modules/audio_output/oss.c

   1 /*****************************************************************************
   2  * oss.c: Open Sound System audio output plugin for VLC
   3  *****************************************************************************
   4  * Copyright (C) 2000-2002 VLC authors and VideoLAN
   5  * Copyright (C) 2007-2012 Rémi Denis-Courmont
   6  *
   7  * Authors: Michel Kaempf <maxx@via.ecp.fr>
   8  *          Sam Hocevar <sam@zoy.org>
   9  *          Christophe Massiot <massiot@via.ecp.fr>
  10  *
  11  * This program is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU Lesser General Public License as published by
  13  * the Free Software Foundation; either version 2.1 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  19  * GNU Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public License
  22  * along with this program; if not, write to the Free Software Foundation,
  23  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  24  *****************************************************************************/
  25
  26 #ifdef HAVE_CONFIG_H
  27 # include "config.h"
  28 #endif
  29
  30 #include <stdlib.h>
  31 #include <math.h>
  32 #include <errno.h>
  33 #include <sys/types.h>
  34 #include <fcntl.h>
  35 #include <sys/ioctl.h>
  36 #ifdef HAVE_SOUNDCARD_H
  37 # include <soundcard.h>
  38 #else
  39 # include <sys/soundcard.h>
  40 #endif
  41
  42 #ifndef SNDCTL_DSP_HALT
  43 # define SNDCTL_DSP_HALT SNDCTL_DSP_RESET
  44 #endif
  45
  46 #include <vlc_common.h>
  47 #include <vlc_plugin.h>
  48 #include <vlc_fs.h>
  49 #include <vlc_cpu.h>
  50 #include <vlc_aout.h>
  51
  52 #define A52_FRAME_NB 1536
  53
  54 struct aout_sys_t
  55 {
  56     int fd;
  57     audio_sample_format_t format;
  58     bool starting;
  59     bool soft_mute;
  60     float soft_gain;
  61     char *device;
  62 };
  63
  64 #include "volume.h"
  65
  66 static int Open (vlc_object_t *);
  67 static void Close (vlc_object_t *);
  68
  69 #define AUDIO_DEV_TEXT N_("Audio output device")
  70 #define AUDIO_DEV_LONGTEXT N_("OSS device node path.")
  71
  72 vlc_module_begin ()
  73     set_shortname( "OSS" )
  74     set_description (N_("Open Sound System audio output"))
  75     set_category( CAT_AUDIO )
  76     set_subcategory( SUBCAT_AUDIO_AOUT )
  77     add_string ("oss-audio-device", "",
  78                 AUDIO_DEV_TEXT, AUDIO_DEV_LONGTEXT, false)
  79     add_sw_gain ()
  80     set_capability( "audio output", 100 )
  81     set_callbacks (Open, Close)
  82 vlc_module_end ()
  83
  84 static int TimeGet (audio_output_t *, mtime_t *);
  85 static void Play (audio_output_t *, block_t *);
  86 static void Pause (audio_output_t *, bool, mtime_t);
  87 static void Flush (audio_output_t *, bool);
  88
  89 static int Start (audio_output_t *aout, audio_sample_format_t *restrict fmt)
  90 {
  91     aout_sys_t* sys = aout->sys;
  92
  93     if (aout_FormatNbChannels(fmt) == 0)
  94         return VLC_EGENERIC;
  95
  96     /* Open the device */
  97     const char *device = sys->device;
  98     if (device == NULL)
  99         device = getenv ("OSS_AUDIODEV");
 100     if (device == NULL)
 101         device = "/dev/dsp";
 102
 103     int fd = vlc_open (device, O_WRONLY);
 104     if (fd == -1)
 105     {
 106         msg_Err (aout, "cannot open OSS device %s: %s", device,
 107                  vlc_strerror_c(errno));
 108         return VLC_EGENERIC;
 109     }
 110     msg_Dbg (aout, "using OSS device: %s", device);
 111
 112     /* Select audio format */
 113     int format;
 114     bool spdif = false;
 115
 116     switch (fmt->i_format)
 117     {
 118 #ifdef AFMT_FLOAT
 119         case VLC_CODEC_FL64:
 120         case VLC_CODEC_FL32:
 121             format = AFMT_FLOAT;
 122             break;
 123 #endif
 124         case VLC_CODEC_S32N:
 125             format = AFMT_S32_NE;
 126             break;
 127         case VLC_CODEC_S16N:
 128             format = AFMT_S16_NE;
 129             break;
 130         case VLC_CODEC_U8:
 131             format = AFMT_U8;
 132             break;
 133         default:
 134             if (AOUT_FMT_SPDIF(fmt))
 135                 spdif = var_InheritBool (aout, "spdif");
