1 /*****************************************************************************
2 * alsa.c: ALSA capture module for VLC
3 *****************************************************************************
4 * Copyright (C) 2012 RĂ©mi Denis-Courmont
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.
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.
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 *****************************************************************************/
26 #include <sys/types.h>
28 #include <alsa/asoundlib.h>
30 #include <vlc_common.h>
31 #include <vlc_demux.h>
33 #include <vlc_plugin.h>
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")
41 static int Open (vlc_object_t *);
42 static void Close (vlc_object_t *);
44 static const int rate_values[] = { 192000, 176400,
45 96000, 88200, 48000, 44100,
46 32000, 22050, 24000, 16000,
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")
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)
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)
69 set_callbacks (Open, Close)
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)
80 if (unlikely(snd_output_buffer_open (&output)))
83 int val = cb (p, output);
86 msg_Warn (obj, "cannot get info: %s", snd_strerror (val));
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);
96 #define Dump(o, m, cb, p) \
97 Dump(VLC_OBJECT(o), m, (int (*)(void *, snd_output_t *))(cb), p)
99 static void DumpDevice (vlc_object_t *obj, snd_pcm_t *pcm)
101 snd_pcm_info_t *info;
103 Dump (obj, " ", snd_pcm_dump, pcm);
104 snd_pcm_info_alloca (&info);
105 if (snd_pcm_info (pcm, info) == 0)
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));
114 static void DumpDeviceStatus (vlc_object_t *obj, snd_pcm_t *pcm)
116 snd_pcm_status_t *status;
118 snd_pcm_status_alloca (&status);
119 snd_pcm_status (pcm, status);
120 Dump (obj, "current status:\n", snd_pcm_status_dump, status);
122 #define DumpDeviceStatus(o, p) DumpDeviceStatus(VLC_OBJECT(o), p)
133 snd_pcm_uframes_t period_size;
137 static void Poll (snd_pcm_t *pcm, int canc)
139 int n = snd_pcm_poll_descriptors_count (pcm);
140 struct pollfd ufd[n];
141 unsigned short revents;
143 snd_pcm_poll_descriptors (pcm, ufd, n);
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);
154 static void *Thread (void *data)
156 demux_t *demux = data;
157 demux_sys_t *sys = demux->p_sys;
158 snd_pcm_t *pcm = sys->pcm;
162 canc = vlc_savecancel ();
163 bytes = snd_pcm_frames_to_bytes (pcm, sys->period_size);
164 val = snd_pcm_start (pcm);
167 msg_Err (demux, "cannot prepare device: %s", snd_strerror (val));
173 block_t *block = block_Alloc (bytes);
174 if (unlikely(block == NULL))
181 snd_pcm_sframes_t frames, delay;
184 frames = snd_pcm_readi (pcm, block->p_buffer, sys->period_size);
188 if (frames == -EAGAIN)
191 val = snd_pcm_recover (pcm, frames, 1);
194 msg_Warn (demux, "cannot read samples: %s",
195 snd_strerror (frames));
198 msg_Err (demux, "cannot recover record stream: %s",
200 DumpDeviceStatus (demux, pcm);
204 /* Compute time stamp */
205 if (snd_pcm_delay (pcm, &delay))
208 pts -= (CLOCK_FREQ * delay) / sys->rate;
210 block->i_buffer = snd_pcm_frames_to_bytes (pcm, frames);
211 block->i_nb_samples = frames;
213 block->i_length = (CLOCK_FREQ * frames) / sys->rate;
215 es_out_Control (demux->out, ES_OUT_SET_PCR, block->i_pts);
216 es_out_Send (demux->out, sys->es, block);
221 static int Control (demux_t *demux, int query, va_list ap)
223 demux_sys_t *sys = demux->p_sys;
228 *va_arg (ap, int64_t *) = mdate () - sys->start;
231 case DEMUX_GET_PTS_DELAY:
232 *va_arg (ap, int64_t *) = sys->caching;
235 //case DEMUX_SET_NEXT_DEMUX_TIME: still needed?
