summaryrefslogtreecommitdiffstats
path: root/audio/out/ao_pulse.c
blob: d553b6700c6b977a9dc9cf4bdb9cda4952883019 (plain)
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
/*
 * PulseAudio audio output driver.
 * Copyright (C) 2006 Lennart Poettering
 * Copyright (C) 2007 Reimar Doeffinger
 *
 * This file is part of mpv.
 *
 * mpv 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.
 *
 * mpv 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 mpv.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <stdint.h>
#include <pthread.h>

#include <pulse/pulseaudio.h>

#include "config.h"
#include "audio/format.h"
#include "common/msg.h"
#include "options/m_option.h"
#include "ao.h"
#include "internal.h"

#define VOL_PA2MP(v) ((v) * 100 / PA_VOLUME_NORM)
#define VOL_MP2PA(v) ((v) * PA_VOLUME_NORM / 100)

struct priv {
    // PulseAudio playback stream object
    struct pa_stream *stream;

    // PulseAudio connection context
    struct pa_context *context;

    // Main event loop object
    struct pa_threaded_mainloop *mainloop;

    // temporary during control()
    struct pa_sink_input_info pi;

    int retval;

    // for wakeup handling
    pthread_mutex_t wakeup_lock;
    pthread_cond_t wakeup;
    int wakeup_status;

    char *cfg_host;
    char *cfg_sink;
    int cfg_buffer;
    int cfg_latency_hacks;
};

#define GENERIC_ERR_MSG(str) \
    MP_ERR(ao, str": %s\n", \
           pa_strerror(pa_context_errno(((struct priv *)ao->priv)->context)))

static void context_state_cb(pa_context *c, void *userdata)
{
    struct ao *ao = userdata;
    struct priv *priv = ao->priv;
    switch (pa_context_get_state(c)) {
    case PA_CONTEXT_READY:
    case PA_CONTEXT_TERMINATED:
    case PA_CONTEXT_FAILED:
        pa_threaded_mainloop_signal(priv->mainloop, 0);
        break;
    }
}

static void subscribe_cb(pa_context *c, pa_subscription_event_type_t t,
                         uint32_t idx, void *userdata)
{
    struct ao *ao = userdata;
    int type = t & PA_SUBSCRIPTION_MASK_SINK;
    int fac = t & PA_SUBSCRIPTION_EVENT_FACILITY_MASK;
    if ((type == PA_SUBSCRIPTION_EVENT_NEW || type == PA_SUBSCRIPTION_EVENT_REMOVE)
        && fac == PA_SUBSCRIPTION_EVENT_SINK)
    {
        ao_hotplug_event(ao);
    }
}

static void context_success_cb(pa_context *c, int success, void *userdata)
{
    struct ao *ao = userdata;
    struct priv *priv = ao->priv;
    priv->retval = success;
    pa_threaded_mainloop_signal(priv->mainloop, 0);
}

static void stream_state_cb(pa_stream *s, void *userdata)
{
    struct ao *ao = userdata;
    struct priv *priv = ao->priv;
    switch (pa_stream_get_state(s)) {
    case PA_STREAM_FAILED:
        MP_VERBOSE(ao, "Stream failed.\n");
        ao_request_reload(ao);
        pa_threaded_mainloop_signal(priv->mainloop, 0);
        break;
    case PA_STREAM_READY:
    case PA_STREAM_TERMINATED:
        pa_threaded_mainloop_signal(priv->mainloop, 0);
        break;
    }
}

static void wakeup(struct ao *ao)
{
    struct priv *priv = ao->priv;
    pthread_mutex_lock(&priv->wakeup_lock);
    priv->wakeup_status = 1;
    pthread_cond_signal(&priv->wakeup);
    pthread_mutex_unlock(&priv->wakeup_lock);
}

