1 /*****************************************************************************
2 * alsa.c : Alsa input module for vlc
3 *****************************************************************************
4 * Copyright (C) 2002-2009 the VideoLAN team
7 * Authors: Benjamin Pracht <bigben at videolan dot org>
8 * Richard Hosking <richard at hovis dot net>
9 * Antoine Cellerier <dionoea at videolan d.t org>
10 * Dennis Lou <dlou99 at yahoo dot com>
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 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 General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
25 *****************************************************************************/
28 * ALSA support based on parts of
29 * http://www.equalarea.com/paul/alsa-audio.html
30 * and hints taken from alsa-utils (aplay/arecord)
31 * http://www.alsa-project.org
34 /*****************************************************************************
36 *****************************************************************************/
42 #include <vlc_common.h>
43 #include <vlc_plugin.h>
44 #include <vlc_access.h>
45 #include <vlc_demux.h>
46 #include <vlc_input.h>
52 #include <sys/ioctl.h>
55 #include <sys/soundcard.h>
57 #define ALSA_PCM_NEW_HW_PARAMS_API
58 #define ALSA_PCM_NEW_SW_PARAMS_API
59 #include <alsa/asoundlib.h>
63 /*****************************************************************************
65 *****************************************************************************/
67 static int DemuxOpen ( vlc_object_t * );
68 static void DemuxClose( vlc_object_t * );
70 #define STEREO_TEXT N_( "Stereo" )
71 #define STEREO_LONGTEXT N_( \
72 "Capture the audio stream in stereo." )
74 #define SAMPLERATE_TEXT N_( "Samplerate" )
75 #define SAMPLERATE_LONGTEXT N_( \
76 "Samplerate of the captured audio stream, in Hz (eg: 11025, 22050, 44100, 48000)" )
78 #define CACHING_TEXT N_("Caching value in ms")
79 #define CACHING_LONGTEXT N_( \
80 "Caching value for Alsa captures. This " \
81 "value should be set in milliseconds." )
83 #define ALSA_DEFAULT "hw"
84 #define CFG_PREFIX "alsa-"
87 set_shortname( N_("Alsa") )
88 set_description( N_("Alsa audio capture input") )
89 set_category( CAT_INPUT )
90 set_subcategory( SUBCAT_INPUT_ACCESS )
92 add_shortcut( "alsa" )
93 set_capability( "access_demux", 10 )
94 set_callbacks( DemuxOpen, DemuxClose )
96 add_bool( CFG_PREFIX "stereo", true, NULL, STEREO_TEXT, STEREO_LONGTEXT,
98 add_integer( CFG_PREFIX "samplerate", 48000, NULL, SAMPLERATE_TEXT,
99 SAMPLERATE_LONGTEXT, true )
100 add_integer( CFG_PREFIX "caching", DEFAULT_PTS_DELAY / 1000, NULL,
101 CACHING_TEXT, CACHING_LONGTEXT, true )
104 /*****************************************************************************
105 * Access: local prototypes
106 *****************************************************************************/
108 static int DemuxControl( demux_t *, int, va_list );
110 static int Demux( demux_t * );
112 static block_t* GrabAudio( demux_t *p_demux );
114 static int OpenAudioDev( demux_t * );
115 static bool ProbeAudioDevAlsa( demux_t *, const char *psz_device );
119 const char *psz_device; /* Alsa device from MRL */
123 unsigned int i_sample_rate;
125 size_t i_max_frame_size;
130 snd_pcm_t *p_alsa_pcm;
131 size_t i_alsa_frame_size;
132 int i_alsa_chunk_size;
