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 uint8_t chans_table[AOUT_CHAN_MAX]; /**< Channels order table */
48 uint8_t chans_to_reorder; /**< Number of channels to reorder */
49 uint8_t bits; /**< Bits per sample per channel */
56 #define A52_FRAME_NB 1536
58 static int Open (vlc_object_t *);
59 static void Close (vlc_object_t *);
60 static int EnumDevices (vlc_object_t *, char const *, char ***, char ***);
62 #define AUDIO_DEV_TEXT N_("Audio output device")
63 #define AUDIO_DEV_LONGTEXT N_("Audio output device (using ALSA syntax).")
65 #define AUDIO_CHAN_TEXT N_("Audio output channels")
66 #define AUDIO_CHAN_LONGTEXT N_("Channels available for audio output. " \
67 "If the input has more channels than the output, it will be down-mixed. " \
68 "This parameter is ignored when digital pass-through is active.")
69 static const int channels[] = {
70 AOUT_CHAN_CENTER, AOUT_CHANS_STEREO, AOUT_CHANS_4_0, AOUT_CHANS_4_1,
71 AOUT_CHANS_5_0, AOUT_CHANS_5_1, AOUT_CHANS_7_1,
73 static const char *const channels_text[] = {
74 N_("Mono"), N_("Stereo"), N_("Surround 4.0"), N_("Surround 4.1"),
75 N_("Surround 5.0"), N_("Surround 5.1"), N_("Surround 7.1"),
79 set_shortname( "ALSA" )
80 set_description( N_("ALSA audio output") )
81 set_category( CAT_AUDIO )
82 set_subcategory( SUBCAT_AUDIO_AOUT )
83 add_string ("alsa-audio-device", "default",
84 AUDIO_DEV_TEXT, AUDIO_DEV_LONGTEXT, false)
85 change_string_cb (EnumDevices)
86 add_integer ("alsa-audio-channels", AOUT_CHANS_FRONT,
87 AUDIO_CHAN_TEXT, AUDIO_CHAN_LONGTEXT, false)
88 change_integer_list (channels, channels_text)
90 set_capability( "audio output", 150 )
91 set_callbacks( Open, Close )
95 /** Helper for ALSA -> VLC debugging output */
96 static void Dump (vlc_object_t *obj, const char *msg,
97 int (*cb)(void *, snd_output_t *), void *p)
102 if (unlikely(snd_output_buffer_open (&output)))
105 int val = cb (p, output);
108 msg_Warn (obj, "cannot get info: %s", snd_strerror (val));
112 size_t len = snd_output_buffer_string (output, &str);
113 if (len > 0 && str[len - 1])
114 len--; /* strip trailing newline */
115 msg_Dbg (obj, "%s%.*s", msg, (int)len, str);
116 snd_output_close (output);
118 #define Dump(o, m, cb, p) \
119 Dump(VLC_OBJECT(o), m, (int (*)(void *, snd_output_t *))(cb), p)
121 static void DumpDevice (vlc_object_t *obj, snd_pcm_t *pcm)
123 snd_pcm_info_t *info;
125 Dump (obj, " ", snd_pcm_dump, pcm);
126 snd_pcm_info_alloca (&info);
127 if (snd_pcm_info (pcm, info) == 0)
129 msg_Dbg (obj, " device name : %s", snd_pcm_info_get_name (info));
130 msg_Dbg (obj, " device ID : %s", snd_pcm_info_get_id (info));
131 msg_Dbg (obj, " subdevice name: %s",
132 snd_pcm_info_get_subdevice_name (info));
136 static void DumpDeviceStatus (vlc_object_t *obj, snd_pcm_t *pcm)
138 snd_pcm_status_t *status;
140 snd_pcm_status_alloca (&status);
141 snd_pcm_status (pcm, status);
142 Dump (obj, "current status:\n", snd_pcm_status_dump, status);
144 #define DumpDeviceStatus(o, p) DumpDeviceStatus(VLC_OBJECT(o), p)
146 static unsigned SetupChannelsUnknown (vlc_object_t *obj,
147 uint16_t *restrict mask)