static void stream_request_cb(pa_stream *s, size_t length, void *userdata)
{
    struct ao *ao = userdata;
    struct priv *priv = ao->priv;
    wakeup(ao);
    pa_threaded_mainloop_signal(priv->mainloop, 0);
}

static int wait_audio(struct ao *ao, pthread_mutex_t *lock)
{
    struct priv *priv = ao->priv;
    // We don't use this mutex, because pulse like to call stream_request_cb
    // while we have the central mutex held.
    pthread_mutex_unlock(lock);
    pthread_mutex_lock(&priv->wakeup_lock);
    while (!priv->wakeup_status)
        pthread_cond_wait(&priv->wakeup, &priv->wakeup_lock);
    priv->wakeup_status = 0;
    pthread_mutex_unlock(&priv->wakeup_lock);
    pthread_mutex_lock(lock);
    return 0;
}

static void stream_latency_update_cb(pa_stream *s, void *userdata)
{
    struct ao *ao = userdata;
    struct priv *priv = ao->priv;
    pa_threaded_mainloop_signal(priv->mainloop, 0);
}

static void success_cb(pa_stream *s, int success, void *userdata)
{
    struct ao *ao = userdata;
    struct priv *priv = ao->priv;
    priv->retval = success;
    pa_threaded_mainloop_signal(priv->mainloop, 0);
}

/**
 * \brief waits for a pulseaudio operation to finish, frees it and
 *        unlocks the mainloop
 * \param op operation to wait for
 * \return 1 if operation has finished normally (DONE state), 0 otherwise
 */
static int waitop(struct priv *priv, pa_operation *op)
{
    if (!op) {
        pa_threaded_mainloop_unlock(priv->mainloop);
        return 0;
    }
    pa_operation_state_t state = pa_operation_get_state(op);
    while (state == PA_OPERATION_RUNNING) {
        pa_threaded_mainloop_wait(priv->mainloop);
        state = pa_operation_get_state(op);
    }
    pa_operation_unref(op);
    pa_threaded_mainloop_unlock(priv->mainloop);
    return state == PA_OPERATION_DONE;
}

static const struct format_map {
    int mp_format;
    pa_sample_format_t pa_format;
} format_maps[] = {
    {AF_FORMAT_S16, PA_SAMPLE_S16NE},
    {AF_FORMAT_S32, PA_SAMPLE_S32NE},
    {AF_FORMAT_FLOAT, PA_SAMPLE_FLOAT32NE},
    {AF_FORMAT_U8, PA_SAMPLE_U8},
    {AF_FORMAT_UNKNOWN, 0}
};

static pa_encoding_t map_digital_format(int format)
{
    switch (format) {
    case AF_FORMAT_S_AC3:   return PA_ENCODING_AC3_IEC61937;
    case AF_FORMAT_S_EAC3:  return PA_ENCODING_EAC3_IEC61937;
    case AF_FORMAT_S_MP3:   return PA_ENCODING_MPEG_IEC61937;
    case AF_FORMAT_S_DTS:
    case AF_FORMAT_S_DTSHD: return PA_ENCODING_DTS_IEC61937;
#ifdef PA_ENCODING_MPEG2_AAC_IEC61937
    case AF_FORMAT_S_AAC:   return PA_ENCODING_MPEG2_AAC_IEC61937;
#endif
    default:
        if (af_fmt_is_spdif(format))
            return PA_ENCODING_ANY;
        return PA_ENCODING_PCM;
    }
}

