modules/access/alsa.c

   1 /*****************************************************************************
   2  * alsa.c: ALSA capture module for VLC
   3  *****************************************************************************
   4  * Copyright (C) 2012 Rémi Denis-Courmont
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2.1 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 #ifdef HAVE_CONFIG_H
  22 # include <config.h>
  23 #endif
  24
  25 #include <assert.h>
  26 #include <sys/types.h>
  27 #include <poll.h>
  28 #include <alsa/asoundlib.h>
  29
  30 #include <vlc_common.h>
  31 #include <vlc_demux.h>
  32 #include <vlc_aout.h>
  33 #include <vlc_plugin.h>
  34
  35 #define HELP_TEXT N_( \
  36     "Pass alsa:// to open the default ALSA capture device, " \
  37     "or alsa://SOURCE to open a specific device named SOURCE.")
  38 #define STEREO_TEXT N_("Stereo")
  39 #define RATE_TEXT N_("Sample rate")
  40
  41 static int Open (vlc_object_t *);
  42 static void Close (vlc_object_t *);
  43
  44 static const int rate_values[] = { 192000, 176400,
  45     96000, 88200, 48000, 44100,
  46     32000, 22050, 24000, 16000,
  47     11025, 8000, 4000
  48 };
  49 static const char *const rate_names[] = { N_("192000 Hz"), N_("176400 Hz"),
  50     N_("96000 Hz"), N_("88200 Hz"), N_("48000 Hz"), N_("44100 Hz"),
  51     N_("32000 Hz"), N_("22050 Hz"), N_("24000 Hz"), N_("16000 Hz"),
  52     N_("11025 Hz"), N_("8000 Hz"), N_("4000 Hz")
  53 };
  54
  55 vlc_module_begin ()
  56     set_shortname (N_("ALSA"))
  57     set_description (N_("ALSA audio capture"))
  58     set_capability ("access_demux", 0)
  59     set_category (CAT_INPUT)
  60     set_subcategory (SUBCAT_INPUT_ACCESS)
  61     set_help (HELP_TEXT)
  62
  63     add_obsolete_string ("alsa-format") /* since 2.1.0 */
  64     add_bool ("alsa-stereo", true, STEREO_TEXT, STEREO_TEXT, true)
  65     add_integer ("alsa-samplerate", 48000, RATE_TEXT, RATE_TEXT, true)
  66         change_integer_list (rate_values, rate_names)
  67
  68     add_shortcut ("alsa")
  69     set_callbacks (Open, Close)
  70 vlc_module_end ()
  71
  72 /** Helper for ALSA -> VLC debugging output */
  73 /** XXX: duplicated from ALSA output */
  74 static void Dump (vlc_object_t *obj, const char *msg,
  75                   int (*cb)(void *, snd_output_t *), void *p)
  76 {
  77     snd_output_t *output;
  78     char *str;
  79
  80     if (unlikely(snd_output_buffer_open (&output)))
  81         return;
  82
  83     int val = cb (p, output);
  84     if (val)
  85     {
  86         msg_Warn (obj, "cannot get info: %s", snd_strerror (val));
  87         return;
  88     }
  89
  90     size_t len = snd_output_buffer_string (output, &str);
  91     if (len > 0 && str[len - 1])
  92         len--; /* strip trailing newline */
  93     msg_Dbg (obj, "%s%.*s", msg, (int)len, str);
  94     snd_output_close (output);
  95 }
  96 #define Dump(o, m, cb, p) \
  97         Dump(VLC_OBJECT(o), m, (int (*)(void *, snd_output_t *))(cb), p)
  98
  99 static void DumpDevice (vlc_object_t *obj, snd_pcm_t *pcm)
 100 {
 101     snd_pcm_info_t *info;
 102
 103     Dump (obj, " ", snd_pcm_dump, pcm);
 104     snd_pcm_info_alloca (&info);
 105     if (snd_pcm_info (pcm, info) == 0)
 106     {
 107         msg_Dbg (obj, " device name   : %s", snd_pcm_info_get_name (info));
 108         msg_Dbg (obj, " device ID     : %s", snd_pcm_info_get_id (info));
 109         msg_Dbg (obj, " subdevice name: %s",
 110                 snd_pcm_info_get_subdevice_name (info));
 111     }
 112 }
 113
 114 static void DumpDeviceStatus (vlc_object_t *obj, snd_pcm_t *pcm)
 115 {
 116     snd_pcm_status_t *status;
 117
 118     snd_pcm_status_alloca (&status);
 119     snd_pcm_status (pcm, status);
 120     Dump (obj, "current status:\n", snd_pcm_status_dump, status);
 121 }
 122 #define DumpDeviceStatus(o, p) DumpDeviceStatus(VLC_OBJECT(o), p)
 123
 124
 125 struct demux_sys_t
 126 {
 127     snd_pcm_t *pcm;