149 uint16_t map = var_InheritInteger (obj, "alsa-audio-channels");
150 uint16_t chans = *mask & map;
152 if (unlikely(chans == 0)) /* WTH? */
153 chans = AOUT_CHANS_STEREO;
155 if (popcount (chans) < popcount (*mask))
156 msg_Dbg (obj, "downmixing from %u to %u channels",
157 popcount (*mask), popcount (chans));
159 msg_Dbg (obj, "keeping %u channels", popcount (chans));
164 #if (SND_LIB_VERSION >= 0x01001B)
165 static const uint16_t vlc_chans[] = {
166 [SND_CHMAP_MONO] = AOUT_CHAN_CENTER,
167 [SND_CHMAP_FL] = AOUT_CHAN_LEFT,
168 [SND_CHMAP_FR] = AOUT_CHAN_RIGHT,
169 [SND_CHMAP_RL] = AOUT_CHAN_REARLEFT,
170 [SND_CHMAP_RR] = AOUT_CHAN_REARRIGHT,
171 [SND_CHMAP_FC] = AOUT_CHAN_CENTER,
172 [SND_CHMAP_LFE] = AOUT_CHAN_LFE,
173 [SND_CHMAP_SL] = AOUT_CHAN_MIDDLELEFT,
174 [SND_CHMAP_SR] = AOUT_CHAN_MIDDLERIGHT,
175 [SND_CHMAP_RC] = AOUT_CHAN_REARCENTER,
178 static int Map2Mask (vlc_object_t *obj, const snd_pcm_chmap_t *restrict map)
182 for (unsigned i = 0; i < map->channels; i++)
184 const unsigned pos = map->pos[i];
185 uint_fast16_t vlc_chan = 0;
187 if (pos < sizeof (vlc_chans) / sizeof (vlc_chans[0]))
188 vlc_chan = vlc_chans[pos];
191 msg_Dbg (obj, " %s channel %u position %u", "unsupported", i, pos);
196 msg_Dbg (obj, " %s channel %u position %u", "duplicate", i, pos);
205 * Compares a fixed ALSA channels map with the VLC channels order.
207 static unsigned SetupChannelsFixed(const snd_pcm_chmap_t *restrict map,
208 uint16_t *restrict mask, uint8_t *restrict tab)
210 uint32_t chans_out[AOUT_CHAN_MAX];
212 for (unsigned i = 0; i < map->channels; i++)
214 uint_fast16_t vlc_chan = vlc_chans[map->pos[i]];
216 chans_out[i] = vlc_chan;
220 return aout_CheckChannelReorder(NULL, chans_out, *mask, tab);
224 * Negotiate channels mapping.
226 static unsigned SetupChannels (vlc_object_t *obj, snd_pcm_t *pcm,
227 uint16_t *restrict mask, uint8_t *restrict tab)
229 snd_pcm_chmap_query_t **maps = snd_pcm_query_chmaps (pcm);
231 { /* Fallback to manual configuration */
232 msg_Dbg(obj, "channels map not provided");
233 return SetupChannelsUnknown (obj, mask);
236 /* Find most appropriate available channels map */
237 unsigned best_offset;
238 unsigned best_score = 0;
240 for (snd_pcm_chmap_query_t *const *p = maps; *p != NULL; p++)
242 snd_pcm_chmap_query_t *map = *p;
246 case SND_CHMAP_TYPE_FIXED:
247 case SND_CHMAP_TYPE_PAIRED:
248 case SND_CHMAP_TYPE_VAR:
251 msg_Err (obj, "unknown channels map type %u", map->type);
255 int chans = Map2Mask (obj, &map->map);
259 unsigned score = popcount (chans & *mask);
260 if (score > best_score)
262 best_offset = p - maps;
269 msg_Err (obj, "cannot find supported channels map");
270 snd_pcm_free_chmaps (maps);
271 return SetupChannelsUnknown (obj, mask);
274 const snd_pcm_chmap_t *map = &maps[best_offset]->map;
275 msg_Dbg (obj, "using channels map %u, type %u, %u channel(s)", best_offset,
276 maps[best_offset]->type, best_score);
278 /* Setup channels map */
279 unsigned to_reorder = SetupChannelsFixed(map, mask, tab);
281 /* TODO: avoid reordering for PAIRED and VAR types */
282 //snd_pcm_set_chmap (pcm, ...)
