1 /*****************************************************************************
2 * alsa.c : alsa plugin for vlc
3 *****************************************************************************
4 * Copyright (C) 2000-2010 VLC authors and VideoLAN
5 * Copyright (C) 2009-2011 RĂ©mi Denis-Courmont
7 * Authors: Henri Fallon <henri@videolan.org> - Original Author
8 * Jeffrey Baker <jwbaker@acm.org> - Port to ALSA 1.0 API
9 * John Paul Lorenti <jpl31@columbia.edu> - Device selection
10 * Arnaud de Bossoreille de Ribou <bozo@via.ecp.fr> - S/PDIF and aout3
12 * This program is free software; you can redistribute it and/or modify it
13 * under the terms of the GNU Lesser General Public License as published by
14 * the Free Software Foundation; either version 2.1 of the License, or
15 * (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Lesser General Public License for more details.
22 * You should have received a copy of the GNU Lesser General Public License
23 * along with this program; if not, write to the Free Software Foundation,
24 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
25 *****************************************************************************/
33 #include <vlc_common.h>
34 #include <vlc_plugin.h>
35 #include <vlc_dialog.h>
39 #include <alsa/asoundlib.h>
40 #include <alsa/version.h>
42 /** Private data for an ALSA PCM playback stream */
46 unsigned rate; /**< Sample rate */
47 vlc_fourcc_t format; /**< Sample format */
48 uint8_t chans_table[AOUT_CHAN_MAX]; /**< Channels order table */
49 uint8_t chans_to_reorder; /**< Number of channels to reorder */
58 #define A52_FRAME_NB 1536
60 static int Open (vlc_object_t *);
61 static void Close (vlc_object_t *);
62 static int EnumDevices (vlc_object_t *, char const *, char ***, char ***);
64 #define AUDIO_DEV_TEXT N_("Audio output device")
65 #define AUDIO_DEV_LONGTEXT N_("Audio output device (using ALSA syntax).")
67 #define AUDIO_CHAN_TEXT N_("Audio output channels")
68 #define AUDIO_CHAN_LONGTEXT N_("Channels available for audio output. " \
69 "If the input has more channels than the output, it will be down-mixed. " \
70 "This parameter is ignored when digital pass-through is active.")
71 static const int channels[] = {
72 AOUT_CHAN_CENTER, AOUT_CHANS_STEREO, AOUT_CHANS_4_0, AOUT_CHANS_4_1,
73 AOUT_CHANS_5_0, AOUT_CHANS_5_1, AOUT_CHANS_7_1,
75 static const char *const channels_text[] = {
76 N_("Mono"), N_("Stereo"), N_("Surround 4.0"), N_("Surround 4.1"),
77 N_("Surround 5.0"), N_("Surround 5.1"), N_("Surround 7.1"),
81 set_shortname( "ALSA" )
82 set_description( N_("ALSA audio output") )
83 set_category( CAT_AUDIO )
84 set_subcategory( SUBCAT_AUDIO_AOUT )
85 add_string ("alsa-audio-device", "default",
86 AUDIO_DEV_TEXT, AUDIO_DEV_LONGTEXT, false)
87 change_string_cb (EnumDevices)
88 add_integer ("alsa-audio-channels", AOUT_CHANS_FRONT,
89 AUDIO_CHAN_TEXT, AUDIO_CHAN_LONGTEXT, false)
