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 */
56 #include "audio_output/volume.h"
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 #if (SND_LIB_VERSION >= 0x01001B)
149 static const uint16_t vlc_chans[] = {
150 [SND_CHMAP_MONO] = AOUT_CHAN_CENTER,
151 [SND_CHMAP_FL] = AOUT_CHAN_LEFT,
152 [SND_CHMAP_FR] = AOUT_CHAN_RIGHT,
153 [SND_CHMAP_RL] = AOUT_CHAN_REARLEFT,
154 [SND_CHMAP_RR] = AOUT_CHAN_REARRIGHT,
155 [SND_CHMAP_FC] = AOUT_CHAN_CENTER,
156 [SND_CHMAP_LFE] = AOUT_CHAN_LFE,
157 [SND_CHMAP_SL] = AOUT_CHAN_MIDDLELEFT,
158 [SND_CHMAP_SR] = AOUT_CHAN_MIDDLERIGHT,
159 [SND_CHMAP_RC] = AOUT_CHAN_REARCENTER,
162 static int Map2Mask (vlc_object_t *obj, const snd_pcm_chmap_t *restrict map)
166 for (unsigned i = 0; i < map->channels; i++)
168 const unsigned pos = map->pos[i];
169 uint_fast16_t vlc_chan = 0;
171 if (pos < sizeof (vlc_chans) / sizeof (vlc_chans[0]))
172 vlc_chan = vlc_chans[pos];
175 msg_Dbg (obj, " %s channel %u position %u", "unsupported", i, pos);
180 msg_Dbg (obj, " %s channel %u position %u", "duplicate", i, pos);
189 * Compares a fixed ALSA channels map with the VLC channels order.
191 static unsigned SetupChannelsFixed(const snd_pcm_chmap_t *restrict map,
192 uint16_t *restrict maskp, uint8_t *restrict tab)
194 uint32_t chans_out[AOUT_CHAN_MAX];
197 for (unsigned i = 0; i < map->channels; i++)
199 uint_fast16_t vlc_chan = vlc_chans[map->pos[i]];
201 chans_out[i] = vlc_chan;
206 return aout_CheckChannelReorder(NULL, chans_out, mask, tab);
210 * Negotiate channels mapping.
212 static unsigned SetupChannels (vlc_object_t *obj, snd_pcm_t *pcm,
213 uint16_t *restrict mask, uint8_t *restrict tab)
215 snd_pcm_chmap_query_t **maps = snd_pcm_query_chmaps (pcm);
217 { /* Fallback to default order if unknown */
218 msg_Dbg(obj, "channels map not provided");
222 /* Find most appropriate available channels map */
223 unsigned best_offset, best_score = 0, to_reorder = 0;
225 for (snd_pcm_chmap_query_t *const *p = maps; *p != NULL; p++)
227 snd_pcm_chmap_query_t *map = *p;
231 case SND_CHMAP_TYPE_FIXED:
232 case SND_CHMAP_TYPE_PAIRED:
233 case SND_CHMAP_TYPE_VAR:
236 msg_Err (obj, "unknown channels map type %u", map->type);
240 int chans = Map2Mask (obj, &map->map);
244 unsigned score = (popcount (chans & *mask) << 8)
245 | (255 - popcount (chans));
246 if (score > best_score)
248 best_offset = p - maps;
255 msg_Err (obj, "cannot find supported channels map");
259 const snd_pcm_chmap_t *map = &maps[best_offset]->map;
260 msg_Dbg (obj, "using channels map %u, type %u, %u channel(s)", best_offset,
261 maps[best_offset]->type, map->channels);
263 /* Setup channels map */
264 to_reorder = SetupChannelsFixed(map, mask, tab);
266 /* TODO: avoid reordering for PAIRED and VAR types */
267 //snd_pcm_set_chmap (pcm, ...)