284 snd_pcm_free_chmaps (maps);
287 #else /* (SND_LIB_VERSION < 0x01001B) */
288 # define SetupChannels(obj, pcm, mask, tab) \
289 SetupChannelsUnknown(obj, mask)
292 static int TimeGet (audio_output_t *aout, mtime_t *);
293 static void Play (audio_output_t *, block_t *);
294 static void Pause (audio_output_t *, bool, mtime_t);
295 static void PauseDummy (audio_output_t *, bool, mtime_t);
296 static void Flush (audio_output_t *, bool);
298 /** Initializes an ALSA playback stream */
299 static int Start (audio_output_t *aout, audio_sample_format_t *restrict fmt)
301 aout_sys_t *sys = aout->sys;
303 /* Get device name */
304 char *device = var_InheritString (aout, "alsa-audio-device");
305 if (unlikely(device == NULL))
308 snd_pcm_format_t pcm_format; /* ALSA sample format */
311 switch (fmt->i_format)
314 pcm_format = SND_PCM_FORMAT_FLOAT64_BE;
317 pcm_format = SND_PCM_FORMAT_FLOAT64_LE;
320 pcm_format = SND_PCM_FORMAT_FLOAT_BE;
323 pcm_format = SND_PCM_FORMAT_FLOAT_LE;
326 pcm_format = SND_PCM_FORMAT_S32_BE;
329 pcm_format = SND_PCM_FORMAT_S32_LE;
332 pcm_format = SND_PCM_FORMAT_S24_3BE;
335 pcm_format = SND_PCM_FORMAT_S24_3LE;
338 pcm_format = SND_PCM_FORMAT_U24_3BE;
341 pcm_format = SND_PCM_FORMAT_U24_3LE;
344 pcm_format = SND_PCM_FORMAT_S16_BE;
347 pcm_format = SND_PCM_FORMAT_S16_LE;
350 pcm_format = SND_PCM_FORMAT_U16_BE;
353 pcm_format = SND_PCM_FORMAT_U16_LE;
356 pcm_format = SND_PCM_FORMAT_S8;
359 pcm_format = SND_PCM_FORMAT_U8;
362 if (AOUT_FMT_SPDIF(fmt))
363 spdif = var_InheritBool (aout, "spdif");
366 fmt->i_format = VLC_CODEC_SPDIFL;
367 pcm_format = SND_PCM_FORMAT_S16;
372 fmt->i_format = VLC_CODEC_FL32;
373 pcm_format = SND_PCM_FORMAT_FLOAT;
377 fmt->i_format = VLC_CODEC_S16N;
378 pcm_format = SND_PCM_FORMAT_S16;
382 /* Choose the IEC device for S/PDIF output:
383 if the device is overridden by the user then it will be the one.
384 Otherwise we compute the default device based on the output format. */
385 if (spdif && !strcmp (device, "default"))
392 case freq: aes3 = IEC958_AES3_CON_FS_ ## freq; break;
393 FS( 44100) /* def. */ FS( 48000) FS( 32000)
394 FS( 22050) FS( 24000)
395 FS( 88200) FS(768000) FS( 96000)
396 FS(176400) FS(192000)
399 aes3 = IEC958_AES3_CON_FS_NOTID;
404 if (asprintf (&device,
405 "iec958:AES0=0x%x,AES1=0x%x,AES2=0x%x,AES3=0x%x",
406 IEC958_AES0_CON_EMPHASIS_NONE | IEC958_AES0_NONAUDIO,
407 IEC958_AES1_CON_ORIGINAL | IEC958_AES1_CON_PCM_CODER,
412 /* Open the device */
414 /* VLC always has a resampler. No need for ALSA's. */
415 const int mode = SND_PCM_NO_AUTO_RESAMPLE;
417 int val = snd_pcm_open (&pcm, device, SND_PCM_STREAM_PLAYBACK, mode);
420 msg_Err (aout, "cannot open ALSA device \"%s\": %s", device,
422 dialog_Fatal (aout, _("Audio output failed"),
423 _("The audio device \"%s\" could not be used:\n%s."),
424 device, snd_strerror (val));
430 /* Print some potentially useful debug */
431 msg_Dbg (aout, "using ALSA device: %s", device);
432 aout_DeviceReport (aout, device);
434 DumpDevice (VLC_OBJECT(aout), pcm);
436 /* Get Initial hardware parameters */
437 snd_pcm_hw_params_t *hw;
440 snd_pcm_hw_params_alloca (&hw);
441 snd_pcm_hw_params_any (pcm, hw);
442 Dump (aout, "initial hardware setup:\n", snd_pcm_hw_params_dump, hw);
444 val = snd_pcm_hw_params_set_rate_resample(pcm, hw, 0);
447 msg_Err (aout, "cannot disable resampling: %s", snd_strerror (val));
451 val = snd_pcm_hw_params_set_access (pcm, hw,
452 SND_PCM_ACCESS_RW_INTERLEAVED);
455 msg_Err (aout, "cannot set access mode: %s", snd_strerror (val));
459 /* Set sample format */
460 if (snd_pcm_hw_params_test_format (pcm, hw, pcm_format) == 0)
463 if (snd_pcm_hw_params_test_format (pcm, hw, SND_PCM_FORMAT_FLOAT) == 0)