90 change_integer_list (channels, channels_text)
92 set_capability( "audio output", 150 )
93 set_callbacks( Open, Close )
97 /** Helper for ALSA -> VLC debugging output */
98 static void Dump (vlc_object_t *obj, const char *msg,
99 int (*cb)(void *, snd_output_t *), void *p)
101 snd_output_t *output;
104 if (unlikely(snd_output_buffer_open (&output)))
107 int val = cb (p, output);
110 msg_Warn (obj, "cannot get info: %s", snd_strerror (val));
114 size_t len = snd_output_buffer_string (output, &str);
115 if (len > 0 && str[len - 1])
116 len--; /* strip trailing newline */
117 msg_Dbg (obj, "%s%.*s", msg, (int)len, str);
118 snd_output_close (output);
120 #define Dump(o, m, cb, p) \
121 Dump(VLC_OBJECT(o), m, (int (*)(void *, snd_output_t *))(cb), p)
123 static void DumpDevice (vlc_object_t *obj, snd_pcm_t *pcm)
125 snd_pcm_info_t *info;
127 Dump (obj, " ", snd_pcm_dump, pcm);
128 snd_pcm_info_alloca (&info);
129 if (snd_pcm_info (pcm, info) == 0)
131 msg_Dbg (obj, " device name : %s", snd_pcm_info_get_name (info));
132 msg_Dbg (obj, " device ID : %s", snd_pcm_info_get_id (info));
133 msg_Dbg (obj, " subdevice name: %s",
134 snd_pcm_info_get_subdevice_name (info));
138 static void DumpDeviceStatus (vlc_object_t *obj, snd_pcm_t *pcm)
140 snd_pcm_status_t *status;
142 snd_pcm_status_alloca (&status);
143 snd_pcm_status (pcm, status);
144 Dump (obj, "current status:\n", snd_pcm_status_dump, status);
146 #define DumpDeviceStatus(o, p) DumpDeviceStatus(VLC_OBJECT(o), p)
148 static unsigned SetupChannelsUnknown (vlc_object_t *obj,
149 uint16_t *restrict mask)
151 uint16_t map = var_InheritInteger (obj, "alsa-audio-channels");
152 uint16_t chans = *mask & map;
154 if (unlikely(chans == 0)) /* WTH? */
155 chans = AOUT_CHANS_STEREO;
157 if (popcount (chans) < popcount (*mask))
158 msg_Dbg (obj, "downmixing from %u to %u channels",
159 popcount (*mask), popcount (chans));
161 msg_Dbg (obj, "keeping %u channels", popcount (chans));
166 #if (SND_LIB_VERSION >= 0x01001B)
167 static const uint16_t vlc_chans[] = {
168 [SND_CHMAP_MONO] = AOUT_CHAN_CENTER,
169 [SND_CHMAP_FL] = AOUT_CHAN_LEFT,
170 [SND_CHMAP_FR] = AOUT_CHAN_RIGHT,
171 [SND_CHMAP_RL] = AOUT_CHAN_REARLEFT,
172 [SND_CHMAP_RR] = AOUT_CHAN_REARRIGHT,
173 [SND_CHMAP_FC] = AOUT_CHAN_CENTER,
174 [SND_CHMAP_LFE] = AOUT_CHAN_LFE,
175 [SND_CHMAP_SL] = AOUT_CHAN_MIDDLELEFT,
176 [SND_CHMAP_SR] = AOUT_CHAN_MIDDLERIGHT,
177 [SND_CHMAP_RC] = AOUT_CHAN_REARCENTER,
180 static int Map2Mask (vlc_object_t *obj, const snd_pcm_chmap_t *restrict map)
184 for (unsigned i = 0; i < map->channels; i++)
186 const unsigned pos = map->pos[i];
187 uint_fast16_t vlc_chan = 0;
189 if (pos < sizeof (vlc_chans) / sizeof (vlc_chans[0]))
190 vlc_chan = vlc_chans[pos];
193 msg_Dbg (obj, " %s channel %u position %u", "unsupported", i, pos);
198 msg_Dbg (obj, " %s channel %u position %u", "duplicate", i, pos);
207 * Compares a fixed ALSA channels map with the VLC channels order.
