aboutsummaryrefslogtreecommitdiffstats
path: root/src/player_thread.c
blob: e648ab375467ae9d01b23c5a80b79ec97922741d (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
/*
 * Copyright (C) 2003-2009 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 "player_thread.h"
#include "player_control.h"
#include "decoder_control.h"
#include "decoder_thread.h"
#include "output_all.h"
#include "pcm_volume.h"
#include "path.h"
#include "event_pipe.h"
#include "crossfade.h"
#include "song.h"
#include "tag.h"
#include "pipe.h"
#include "chunk.h"
#include "idle.h"
#include "main.h"
#include "buffer.h"

#include <glib.h>

#undef G_LOG_DOMAIN
#define G_LOG_DOMAIN "player_thread"

enum xfade_state {
	XFADE_DISABLED = -1,
	XFADE_UNKNOWN = 0,
	XFADE_ENABLED = 1
};

struct player {
	struct decoder_control *dc;

	struct music_pipe *pipe;

	/**
	 * are we waiting for buffered_before_play?
	 */
	bool buffering;

	/**
	 * true if the decoder is starting and did not provide data
	 * yet
	 */
	bool decoder_starting;

	/**
	 * is the player paused?
	 */
	bool paused;

	/**
	 * is there a new song in pc.next_song?
	 */
	bool queued;

	/**
	 * the song currently being played
	 */
	struct song *song;

	/**
	 * is cross fading enabled?
	 */
	enum xfade_state xfade;

	/**
	 * has cross-fading begun?
	 */
	bool cross_fading;

	/**
	 * The number of chunks used for crossfading.
	 */
	unsigned cross_fade_chunks;

	/**
	 * The current audio format for the audio outputs.
	 */
	struct audio_format play_audio_format;

	/**
	 * The time stamp of the chunk most recently sent to the
	 * output thread.  This attribute is only used if
	 * audio_output_all_get_elapsed_time() didn't return a usable
	 * value; the output thread can estimate the elapsed time more
	 * precisly.
	 */
	float elapsed_time;
};

static struct music_buffer *player_buffer;

static void player_command_finished_locked(void)
{
	assert(pc.command != PLAYER_COMMAND_NONE);

	pc.command = PLAYER_COMMAND_NONE;
	g_cond_signal(main_cond);
}

static void player_command_finished(void)
{
	player_lock();
	player_command_finished_locked();
	player_unlock();
}

/**
 * Stop the decoder and clears (and frees) its music pipe.
 *
 * Player lock is not held.
 */
static void
player_dc_stop(struct player *player)
{
	struct decoder_control *dc = player->dc;

	dc_stop(dc);

	if (dc->pipe != NULL) {
		/* clear and free the decoder pipe */

		music_pipe_clear(dc->pipe, player_buffer);

		if (dc->pipe != player->pipe)
			music_pipe_free(dc->pipe);

		dc->pipe = NULL;
	}
}

/**
 * After the decoder has been started asynchronously, wait for the
 * "START" command to finish.  The decoder may not be initialized yet,
 * i.e. there is no audio_format information yet.
 *
 * The player lock is not held.
 */
static bool
player_wait_for_decoder(struct player *player)
{
	struct decoder_control *dc = player->dc;

	if (decoder_lock_has_failed(dc)) {
		assert(dc->next_song == NULL || dc->next_song->uri != NULL);

		player_lock();
		pc.errored_song = dc->next_song;
		pc.error = PLAYER_ERROR_FILE;
		pc.next_song = NULL;
		player_unlock();

		player->queued = false;
		return false;
	}

	pc.total_time = pc.next_song->tag != NULL
		? pc.next_song->tag->time : 0;
	pc.bit_rate = 0;
	audio_format_clear(&pc.audio_format);

	player->song = pc.next_song;
	pc.next_song = NULL;
	player->queued = false;
	player->elapsed_time = 0.0;

	/* set the "starting" flag, which will be cleared by
	   player_check_decoder_startup() */
	player->decoder_starting = true;

	/* call syncPlaylistWithQueue() in the main thread */
	event_pipe_emit(PIPE_EVENT_PLAYLIST);