134 int64_t i_next_demux_date; /* Used to handle alsa:// as input-slave properly */
137 static int FindMainDevice( demux_t *p_demux )
139 /* TODO: if using default device, loop through all alsa devices until
141 msg_Dbg( p_demux, "opening device '%s'", p_demux->p_sys->psz_device );
142 if( ProbeAudioDevAlsa( p_demux, p_demux->p_sys->psz_device ) )
144 msg_Dbg( p_demux, "'%s' is an audio device",
145 p_demux->p_sys->psz_device );
146 OpenAudioDev( p_demux );
149 if( p_demux->p_sys->p_alsa_pcm == NULL )
154 static void ListAvailableDevices( demux_t *p_demux )
156 snd_ctl_card_info_t *p_info = NULL;
157 snd_ctl_card_info_alloca( &p_info );
159 snd_pcm_info_t *p_pcminfo = NULL;
160 snd_pcm_info_alloca( &p_pcminfo );
162 msg_Dbg( p_demux, "Available alsa capture devices:" );
164 while( !snd_card_next( &i_card ) && i_card >= 0 )
166 char psz_devname[10];
167 snprintf( psz_devname, 10, "hw:%d", i_card );
169 snd_ctl_t *p_ctl = NULL;
170 if( snd_ctl_open( &p_ctl, psz_devname, 0 ) < 0 ) continue;
172 snd_ctl_card_info( p_ctl, p_info );
173 msg_Dbg( p_demux, " %s (%s)",
174 snd_ctl_card_info_get_id( p_info ),
175 snd_ctl_card_info_get_name( p_info ) );
178 while( !snd_ctl_pcm_next_device( p_ctl, &i_dev ) && i_dev >= 0 )
180 snd_pcm_info_set_device( p_pcminfo, i_dev );
181 snd_pcm_info_set_subdevice( p_pcminfo, 0 );
182 snd_pcm_info_set_stream( p_pcminfo, SND_PCM_STREAM_CAPTURE );
183 if( snd_ctl_pcm_info( p_ctl, p_pcminfo ) < 0 ) continue;
185 msg_Dbg( p_demux, " hw:%d,%d : %s (%s)", i_card, i_dev,
186 snd_pcm_info_get_id( p_pcminfo ),
187 snd_pcm_info_get_name( p_pcminfo ) );
190 snd_ctl_close( p_ctl );
194 /*****************************************************************************
195 * DemuxOpen: opens alsa device, access_demux callback
196 *****************************************************************************
198 * url: <alsa device>::::
200 *****************************************************************************/
201 static int DemuxOpen( vlc_object_t *p_this )
203 demux_t *p_demux = (demux_t*)p_this;
206 /* Only when selected */
207 if( *p_demux->psz_access == '\0' ) return VLC_EGENERIC;
210 p_demux->pf_control = DemuxControl;
211 p_demux->pf_demux = Demux;
212 p_demux->info.i_update = 0;
213 p_demux->info.i_title = 0;
214 p_demux->info.i_seekpoint = 0;
216 p_demux->p_sys = p_sys = calloc( 1, sizeof( demux_sys_t ) );
217 if( p_sys == NULL ) return VLC_ENOMEM;
219 p_sys->i_sample_rate = var_CreateGetInteger( p_demux, CFG_PREFIX "samplerate" );
220 p_sys->b_stereo = var_CreateGetBool( p_demux, CFG_PREFIX "stereo" );
221 p_sys->i_cache = var_CreateGetInteger( p_demux, CFG_PREFIX "caching" );
223 p_sys->p_block = NULL;
224 p_sys->i_next_demux_date = -1;
226 if( p_demux->psz_path && *p_demux->psz_path )
227 p_sys->psz_device = p_demux->psz_path;
230 p_sys->psz_device = ALSA_DEFAULT;
231 ListAvailableDevices( p_demux );
234 if( FindMainDevice( p_demux ) != VLC_SUCCESS )
236 DemuxClose( p_this );
243 /*****************************************************************************
244 * Close: close device, free resources
245 *****************************************************************************/
246 static void DemuxClose( vlc_object_t *p_this )
248 demux_t *p_demux = (demux_t *)p_this;
249 demux_sys_t *p_sys = p_demux->p_sys;
251 if( p_sys->p_alsa_pcm )