209 static unsigned SetupChannelsFixed(const snd_pcm_chmap_t *restrict map,
210 uint16_t *restrict mask, uint8_t *restrict tab)
212 uint32_t chans_out[AOUT_CHAN_MAX];
214 for (unsigned i = 0; i < map->channels; i++)
216 uint_fast16_t vlc_chan = vlc_chans[map->pos[i]];
218 chans_out[i] = vlc_chan;
222 return aout_CheckChannelReorder(NULL, chans_out, *mask, tab);
226 * Negotiate channels mapping.
228 static unsigned SetupChannels (vlc_object_t *obj, snd_pcm_t *pcm,
229 uint16_t *restrict mask, uint8_t *restrict tab)
231 snd_pcm_chmap_query_t **maps = snd_pcm_query_chmaps (pcm);
233 { /* Fallback to manual configuration */
234 msg_Dbg(obj, "channels map not provided");
235 return SetupChannelsUnknown (obj, mask);
238 /* Find most appropriate available channels map */
239 unsigned best_offset;
240 unsigned best_score = 0;
242 for (snd_pcm_chmap_query_t *const *p = maps; *p != NULL; p++)
244 snd_pcm_chmap_query_t *map = *p;
248 case SND_CHMAP_TYPE_FIXED:
249 case SND_CHMAP_TYPE_PAIRED:
250 case SND_CHMAP_TYPE_VAR:
253 msg_Err (obj, "unknown channels map type %u", map->type);
257 int chans = Map2Mask (obj, &map->map);
261 unsigned score = popcount (chans & *mask);
262 if (score > best_score)
264 best_offset = p - maps;
271 msg_Err (obj, "cannot find supported channels map");
272 snd_pcm_free_chmaps (maps);
273 return SetupChannelsUnknown (obj, mask);
276 const snd_pcm_chmap_t *map = &maps[best_offset]->map;
277 msg_Dbg (obj, "using channels map %u, type %u, %u channel(s)", best_offset,
278 maps[best_offset]->type, best_score);
280 /* Setup channels map */
281 unsigned to_reorder = SetupChannelsFixed(map, mask, tab);
283 /* TODO: avoid reordering for PAIRED and VAR types */
284 //snd_pcm_set_chmap (pcm, ...)
286 snd_pcm_free_chmaps (maps);
289 #else /* (SND_LIB_VERSION < 0x01001B) */
290 # define SetupChannels(obj, pcm, mask, tab) \
291 SetupChannelsUnknown(obj, mask)
294 static int TimeGet (audio_output_t *aout, mtime_t *);
295 static void Play (audio_output_t *, block_t *);
296 static void Pause (audio_output_t *, bool, mtime_t);
297 static void PauseDummy (audio_output_t *, bool, mtime_t);
298 static void Flush (audio_output_t *, bool);
300 /** Initializes an ALSA playback stream */
301 static int Start (audio_output_t *aout, audio_sample_format_t *restrict fmt)
303 aout_sys_t *sys = aout->sys;
304 snd_pcm_format_t pcm_format; /* ALSA sample format */
307 switch (fmt->i_format)
310 pcm_format = SND_PCM_FORMAT_FLOAT64;
313 pcm_format = SND_PCM_FORMAT_FLOAT;
316 pcm_format = SND_PCM_FORMAT_S32;
319 pcm_format = SND_PCM_FORMAT_S16;
322 pcm_format = SND_PCM_FORMAT_U8;
325 if (AOUT_FMT_SPDIF(fmt))
326 spdif = var_InheritBool (aout, "spdif");
329 fmt->i_format = VLC_CODEC_SPDIFL;
330 pcm_format = SND_PCM_FORMAT_S16;
335 fmt->i_format = VLC_CODEC_FL32;