	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 decoder_control *dc = player->dc;

	assert(player->decoder_starting);

	decoder_lock(dc);

	if (decoder_has_failed(dc)) {
		/* the decoder failed */
		assert(dc->next_song == NULL || dc->next_song->uri != NULL);

		decoder_unlock(dc);

		pc.errored_song = dc->next_song;
		pc.error = PLAYER_ERROR_FILE;

		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(1))
			/* the output devices havn't finished playing
			   all chunks yet - wait for that */
			return true;

		pc.total_time = dc->total_time;
		pc.audio_format = dc->in_audio_format;
		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->next_song);
			g_warning("problems opening audio device "
				  "while playing \"%s\"", uri);
			g_free(uri);

			assert(dc->next_song == NULL || dc->next_song->uri != NULL);
			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;
			return true;
		}

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

		return true;
	}
}

/**
 * Sends a chunk of silence to the audio outputs.  This is called when
 * there is not enough decoded data in the pipe yet, to prevent
 * underruns in the hardware buffers.
 *
 * The player lock is not held.
 */
static bool
player_send_silence(struct player *player)
{
	struct music_chunk *chunk;
	size_t frame_size =
		audio_format_frame_size(&player->play_audio_format);
	/* this formula ensures that we don't send
	   partial frames */
	unsigned num_frames = sizeof(chunk->data) / frame_size;

	assert(audio_format_defined(&player->play_audio_format));

	chunk = music_buffer_allocate(player_buffer);
	if (chunk == NULL) {
		g_warning("Failed to allocate silence buffer");
		return false;
	}

#ifndef NDEBUG
	chunk->audio_format = player->play_audio_format;
#endif

	chunk->length = num_frames * frame_size;
	memset(chunk->data, 0, chunk->length);

	if (!audio_output_all_play(chunk)) {
		music_buffer_return(player_buffer, chunk);
		return false;
	}

	return true;
}

/**
 * This is the handler for the #PLAYER_COMMAND_SEEK command.
 *
 * The player lock is not held.
 */
static bool player_seek_decoder(struct player *player)
{
	struct decoder_control *dc = player->dc;
	double where;
	bool ret;

	assert(pc.next_song != NULL);

	if (decoder_current_song(dc) != pc.next_song) {
		/* the decoder is already decoding the "next" song -
		   stop it and start the previous song again */

		player_dc_stop(player);

		/* clear music chunks which might still reside in the
		   pipe */
		music_pipe_clear(player->pipe, player_buffer);
		dc->pipe = player->pipe;

		/* re-start the decoder */
		dc_start(dc, pc.next_song);
		ret = player_wait_for_decoder(player);
		if (!ret) {
			/* decoder failure */
			player_command_finished();
			return false;
		}
	} else {
		pc.next_song = NULL;
		player->queued = false;
	}

	/* wait for the decoder to complete initialization */

	while (player->decoder_starting) {
		ret = player_check_decoder_startup(player);
		if (!ret) {
			/* decoder failure */
			player_command_finished();
			return false;
		}
	}

	/* send the SEEK command */

	where = pc.seek_where;
	if (where > pc.total_time)
		where = pc.total_time - 0.1;
	if (where < 0.0)
		where = 0.0;

	ret = dc_seek(dc, where);
	if (!ret) {
		/* decoder failure */
		player_command_finished();
		return false;
	}

	player->elapsed_time = where;

	player_command_finished();

	player->xfade = XFADE_UNKNOWN;

	/* re-fill the buffer after seeking */
	player->buffering = true;

	audio_output_all_cancel();

	return true;
}

/**
 * Player lock must be held before calling.
 */
static void player_process_command(struct player *player)
{
	struct decoder_control *dc = player->dc;

	switch (pc.command) {
	case PLAYER_COMMAND_NONE:
	case PLAYER_COMMAND_STOP:
	case PLAYER_COMMAND_EXIT:
	case PLAYER_COMMAND_CLOSE_AUDIO:
		break;

