1 /*****************************************************************************
2 * oss.c : OSS /dev/dsp module for vlc
3 *****************************************************************************
4 * Copyright (C) 2000-2002 VideoLAN
5 * $Id: oss.c,v 1.32 2002/10/25 15:21:42 gbazin Exp $
7 * Authors: Michel Kaempf <maxx@via.ecp.fr>
8 * Samuel Hocevar <sam@zoy.org>
9 * Christophe Massiot <massiot@via.ecp.fr>
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
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 General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
24 *****************************************************************************/
26 /*****************************************************************************
28 *****************************************************************************/
29 #include <errno.h> /* ENOMEM */
30 #include <fcntl.h> /* open(), O_WRONLY */
31 #include <sys/ioctl.h> /* ioctl() */
32 #include <string.h> /* strerror() */
33 #include <unistd.h> /* write(), close() */
34 #include <stdlib.h> /* calloc(), malloc(), free() */
44 #include "aout_internal.h"
46 /* SNDCTL_DSP_RESET, SNDCTL_DSP_SETFMT, SNDCTL_DSP_STEREO, SNDCTL_DSP_SPEED,
47 * SNDCTL_DSP_GETOSPACE */
48 #ifdef HAVE_SOUNDCARD_H
49 # include <soundcard.h>
50 #elif defined( HAVE_SYS_SOUNDCARD_H )
51 # include <sys/soundcard.h>
52 #elif defined( HAVE_MACHINE_SOUNDCARD_H )
53 # include <machine/soundcard.h>
56 /*****************************************************************************
57 * aout_sys_t: OSS audio output method descriptor
58 *****************************************************************************
59 * This structure is part of the audio output thread descriptor.
60 * It describes the dsp specific properties of an audio device.
61 *****************************************************************************/
65 int b_workaround_buggy_driver;
67 mtime_t max_buffer_duration;
70 /* This must be a power of 2. */
71 #define FRAME_SIZE 1024
73 #define A52_FRAME_NB 1536
75 /*****************************************************************************
77 *****************************************************************************/
78 static int Open ( vlc_object_t * );
79 static void Close ( vlc_object_t * );
81 static void Play ( aout_instance_t * );
82 static int OSSThread ( aout_instance_t * );
84 static mtime_t BufferDuration( aout_instance_t * p_aout );
86 /*****************************************************************************
88 *****************************************************************************/
89 #define BUGGY_TEXT N_("Try to work around buggy OSS drivers")
90 #define BUGGY_LONGTEXT N_( \
91 "Some buggy OSS drivers just don't like when their internal buffers " \
92 "are completely filled (the sound gets heavily hashed). If you have one " \
93 "of these drivers, then you need to enable this option." )
96 add_category_hint( N_("OSS"), NULL );
97 add_file( "dspdev", "/dev/dsp", aout_FindAndRestart,
98 N_("OSS dsp device"), NULL );
99 add_bool( "oss-buggy", 0, NULL, BUGGY_TEXT, BUGGY_LONGTEXT );
100 set_description( _("Linux OSS /dev/dsp module") );
101 set_capability( "audio output", 100 );
102 add_shortcut( "oss" );
103 set_callbacks( Open, Close );
106 /*****************************************************************************
107 * Open: open the audio device (the digital sound processor)
108 *****************************************************************************
109 * This function opens the dsp as a usual non-blocking write-only file, and
110 * modifies the p_aout->p_sys->i_fd with the file's descriptor.