269 snd_pcm_free_chmaps (maps);
272 #else /* (SND_LIB_VERSION < 0x01001B) */
273 # define SetupChannels(obj, pcm, mask, tab) (0)
276 static int TimeGet (audio_output_t *aout, mtime_t *);
277 static void Play (audio_output_t *, block_t *);
278 static void Pause (audio_output_t *, bool, mtime_t);
279 static void PauseDummy (audio_output_t *, bool, mtime_t);
280 static void Flush (audio_output_t *, bool);
282 /** Initializes an ALSA playback stream */
283 static int Start (audio_output_t *aout, audio_sample_format_t *restrict fmt)
285 aout_sys_t *sys = aout->sys;
286 snd_pcm_format_t pcm_format; /* ALSA sample format */
289 switch (fmt->i_format)
292 pcm_format = SND_PCM_FORMAT_FLOAT64;
295 pcm_format = SND_PCM_FORMAT_FLOAT;
298 pcm_format = SND_PCM_FORMAT_S32;
301 pcm_format = SND_PCM_FORMAT_S16;
304 pcm_format = SND_PCM_FORMAT_U8;
307 if (AOUT_FMT_SPDIF(fmt))
308 spdif = var_InheritBool (aout, "spdif");
311 fmt->i_format = VLC_CODEC_SPDIFL;
312 pcm_format = SND_PCM_FORMAT_S16;
317 fmt->i_format = VLC_CODEC_FL32;
318 pcm_format = SND_PCM_FORMAT_FLOAT;
322 fmt->i_format = VLC_CODEC_S16N;
323 pcm_format = SND_PCM_FORMAT_S16;
327 const char *device = sys->device;
329 /* Choose the IEC device for S/PDIF output */
337 case freq: aes3 = IEC958_AES3_CON_FS_ ## freq; break;
338 FS( 44100) /* def. */ FS( 48000) FS( 32000)
339 FS( 22050) FS( 24000)
340 FS( 88200) FS(768000) FS( 96000)
341 FS(176400) FS(192000)
344 aes3 = IEC958_AES3_CON_FS_NOTID;
349 if (!strcmp (device, "default"))
350 device = "iec958"; /* TODO: hdmi */
353 opt = strchr(device, ':');
354 if (opt && opt[1] == '\0') {
355 /* if device is terminated by : but there's no options,
356 * remove ':', we'll add it back in the format string. */
362 if (asprintf (&devbuf,
363 "%s%cAES0=0x%x,AES1=0x%x,AES2=0x%x,AES3=0x%x", device,
365 IEC958_AES0_CON_EMPHASIS_NONE | IEC958_AES0_NONAUDIO,
366 IEC958_AES1_CON_ORIGINAL | IEC958_AES1_CON_PCM_CODER,
372 /* Open the device */
374 /* VLC always has a resampler. No need for ALSA's. */
375 const int mode = SND_PCM_NO_AUTO_RESAMPLE;
377 int val = snd_pcm_open (&pcm, device, SND_PCM_STREAM_PLAYBACK, mode);
381 msg_Err (aout, "cannot open ALSA device \"%s\": %s", sys->device,
383 dialog_Fatal (aout, _("Audio output failed"),
384 _("The audio device \"%s\" could not be used:\n%s."),
385 sys->device, snd_strerror (val));
390 /* Print some potentially useful debug */
391 msg_Dbg (aout, "using ALSA device: %s", sys->device);
392 DumpDevice (VLC_OBJECT(aout), pcm);
394 /* Get Initial hardware parameters */
395 snd_pcm_hw_params_t *hw;
398 snd_pcm_hw_params_alloca (&hw);
399 snd_pcm_hw_params_any (pcm, hw);
400 Dump (aout, "initial hardware setup:\n", snd_pcm_hw_params_dump, hw);
402 val = snd_pcm_hw_params_set_rate_resample(pcm, hw, 0);
405 msg_Err (aout, "cannot disable resampling: %s", snd_strerror (val));
409 val = snd_pcm_hw_params_set_access (pcm, hw,
410 SND_PCM_ACCESS_RW_INTERLEAVED);
413 msg_Err (aout, "cannot set access mode: %s", snd_strerror (val));
417 /* Set sample format */
418 if (snd_pcm_hw_params_test_format (pcm, hw, pcm_format) == 0)
421 if (snd_pcm_hw_params_test_format (pcm, hw, SND_PCM_FORMAT_FLOAT) == 0)
423 fmt->i_format = VLC_CODEC_FL32;
424 pcm_format = SND_PCM_FORMAT_FLOAT;
427 if (snd_pcm_hw_params_test_format (pcm, hw, SND_PCM_FORMAT_S32) == 0)
429 fmt->i_format = VLC_CODEC_S32N;
430 pcm_format = SND_PCM_FORMAT_S32;
433 if (snd_pcm_hw_params_test_format (pcm, hw, SND_PCM_FORMAT_S16) == 0)
435 fmt->i_format = VLC_CODEC_S16N;