253 snd_pcm_close( p_sys->p_alsa_pcm );
256 if( p_sys->p_block ) block_Release( p_sys->p_block );
261 /*****************************************************************************
263 *****************************************************************************/
264 static int DemuxControl( demux_t *p_demux, int i_query, va_list args )
266 demux_sys_t *p_sys = p_demux->p_sys;
272 /* Special for access_demux */
273 case DEMUX_CAN_PAUSE:
275 case DEMUX_SET_PAUSE_STATE:
276 case DEMUX_CAN_CONTROL_PACE:
277 pb = (bool*)va_arg( args, bool * );
281 case DEMUX_GET_PTS_DELAY:
282 pi64 = (int64_t*)va_arg( args, int64_t * );
283 *pi64 = (int64_t)p_sys->i_cache * 1000;
287 pi64 = (int64_t*)va_arg( args, int64_t * );
291 case DEMUX_SET_NEXT_DEMUX_TIME:
292 p_sys->i_next_demux_date = (int64_t)va_arg( args, int64_t );
295 /* TODO implement others */
303 /*****************************************************************************
304 * Demux: Processes the audio frame
305 *****************************************************************************/
306 static int Demux( demux_t *p_demux )
308 demux_sys_t *p_sys = p_demux->p_sys;
310 block_t *p_block = NULL;
316 es_out_Send( p_demux->out, p_sys->p_es, p_block );
321 int i_wait = snd_pcm_wait( p_sys->p_alsa_pcm, 500 );
326 p_block = GrabAudio( p_demux );
328 es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block->i_pts );
331 /* FIXME: this is a copy paste from below. Shouldn't be needed
335 snd_pcm_prepare( p_sys->p_alsa_pcm );
340 int i_resume = snd_pcm_resume( p_sys->p_alsa_pcm );
341 if( i_resume < 0 && i_resume != -EAGAIN ) snd_pcm_prepare( p_sys->p_alsa_pcm );
346 } while( p_block && p_sys->i_next_demux_date > 0 &&
347 p_block->i_pts < p_sys->i_next_demux_date );
350 es_out_Send( p_demux->out, p_sys->p_es, p_block );
356 /*****************************************************************************
357 * GrabAudio: Grab an audio frame
358 *****************************************************************************/
359 static block_t* GrabAudio( demux_t *p_demux )
361 demux_sys_t *p_sys = p_demux->p_sys;
362 int i_read, i_correct;
365 if( p_sys->p_block ) p_block = p_sys->p_block;
366 else p_block = block_New( p_demux, p_sys->i_max_frame_size );
370 msg_Warn( p_demux, "cannot get block" );
374 p_sys->p_block = p_block;
377 i_read = snd_pcm_readi( p_sys->p_alsa_pcm, p_block->p_buffer, p_sys->i_alsa_chunk_size );
387 snd_pcm_prepare( p_sys->p_alsa_pcm );
391 i_resume = snd_pcm_resume( p_sys->p_alsa_pcm );
392 if( i_resume < 0 && i_resume != -EAGAIN ) snd_pcm_prepare( p_sys->p_alsa_pcm );
395 msg_Err( p_demux, "Failed to read alsa frame (%s)", snd_strerror( i_read ) );
401 /* convert from frames to bytes */
402 i_read *= p_sys->i_alsa_frame_size;
405 if( i_read <= 0 ) return 0;
407 p_block->i_buffer = i_read;
410 /* Correct the date because of kernel buffering */
414 snd_pcm_sframes_t delay = 0;
415 if( ( i_err = snd_pcm_delay( p_sys->p_alsa_pcm, &delay ) ) >= 0 )
417 size_t i_correction_delta = delay * p_sys->i_alsa_frame_size;
418 /* Test for overrun */
419 if( i_correction_delta > p_sys->i_max_frame_size )
421 msg_Warn( p_demux, "ALSA read overrun (%zu > %zu)",
422 i_correction_delta, p_sys->i_max_frame_size );
423 i_correction_delta = p_sys->i_max_frame_size;
424 snd_pcm_prepare( p_sys->p_alsa_pcm );