static const int speaker_map[][2] = {
  {PA_CHANNEL_POSITION_FRONT_LEFT,              MP_SPEAKER_ID_FL},
  {PA_CHANNEL_POSITION_FRONT_RIGHT,             MP_SPEAKER_ID_FR},
  {PA_CHANNEL_POSITION_FRONT_CENTER,            MP_SPEAKER_ID_FC},
  {PA_CHANNEL_POSITION_REAR_CENTER,             MP_SPEAKER_ID_BC},
  {PA_CHANNEL_POSITION_REAR_LEFT,               MP_SPEAKER_ID_BL},
  {PA_CHANNEL_POSITION_REAR_RIGHT,              MP_SPEAKER_ID_BR},
  {PA_CHANNEL_POSITION_LFE,                     MP_SPEAKER_ID_LFE},
  {PA_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER,    MP_SPEAKER_ID_FLC},
  {PA_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER,   MP_SPEAKER_ID_FRC},
  {PA_CHANNEL_POSITION_SIDE_LEFT,               MP_SPEAKER_ID_SL},
  {PA_CHANNEL_POSITION_SIDE_RIGHT,              MP_SPEAKER_ID_SR},
  {PA_CHANNEL_POSITION_TOP_CENTER,              MP_SPEAKER_ID_TC},
  {PA_CHANNEL_POSITION_TOP_FRONT_LEFT,          MP_SPEAKER_ID_TFL},
  {PA_CHANNEL_POSITION_TOP_FRONT_RIGHT,         MP_SPEAKER_ID_TFR},
  {PA_CHANNEL_POSITION_TOP_FRONT_CENTER,        MP_SPEAKER_ID_TFC},
  {PA_CHANNEL_POSITION_TOP_REAR_LEFT,           MP_SPEAKER_ID_TBL},
  {PA_CHANNEL_POSITION_TOP_REAR_RIGHT,          MP_SPEAKER_ID_TBR},
  {PA_CHANNEL_POSITION_TOP_REAR_CENTER,         MP_SPEAKER_ID_TBC},
  {PA_CHANNEL_POSITION_INVALID,                 -1}
};

static bool chmap_pa_from_mp(pa_channel_map *dst, struct mp_chmap *src)
{
    if (src->num > PA_CHANNELS_MAX)
        return false;
    dst->channels = src->num;
    if (mp_chmap_equals(src, &(const struct mp_chmap)MP_CHMAP_INIT_MONO)) {
        dst->map[0] = PA_CHANNEL_POSITION_MONO;
        return true;
    }
    for (int n = 0; n < src->num; n++) {
        int mp_speaker = src->speaker[n];
        int pa_speaker = PA_CHANNEL_POSITION_INVALID;
        for (int i = 0; speaker_map[i][1] != -1; i++) {
            if (speaker_map[i][1] == mp_speaker) {
                pa_speaker = speaker_map[i][0];
                break;
            }
        }
        if (pa_speaker == PA_CHANNEL_POSITION_INVALID)
            return false;
        dst->map[n] = pa_speaker;
    }
    return true;
}

static bool select_chmap(struct ao *ao, pa_channel_map *dst)
{
    struct mp_chmap_sel sel = {0};
    for (int n = 0; speaker_map[n][1] != -1; n++)
        mp_chmap_sel_add_speaker(&sel, speaker_map[n][1]);
    return ao_chmap_sel_adjust(ao, &sel, &ao->channels) &&
           chmap_pa_from_mp(dst, &ao->channels);
}

static void drain(struct ao *ao)
{
    struct priv *priv = ao->priv;
    if (priv->stream) {
        pa_threaded_mainloop_lock(priv->mainloop);
        waitop(priv, pa_stream_drain(priv->stream, success_cb, ao));
    }
}

static void uninit(struct ao *ao)
{
    struct priv *priv = ao->priv;

    if (priv->mainloop)
        pa_threaded_mainloop_stop(priv->mainloop);

    if (priv->stream) {
        pa_stream_disconnect(priv->stream);
        pa_stream_unref(priv->stream);
        priv->stream = NULL;
    }

    if (priv->context) {
        pa_context_disconnect(priv->context);
        pa_context_unref(priv->context);
        priv->context = NULL;
    }

    if (priv->mainloop) {
        pa_threaded_mainloop_free(priv->mainloop);
        priv->mainloop = NULL;
    }

    pthread_cond_destroy(&priv->wakeup);
    pthread_mutex_destroy(&priv->wakeup_lock);
}