436 pcm_format = SND_PCM_FORMAT_S16;
440 msg_Err (aout, "no supported sample format");
444 val = snd_pcm_hw_params_set_format (pcm, hw, pcm_format);
447 msg_Err (aout, "cannot set sample format: %s", snd_strerror (val));
451 /* Set channels count */
455 uint16_t map = var_InheritInteger (aout, "alsa-audio-channels");
457 sys->chans_to_reorder = SetupChannels (VLC_OBJECT(aout), pcm, &map,
459 fmt->i_physical_channels = map;
460 fmt->i_original_channels = map;
461 channels = popcount (map);
465 sys->chans_to_reorder = 0;
469 /* By default, ALSA plug will pad missing channels with zeroes, which is
470 * usually fine. However, it will also discard extraneous channels, which
471 * is not acceptable. Thus the user must configure the physically
472 * available channels, and VLC will downmix if needed. */
473 val = snd_pcm_hw_params_set_channels (pcm, hw, channels);
476 msg_Err (aout, "cannot set %u channels: %s", channels,
481 /* Set sample rate */
482 val = snd_pcm_hw_params_set_rate_near (pcm, hw, &fmt->i_rate, NULL);
485 msg_Err (aout, "cannot set sample rate: %s", snd_strerror (val));
488 sys->rate = fmt->i_rate;
490 #if 1 /* work-around for period-long latency outputs (e.g. PulseAudio): */
491 param = AOUT_MIN_PREPARE_TIME;
492 val = snd_pcm_hw_params_set_period_time_near (pcm, hw, ¶m, NULL);
495 msg_Err (aout, "cannot set period: %s", snd_strerror (val));
499 /* Set buffer size */
500 param = AOUT_MAX_ADVANCE_TIME;
501 val = snd_pcm_hw_params_set_buffer_time_near (pcm, hw, ¶m, NULL);
504 msg_Err (aout, "cannot set buffer duration: %s", snd_strerror (val));
508 val = snd_pcm_hw_params_get_buffer_time (hw, ¶m, NULL);
511 msg_Warn (aout, "cannot get buffer time: %s", snd_strerror(val));
512 param = AOUT_MIN_PREPARE_TIME;
516 val = snd_pcm_hw_params_set_period_time_near (pcm, hw, ¶m, NULL);
519 msg_Err (aout, "cannot set period: %s", snd_strerror (val));
524 /* Commit hardware parameters */
525 val = snd_pcm_hw_params (pcm, hw);
528 msg_Err (aout, "cannot commit hardware parameters: %s",
532 Dump (aout, "final HW setup:\n", snd_pcm_hw_params_dump, hw);
534 /* Get Initial software parameters */
535 snd_pcm_sw_params_t *sw;
537 snd_pcm_sw_params_alloca (&sw);
538 snd_pcm_sw_params_current (pcm, sw);
539 Dump (aout, "initial software parameters:\n", snd_pcm_sw_params_dump, sw);
542 //snd_pcm_sw_params_set_avail_min( pcm, sw, i_period_size );
544 val = snd_pcm_sw_params_set_start_threshold (pcm, sw, 1);
547 msg_Err( aout, "unable to set start threshold (%s)",
548 snd_strerror( val ) );
553 /* Commit software parameters. */
554 val = snd_pcm_sw_params (pcm, sw);
557 msg_Err (aout, "cannot commit software parameters: %s",
561 Dump (aout, "final software parameters:\n", snd_pcm_sw_params_dump, sw);
563 val = snd_pcm_prepare (pcm);
566 msg_Err (aout, "cannot prepare device: %s", snd_strerror (val));
570 /* Setup audio_output_t */
573 fmt->i_bytes_per_frame = AOUT_SPDIF_SIZE;
574 fmt->i_frame_length = A52_FRAME_NB;
576 sys->format = fmt->i_format;
578 aout->time_get = TimeGet;
580 if (snd_pcm_hw_params_can_pause (hw))
584 aout->pause = PauseDummy;
585 msg_Warn (aout, "device cannot be paused");
588 aout_SoftVolumeStart (aout);
596 static int TimeGet (audio_output_t *aout, mtime_t *restrict delay)
598 aout_sys_t *sys = aout->sys;
599 snd_pcm_sframes_t frames;
601 int val = snd_pcm_delay (sys->pcm, &frames);
604 msg_Err (aout, "cannot estimate delay: %s", snd_strerror (val));
607 *delay = frames * CLOCK_FREQ / sys->rate;
612 * Queues one audio buffer to the hardware.