426 i_correct += i_correction_delta;
430 /* delay failed so reset */
431 msg_Warn( p_demux, "ALSA snd_pcm_delay failed (%s)", snd_strerror( i_err ) );
432 snd_pcm_prepare( p_sys->p_alsa_pcm );
436 p_block->i_pts = p_block->i_dts =
437 mdate() - INT64_C(1000000) * (mtime_t)i_correct /
438 2 / ( p_sys->b_stereo ? 2 : 1) / p_sys->i_sample_rate;
443 /*****************************************************************************
444 * OpenAudioDev: open and set up the audio device and probe for capabilities
445 *****************************************************************************/
446 static int OpenAudioDevAlsa( demux_t *p_demux )
448 demux_sys_t *p_sys = p_demux->p_sys;
449 const char *psz_device = p_sys->psz_device;
450 p_sys->p_alsa_pcm = NULL;
451 snd_pcm_hw_params_t *p_hw_params = NULL;
452 snd_pcm_uframes_t buffer_size;
453 snd_pcm_uframes_t chunk_size;
458 if( ( i_err = snd_pcm_open( &p_sys->p_alsa_pcm, psz_device,
459 SND_PCM_STREAM_CAPTURE, SND_PCM_NONBLOCK ) ) < 0)
461 msg_Err( p_demux, "Cannot open ALSA audio device %s (%s)",
462 psz_device, snd_strerror( i_err ) );
466 if( ( i_err = snd_pcm_nonblock( p_sys->p_alsa_pcm, 1 ) ) < 0)
468 msg_Err( p_demux, "Cannot set ALSA nonblock (%s)",
469 snd_strerror( i_err ) );
473 /* Begin setting hardware parameters */
475 if( ( i_err = snd_pcm_hw_params_malloc( &p_hw_params ) ) < 0 )
478 "ALSA: cannot allocate hardware parameter structure (%s)",
479 snd_strerror( i_err ) );
483 if( ( i_err = snd_pcm_hw_params_any( p_sys->p_alsa_pcm, p_hw_params ) ) < 0 )
486 "ALSA: cannot initialize hardware parameter structure (%s)",
487 snd_strerror( i_err ) );
491 /* Set Interleaved access */
492 if( ( i_err = snd_pcm_hw_params_set_access( p_sys->p_alsa_pcm, p_hw_params, SND_PCM_ACCESS_RW_INTERLEAVED ) ) < 0 )
494 msg_Err( p_demux, "ALSA: cannot set access type (%s)",
495 snd_strerror( i_err ) );
499 /* Set 16 bit little endian */
500 if( ( i_err = snd_pcm_hw_params_set_format( p_sys->p_alsa_pcm, p_hw_params, SND_PCM_FORMAT_S16_LE ) ) < 0 )
502 msg_Err( p_demux, "ALSA: cannot set sample format (%s)",
503 snd_strerror( i_err ) );
507 /* Set sample rate */
508 #ifdef HAVE_ALSA_NEW_API
509 i_err = snd_pcm_hw_params_set_rate_near( p_sys->p_alsa_pcm, p_hw_params, &p_sys->i_sample_rate, NULL );
511 i_err = snd_pcm_hw_params_set_rate_near( p_sys->p_alsa_pcm, p_hw_params, p_sys->i_sample_rate, NULL );
515 msg_Err( p_demux, "ALSA: cannot set sample rate (%s)",
516 snd_strerror( i_err ) );
521 unsigned int channels = p_sys->b_stereo ? 2 : 1;
522 if( ( i_err = snd_pcm_hw_params_set_channels( p_sys->p_alsa_pcm, p_hw_params, channels ) ) < 0 )
524 channels = ( channels==1 ) ? 2 : 1;
525 msg_Warn( p_demux, "ALSA: cannot set channel count (%s). "
526 "Trying with channels=%d",
527 snd_strerror( i_err ),
529 if( ( i_err = snd_pcm_hw_params_set_channels( p_sys->p_alsa_pcm, p_hw_params, channels ) ) < 0 )
531 msg_Err( p_demux, "ALSA: cannot set channel count (%s)",
532 snd_strerror( i_err ) );
535 p_sys->b_stereo = ( channels == 2 );
538 /* Set metrics for buffer calculations later */
539 unsigned int buffer_time;
540 if( ( i_err = snd_pcm_hw_params_get_buffer_time_max(p_hw_params, &buffer_time, 0) ) < 0 )
542 msg_Err( p_demux, "ALSA: cannot get buffer time max (%s)",
543 snd_strerror( i_err ) );
546 if( buffer_time > 500000 ) buffer_time = 500000;