237 case DEMUX_HAS_UNSUPPORTED_META:
238 case DEMUX_CAN_RECORD:
239 case DEMUX_CAN_PAUSE:
240 case DEMUX_CAN_CONTROL_PACE:
241 case DEMUX_CAN_CONTROL_RATE:
243 *va_arg (ap, bool *) = false;
253 static const vlc_fourcc_t formats[] = {
254 [SND_PCM_FORMAT_S8] = VLC_CODEC_S8,
255 [SND_PCM_FORMAT_U8] = VLC_CODEC_U8,
256 [SND_PCM_FORMAT_S16_LE] = VLC_CODEC_S16L,
257 [SND_PCM_FORMAT_S16_BE] = VLC_CODEC_S16B,
258 [SND_PCM_FORMAT_U16_LE] = VLC_CODEC_U16L,
259 [SND_PCM_FORMAT_U16_BE] = VLC_CODEC_U16B,
260 [SND_PCM_FORMAT_S24_LE] = VLC_CODEC_S24L32,
261 [SND_PCM_FORMAT_S24_BE] = VLC_CODEC_S24B32,
262 [SND_PCM_FORMAT_U24_LE] = VLC_CODEC_U32L, // TODO: replay gain
263 [SND_PCM_FORMAT_U24_BE] = VLC_CODEC_U32B, // ^
264 [SND_PCM_FORMAT_S32_LE] = VLC_CODEC_S32L,
265 [SND_PCM_FORMAT_S32_BE] = VLC_CODEC_S32B,
266 [SND_PCM_FORMAT_U32_LE] = VLC_CODEC_U32L,
267 [SND_PCM_FORMAT_U32_BE] = VLC_CODEC_U32B,
268 [SND_PCM_FORMAT_FLOAT_LE] = VLC_CODEC_F32L,
269 [SND_PCM_FORMAT_FLOAT_BE] = VLC_CODEC_F32B,
270 [SND_PCM_FORMAT_FLOAT64_LE] = VLC_CODEC_F32L,
271 [SND_PCM_FORMAT_FLOAT64_BE] = VLC_CODEC_F32B,
272 //[SND_PCM_FORMAT_IEC958_SUBFRAME_LE] = VLC_CODEC_SPDIFL,
273 //[SND_PCM_FORMAT_IEC958_SUBFRAME_BE] = VLC_CODEC_SPDIFB,
274 [SND_PCM_FORMAT_MU_LAW] = VLC_CODEC_MULAW,
275 [SND_PCM_FORMAT_A_LAW] = VLC_CODEC_ALAW,
276 //[SND_PCM_FORMAT_IMA_ADPCM] = VLC_CODEC_ADPCM_?, // XXX: which one?
277 [SND_PCM_FORMAT_MPEG] = VLC_CODEC_MPGA,
278 [SND_PCM_FORMAT_GSM] = VLC_CODEC_GSM,
279 //[SND_PCM_FORMAT_SPECIAL] = VLC_CODEC_?
280 [SND_PCM_FORMAT_S24_3LE] = VLC_CODEC_S24L,
281 [SND_PCM_FORMAT_S24_3BE] = VLC_CODEC_S24B,
282 [SND_PCM_FORMAT_U24_3LE] = VLC_CODEC_U24L,
283 [SND_PCM_FORMAT_U24_3BE] = VLC_CODEC_U24B,
284 [SND_PCM_FORMAT_S20_3LE] = VLC_CODEC_S24L, // TODO: replay gain
285 [SND_PCM_FORMAT_S20_3BE] = VLC_CODEC_S24B, // ^
286 [SND_PCM_FORMAT_U20_3LE] = VLC_CODEC_U24L, // ^
287 [SND_PCM_FORMAT_U20_3BE] = VLC_CODEC_U24B, // ^
288 [SND_PCM_FORMAT_S18_3LE] = VLC_CODEC_S24L, // ^
289 [SND_PCM_FORMAT_S18_3BE] = VLC_CODEC_S24B, // ^
290 [SND_PCM_FORMAT_U18_3LE] = VLC_CODEC_U24L, // ^
291 [SND_PCM_FORMAT_U18_3BE] = VLC_CODEC_U24B, // ^
294 #ifdef WORDS_BIGENDIAN
295 # define C(f) f##BE, f##LE
297 # define C(f) f##LE, f##BE
300 /* Formats in order of decreasing preference */
301 static const uint8_t choices[] = {
302 C(SND_PCM_FORMAT_FLOAT_),
303 C(SND_PCM_FORMAT_S32_),
304 C(SND_PCM_FORMAT_U32_),
305 C(SND_PCM_FORMAT_S16_),
306 C(SND_PCM_FORMAT_U16_),
307 C(SND_PCM_FORMAT_FLOAT64_),
308 C(SND_PCM_FORMAT_S24_3),
309 C(SND_PCM_FORMAT_U24_3),
312 SND_PCM_FORMAT_MU_LAW,
313 SND_PCM_FORMAT_A_LAW,
318 static uint16_t channel_maps[] = {
319 AOUT_CHAN_CENTER, AOUT_CHANS_2_0, AOUT_CHANS_3_0 /* ? */,
320 AOUT_CHANS_4_0, AOUT_CHANS_5_0 /* ? */, AOUT_CHANS_5_1,
321 /* TODO: support 7-8 channels - need channels reodering */
324 static int Open (vlc_object_t *obj)
326 demux_t *demux = (demux_t *)obj;
327 demux_sys_t *sys = malloc (sizeof (*sys));
329 if (unlikely(sys == NULL))
332 /* Open the device */
333 const char *device = demux->psz_location;
334 if (device == NULL || !device[0])
337 const int mode = SND_PCM_NONBLOCK
338 /*| SND_PCM_NO_AUTO_RESAMPLE*/
339 | SND_PCM_NO_AUTO_CHANNELS
340 /*| SND_PCM_NO_AUTO_FORMAT*/;
342 int val = snd_pcm_open (&pcm, device, SND_PCM_STREAM_CAPTURE, mode);
345 msg_Err (demux, "cannot open ALSA device \"%s\": %s", device,