336 pcm_format = SND_PCM_FORMAT_FLOAT;
340 fmt->i_format = VLC_CODEC_S16N;
341 pcm_format = SND_PCM_FORMAT_S16;
345 const char *device = sys->device;
347 /* Choose the IEC device for S/PDIF output */
348 if (spdif && !strcmp (device, "default"))
355 case freq: aes3 = IEC958_AES3_CON_FS_ ## freq; break;
356 FS( 44100) /* def. */ FS( 48000) FS( 32000)
357 FS( 22050) FS( 24000)
358 FS( 88200) FS(768000) FS( 96000)
359 FS(176400) FS(192000)
362 aes3 = IEC958_AES3_CON_FS_NOTID;
366 if (asprintf (&devbuf,
367 "iec958:AES0=0x%x,AES1=0x%x,AES2=0x%x,AES3=0x%x",
368 IEC958_AES0_CON_EMPHASIS_NONE | IEC958_AES0_NONAUDIO,
369 IEC958_AES1_CON_ORIGINAL | IEC958_AES1_CON_PCM_CODER,
375 /* Open the device */
377 /* VLC always has a resampler. No need for ALSA's. */
378 const int mode = SND_PCM_NO_AUTO_RESAMPLE;
380 int val = snd_pcm_open (&pcm, device, SND_PCM_STREAM_PLAYBACK, mode);
384 msg_Err (aout, "cannot open ALSA device \"%s\": %s", sys->device,
386 dialog_Fatal (aout, _("Audio output failed"),
387 _("The audio device \"%s\" could not be used:\n%s."),
388 sys->device, snd_strerror (val));
393 /* Print some potentially useful debug */
394 msg_Dbg (aout, "using ALSA device: %s", sys->device);
395 DumpDevice (VLC_OBJECT(aout), pcm);
397 /* Get Initial hardware parameters */
398 snd_pcm_hw_params_t *hw;
401 snd_pcm_hw_params_alloca (&hw);
402 snd_pcm_hw_params_any (pcm, hw);
403 Dump (aout, "initial hardware setup:\n", snd_pcm_hw_params_dump, hw);
405 val = snd_pcm_hw_params_set_rate_resample(pcm, hw, 0);
408 msg_Err (aout, "cannot disable resampling: %s", snd_strerror (val));
412 val = snd_pcm_hw_params_set_access (pcm, hw,
413 SND_PCM_ACCESS_RW_INTERLEAVED);
416 msg_Err (aout, "cannot set access mode: %s", snd_strerror (val));
420 /* Set sample format */
421 if (snd_pcm_hw_params_test_format (pcm, hw, pcm_format) == 0)
424 if (snd_pcm_hw_params_test_format (pcm, hw, SND_PCM_FORMAT_FLOAT) == 0)
426 fmt->i_format = VLC_CODEC_FL32;
427 pcm_format = SND_PCM_FORMAT_FLOAT;
430 if (snd_pcm_hw_params_test_format (pcm, hw, SND_PCM_FORMAT_S32) == 0)
432 fmt->i_format = VLC_CODEC_S32N;
433 pcm_format = SND_PCM_FORMAT_S32;
436 if (snd_pcm_hw_params_test_format (pcm, hw, SND_PCM_FORMAT_S16) == 0)
438 fmt->i_format = VLC_CODEC_S16N;
439 pcm_format = SND_PCM_FORMAT_S16;
443 msg_Err (aout, "no supported sample format");
447 val = snd_pcm_hw_params_set_format (pcm, hw, pcm_format);
450 msg_Err (aout, "cannot set sample format: %s", snd_strerror (val));
454 /* Set channels count */
458 sys->chans_to_reorder = SetupChannels (VLC_OBJECT(aout), pcm,
459 &fmt->i_physical_channels, sys->chans_table);
460 channels = popcount (fmt->i_physical_channels);
464 fmt->i_original_channels = fmt->i_physical_channels;
466 /* By default, ALSA plug will pad missing channels with zeroes, which is