static int pa_init_boilerplate(struct ao *ao)
{
    struct priv *priv = ao->priv;
    char *host = priv->cfg_host && priv->cfg_host[0] ? priv->cfg_host : NULL;
    bool locked = false;

    pthread_mutex_init(&priv->wakeup_lock, NULL);
    pthread_cond_init(&priv->wakeup, NULL);

    if (!(priv->mainloop = pa_threaded_mainloop_new())) {
        MP_ERR(ao, "Failed to allocate main loop\n");
        goto fail;
    }

    if (pa_threaded_mainloop_start(priv->mainloop) < 0)
        goto fail;

    pa_threaded_mainloop_lock(priv->mainloop);
    locked = true;

    if (!(priv->context = pa_context_new(pa_threaded_mainloop_get_api(
                                         priv->mainloop), ao->client_name)))
    {
        MP_ERR(ao, "Failed to allocate context\n");
        goto fail;
    }

    MP_VERBOSE(ao, "Library version: %s\n", pa_get_library_version());
    MP_VERBOSE(ao, "Proto: %lu\n",
        (long)pa_context_get_protocol_version(priv->context));
    MP_VERBOSE(ao, "Server proto: %lu\n",
        (long)pa_context_get_server_protocol_version(priv->context));

    pa_context_set_state_callback(priv->context, context_state_cb, ao);
    pa_context_set_subscribe_callback(priv->context, subscribe_cb, ao);

    if (pa_context_connect(priv->context, host, 0, NULL) < 0)
        goto fail;

    /* Wait until the context is ready */
    while (1) {
        int state = pa_context_get_state(priv->context);
        if (state == PA_CONTEXT_READY)
            break;
        if (!PA_CONTEXT_IS_GOOD(state))
            goto fail;
        pa_threaded_mainloop_wait(priv->mainloop);
    }

    pa_threaded_mainloop_unlock(priv->mainloop);
    return 0;

fail:
    if (locked)
        pa_threaded_mainloop_unlock(priv->mainloop);

    if (priv->context) {
        pa_threaded_mainloop_lock(priv->mainloop);
        if (!(pa_context_errno(priv->context) == PA_ERR_CONNECTIONREFUSED
              && ao->probing))
            GENERIC_ERR_MSG("Init failed");
        pa_threaded_mainloop_unlock(priv->mainloop);
    }
    uninit(ao);
    return -1;
}

static bool set_format(struct ao *ao, pa_format_info *format)
{
    ao->format = af_fmt_from_planar(ao->format);

    format->encoding = map_digital_format(ao->format);
    if (format->encoding == PA_ENCODING_PCM) {
        const struct format_map *fmt_map = format_maps;

        while (fmt_map->mp_format != ao->format) {
            if (fmt_map->mp_format == AF_FORMAT_UNKNOWN) {
                MP_VERBOSE(ao, "Unsupported format, using default\n");
                fmt_map = format_maps;
                break;
            }
            fmt_map++;
        }
        ao->format = fmt_map->mp_format;

        pa_format_info_set_sample_format(format, fmt_map->pa_format);
    }

    struct pa_channel_map map;

    if (!select_chmap(ao, &map))
        return false;

    pa_format_info_set_rate(format, ao->samplerate);
    pa_format_info_set_channels(format, ao->channels.num);
    pa_format_info_set_channel_map(format, &map);

    return ao->samplerate < PA_RATE_MAX && pa_format_info_valid(format);
}

static int init(struct ao *ao)
{
    pa_proplist *proplist = NULL;
    pa_format_info *format = NULL;
    struct priv *priv = ao->priv;
    char *sink = priv->cfg_sink && priv->cfg_sink[0] ? priv->cfg_sink : ao->device;

    if (pa_init_boilerplate(ao) < 0)
        return -1;

    pa_threaded_mainloop_lock(priv->mainloop);

