUEUE:
			assert(pc->next_song != NULL);

			do_play(pc, dc);
			break;

		case PLAYER_COMMAND_STOP:
			player_unlock(pc);
			audio_output_all_cancel();
			player_lock(pc);

			/* fall through */

		case PLAYER_COMMAND_SEEK:
		case PLAYER_COMMAND_PAUSE:
			pc->next_song = NULL;
			player_command_finished_locked(pc);
			break;

		case PLAYER_COMMAND_CLOSE_AUDIO:
			player_unlock(pc);

			audio_output_all_release();

			player_lock(pc);
			player_command_finished_locked(pc);

#ifndef NDEBUG
			/* in the DEBUG build, check for leaked
			   music_chunk objects by freeing the
			   music_buffer */
			music_buffer_free(player_buffer);
			player_buffer = music_buffer_new(pc->buffer_chunks);
#endif

			break;

		case PLAYER_COMMAND_UPDATE_AUDIO:
			player_unlock(pc);
			audio_output_all_enable_disable();
			player_lock(pc);
			player_command_finished_locked(pc);
			break;

		case PLAYER_COMMAND_EXIT:
			player_unlock(pc);

			dc_quit(dc);
			dc_free(dc);
			audio_output_all_close();
			music_buffer_free(player_buffer);

			player_command_finished(pc);
			return NULL;

		case PLAYER_COMMAND_CANCEL:
			pc->next_song = NULL;
			player_command_finished_locked(pc);
			break;

		case PLAYER_COMMAND_REFRESH:
			/* no-op when not playing */
			player_command_finished_locked(pc);
			break;

		case PLAYER_COMMAND_NONE:
			player_wait(pc);
			break;
		}
	}
}

void
player_create(struct player_control *pc)
{
	assert(pc->thread == NULL);

	GError *e = NULL;
	pc->thread = g_thread_create(player_task, pc, true, &e);
	if (pc->thread == NULL)
		MPD_ERROR("Failed to spawn player task: %s", e->message);
}
/**
 * Obtains the next chunk from the music pipe, optionally applies
 * cross-fading, and sends it to all audio outputs.
 *
 * @return true on success, false on error (playback will be stopped)
 */
static bool
play_next_chunk(struct player *player)
{
	struct player_control *pc = player->pc;
	struct decoder_control *dc = player->dc;

	if (!audio_output_all_wait(pc, 64))
		/* the output pipe is still large enough, don't send
		   another chunk */
		return true;

	unsigned cross_fade_position;
	struct music_chunk *chunk = NULL;
	if (player->xfade == XFADE_ENABLED &&
	    player_dc_at_next_song(player) &&
	    (cross_fade_position = music_pipe_size(player->pipe))
	    <= player->cross_fade_chunks) {
		/* perform cross fade */
		struct music_chunk *other_chunk =
			music_pipe_shift(dc->pipe);

		if (!player->cross_fading) {
			/* beginning of the cross fade - adjust
			   crossFadeChunks which might be bigger than
			   the remaining number of chunks in the old
			   song */
			player->cross_fade_chunks = cross_fade_position;
			player->cross_fading = true;
		}

		if (other_chunk != NULL) {
			chunk = music_pipe_shift(player->pipe);
			assert(chunk != NULL);
			assert(chunk->other == NULL);

			/* don't send the tags of the new song (which
			   is being faded in) yet; postpone it until
			   the current song is faded out */
			player->cross_fade_tag =
				tag_merge_replace(player->cross_fade_tag,
						  other_chunk->tag);
			other_chunk->tag = NULL;

			if (isnan(pc->mixramp_delay_seconds)) {
				chunk->mix_ratio = ((float)cross_fade_position)
					     / player->cross_fade_chunks;
			} else {
				chunk->mix_ratio = nan("");
			}

			if (music_chunk_is_empty(other_chunk)) {
				/* the "other" chunk was a music_chunk
				   which had only a tag, but no music
				   data - we cannot cross-fade that;
				   but since this happens only at the
				   beginning of the new song, we can
				   easily recover by throwing it away
				   now */
				music_buffer_return(player_buffer,
						    other_chunk);
				other_chunk = NULL;
			}