467 * usually fine. However, it will also discard extraneous channels, which
468 * is not acceptable. Thus the user must configure the physically
469 * available channels, and VLC will downmix if needed. */
470 val = snd_pcm_hw_params_set_channels (pcm, hw, channels);
473 msg_Err (aout, "cannot set %u channels: %s", channels,
478 /* Set sample rate */
479 val = snd_pcm_hw_params_set_rate_near (pcm, hw, &fmt->i_rate, NULL);
482 msg_Err (aout, "cannot set sample rate: %s", snd_strerror (val));
485 sys->rate = fmt->i_rate;
487 /* Set buffer size */
488 param = AOUT_MAX_ADVANCE_TIME;
489 val = snd_pcm_hw_params_set_buffer_time_near (pcm, hw, ¶m, NULL);
492 msg_Err (aout, "cannot set buffer duration: %s", snd_strerror (val));
496 val = snd_pcm_hw_params_get_buffer_time (hw, ¶m, NULL);
499 msg_Warn (aout, "cannot get buffer time: %s", snd_strerror(val));
500 param = AOUT_MIN_PREPARE_TIME;
504 #else /* work-around for period-long latency outputs (e.g. PulseAudio): */
505 param = AOUT_MIN_PREPARE_TIME;
507 val = snd_pcm_hw_params_set_period_time_near (pcm, hw, ¶m, NULL);
510 msg_Err (aout, "cannot set period: %s", snd_strerror (val));
514 /* Commit hardware parameters */
515 val = snd_pcm_hw_params (pcm, hw);
518 msg_Err (aout, "cannot commit hardware parameters: %s",
522 Dump (aout, "final HW setup:\n", snd_pcm_hw_params_dump, hw);
524 /* Get Initial software parameters */
525 snd_pcm_sw_params_t *sw;
527 snd_pcm_sw_params_alloca (&sw);
528 snd_pcm_sw_params_current (pcm, sw);
529 Dump (aout, "initial software parameters:\n", snd_pcm_sw_params_dump, sw);
532 //snd_pcm_sw_params_set_avail_min( pcm, sw, i_period_size );
534 val = snd_pcm_sw_params_set_start_threshold (pcm, sw, 1);
537 msg_Err( aout, "unable to set start threshold (%s)",
538 snd_strerror( val ) );
543 /* Commit software parameters. */
544 val = snd_pcm_sw_params (pcm, sw);
547 msg_Err (aout, "cannot commit software parameters: %s",
551 Dump (aout, "final software parameters:\n", snd_pcm_sw_params_dump, sw);
553 val = snd_pcm_prepare (pcm);
556 msg_Err (aout, "cannot prepare device: %s", snd_strerror (val));
560 /* Setup audio_output_t */
563 fmt->i_bytes_per_frame = AOUT_SPDIF_SIZE;
564 fmt->i_frame_length = A52_FRAME_NB;
566 sys->format = fmt->i_format;
568 aout->time_get = TimeGet;
570 if (snd_pcm_hw_params_can_pause (hw))
574 aout->pause = PauseDummy;
575 msg_Warn (aout, "device cannot be paused");
578 aout_SoftVolumeStart (aout);
586 static int TimeGet (audio_output_t *aout, mtime_t *restrict delay)
588 aout_sys_t *sys = aout->sys;
589 snd_pcm_sframes_t frames;
591 int val = snd_pcm_delay (sys->pcm, &frames);
594 msg_Err (aout, "cannot estimate delay: %s", snd_strerror (val));
597 *delay = frames * CLOCK_FREQ / sys->rate;
602 * Queues one audio buffer to the hardware.