    if (!(proplist = pa_proplist_new())) {
        MP_ERR(ao, "Failed to allocate proplist\n");
        goto unlock_and_fail;
    }
    (void)pa_proplist_sets(proplist, PA_PROP_MEDIA_ICON_NAME, ao->client_name);

    if (!(format = pa_format_info_new()))
        goto unlock_and_fail;

    if (!set_format(ao, format)) {
        ao->channels = (struct mp_chmap) MP_CHMAP_INIT_STEREO;
        ao->samplerate = 48000;
        ao->format = AF_FORMAT_FLOAT;
        if (!set_format(ao, format)) {
            MP_ERR(ao, "Invalid audio format\n");
            goto unlock_and_fail;
        }
    }

    if (!(priv->stream = pa_stream_new_extended(priv->context, "audio stream",
                                                &format, 1, proplist)))
        goto unlock_and_fail;

    pa_format_info_free(format);
    format = NULL;

    pa_proplist_free(proplist);
    proplist = NULL;

    pa_stream_set_state_callback(priv->stream, stream_state_cb, ao);
    pa_stream_set_write_callback(priv->stream, stream_request_cb, ao);
    pa_stream_set_latency_update_callback(priv->stream,
                                          stream_latency_update_cb, ao);
    int buf_size = af_fmt_seconds_to_bytes(ao->format, priv->cfg_buffer / 1000.0,
                                           ao->channels.num, ao->samplerate);
    pa_buffer_attr bufattr = {
        .maxlength = -1,
        .tlength = buf_size > 0 ? buf_size : (uint32_t)-1,
        .prebuf = -1,
        .minreq = -1,
        .fragsize = -1,
    };

    int flags = PA_STREAM_NOT_MONOTONIC;
    if (!priv->cfg_latency_hacks)
        flags |= PA_STREAM_INTERPOLATE_TIMING|PA_STREAM_AUTO_TIMING_UPDATE;

    if (pa_stream_connect_playback(priv->stream, sink, &bufattr,
                                   flags, NULL, NULL) < 0)
        goto unlock_and_fail;

    /* Wait until the stream is ready */
    while (1) {
        int state = pa_stream_get_state(priv->stream);
        if (state == PA_STREAM_READY)
            break;
        if (!PA_STREAM_IS_GOOD(state))
            goto unlock_and_fail;
        pa_threaded_mainloop_wait(priv->mainloop);
    }

    if (pa_stream_is_suspended(priv->stream)) {
        MP_ERR(ao, "The stream is suspended. Bailing out.\n");
        goto unlock_and_fail;
    }

    pa_threaded_mainloop_unlock(priv->mainloop);
    return 0;

unlock_and_fail:
    pa_threaded_mainloop_unlock(priv->mainloop);

    if (format)
        pa_format_info_free(format);

    if (proplist)
        pa_proplist_free(proplist);

    uninit(ao);
    return -1;
}

static void cork(struct ao *ao, bool pause)
{
    struct priv *priv = ao->priv;
    pa_threaded_mainloop_lock(priv->mainloop);
    priv->retval = 0;
    if (!waitop(priv, pa_stream_cork(priv->stream, pause, success_cb, ao)) ||
        !priv->retval)
        GENERIC_ERR_MSG("pa_stream_cork() failed");
}

// Play the specified data to the pulseaudio server
static int play(struct ao *ao, void **data, int samples, int flags)
{
    struct priv *priv = ao->priv;
    pa_threaded_mainloop_lock(priv->mainloop);
    if (pa_stream_write(priv->stream, data[0], samples * ao->sstride, NULL, 0,
                        PA_SEEK_RELATIVE) < 0) {
        GENERIC_ERR_MSG("pa_stream_write() failed");
        samples = -1;
    }
    if (flags & AOPLAY_FINAL_CHUNK) {
        // Force start in case the stream was too short for prebuf
        pa_operation *op = pa_stream_trigger(priv->stream, NULL, NULL);
        pa_operation_unref(op);
    }
    pa_threaded_mainloop_unlock(priv->mainloop);
    return samples;
}