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

	case PLAYER_COMMAND_QUEUE:
		assert(pc.next_song != NULL);
		assert(!player->queued);
		assert(dc->pipe == NULL || dc->pipe == player->pipe);

		player->queued = true;
		player_command_finished_locked();
		break;

	case PLAYER_COMMAND_PAUSE:
		player_unlock();

		player->paused = !player->paused;
		if (player->paused) {
			audio_output_all_pause();
			player_lock();

			pc.state = PLAYER_STATE_PAUSE;
		} else if (!audio_format_defined(&player->play_audio_format)) {
			/* the decoder hasn't provided an audio format
			   yet - don't open the audio device yet */
			player_lock();

			pc.state = PLAYER_STATE_PLAY;
		} else if (audio_output_all_open(&player->play_audio_format, player_buffer)) {
			/* unpaused, continue playing */
			player_lock();

			pc.state = PLAYER_STATE_PLAY;
		} else {
			/* the audio device has failed - rollback to
			   pause mode */
			assert(dc->next_song == NULL || dc->next_song->uri != NULL);
			pc.error = PLAYER_ERROR_AUDIO;

			player->paused = true;

			player_lock();
		}

		player_command_finished_locked();
		break;

	case PLAYER_COMMAND_SEEK:
		player_unlock();
		player_seek_decoder(player);
		player_lock();
		break;

	case PLAYER_COMMAND_CANCEL:
		if (pc.next_song == NULL) {
			/* the cancel request arrived too late, we're
			   already playing the queued song...  stop
			   everything now */
			pc.command = PLAYER_COMMAND_STOP;
			return;
		}

		if (dc->pipe != NULL && dc->pipe != player->pipe) {
			/* the decoder is already decoding the song -
			   stop it and reset the position */
			player_unlock();
			player_dc_stop(player);
			player_lock();
		}

		pc.next_song = NULL;
		player->queued = false;
		player_command_finished_locked();
		break;

	case PLAYER_COMMAND_REFRESH:
		if (audio_format_defined(&player->play_audio_format) &&
		    !player->paused) {
			player_unlock();
			audio_output_all_check();
			player_lock();
		}

		pc.elapsed_time = audio_output_all_get_elapsed_time();
		if (pc.elapsed_time < 0.0)
			pc.elapsed_time = player->elapsed_time;

		player_command_finished_locked();
		break;
	}
}

static void
update_song_tag(struct song *song, const struct tag *new_tag)
{
	struct tag *old_tag;

	if (song_is_file(song))
		/* don't update tags of local files, only remote
		   streams may change tags dynamically */
		return;

	old_tag = song->tag;
	song->tag = tag_dup(new_tag);

	if (old_tag != NULL)
		tag_free(old_tag);

	/* the main thread will update the playlist version when he
	   receives this event */
	event_pipe_emit(PIPE_EVENT_TAG);

	/* notify all clients that the tag of the current song has
	   changed */
	idle_add(IDLE_PLAYER);
}

/**
 * Plays a #music_chunk object (after applying software volume).  If
 * it contains a (stream) tag, copy it to the current song, so MPD's
 * playlist reflects the new stream tag.
 *
 * Player lock is not held.
 */
static bool
play_chunk(struct song *song, struct music_chunk *chunk,
	   const struct audio_format *format)
{
	assert(music_chunk_check_format(chunk, format));

	if (chunk->tag != NULL)
		update_song_tag(song, chunk->tag);

	if (chunk->length == 0) {
		music_buffer_return(player_buffer, chunk);
		return true;
	}

	pc.bit_rate = chunk->bit_rate;

	/* send the chunk to the audio outputs */

	if (!audio_output_all_play(chunk))
		return false;

	pc.total_play_time += (double)chunk->length /
		audio_format_time_to_size(format);
	return true;
}

/**
 * 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 decoder_control *dc = player->dc;
	struct music_chunk *chunk = NULL;
	unsigned cross_fade_position;
	bool success;

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

	if (player->xfade == XFADE_ENABLED &&
	    dc->pipe != NULL && dc->pipe != player->pipe &&
	    (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);

			cross_fade_apply(chunk, other_chunk,
					 &dc->out_audio_format,
					 cross_fade_position,
					 player->cross_fade_chunks);
			music_buffer_return(player_buffer, 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(dc);
				decoder_unlock(dc);

				return true;
			}
		}
	}

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

	assert(chunk != NULL);