111 *****************************************************************************/
112 static int Open( vlc_object_t *p_this )
114 aout_instance_t * p_aout = (aout_instance_t *)p_this;
115 struct aout_sys_t * p_sys;
118 /* Allocate structure */
119 p_aout->output.p_sys = p_sys = malloc( sizeof( aout_sys_t ) );
122 msg_Err( p_aout, "out of memory" );
126 /* Get device name */
127 if( (psz_device = config_GetPsz( p_aout, "dspdev" )) == NULL )
129 msg_Err( p_aout, "no audio device given (maybe /dev/dsp ?)" );
134 /* Open the sound device */
135 p_sys->i_fd = open( psz_device, O_WRONLY );
137 if( p_sys->i_fd < 0 )
139 msg_Err( p_aout, "cannot open audio device (%s)", psz_device );
144 p_aout->output.pf_play = Play;
146 /* Reset the DSP device */
147 if( ioctl( p_sys->i_fd, SNDCTL_DSP_RESET, NULL ) < 0 )
149 msg_Err( p_aout, "cannot reset OSS audio device" );
150 close( p_sys->i_fd );
155 /* Set the output format */
156 if ( AOUT_FMT_NON_LINEAR( &p_aout->output.output ) )
158 int i_format = AFMT_AC3;
160 if( ioctl( p_sys->i_fd, SNDCTL_DSP_SETFMT, &i_format ) < 0
161 || i_format != AFMT_AC3 )
163 p_aout->output.output.i_format = AOUT_FMT_S16_NE;
167 p_aout->output.output.i_format = VLC_FOURCC('s','p','d','i');
168 p_aout->output.i_nb_samples = A52_FRAME_NB;
169 p_aout->output.output.i_bytes_per_frame = AOUT_SPDIF_SIZE;
170 p_aout->output.output.i_frame_length = A52_FRAME_NB;
172 aout_VolumeNoneInit( p_aout );
176 if ( !AOUT_FMT_NON_LINEAR( &p_aout->output.output ) )
178 int i_format = AFMT_S16_NE;
179 int i_frame_size, i_fragments;
182 audio_buf_info audio_buf;
184 if( ioctl( p_sys->i_fd, SNDCTL_DSP_SETFMT, &i_format ) < 0 )
186 msg_Err( p_aout, "cannot set audio output format" );
187 close( p_sys->i_fd );
195 p_aout->output.output.i_format = VLC_FOURCC('u','8',' ',' ');
198 p_aout->output.output.i_format = VLC_FOURCC('s','8',' ',' ');
201 p_aout->output.output.i_format = VLC_FOURCC('u','1','6','l');
204 p_aout->output.output.i_format = VLC_FOURCC('s','1','6','l');
207 p_aout->output.output.i_format = VLC_FOURCC('u','1','6','b');
210 p_aout->output.output.i_format = VLC_FOURCC('s','1','6','b');
213 msg_Err( p_aout, "OSS fell back to an unknown format (%d)",
215 close( p_sys->i_fd );
220 /* These cases are desperate because of the OSS API and A/52 spec. */
221 switch ( p_aout->output.output.i_channels )
226 case AOUT_CHAN_STEREO | AOUT_CHAN_LFE:
227 case AOUT_CHAN_2F1R | AOUT_CHAN_LFE:
228 case AOUT_CHAN_3F1R | AOUT_CHAN_LFE:
229 case AOUT_CHAN_DOLBY | AOUT_CHAN_LFE:
230 p_aout->output.output.i_channels = AOUT_CHAN_STEREO;
232 case AOUT_CHAN_CHANNEL | AOUT_CHAN_LFE:
233 case AOUT_CHAN_CHANNEL1 | AOUT_CHAN_LFE:
234 case AOUT_CHAN_CHANNEL2 | AOUT_CHAN_LFE:
235 case AOUT_CHAN_MONO | AOUT_CHAN_LFE:
236 case AOUT_CHAN_2F2R | AOUT_CHAN_LFE:
237 p_aout->output.output.i_channels &= ~AOUT_CHAN_LFE;
240 p_aout->output.output.i_channels = AOUT_CHAN_2F2R;
243 /* In a nutshell, possible types : AOUT_CHAN_STEREO (and al.),
244 AOUT_CHAN_2F2R, AOUT_CHAN_3F1R | AOUT_CHAN_LFE. */
246 i_nb_channels = aout_FormatNbChannels( &p_aout->output.output );
248 if ( i_nb_channels > 2 )
250 /* Check that the device supports this. */
252 #ifdef SNDCTL_DSP_GETCHANNELMASK
254 if ( ioctl( p_sys->i_fd, SNDCTL_DSP_GETCHANNELMASK,
257 if ( !(i_chanmask & DSP_BIND_FRONT) )
259 msg_Err( p_aout, "No front channels ! (%x)",
261 close( p_sys->i_fd );
266 if ( !(i_chanmask & DSP_BIND_SURR) )
268 p_aout->output.output.i_channels = AOUT_CHAN_STEREO;
272 if ( p_aout->output.output.i_channels ==
273 (AOUT_CHAN_3F2R | AOUT_CHAN_LFE)
274 && !(i_chanmask & DSP_BIND_CENTER_LFE) )
276 p_aout->output.output.i_channels = AOUT_CHAN_2F2R;
283 /* The driver doesn't support this call, assume it is stereo. */
284 p_aout->output.output.i_channels = AOUT_CHAN_STEREO;
289 /* Set the number of channels */
290 if( ioctl( p_sys->i_fd, SNDCTL_DSP_CHANNELS, &i_nb_channels ) < 0 )
292 msg_Err( p_aout, "cannot set number of audio channels (%i)",
293 p_aout->output.output.i_channels );