604 static void Play (audio_output_t *aout, block_t *block)
606 aout_sys_t *sys = aout->sys;
608 if (sys->chans_to_reorder != 0)
609 aout_ChannelReorder(block->p_buffer, block->i_buffer,
610 sys->chans_to_reorder, sys->chans_table, sys->format);
612 snd_pcm_t *pcm = sys->pcm;
614 /* TODO: better overflow handling */
615 /* TODO: no period wake ups */
617 while (block->i_nb_samples > 0)
619 snd_pcm_sframes_t frames;
621 frames = snd_pcm_writei (pcm, block->p_buffer, block->i_nb_samples);
624 size_t bytes = snd_pcm_frames_to_bytes (pcm, frames);
625 block->i_nb_samples -= frames;
626 block->p_buffer += bytes;
627 block->i_buffer -= bytes;
632 int val = snd_pcm_recover (pcm, frames, 1);
635 msg_Err (aout, "cannot recover playback stream: %s",
637 DumpDeviceStatus (aout, pcm);
640 msg_Warn (aout, "cannot write samples: %s", snd_strerror (frames));
643 block_Release (block);
647 * Pauses/resumes the audio playback.
649 static void Pause (audio_output_t *aout, bool pause, mtime_t date)
651 snd_pcm_t *pcm = aout->sys->pcm;
653 int val = snd_pcm_pause (pcm, pause);
655 PauseDummy (aout, pause, date);
658 static void PauseDummy (audio_output_t *aout, bool pause, mtime_t date)
660 snd_pcm_t *pcm = aout->sys->pcm;
662 /* Stupid device cannot pause. Discard samples. */
666 snd_pcm_prepare (pcm);
671 * Flushes/drains the audio playback buffer.
673 static void Flush (audio_output_t *aout, bool wait)
675 snd_pcm_t *pcm = aout->sys->pcm;
681 snd_pcm_prepare (pcm);
686 * Releases the audio output.
688 static void Stop (audio_output_t *aout)
690 aout_sys_t *sys = aout->sys;
691 snd_pcm_t *pcm = sys->pcm;
698 * Enumerates ALSA output devices.
700 static int EnumDevices(vlc_object_t *obj, char const *varname,
701 char ***restrict idp, char ***restrict namep)
705 msg_Dbg (obj, "Available ALSA PCM devices:");
706 if (snd_device_name_hint(-1, "pcm", &hints) < 0)
709 char **ids = NULL, **names = NULL;
712 for (size_t i = 0; hints[i] != NULL; i++)
714 void *hint = hints[i];
716 char *name = snd_device_name_get_hint(hint, "NAME");
717 if (unlikely(name == NULL))
720 char *desc = snd_device_name_get_hint(hint, "DESC");
722 for (char *lf = strchr(desc, '\n'); lf; lf = strchr(lf, '\n'))
724 msg_Dbg (obj, "%s (%s)", (desc != NULL) ? desc : name, name);
726 ids = xrealloc (ids, (n + 1) * sizeof (*ids));
727 names = xrealloc (names, (n + 1) * sizeof (*names));
733 snd_device_name_free_hint(hints);
740 static int DevicesEnum (audio_output_t *aout, char ***idp, char ***namep)
742 return EnumDevices (VLC_OBJECT(aout), NULL, idp, namep);
745 static int DeviceSelect (audio_output_t *aout, const char *id)
747 aout_sys_t *sys = aout->sys;
749 char *device = strdup (id ? id : "default");
750 if (unlikely(device == NULL))
754 sys->device = device;
755 aout_DeviceReport (aout, device);
756 aout_RestartRequest (aout, AOUT_RESTART_OUTPUT);
760 static int Open(vlc_object_t *obj)
762 audio_output_t *aout = (audio_output_t *)obj;
763 aout_sys_t *sys = malloc (sizeof (*sys));
765 if (unlikely(sys == NULL))
767 sys->device = var_InheritString (aout, "alsa-audio-device");
768 if (unlikely(sys->device == NULL))
774 aout_SoftVolumeInit (aout);
775 aout->device_enum = DevicesEnum;
776 aout->device_select = DeviceSelect;
777 aout_DeviceReport (aout, sys->device);
784 static void Close(vlc_object_t *obj)
786 audio_output_t *aout = (audio_output_t *)obj;
787 aout_sys_t *sys = aout->sys;