 128     es_out_id_t *es;
 129     vlc_thread_t thread;
 130
 131     mtime_t start;
 132     mtime_t caching;
 133     snd_pcm_uframes_t period_size;
 134     unsigned rate;
 135 };
 136
 137 static void Poll (snd_pcm_t *pcm, int canc)
 138 {
 139     int n = snd_pcm_poll_descriptors_count (pcm);
 140     struct pollfd ufd[n];
 141     unsigned short revents;
 142
 143     snd_pcm_poll_descriptors (pcm, ufd, n);
 144     do
 145     {
 146         vlc_restorecancel (canc);
 147         while (poll (ufd, n, -1) == -1);
 148         canc = vlc_savecancel ();
 149         snd_pcm_poll_descriptors_revents (pcm, ufd, n, &revents);
 150     }
 151     while (!revents);
 152 }
 153
 154 static void *Thread (void *data)
 155 {
 156     demux_t *demux = data;
 157     demux_sys_t *sys = demux->p_sys;
 158     snd_pcm_t *pcm = sys->pcm;
 159     size_t bytes;
 160     int canc, val;
 161
 162     canc = vlc_savecancel ();
 163     bytes = snd_pcm_frames_to_bytes (pcm, sys->period_size);
 164     val = snd_pcm_start (pcm);
 165     if (val)
 166     {
 167         msg_Err (demux, "cannot prepare device: %s", snd_strerror (val));
 168         return NULL;
 169     }
 170
 171     for (;;)
 172     {
 173         block_t *block = block_Alloc (bytes);
 174         if (unlikely(block == NULL))
 175             break;
 176
 177         /* Wait for data */
 178         Poll (pcm, canc);
 179
 180         /* Read data */
 181         snd_pcm_sframes_t frames, delay;
 182         mtime_t pts;
 183
 184         frames = snd_pcm_readi (pcm, block->p_buffer, sys->period_size);
 185         pts = mdate ();
 186         if (frames < 0)
 187         {
 188             block_Release (block);
 189             if (frames == -EAGAIN)
 190                 continue;
 191
 192             val = snd_pcm_recover (pcm, frames, 1);
 193             if (val == 0)
 194             {
 195                 msg_Warn (demux, "cannot read samples: %s",
 196                           snd_strerror (frames));
 197                 snd_pcm_state_t state = snd_pcm_state (pcm);
 198                 switch (state)
 199                 {
 200                 case SND_PCM_STATE_PREPARED:
 201                     val = snd_pcm_start (pcm);
 202                     if (val < 0)
 203                     {
 204                         msg_Err (demux, "cannot prepare device: %s",
 205                                  snd_strerror (val));
 206                         return NULL;
 207                     }
 208                     continue;
 209                 case SND_PCM_STATE_RUNNING:
 210                     continue;
 211                 default:
 212                     break;
 213                 }
 214             }
 215             msg_Err (demux, "cannot recover record stream: %s",
 216                      snd_strerror (val));
 217             DumpDeviceStatus (demux, pcm);
 218             break;
 219         }
 220
 221         /* Compute time stamp */
 222         if (snd_pcm_delay (pcm, &delay))
 223             delay = 0;
 224         delay += frames;
 225         pts -= (CLOCK_FREQ * delay) / sys->rate;
 226
 227         block->i_buffer = snd_pcm_frames_to_bytes (pcm, frames);
 228         block->i_nb_samples = frames;
 229         block->i_pts = pts;
 230         block->i_length = (CLOCK_FREQ * frames) / sys->rate;
 231
 232         es_out_SetPCR(demux->out, block->i_pts);
 233         es_out_Send (demux->out, sys->es, block);
 234     }
 235     return NULL;
 236 }
 237
 238 static int Control (demux_t *demux, int query, va_list ap)
 239 {
 240     demux_sys_t *sys = demux->p_sys;
 241
 242     switch (query)
 243     {
 244         case DEMUX_GET_TIME:
 245             *va_arg (ap, int64_t *) = mdate () - sys->start;
 246             break;
 247
 248         case DEMUX_GET_PTS_DELAY:
 249             *va_arg (ap, int64_t *) = sys->caching;
 250             break;
 251
 252         //case DEMUX_SET_NEXT_DEMUX_TIME: still needed?