// Reset the audio stream, i.e. flush the playback buffer on the server side
static void reset(struct ao *ao)
{
    // pa_stream_flush() works badly if not corked
    cork(ao, true);
    struct priv *priv = ao->priv;
    pa_threaded_mainloop_lock(priv->mainloop);
    priv->retval = 0;
    if (!waitop(priv, pa_stream_flush(priv->stream, success_cb, ao)) ||
        !priv->retval)
        GENERIC_ERR_MSG("pa_stream_flush() failed");
    cork(ao, false);
}

// Pause the audio stream by corking it on the server
static void pause(struct ao *ao)
{
    cork(ao, true);
}

// Resume the audio stream by uncorking it on the server
static void resume(struct ao *ao)
{
    cork(ao, false);
}

// Return number of samples that may be written to the server without blocking
static int get_space(struct ao *ao)
{
    struct priv *priv = ao->priv;
    pa_threaded_mainloop_lock(priv->mainloop);
    size_t space = pa_stream_writable_size(priv->stream);
    pa_threaded_mainloop_unlock(priv->mainloop);
    return space / ao->sstride;
}

static double get_delay_hackfixed(struct ao *ao)
{
    /* This code basically does what pa_stream_get_latency() _should_
     * do, but doesn't due to multiple known bugs in PulseAudio (at
     * PulseAudio version 2.1). In particular, the timing interpolation
     * mode (PA_STREAM_INTERPOLATE_TIMING) can return completely bogus
     * values, and the non-interpolating code has a bug causing too
     * large results at end of stream (so a stream never seems to finish).
     * This code can still return wrong values in some cases due to known
     * PulseAudio bugs that can not be worked around on the client side.
     *
     * We always query the server for latest timing info. This may take
     * too long to work well with remote audio servers, but at least
     * this should be enough to fix the normal local playback case.
     */
    struct priv *priv = ao->priv;
    pa_threaded_mainloop_lock(priv->mainloop);
    if (!waitop(priv, pa_stream_update_timing_info(priv->stream, NULL, NULL))) {
        GENERIC_ERR_MSG("pa_stream_update_timing_info() failed");
        return 0;
    }
    pa_threaded_mainloop_lock(priv->mainloop);
    const pa_timing_info *ti = pa_stream_get_timing_info(priv->stream);
    if (!ti) {
        pa_threaded_mainloop_unlock(priv->mainloop);
        GENERIC_ERR_MSG("pa_stream_get_timing_info() failed");
        return 0;
    }
    const struct pa_sample_spec *ss = pa_stream_get_sample_spec(priv->stream);
    if (!ss) {
        pa_threaded_mainloop_unlock(priv->mainloop);
        GENERIC_ERR_MSG("pa_stream_get_sample_spec() failed");
        return 0;
    }
    // data left in PulseAudio's main buffers (not written to sink yet)
    int64_t latency = pa_bytes_to_usec(ti->write_index - ti->read_index, ss);
    // since this info may be from a while ago, playback has progressed since
    latency -= ti->transport_usec;
    // data already moved from buffers to sink, but not played yet
    int64_t sink_latency = ti->sink_usec;
    if (!ti->playing)
        /* At the end of a stream, part of the data "left" in the sink may
         * be padding silence after the end; that should be subtracted to
         * get the amount of real audio from our stream. This adjustment
         * is missing from Pulseaudio's own get_latency calculations
         * (as of PulseAudio 2.1). */
        sink_latency -= pa_bytes_to_usec(ti->since_underrun, ss);
    if (sink_latency > 0)
        latency += sink_latency;
    if (latency < 0)
        latency = 0;
    pa_threaded_mainloop_unlock(priv->mainloop);
    return latency / 1e6;
}