	/* play the current chunk */

	success = play_chunk(player->song, chunk, &player->play_audio_format);

	if (!success) {
		music_buffer_return(player_buffer, chunk);

		player_lock();

		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();

		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;
}

/**
 * This is called at the border between two songs: the audio output
 * has consumed all chunks of the current song, and we should start
 * sending chunks from the next one.
 *
 * The player lock is not held.
 *
 * @return true on success, false on error (playback will be stopped)
 */
static bool
player_song_border(struct player *player)
{
	char *uri;

	player->xfade = XFADE_UNKNOWN;

	uri = song_get_uri(player->song);
	g_message("played \"%s\"", uri);
	g_free(uri);

	music_pipe_free(player->pipe);
	player->pipe = player->dc->pipe;

	if (!player_wait_for_decoder(player))
		return false;

	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 decoder_control *dc)
{
	struct player player = {
		.dc = dc,
		.buffering = true,
		.decoder_starting = false,
		.paused = false,
		.queued = false,
		.song = NULL,
		.xfade = XFADE_UNKNOWN,
		.cross_fading = false,
		.cross_fade_chunks = 0,
		.elapsed_time = 0.0,
	};

	player_unlock();

	player.pipe = music_pipe_new();

	dc->buffer = player_buffer;
	dc->pipe = player.pipe;
	dc_start(dc, pc.next_song);
	if (!player_wait_for_decoder(&player)) {
		player_dc_stop(&player);
		player_command_finished();
		music_pipe_free(player.pipe);
		event_pipe_emit(PIPE_EVENT_PLAYLIST);
		player_lock();
		return;
	}

	player_lock();
	pc.state = PLAYER_STATE_PLAY;
	player_command_finished_locked();

	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();
			audio_output_all_cancel();
			break;
		}

		player_unlock();

		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(dc);
				decoder_unlock(dc);
				player_lock();
				continue;
			} else {
				/* buffering is complete */
				player.buffering = false;
			}
		}

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

			success = player_check_decoder_startup(&player);
			if (!success)
				break;

			player_lock();
			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) {
			/* the decoder has finished the current song;
			   make it decode the next song */
			assert(pc.next_song != NULL);
			assert(dc->pipe == NULL || dc->pipe == player.pipe);

			player.queued = false;
			dc->pipe = music_pipe_new();
			dc_start(dc, pc.next_song);
		}

		if (dc->pipe != NULL && dc->pipe != player.pipe &&
		    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,
						&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();

			if (pc.command == PLAYER_COMMAND_NONE)
				player_wait();
			continue;
		} else if (music_pipe_size(player.pipe) > 0) {
			/* 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 (dc->pipe != NULL && dc->pipe != player.pipe) {
			/* 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_size(player.pipe) == 0)
				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();
	}

	player_dc_stop(&player);

	assert(!player.queued || pc.next_song != NULL);
	pc.next_song = NULL;

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

	player_lock();
	pc.state = PLAYER_STATE_STOP;
	player_unlock();

	event_pipe_emit(PIPE_EVENT_PLAYLIST);

	player_lock();
}

static gpointer player_task(G_GNUC_UNUSED gpointer arg)
{
	struct decoder_control dc;

	dc_init(&dc);
	decoder_thread_start(&dc);

	player_buffer = music_buffer_new(pc.buffer_chunks);

	player_lock();

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

			do_play(&dc);
			break;

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

			/* fall through */

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

		case PLAYER_COMMAND_CLOSE_AUDIO:
			player_unlock();

			audio_output_all_close();

			player_lock();
			player_command_finished_locked();

#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();
			audio_output_all_enable_disable();
			player_lock();
			player_command_finished_locked();
			break;

		case PLAYER_COMMAND_EXIT:
			player_unlock();

			dc_quit(&dc);
			dc_deinit(&dc);
			audio_output_all_close();
			music_buffer_free(player_buffer);

			player_command_finished();
			return NULL;

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

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

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

void player_create(void)
{
	GError *e = NULL;

	assert(pc.thread == NULL);

	pc.thread = g_thread_create(player_task, NULL, true, &e);
	if (pc.thread == NULL)
		g_error("Failed to spawn player task: %s", e->message);
}