 253
 254         case DEMUX_HAS_UNSUPPORTED_META:
 255         case DEMUX_CAN_RECORD:
 256         case DEMUX_CAN_PAUSE:
 257         case DEMUX_CAN_CONTROL_PACE:
 258         case DEMUX_CAN_CONTROL_RATE:
 259         case DEMUX_CAN_SEEK:
 260             *va_arg (ap, bool *) = false;
 261             break;;
 262
 263         default:
 264             return VLC_EGENERIC;
 265     }
 266
 267     return VLC_SUCCESS;
 268 }
 269
 270 static const vlc_fourcc_t formats[] = {
 271     [SND_PCM_FORMAT_S8]                 = VLC_CODEC_S8,
 272     [SND_PCM_FORMAT_U8]                 = VLC_CODEC_U8,
 273     [SND_PCM_FORMAT_S16_LE]             = VLC_CODEC_S16L,
 274     [SND_PCM_FORMAT_S16_BE]             = VLC_CODEC_S16B,
 275     [SND_PCM_FORMAT_U16_LE]             = VLC_CODEC_U16L,
 276     [SND_PCM_FORMAT_U16_BE]             = VLC_CODEC_U16B,
 277     [SND_PCM_FORMAT_S24_LE]             = VLC_CODEC_S24L32,
 278     [SND_PCM_FORMAT_S24_BE]             = VLC_CODEC_S24B32,
 279     [SND_PCM_FORMAT_U24_LE]             = VLC_CODEC_U32L, // TODO: replay gain
 280     [SND_PCM_FORMAT_U24_BE]             = VLC_CODEC_U32B, // ^
 281     [SND_PCM_FORMAT_S32_LE]             = VLC_CODEC_S32L,
 282     [SND_PCM_FORMAT_S32_BE]             = VLC_CODEC_S32B,
 283     [SND_PCM_FORMAT_U32_LE]             = VLC_CODEC_U32L,
 284     [SND_PCM_FORMAT_U32_BE]             = VLC_CODEC_U32B,
 285     [SND_PCM_FORMAT_FLOAT_LE]           = VLC_CODEC_F32L,
 286     [SND_PCM_FORMAT_FLOAT_BE]           = VLC_CODEC_F32B,
 287     [SND_PCM_FORMAT_FLOAT64_LE]         = VLC_CODEC_F32L,
 288     [SND_PCM_FORMAT_FLOAT64_BE]         = VLC_CODEC_F32B,
 289   //[SND_PCM_FORMAT_IEC958_SUBFRAME_LE] = VLC_CODEC_SPDIFL,
 290   //[SND_PCM_FORMAT_IEC958_SUBFRAME_BE] = VLC_CODEC_SPDIFB,
 291     [SND_PCM_FORMAT_MU_LAW]             = VLC_CODEC_MULAW,
 292     [SND_PCM_FORMAT_A_LAW]              = VLC_CODEC_ALAW,
 293   //[SND_PCM_FORMAT_IMA_ADPCM]          = VLC_CODEC_ADPCM_?, // XXX: which one?
 294     [SND_PCM_FORMAT_MPEG]               = VLC_CODEC_MPGA,
 295     [SND_PCM_FORMAT_GSM]                = VLC_CODEC_GSM,
 296   //[SND_PCM_FORMAT_SPECIAL]            = VLC_CODEC_?