static double get_delay_pulse(struct ao *ao)
{
    struct priv *priv = ao->priv;
    pa_usec_t latency = (pa_usec_t) -1;
    pa_threaded_mainloop_lock(priv->mainloop);
    while (pa_stream_get_latency(priv->stream, &latency, NULL) < 0) {
        if (pa_context_errno(priv->context) != PA_ERR_NODATA) {
            GENERIC_ERR_MSG("pa_stream_get_latency() failed");
            break;
        }
        /* Wait until latency data is available again */
        pa_threaded_mainloop_wait(priv->mainloop);
    }
    pa_threaded_mainloop_unlock(priv->mainloop);
    return latency == (pa_usec_t) -1 ? 0 : latency / 1000000.0;
}

// Return the current latency in seconds
static double get_delay(struct ao *ao)
{
    struct priv *priv = ao->priv;
    if (priv->cfg_latency_hacks) {
        return get_delay_hackfixed(ao);
    } else {
        return get_delay_pulse(ao);
    }
}

/* A callback function that is called when the
 * pa_context_get_sink_input_info() operation completes. Saves the
 * volume field of the specified structure to the global variable volume.
 */
static void info_func(struct pa_context *c, const struct pa_sink_input_info *i,
                      int is_last, void *userdata)
{
    struct ao *ao = userdata;
    struct priv *priv = ao->priv;
    if (is_last < 0) {
        GENERIC_ERR_MSG("Failed to get sink input info");
        return;
    }
    if (!i)
        return;
    priv->pi = *i;
    pa_threaded_mainloop_signal(priv->mainloop, 0);
}

static int control(struct ao *ao, enum aocontrol cmd, void *arg)
{
    struct priv *priv = ao->priv;
    switch (cmd) {
    case AOCONTROL_GET_MUTE:
    case AOCONTROL_GET_VOLUME: {
        uint32_t devidx = pa_stream_get_index(priv->stream);
        pa_threaded_mainloop_lock(priv->mainloop);
        if (!waitop(priv, pa_context_get_sink_input_info(priv->context, devidx,
                                                         info_func, ao))) {
            GENERIC_ERR_MSG("pa_context_get_sink_input_info() failed");
            return CONTROL_ERROR;
        }
        // Warning: some information in pi might be unaccessible, because
        // we naively copied the struct, without updating pointers etc.
        // Pointers might point to invalid data, accessors might fail.
        if (cmd == AOCONTROL_GET_VOLUME) {
            ao_control_vol_t *vol = arg;
            if (priv->pi.volume.channels != 2)
                vol->left = vol->right =
                    VOL_PA2MP(pa_cvolume_avg(&priv->pi.volume));
            else {
                vol->left = VOL_PA2MP(priv->pi.volume.values[0]);
                vol->right = VOL_PA2MP(priv->pi.volume.values[1]);
            }
        } else if (cmd == AOCONTROL_GET_MUTE) {
            bool *mute = arg;
            *mute = priv->pi.mute;
        }
        return CONTROL_OK;
    }

    case AOCONTROL_SET_MUTE:
    case AOCONTROL_SET_VOLUME: {
        pa_operation *o;

        pa_threaded_mainloop_lock(priv->mainloop);
        uint32_t stream_index = pa_stream_get_index(priv->stream);
        if (cmd == AOCONTROL_SET_VOLUME) {
            const ao_control_vol_t *vol = arg;
            struct pa_cvolume volume;