548 /* Set period time */
549 unsigned int period_time = buffer_time / 4;
550 #ifdef HAVE_ALSA_NEW_API
551 i_err = snd_pcm_hw_params_set_period_time_near( p_sys->p_alsa_pcm, p_hw_params, &period_time, 0 );
553 i_err = snd_pcm_hw_params_set_period_time_near( p_sys->p_alsa_pcm, p_hw_params, period_time, 0 );
557 msg_Err( p_demux, "ALSA: cannot set period time (%s)",
558 snd_strerror( i_err ) );
562 /* Set buffer time */
563 #ifdef HAVE_ALSA_NEW_API
564 i_err = snd_pcm_hw_params_set_buffer_time_near( p_sys->p_alsa_pcm, p_hw_params, &buffer_time, 0 );
566 i_err = snd_pcm_hw_params_set_buffer_time_near( p_sys->p_alsa_pcm, p_hw_params, buffer_time, 0 );
570 msg_Err( p_demux, "ALSA: cannot set buffer time (%s)",
571 snd_strerror( i_err ) );
575 /* Apply new hardware parameters */
576 if( ( i_err = snd_pcm_hw_params( p_sys->p_alsa_pcm, p_hw_params ) ) < 0 )
578 msg_Err( p_demux, "ALSA: cannot set hw parameters (%s)",
579 snd_strerror( i_err ) );
583 /* Get various buffer metrics */
584 snd_pcm_hw_params_get_period_size( p_hw_params, &chunk_size, 0 );
585 snd_pcm_hw_params_get_buffer_size( p_hw_params, &buffer_size );
586 if( chunk_size == buffer_size )
589 "ALSA: period cannot equal buffer size (%lu == %lu)",
590 chunk_size, buffer_size);
594 int bits_per_sample = snd_pcm_format_physical_width(SND_PCM_FORMAT_S16_LE);
595 int bits_per_frame = bits_per_sample * channels;
597 p_sys->i_alsa_chunk_size = chunk_size;
598 p_sys->i_alsa_frame_size = bits_per_frame / 8;
599 p_sys->i_max_frame_size = chunk_size * bits_per_frame / 8;
601 snd_pcm_hw_params_free( p_hw_params );
605 if( ( i_err = snd_pcm_prepare( p_sys->p_alsa_pcm ) ) < 0 )
608 "ALSA: cannot prepare audio interface for use (%s)",
609 snd_strerror( i_err ) );
613 snd_pcm_start( p_sys->p_alsa_pcm );
619 if( p_hw_params ) snd_pcm_hw_params_free( p_hw_params );
620 if( p_sys->p_alsa_pcm ) snd_pcm_close( p_sys->p_alsa_pcm );
621 p_sys->p_alsa_pcm = NULL;
627 static int OpenAudioDev( demux_t *p_demux )
629 demux_sys_t *p_sys = p_demux->p_sys;
630 if( OpenAudioDevAlsa( p_demux ) != VLC_SUCCESS )
633 msg_Dbg( p_demux, "opened adev=`%s' %s %dHz",
634 p_sys->psz_device, p_sys->b_stereo ? "stereo" : "mono",
635 p_sys->i_sample_rate );
638 es_format_Init( &fmt, AUDIO_ES, VLC_FOURCC('a','r','a','w') );
640 fmt.audio.i_channels = p_sys->b_stereo ? 2 : 1;
641 fmt.audio.i_rate = p_sys->i_sample_rate;
642 fmt.audio.i_bitspersample = 16;
643 fmt.audio.i_blockalign = fmt.audio.i_channels * fmt.audio.i_bitspersample / 8;
644 fmt.i_bitrate = fmt.audio.i_channels * fmt.audio.i_rate * fmt.audio.i_bitspersample;
646 msg_Dbg( p_demux, "new audio es %d channels %dHz",
647 fmt.audio.i_channels, fmt.audio.i_rate );
649 p_sys->p_es = es_out_Add( p_demux->out, &fmt );
654 /*****************************************************************************
655 * ProbeAudioDevAlsa: probe audio for capabilities
656 *****************************************************************************/
657 static bool ProbeAudioDevAlsa( demux_t *p_demux, const char *psz_device )
660 snd_pcm_t *p_alsa_pcm;
662 if( ( i_err = snd_pcm_open( &p_alsa_pcm, psz_device, SND_PCM_STREAM_CAPTURE, SND_PCM_NONBLOCK ) ) < 0 )
664 msg_Err( p_demux, "cannot open device %s for ALSA audio (%s)", psz_device, snd_strerror( i_err ) );
668 snd_pcm_close( p_alsa_pcm );