 297     [SND_PCM_FORMAT_S24_3LE]            = VLC_CODEC_S24L,
 298     [SND_PCM_FORMAT_S24_3BE]            = VLC_CODEC_S24B,
 299     [SND_PCM_FORMAT_U24_3LE]            = VLC_CODEC_U24L,
 300     [SND_PCM_FORMAT_U24_3BE]            = VLC_CODEC_U24B,
 301     [SND_PCM_FORMAT_S20_3LE]            = VLC_CODEC_S24L, // TODO: replay gain
 302     [SND_PCM_FORMAT_S20_3BE]            = VLC_CODEC_S24B, // ^
 303     [SND_PCM_FORMAT_U20_3LE]            = VLC_CODEC_U24L, // ^
 304     [SND_PCM_FORMAT_U20_3BE]            = VLC_CODEC_U24B, // ^
 305     [SND_PCM_FORMAT_S18_3LE]            = VLC_CODEC_S24L, // ^
 306     [SND_PCM_FORMAT_S18_3BE]            = VLC_CODEC_S24B, // ^
 307     [SND_PCM_FORMAT_U18_3LE]            = VLC_CODEC_U24L, // ^
 308     [SND_PCM_FORMAT_U18_3BE]            = VLC_CODEC_U24B, // ^
 309 };
 310
 311 #ifdef WORDS_BIGENDIAN
 312 # define C(f) f##BE, f##LE
 313 #else
 314 # define C(f) f##LE, f##BE
 315 #endif
 316
 317 /* Formats in order of decreasing preference */
 318 static const uint8_t choices[] = {
 319     C(SND_PCM_FORMAT_FLOAT_),
 320     C(SND_PCM_FORMAT_S32_),
 321     C(SND_PCM_FORMAT_U32_),
 322     C(SND_PCM_FORMAT_S16_),
 323     C(SND_PCM_FORMAT_U16_),
 324     C(SND_PCM_FORMAT_FLOAT64_),
 325     C(SND_PCM_FORMAT_S24_3),
 326     C(SND_PCM_FORMAT_U24_3),
 327     SND_PCM_FORMAT_MPEG,
 328     SND_PCM_FORMAT_GSM,
 329     SND_PCM_FORMAT_MU_LAW,
 330     SND_PCM_FORMAT_A_LAW,
 331     SND_PCM_FORMAT_S8,
 332     SND_PCM_FORMAT_U8,
 333 };
 334
 335 static uint16_t channel_maps[] = {
 336     AOUT_CHAN_CENTER, AOUT_CHANS_2_0, AOUT_CHANS_3_0 /* ? */,
 337     AOUT_CHANS_4_0, AOUT_CHANS_5_0 /* ? */, AOUT_CHANS_5_1,
 338     /* TODO: support 7-8 channels - need channels reodering */
 339 };
 340
 341 static int Open (vlc_object_t *obj)
 342 {
 343     demux_t *demux = (demux_t *)obj;
 344     demux_sys_t *sys = vlc_obj_malloc(obj, sizeof (*sys));
 345     if (unlikely(sys == NULL))
 346         return VLC_ENOMEM;
 347
 348     /* Open the device */
 349     const char *device = demux->psz_location;
 350     if (device == NULL || !device[0])
 351         device = "default";
 352
 353     const int mode = SND_PCM_NONBLOCK
 354                  /*| SND_PCM_NO_AUTO_RESAMPLE*/
 355                    | SND_PCM_NO_AUTO_CHANNELS
 356                  /*| SND_PCM_NO_AUTO_FORMAT*/;
 357     snd_pcm_t *pcm;
 358     int val = snd_pcm_open (&pcm, device, SND_PCM_STREAM_CAPTURE, mode);
 359     if (val != 0)
 360     {
 361         msg_Err (demux, "cannot open ALSA device \"%s\": %s", device,
 362                  snd_strerror (val));
 363         return VLC_EGENERIC;
 364     }
 365     sys->pcm = pcm;
 366     msg_Dbg (demux, "using ALSA device: %s", device);
 367     DumpDevice (VLC_OBJECT(demux), pcm);
 368
 369     /* Negotiate capture parameters */
 370     snd_pcm_hw_params_t *hw;
 371     es_format_t fmt;
 372     unsigned param;
 373     int dir;
 374
 375     snd_pcm_hw_params_alloca (&hw);
 376     snd_pcm_hw_params_any (pcm, hw);
 377     Dump (demux, "initial hardware setup:\n", snd_pcm_hw_params_dump, hw);
 378
 379     val = snd_pcm_hw_params_set_rate_resample (pcm, hw, 0);
 380     if (val)
 381     {
 382         msg_Err (demux, "cannot disable resampling: %s", snd_strerror (val));
 383         goto error;
 384     }
 385
 386     val = snd_pcm_hw_params_set_access (pcm, hw,
 387                                         SND_PCM_ACCESS_RW_INTERLEAVED);
 388     if (val)
 389     {
 390         msg_Err (demux, "cannot set access mode: %s", snd_strerror (val));
 391         goto error;
 392     }
 393
 394     snd_pcm_format_t format = SND_PCM_FORMAT_UNKNOWN;
 395     for (size_t i = 0; i < sizeof (choices) / sizeof (choices[0]); i++)
 396         if (snd_pcm_hw_params_test_format (pcm, hw, choices[i]) == 0)
 397         {
 398             val = snd_pcm_hw_params_set_format (pcm, hw, choices[i]);
 399             if (val)
 400             {
 401                 msg_Err (demux, "cannot set sample format: %s",