 136             if (spdif)
 137                 format = AFMT_AC3;
 138 #ifdef AFMT_FLOAT
 139             else if (HAVE_FPU)
 140                 format = AFMT_FLOAT;
 141 #endif
 142             else
 143                 format = AFMT_S16_NE;
 144     }
 145
 146     if (ioctl (fd, SNDCTL_DSP_SETFMT, &format) < 0)
 147     {
 148         msg_Err (aout, "cannot set audio format 0x%X: %s", format,
 149                  vlc_strerror_c(errno));
 150         goto error;
 151     }
 152
 153     switch (format)
 154     {
 155         case AFMT_U8:     fmt->i_format = VLC_CODEC_U8;   break;
 156         case AFMT_S16_NE: fmt->i_format = VLC_CODEC_S16N; break;
 157         case AFMT_S32_NE: fmt->i_format = VLC_CODEC_S32N; break;
 158 #ifdef AFMT_FLOAT
 159         case AFMT_FLOAT:  fmt->i_format = VLC_CODEC_FL32; break;
 160 #endif
 161         case AFMT_AC3:
 162             if (spdif)
 163             {
 164                 fmt->i_format = VLC_CODEC_SPDIFL;
 165                 break;
 166             }
 167         default:
 168             msg_Err (aout, "unsupported audio format 0x%X", format);
 169             goto error;
 170     }
 171
 172     /* Select channels count */
 173     int channels = spdif ? 2 : aout_FormatNbChannels (fmt);
 174     if (ioctl (fd, SNDCTL_DSP_CHANNELS, &channels) < 0)
 175     {
 176         msg_Err (aout, "cannot set %d channels: %s", channels,
 177                  vlc_strerror_c(errno));
 178         goto error;
 179     }
 180
 181     switch (channels)
 182     {
 183         case 1: channels = AOUT_CHAN_CENTER;  break;
 184         case 2: channels = AOUT_CHANS_STEREO; break;
 185         case 4: channels = AOUT_CHANS_4_0;    break;
 186         case 6: channels = AOUT_CHANS_5_1;    break;
 187         case 8: channels = AOUT_CHANS_7_1;    break;
 188         default:
 189             msg_Err (aout, "unsupported channels count %d", channels);
 190             goto error;
 191     }
 192
 193     /* Select sample rate */
 194     int rate = spdif ? 48000 : fmt->i_rate;
 195     if (ioctl (fd, SNDCTL_DSP_SPEED, &rate) < 0)
 196     {
 197         msg_Err (aout, "cannot set %d Hz sample rate: %s", rate,
 198                  vlc_strerror_c(errno));
 199         goto error;
 200     }
 201
 202     /* Setup audio_output_t */
 203     aout->time_get = TimeGet;
 204     aout->play = Play;
 205     aout->pause = Pause;
 206     aout->flush = Flush;
 207
 208     if (spdif)
 209     {
 210         fmt->i_bytes_per_frame = AOUT_SPDIF_SIZE;
 211         fmt->i_frame_length = A52_FRAME_NB;
 212     }
 213     else
 214     {
 215         fmt->i_rate = rate;
 216         fmt->i_physical_channels = channels;
 217     }
 218     fmt->channel_type = AUDIO_CHANNEL_TYPE_BITMAP;
 219     aout_FormatPrepare (fmt);
 220
 221     /* Select timing */
 222     unsigned bytes;
 223     if (spdif)
 224         bytes = AOUT_SPDIF_SIZE;
 225     else
 226         bytes = fmt->i_rate / (CLOCK_FREQ / AOUT_MIN_PREPARE_TIME)
 227                 * fmt->i_bytes_per_frame;
 228     if (unlikely(bytes < 16))
 229         bytes = 16;
 230
 231     int frag = (AOUT_MAX_ADVANCE_TIME / AOUT_MIN_PREPARE_TIME) << 16
 232              | (32 - clz32(bytes - 1));
 233     if (ioctl (fd, SNDCTL_DSP_SETFRAGMENT, &frag) < 0)
 234         msg_Err (aout, "cannot set 0x%08x fragment: %s", frag,
 235                  vlc_strerror_c(errno));
 236
 237     sys->fd = fd;
 238     aout_SoftVolumeStart (aout);
 239     sys->starting = true;
 240     sys->format = *fmt;
 241     return VLC_SUCCESS;
 242 error:
 243     vlc_close (fd);
 244     return VLC_EGENERIC;
 245 }
 246
 247 static int TimeGet (audio_output_t *aout, mtime_t *restrict pts)
 248 {
 249     aout_sys_t *sys = aout->sys;
 250     int delay;
 251
 252     if (ioctl (sys->fd, SNDCTL_DSP_GETODELAY, &delay) < 0)
 253     {
 254         msg_Warn (aout, "cannot get delay: %s", vlc_strerror_c(errno));
 255         return -1;
 256     }
 257
 258     *pts = (delay * CLOCK_FREQ * sys->format.i_frame_length)
 259                         / (sys->format.i_rate * sys->format.i_bytes_per_frame);
 260     return 0;
 261 }
 262
 263 /**
 264  * Queues one audio buffer to the hardware.