465 fmt->i_format = VLC_CODEC_FL32;
466 pcm_format = SND_PCM_FORMAT_FLOAT;
469 if (snd_pcm_hw_params_test_format (pcm, hw, SND_PCM_FORMAT_S32) == 0)
471 fmt->i_format = VLC_CODEC_S32N;
472 pcm_format = SND_PCM_FORMAT_S32;
475 if (snd_pcm_hw_params_test_format (pcm, hw, SND_PCM_FORMAT_S16) == 0)
477 fmt->i_format = VLC_CODEC_S16N;
478 pcm_format = SND_PCM_FORMAT_S16;
482 msg_Err (aout, "no supported sample format");
486 val = snd_pcm_hw_params_set_format (pcm, hw, pcm_format);
489 msg_Err (aout, "cannot set sample format: %s", snd_strerror (val));
493 /* Set channels count */
497 sys->chans_to_reorder = SetupChannels (VLC_OBJECT(aout), pcm,
498 &fmt->i_physical_channels, sys->chans_table);
499 channels = popcount (fmt->i_physical_channels);
503 fmt->i_original_channels = fmt->i_physical_channels;
505 /* By default, ALSA plug will pad missing channels with zeroes, which is
506 * usually fine. However, it will also discard extraneous channels, which
507 * is not acceptable. Thus the user must configure the physically
508 * available channels, and VLC will downmix if needed. */
509 val = snd_pcm_hw_params_set_channels (pcm, hw, channels);
512 msg_Err (aout, "cannot set %u channels: %s", channels,
517 /* Set sample rate */
518 val = snd_pcm_hw_params_set_rate_near (pcm, hw, &fmt->i_rate, NULL);
521 msg_Err (aout, "cannot set sample rate: %s", snd_strerror (val));
524 sys->rate = fmt->i_rate;
526 /* Set buffer size */
527 param = AOUT_MAX_ADVANCE_TIME;
528 val = snd_pcm_hw_params_set_buffer_time_near (pcm, hw, ¶m, NULL);
531 msg_Err (aout, "cannot set buffer duration: %s", snd_strerror (val));
535 val = snd_pcm_hw_params_get_buffer_time (hw, ¶m, NULL);
538 msg_Warn (aout, "cannot get buffer time: %s", snd_strerror(val));
539 param = AOUT_MIN_PREPARE_TIME;
543 #else /* work-around for period-long latency outputs (e.g. PulseAudio): */
544 param = AOUT_MIN_PREPARE_TIME;
546 val = snd_pcm_hw_params_set_period_time_near (pcm, hw, ¶m, NULL);
549 msg_Err (aout, "cannot set period: %s", snd_strerror (val));
553 /* Commit hardware parameters */
554 val = snd_pcm_hw_params (pcm, hw);
557 msg_Err (aout, "cannot commit hardware parameters: %s",
561 Dump (aout, "final HW setup:\n", snd_pcm_hw_params_dump, hw);
563 /* Get Initial software parameters */
564 snd_pcm_sw_params_t *sw;
566 snd_pcm_sw_params_alloca (&sw);
567 snd_pcm_sw_params_current (pcm, sw);
568 Dump (aout, "initial software parameters:\n", snd_pcm_sw_params_dump, sw);
571 //snd_pcm_sw_params_set_avail_min( pcm, sw, i_period_size );
573 val = snd_pcm_sw_params_set_start_threshold (pcm, sw, 1);
576 msg_Err( aout, "unable to set start threshold (%s)",
577 snd_strerror( val ) );
582 /* Commit software parameters. */
583 val = snd_pcm_sw_params (pcm, sw);
586 msg_Err (aout, "cannot commit software parameters: %s",
590 Dump (aout, "final software parameters:\n", snd_pcm_sw_params_dump, sw);
592 val = snd_pcm_prepare (pcm);
595 msg_Err (aout, "cannot prepare device: %s", snd_strerror (val));
599 /* Setup audio_output_t */
602 fmt->i_bytes_per_frame = AOUT_SPDIF_SIZE;
603 fmt->i_frame_length = A52_FRAME_NB;
607 aout_FormatPrepare (fmt);
608 sys->bits = fmt->i_bitspersample;
611 aout->time_get = TimeGet;
613 if (snd_pcm_hw_params_can_pause (hw))
617 aout->pause = PauseDummy;
618 msg_Warn (aout, "device cannot be paused");
621 aout_SoftVolumeStart (aout);
630 static int TimeGet (audio_output_t *aout, mtime_t *restrict delay)
632 aout_sys_t *sys = aout->sys;
633 snd_pcm_sframes_t frames;
635 int val = snd_pcm_delay (sys->pcm, &frames);
638 msg_Err (aout, "cannot estimate delay: %s", snd_strerror (val));
641 *delay = frames * CLOCK_FREQ / sys->rate;
646 * Queues one audio buffer to the hardware.