 402                          snd_strerror (val));
 403                 goto error;
 404             }
 405             format = choices[i];
 406             break;
 407         }
 408
 409     if (format == SND_PCM_FORMAT_UNKNOWN)
 410     {
 411         msg_Err (demux, "no supported sample format");
 412         goto error;
 413     }
 414
 415     assert ((size_t)format < (sizeof (formats) / sizeof (formats[0])));
 416     es_format_Init (&fmt, AUDIO_ES, formats[format]);
 417     fmt.audio.i_format = fmt.i_codec;
 418
 419     param = 1 + var_InheritBool (demux, "alsa-stereo");
 420     val = snd_pcm_hw_params_set_channels_max (pcm, hw, &param);
 421     if (val)
 422     {
 423         msg_Err (demux, "cannot restrict channels count: %s",
 424                  snd_strerror (val));
 425         goto error;
 426     }
 427     val = snd_pcm_hw_params_set_channels_last (pcm, hw, &param);
 428     if (val)
 429     {
 430         msg_Err (demux, "cannot set channels count: %s", snd_strerror (val));
 431         goto error;
 432     }
 433     assert (param > 0);
 434     assert (param < (sizeof (channel_maps) / sizeof (channel_maps[0])));
 435     fmt.audio.i_channels = param;
 436     fmt.audio.i_physical_channels = channel_maps[param - 1];
 437
 438     param = var_InheritInteger (demux, "alsa-samplerate");
 439     val = snd_pcm_hw_params_set_rate_max (pcm, hw, &param, NULL);
 440     if (val)
 441     {
 442         msg_Err (demux, "cannot restrict rate to %u Hz or less: %s", 192000,
 443                  snd_strerror (val));
 444         goto error;
 445     }
 446     val = snd_pcm_hw_params_set_rate_last (pcm, hw, &param, &dir);
 447     if (val)
 448     {
 449         msg_Err (demux, "cannot set sample rate: %s", snd_strerror (val));
 450         goto error;
 451     }
 452     if (dir)
 453         msg_Warn (demux, "sample rate is not integral");
 454     fmt.audio.i_rate = param;
 455     sys->rate = param;
 456
 457     sys->start = mdate ();
 458     sys->caching = INT64_C(1000) * var_InheritInteger (demux, "live-caching");
 459     param = sys->caching;
 460     val = snd_pcm_hw_params_set_buffer_time_near (pcm, hw, &param, NULL);
 461     if (val)
 462     {
 463         msg_Err (demux, "cannot set buffer duration: %s", snd_strerror (val));
 464         goto error;
 465     }
 466
 467     param /= 4;
 468     val = snd_pcm_hw_params_set_period_time_near (pcm, hw, &param, NULL);
 469     if (val)
 470     {
 471         msg_Err (demux, "cannot set period: %s", snd_strerror (val));
 472         goto error;
 473     }
 474
 475     val = snd_pcm_hw_params_get_period_size (hw, &sys->period_size, &dir);
 476     if (val)
 477     {
 478         msg_Err (demux, "cannot get period size: %s", snd_strerror (val));
 479         goto error;
 480     }
 481     if (dir > 0)
 482         sys->period_size++;
 483
 484     /* Commit hardware parameters */
 485     val = snd_pcm_hw_params (pcm, hw);
 486     if (val)
 487     {
 488         msg_Err (demux, "cannot commit hardware parameters: %s",
 489                  snd_strerror (val));
 490         goto error;
 491     }
 492     Dump (demux, "final HW setup:\n", snd_pcm_hw_params_dump, hw);
 493
 494     /* Kick recording */
 495     aout_FormatPrepare (&fmt.audio);
 496     sys->es = es_out_Add (demux->out, &fmt);
 497     demux->p_sys = sys;
 498
 499     if (vlc_clone (&sys->thread, Thread, demux, VLC_THREAD_PRIORITY_INPUT))
 500     {
 501         es_out_Del (demux->out, sys->es);
 502         goto error;
 503     }
 504
 505     demux->pf_demux = NULL;
 506     demux->pf_control = Control;
 507     return VLC_SUCCESS;
 508 error:
 509     snd_pcm_close (pcm);
 510     return VLC_EGENERIC;
 511 }
 512
 513 static void Close (vlc_object_t *obj)
 514 {
 515     demux_t *demux = (demux_t *)obj;
 516     demux_sys_t *sys = demux->p_sys;
 517
 518     vlc_cancel (sys->thread);
 519     vlc_join (sys->thread, NULL);
 520
 521     snd_pcm_close (sys->pcm);
 522 }