			chunk->other = other_chunk;
		} else {
			/* there are not enough decoded chunks yet */

			decoder_lock(dc);

			if (decoder_is_idle(dc)) {
				/* the decoder isn't running, abort
				   cross fading */
				decoder_unlock(dc);

				player->xfade = XFADE_DISABLED;
			} else {
				/* wait for the decoder */
				decoder_signal(dc);
				player_wait_decoder(pc, dc);
				decoder_unlock(dc);

				return true;
			}
		}
	}

	if (chunk == NULL)
		chunk = music_pipe_shift(player->pipe);

	assert(chunk != NULL);

	/* insert the postponed tag if cross-fading is finished */

	if (player->xfade != XFADE_ENABLED && player->cross_fade_tag != NULL) {
		chunk->tag = tag_merge_replace(chunk->tag,
					       player->cross_fade_tag);
		player->cross_fade_tag = NULL;
	}

	/* play the current chunk */

	if (!play_chunk(player->pc, player->song, chunk,
			&player->play_audio_format)) {
		music_buffer_return(player_buffer, chunk);

		player_lock(pc);

		pc->error = PLAYER_ERROR_AUDIO;

		/* pause: the user may resume playback as soon as an
		   audio output becomes available */
		pc->state = PLAYER_STATE_PAUSE;
		player->paused = true;

		player_unlock(pc);

		return false;
	}

	/* this formula should prevent that the decoder gets woken up
	   with each chunk; it is more efficient to make it decode a
	   larger block at a time */
	decoder_lock(dc);
	if (!decoder_is_idle(dc) &&
	    music_pipe_size(dc->pipe) <= (pc->buffered_before_play +
					 music_buffer_size(player_buffer) * 3) / 4)
		decoder_signal(dc);
	decoder_unlock(dc);

	return true;
}
/**
 * The decoder has acknowledged the "START" command (see
 * player_wait_for_decoder()).  This function checks if the decoder
 * initialization has completed yet.
 *
 * The player lock is not held.
 */
static bool
player_check_decoder_startup(struct player *player)
{
	struct player_control *pc = player->pc;
	struct decoder_control *dc = player->dc;

	assert(player->decoder_starting);

	decoder_lock(dc);

	if (decoder_has_failed(dc)) {
		/* the decoder failed */
		decoder_unlock(dc);

		player_lock(pc);
		pc->errored_song = dc->song;
		pc->error = PLAYER_ERROR_FILE;
		player_unlock(pc);

		return false;
	} else if (!decoder_is_starting(dc)) {
		/* the decoder is ready and ok */

		decoder_unlock(dc);

		if (audio_format_defined(&player->play_audio_format) &&
		    !audio_output_all_wait(pc, 1))
			/* the output devices havn't finished playing
			   all chunks yet - wait for that */
			return true;

		player_lock(pc);
		pc->total_time = real_song_duration(dc->song, dc->total_time);
		pc->audio_format = dc->in_audio_format;
		player_unlock(pc);

		player->play_audio_format = dc->out_audio_format;
		player->decoder_starting = false;

		if (!player->paused &&
		    !audio_output_all_open(&dc->out_audio_format,
					   player_buffer)) {
			char *uri = song_get_uri(dc->song);
			g_warning("problems opening audio device "
				  "while playing \"%s\"", uri);
			g_free(uri);

			player_lock(pc);
			pc->error = PLAYER_ERROR_AUDIO;

			/* pause: the user may resume playback as soon
			   as an audio output becomes available */
			pc->state = PLAYER_STATE_PAUSE;
			player_unlock(pc);

			player->paused = true;
			return true;
		}

		return true;
	} else {
		/* the decoder is not yet ready; wait
		   some more */
		player_wait_decoder(pc, dc);
		decoder_unlock(dc);

		return true;
	}
}