 265  */
 266 static void Play (audio_output_t *aout, block_t *block)
 267 {
 268     aout_sys_t *sys = aout->sys;
 269     int fd = sys->fd;
 270
 271     while (block->i_buffer > 0)
 272     {
 273         ssize_t bytes = write (fd, block->p_buffer, block->i_buffer);
 274         if (bytes >= 0)
 275         {
 276             block->p_buffer += bytes;
 277             block->i_buffer -= bytes;
 278         }
 279         else
 280             msg_Err (aout, "cannot write samples: %s", vlc_strerror_c(errno));
 281     }
 282     block_Release (block);
 283 }
 284
 285 /**
 286  * Pauses/resumes the audio playback.
 287  */
 288 static void Pause (audio_output_t *aout, bool pause, mtime_t date)
 289 {
 290     aout_sys_t *sys = aout->sys;
 291     int fd = sys->fd;
 292
 293     (void) date;
 294     ioctl (fd, pause ? SNDCTL_DSP_SILENCE : SNDCTL_DSP_SKIP, NULL);
 295 }
 296
 297 /**
 298  * Flushes/drains the audio playback buffer.
 299  */
 300 static void Flush (audio_output_t *aout, bool wait)
 301 {
 302     aout_sys_t *sys = aout->sys;
 303     int fd = sys->fd;
 304
 305     if (wait)
 306         return; /* drain is implicit with OSS */
 307     ioctl (fd, SNDCTL_DSP_HALT, NULL);
 308 }
 309
 310 /**
 311  * Releases the audio output device.
 312  */
 313 static void Stop (audio_output_t *aout)
 314 {
 315     aout_sys_t *sys = aout->sys;
 316     int fd = sys->fd;
 317
 318     ioctl (fd, SNDCTL_DSP_HALT, NULL);
 319     vlc_close (fd);
 320     sys->fd = -1;
 321 }
 322
 323 static int DevicesEnum (audio_output_t *aout)
 324 {
 325     int fd = vlc_open ("/dev/dsp", O_WRONLY);
 326     if (fd == -1)
 327         return -1;
 328
 329     oss_sysinfo si;
 330     int n = -1;
 331
 332     if (ioctl (fd, SNDCTL_SYSINFO, &si) < 0)
 333     {
 334         msg_Err (aout, "cannot get system infos: %s", vlc_strerror(errno));
 335         goto out;
 336     }
 337
 338     msg_Dbg (aout, "using %s version %s (0x%06X) under %s", si.product,
 339              si.version, si.versionnum, si.license);
 340
 341     for (int i = 0; i < si.numaudios; i++)
 342     {
 343         oss_audioinfo ai = { .dev = i };
 344
 345         if (ioctl (fd, SNDCTL_AUDIOINFO, &ai) < 0)
 346         {
 347             msg_Warn (aout, "cannot get device %d infos: %s", i,
 348                       vlc_strerror_c(errno));
 349             continue;
 350         }
 351         if (ai.caps & (PCM_CAP_HIDDEN|PCM_CAP_MODEM))
 352             continue;
 353         if (!(ai.caps & PCM_CAP_OUTPUT))
 354             continue;
 355         if (!ai.enabled)
 356             continue;
 357
 358         aout_HotplugReport (aout, ai.devnode, ai.name);
 359         n++;
 360     }
 361 out:
 362     vlc_close (fd);
 363     return n;
 364 }
 365
 366 static int DeviceSelect (audio_output_t *aout, const char *id)
 367 {
 368     aout_sys_t *sys = aout->sys;
 369     char *path = NULL;
 370
 371     if (id != NULL)
 372     {
 373         path = strdup (id);
 374         if (unlikely(path == NULL))
 375             return -1;
 376     }
 377
 378     free (sys->device);
 379     sys->device = path;
 380     aout_DeviceReport (aout, path);
 381     aout_RestartRequest (aout, AOUT_RESTART_OUTPUT);
 382     return 0;
 383 }
 384
 385 static int Open (vlc_object_t *obj)
 386 {
 387     audio_output_t *aout = (audio_output_t *)obj;
 388
 389     aout_sys_t *sys = malloc (sizeof (*sys));
 390     if(unlikely( sys == NULL ))
 391         return VLC_ENOMEM;
 392
 393     sys->fd = -1;
 394     sys->device = var_InheritString (aout, "oss-audio-device");
 395
 396     aout->sys = sys;
 397     aout->start = Start;
 398     aout->stop = Stop;
 399     aout->device_select = DeviceSelect;
 400     aout_DeviceReport (aout, sys->device);
 401     aout_SoftVolumeInit (aout);
 402
 403     DevicesEnum (aout);
 404     return VLC_SUCCESS;
 405 }
 406
 407 static void Close (vlc_object_t *obj)
 408 {
 409     audio_output_t *aout = (audio_output_t *)obj;
 410     aout_sys_t *sys = aout->sys;
 411
 412     free (sys->device);
 413     free (sys);
 414 }