351 msg_Dbg (demux, "using ALSA device: %s", device);
352 DumpDevice (VLC_OBJECT(demux), pcm);
354 /* Negotiate capture parameters */
355 snd_pcm_hw_params_t *hw;
360 snd_pcm_hw_params_alloca (&hw);
361 snd_pcm_hw_params_any (pcm, hw);
362 Dump (demux, "initial hardware setup:\n", snd_pcm_hw_params_dump, hw);
364 val = snd_pcm_hw_params_set_rate_resample (pcm, hw, 0);
367 msg_Err (demux, "cannot disable resampling: %s", snd_strerror (val));
371 val = snd_pcm_hw_params_set_access (pcm, hw,
372 SND_PCM_ACCESS_RW_INTERLEAVED);
375 msg_Err (demux, "cannot set access mode: %s", snd_strerror (val));
379 snd_pcm_format_t format = SND_PCM_FORMAT_UNKNOWN;
380 for (size_t i = 0; i < sizeof (choices) / sizeof (choices[0]); i++)
381 if (snd_pcm_hw_params_test_format (pcm, hw, choices[i]) == 0)
383 val = snd_pcm_hw_params_set_format (pcm, hw, choices[i]);
386 msg_Err (demux, "cannot set sample format: %s",
394 if (format == SND_PCM_FORMAT_UNKNOWN)
396 msg_Err (demux, "no supported sample format");
400 assert ((size_t)format < (sizeof (formats) / sizeof (formats[0])));
401 es_format_Init (&fmt, AUDIO_ES, formats[format]);
402 fmt.audio.i_format = fmt.i_codec;
404 param = 1 + var_InheritBool (demux, "alsa-stereo");
405 val = snd_pcm_hw_params_set_channels_max (pcm, hw, ¶m);
408 msg_Err (demux, "cannot restrict channels count: %s",
412 val = snd_pcm_hw_params_set_channels_last (pcm, hw, ¶m);
415 msg_Err (demux, "cannot set channels count: %s", snd_strerror (val));
419 assert (param < (sizeof (channel_maps) / sizeof (channel_maps[0])));
420 fmt.audio.i_channels = param;
421 fmt.audio.i_original_channels =
422 fmt.audio.i_physical_channels = channel_maps[param - 1];
424 param = var_InheritInteger (demux, "alsa-samplerate");
425 val = snd_pcm_hw_params_set_rate_max (pcm, hw, ¶m, NULL);
428 msg_Err (demux, "cannot restrict rate to %u Hz or less: %s", 192000,
432 val = snd_pcm_hw_params_set_rate_last (pcm, hw, ¶m, &dir);
435 msg_Err (demux, "cannot set sample rate: %s", snd_strerror (val));
439 msg_Warn (demux, "sample rate is not integral");
440 fmt.audio.i_rate = param;
443 sys->start = mdate ();
444 sys->caching = INT64_C(1000) * var_InheritInteger (demux, "live-caching");
445 param = sys->caching;
446 val = snd_pcm_hw_params_set_buffer_time_near (pcm, hw, ¶m, NULL);
449 msg_Err (demux, "cannot set buffer duration: %s", snd_strerror (val));
454 val = snd_pcm_hw_params_set_period_time_near (pcm, hw, ¶m, NULL);
457 msg_Err (demux, "cannot set period: %s", snd_strerror (val));
461 val = snd_pcm_hw_params_get_period_size (hw, &sys->period_size, &dir);
464 msg_Err (demux, "cannot get period size: %s", snd_strerror (val));
470 /* Commit hardware parameters */
471 val = snd_pcm_hw_params (pcm, hw);
474 msg_Err (demux, "cannot commit hardware parameters: %s",
478 Dump (demux, "final HW setup:\n", snd_pcm_hw_params_dump, hw);
481 aout_FormatPrepare (&fmt.audio);
482 sys->es = es_out_Add (demux->out, &fmt);
485 if (vlc_clone (&sys->thread, Thread, demux, VLC_THREAD_PRIORITY_INPUT))
487 es_out_Del (demux->out, sys->es);
491 demux->pf_demux = NULL;
492 demux->pf_control = Control;
500 static void Close (vlc_object_t *obj)
502 demux_t *demux = (demux_t *)obj;
503 demux_sys_t *sys = demux->p_sys;
505 vlc_cancel (sys->thread);
506 vlc_join (sys->thread, NULL);
508 snd_pcm_close (sys->pcm);