            pa_cvolume_reset(&volume, ao->channels.num);
            if (volume.channels != 2)
                pa_cvolume_set(&volume, volume.channels, VOL_MP2PA(vol->left));
            else {
                volume.values[0] = VOL_MP2PA(vol->left);
                volume.values[1] = VOL_MP2PA(vol->right);
            }
            o = pa_context_set_sink_input_volume(priv->context, stream_index,
                                                 &volume, NULL, NULL);
            if (!o) {
                pa_threaded_mainloop_unlock(priv->mainloop);
                GENERIC_ERR_MSG("pa_context_set_sink_input_volume() failed");
                return CONTROL_ERROR;
            }
        } else if (cmd == AOCONTROL_SET_MUTE) {
            const bool *mute = arg;
            o = pa_context_set_sink_input_mute(priv->context, stream_index,
                                               *mute, NULL, NULL);
            if (!o) {
                pa_threaded_mainloop_unlock(priv->mainloop);
                GENERIC_ERR_MSG("pa_context_set_sink_input_mute() failed");
                return CONTROL_ERROR;
            }
        } else
            abort();
        /* We don't wait for completion here */
        pa_operation_unref(o);
        pa_threaded_mainloop_unlock(priv->mainloop);
        return CONTROL_OK;
    }

    case AOCONTROL_HAS_PER_APP_VOLUME:
        return CONTROL_TRUE;

    case AOCONTROL_UPDATE_STREAM_TITLE: {
        char *title = (char *)arg;
        pa_threaded_mainloop_lock(priv->mainloop);
        if (!waitop(priv, pa_stream_set_name(priv->stream, title,
                                             success_cb, ao)))
        {
            GENERIC_ERR_MSG("pa_stream_set_name() failed");
            return CONTROL_ERROR;
        }
        return CONTROL_OK;
    }

    default:
        return CONTROL_UNKNOWN;
    }
}

struct sink_cb_ctx {
    struct ao *ao;
    struct ao_device_list *list;
};

static void sink_info_cb(pa_context *c, const pa_sink_info *i, int eol, void *ud)
{
    struct sink_cb_ctx *ctx = ud;
    struct priv *priv = ctx->ao->priv;

    if (eol) {
        pa_threaded_mainloop_signal(priv->mainloop, 0); // wakeup waitop()
        return;
    }

    struct ao_device_desc entry = {.name = i->name, .desc = i->description};
    ao_device_list_add(ctx->list, ctx->ao, &entry);
}

static int hotplug_init(struct ao *ao)
{
    struct priv *priv = ao->priv;
    if (pa_init_boilerplate(ao) < 0)
        return -1;

    pa_threaded_mainloop_lock(priv->mainloop);
    waitop(priv, pa_context_subscribe(priv->context, PA_SUBSCRIPTION_MASK_SINK,
                                      context_success_cb, ao));

    return 0;
}

static void list_devs(struct ao *ao, struct ao_device_list *list)
{
    struct priv *priv = ao->priv;
    struct sink_cb_ctx ctx = {ao, list};

    pa_threaded_mainloop_lock(priv->mainloop);
    waitop(priv, pa_context_get_sink_info_list(priv->context, sink_info_cb, &ctx));
}

static void hotplug_uninit(struct ao *ao)
{
    uninit(ao);
}

#define OPT_BASE_STRUCT struct priv

const struct ao_driver audio_out_pulse = {
    .description = "PulseAudio audio output",
    .name      = "pulse",
    .control   = control,
    .init      = init,
    .uninit    = uninit,
    .reset     = reset,
    .get_space = get_space,
    .play      = play,
    .get_delay = get_delay,
    .pause     = pause,
    .resume    = resume,
    .drain     = drain,
    .wait      = wait_audio,
    .wakeup    = wakeup,
    .hotplug_init = hotplug_init,
    .hotplug_uninit = hotplug_uninit,
    .list_devs = list_devs,
    .priv_size = sizeof(struct priv),
    .priv_defaults = &(const struct priv) {
        .cfg_buffer = 250,
    },
    .options = (const struct m_option[]) {
        OPT_STRING("host", cfg_host, 0),
        OPT_STRING("sink", cfg_sink, 0),
        OPT_CHOICE_OR_INT("buffer", cfg_buffer, 0, 1, 2000, ({"native", 0})),
        OPT_FLAG("latency-hacks", cfg_latency_hacks, 0),
        {0}
    },
};