648 static void Play (audio_output_t *aout, block_t *block)
650 aout_sys_t *sys = aout->sys;
652 if (sys->chans_to_reorder != 0)
653 aout_ChannelReorder(block->p_buffer, block->i_buffer,
654 sys->chans_to_reorder, sys->chans_table, sys->bits);
656 snd_pcm_t *pcm = sys->pcm;
658 /* TODO: better overflow handling */
659 /* TODO: no period wake ups */
661 while (block->i_nb_samples > 0)
663 snd_pcm_sframes_t frames;
665 frames = snd_pcm_writei (pcm, block->p_buffer, block->i_nb_samples);
668 size_t bytes = snd_pcm_frames_to_bytes (pcm, frames);
669 block->i_nb_samples -= frames;
670 block->p_buffer += bytes;
671 block->i_buffer -= bytes;
676 int val = snd_pcm_recover (pcm, frames, 1);
679 msg_Err (aout, "cannot recover playback stream: %s",
681 DumpDeviceStatus (aout, pcm);
684 msg_Warn (aout, "cannot write samples: %s", snd_strerror (frames));
687 block_Release (block);
691 * Pauses/resumes the audio playback.
693 static void Pause (audio_output_t *aout, bool pause, mtime_t date)
695 snd_pcm_t *pcm = aout->sys->pcm;
697 int val = snd_pcm_pause (pcm, pause);
699 PauseDummy (aout, pause, date);
702 static void PauseDummy (audio_output_t *aout, bool pause, mtime_t date)
704 snd_pcm_t *pcm = aout->sys->pcm;
706 /* Stupid device cannot pause. Discard samples. */
710 snd_pcm_prepare (pcm);
715 * Flushes/drains the audio playback buffer.
717 static void Flush (audio_output_t *aout, bool wait)
719 snd_pcm_t *pcm = aout->sys->pcm;
725 snd_pcm_prepare (pcm);
730 * Releases the audio output.
732 static void Stop (audio_output_t *aout)
734 aout_sys_t *sys = aout->sys;
735 snd_pcm_t *pcm = sys->pcm;
742 * Enumerates ALSA output devices.
744 static int EnumDevices(vlc_object_t *obj, char const *varname,
745 char ***restrict idp, char ***restrict namep)
749 msg_Dbg (obj, "Available ALSA PCM devices:");
750 if (snd_device_name_hint(-1, "pcm", &hints) < 0)
753 char **ids = NULL, **names = NULL;
756 for (size_t i = 0; hints[i] != NULL; i++)
758 void *hint = hints[i];
760 char *name = snd_device_name_get_hint(hint, "NAME");
761 if (unlikely(name == NULL))
764 char *desc = snd_device_name_get_hint(hint, "DESC");
766 for (char *lf = strchr(desc, '\n'); lf; lf = strchr(lf, '\n'))
768 msg_Dbg (obj, "%s (%s)", (desc != NULL) ? desc : name, name);
770 ids = xrealloc (ids, (n + 1) * sizeof (*ids));
771 names = xrealloc (names, (n + 1) * sizeof (*names));
777 snd_device_name_free_hint(hints);
784 static int DevicesEnum (audio_output_t *aout, char ***idp, char ***namep)
786 return EnumDevices (VLC_OBJECT(aout), NULL, idp, namep);
789 static int DeviceSelect (audio_output_t *aout, const char *id)
791 if (!var_Type (aout, "alsa-audio-device"))
792 var_Create (aout, "alsa-audio-device", VLC_VAR_STRING);
793 var_SetString (aout, "alsa-audio-device", id);
795 aout_RestartRequest (aout, AOUT_RESTART_OUTPUT);
799 static int Open(vlc_object_t *obj)
801 audio_output_t *aout = (audio_output_t *)obj;
802 aout_sys_t *sys = malloc (sizeof (*sys));
804 if (unlikely(sys == NULL))
809 aout_SoftVolumeInit (aout);
810 aout->device_enum = DevicesEnum;
811 aout->device_select = DeviceSelect;
815 static void Close(vlc_object_t *obj)
817 audio_output_t *aout = (audio_output_t *)obj;
818 aout_sys_t *sys = aout->sys;