614 static void Play (audio_output_t *aout, block_t *block)
616 aout_sys_t *sys = aout->sys;
618 if (sys->chans_to_reorder != 0)
619 aout_ChannelReorder(block->p_buffer, block->i_buffer,
620 sys->chans_to_reorder, sys->chans_table, sys->format);
622 snd_pcm_t *pcm = sys->pcm;
624 /* TODO: better overflow handling */
625 /* TODO: no period wake ups */
627 while (block->i_nb_samples > 0)
629 snd_pcm_sframes_t frames;
631 frames = snd_pcm_writei (pcm, block->p_buffer, block->i_nb_samples);
634 size_t bytes = snd_pcm_frames_to_bytes (pcm, frames);
635 block->i_nb_samples -= frames;
636 block->p_buffer += bytes;
637 block->i_buffer -= bytes;
642 int val = snd_pcm_recover (pcm, frames, 1);
645 msg_Err (aout, "cannot recover playback stream: %s",
647 DumpDeviceStatus (aout, pcm);
650 msg_Warn (aout, "cannot write samples: %s", snd_strerror (frames));
653 block_Release (block);
657 * Pauses/resumes the audio playback.
659 static void Pause (audio_output_t *aout, bool pause, mtime_t date)
661 snd_pcm_t *pcm = aout->sys->pcm;
663 int val = snd_pcm_pause (pcm, pause);
665 PauseDummy (aout, pause, date);
668 static void PauseDummy (audio_output_t *aout, bool pause, mtime_t date)
670 snd_pcm_t *pcm = aout->sys->pcm;
672 /* Stupid device cannot pause. Discard samples. */
676 snd_pcm_prepare (pcm);
681 * Flushes/drains the audio playback buffer.
683 static void Flush (audio_output_t *aout, bool wait)
685 snd_pcm_t *pcm = aout->sys->pcm;
691 snd_pcm_prepare (pcm);
696 * Releases the audio output.
698 static void Stop (audio_output_t *aout)
700 aout_sys_t *sys = aout->sys;
701 snd_pcm_t *pcm = sys->pcm;
708 * Enumerates ALSA output devices.
710 static int EnumDevices(vlc_object_t *obj, char const *varname,
711 char ***restrict idp, char ***restrict namep)
715 msg_Dbg (obj, "Available ALSA PCM devices:");
716 if (snd_device_name_hint(-1, "pcm", &hints) < 0)
719 char **ids = NULL, **names = NULL;
722 for (size_t i = 0; hints[i] != NULL; i++)
724 void *hint = hints[i];
726 char *name = snd_device_name_get_hint(hint, "NAME");
727 if (unlikely(name == NULL))
730 char *desc = snd_device_name_get_hint(hint, "DESC");
732 for (char *lf = strchr(desc, '\n'); lf; lf = strchr(lf, '\n'))
734 msg_Dbg (obj, "%s (%s)", (desc != NULL) ? desc : name, name);
736 ids = xrealloc (ids, (n + 1) * sizeof (*ids));
737 names = xrealloc (names, (n + 1) * sizeof (*names));
743 snd_device_name_free_hint(hints);
750 static int DeviceSelect (audio_output_t *aout, const char *id)
752 aout_sys_t *sys = aout->sys;
754 char *device = strdup (id ? id : "default");
755 if (unlikely(device == NULL))
759 sys->device = device;
760 aout_DeviceReport (aout, device);
761 aout_RestartRequest (aout, AOUT_RESTART_OUTPUT);
765 static int Open(vlc_object_t *obj)
767 audio_output_t *aout = (audio_output_t *)obj;
768 aout_sys_t *sys = malloc (sizeof (*sys));
770 if (unlikely(sys == NULL))
772 sys->device = var_InheritString (aout, "alsa-audio-device");
773 if (unlikely(sys->device == NULL))
779 aout_SoftVolumeInit (aout);
780 aout->device_select = DeviceSelect;
781 aout_DeviceReport (aout, sys->device);
783 /* ALSA does not support hot-plug events so list devices at startup */
785 int count = EnumDevices (VLC_OBJECT(aout), NULL, &ids, &names);
788 for (int i = 0; i < count; i++)
790 aout_HotplugReport (aout, ids[i], names[i]);
804 static void Close(vlc_object_t *obj)
806 audio_output_t *aout = (audio_output_t *)obj;
807 aout_sys_t *sys = aout->sys;