294 close( p_sys->i_fd );
299 if ( i_nb_channels != aout_FormatNbChannels( &p_aout->output.output ) )
301 switch ( i_nb_channels )
303 case 1: p_aout->output.output.i_channels = AOUT_CHAN_MONO; break;
304 case 2: p_aout->output.output.i_channels = AOUT_CHAN_STEREO; break;
305 case 4: p_aout->output.output.i_channels = AOUT_CHAN_2F2R; break;
307 msg_Err( p_aout, "Unsupported downmixing (%d)", i_nb_channels );
308 close( p_sys->i_fd );
314 /* Set the output rate */
315 i_rate = p_aout->output.output.i_rate;
316 if( ioctl( p_sys->i_fd, SNDCTL_DSP_SPEED, &i_rate ) < 0 )
318 msg_Err( p_aout, "cannot set audio output rate (%i)",
319 p_aout->output.output.i_rate );
320 close( p_sys->i_fd );
325 if( i_rate != p_aout->output.output.i_rate )
327 p_aout->output.output.i_rate = i_rate;
330 /* Set the fragment size */
331 aout_FormatPrepare( &p_aout->output.output );
333 /* i_fragment = xxxxyyyy where: xxxx is fragtotal
334 * 1 << yyyy is fragsize */
336 i_frame_size = FRAME_SIZE * p_aout->output.output.i_bytes_per_frame;
337 while( i_frame_size >>= 1 )
341 i_fragments |= FRAME_COUNT << 16;
342 if( ioctl( p_sys->i_fd, SNDCTL_DSP_SETFRAGMENT, &i_fragments ) < 0 )
344 msg_Warn( p_aout, "cannot set fragment size (%.8x)", i_fragments );
347 if( ioctl( p_sys->i_fd, SNDCTL_DSP_GETOSPACE, &audio_buf ) < 0 )
349 msg_Warn( p_aout, "cannot get fragment size" );
350 close( p_sys->i_fd );
356 /* Number of fragments actually allocated */
357 p_aout->output.p_sys->i_fragstotal = audio_buf.fragstotal;
359 /* Maximum duration the soundcard's buffer can hold */
360 p_aout->output.p_sys->max_buffer_duration =
361 (mtime_t)audio_buf.fragstotal * audio_buf.fragsize * 1000000
362 / p_aout->output.output.i_bytes_per_frame
363 / p_aout->output.output.i_rate
364 * p_aout->output.output.i_frame_length;
366 p_aout->output.i_nb_samples = audio_buf.fragsize /
367 p_aout->output.output.i_bytes_per_frame;
370 aout_VolumeSoftInit( p_aout );
373 /* Create OSS thread and wait for its readiness. */
374 if( vlc_thread_create( p_aout, "aout", OSSThread,
375 VLC_THREAD_PRIORITY_OUTPUT, VLC_FALSE ) )
377 msg_Err( p_aout, "cannot create OSS thread (%s)", strerror(errno) );
378 close( p_sys->i_fd );
383 p_aout->output.p_sys->b_workaround_buggy_driver =
384 config_GetInt( p_aout, "oss-buggy" );
389 /*****************************************************************************
390 * Play: nothing to do
391 *****************************************************************************/
392 static void Play( aout_instance_t *p_aout )
396 /*****************************************************************************
397 * Close: close the dsp audio device
398 *****************************************************************************/
399 static void Close( vlc_object_t * p_this )
401 aout_instance_t *p_aout = (aout_instance_t *)p_this;
402 struct aout_sys_t * p_sys = p_aout->output.p_sys;
404 p_aout->b_die = VLC_TRUE;
405 vlc_thread_join( p_aout );
406 p_aout->b_die = VLC_FALSE;
408 ioctl( p_sys->i_fd, SNDCTL_DSP_RESET, NULL );
409 close( p_sys->i_fd );
414 /*****************************************************************************
415 * BufferDuration: buffer status query
416 *****************************************************************************
417 * This function returns the duration in microseconds of the current buffer.
418 *****************************************************************************/
419 static mtime_t BufferDuration( aout_instance_t * p_aout )
421 struct aout_sys_t * p_sys = p_aout->output.p_sys;
422 audio_buf_info audio_buf;
425 /* Fill the audio_buf_info structure:
426 * - fragstotal: total number of fragments allocated
427 * - fragsize: size of a fragment in bytes
428 * - bytes: available space in bytes (includes partially used fragments)
429 * Note! 'bytes' could be more than fragments*fragsize */
430 ioctl( p_sys->i_fd, SNDCTL_DSP_GETOSPACE, &audio_buf );
432 /* calculate number of available fragments (not partially used ones) */
433 i_bytes = (audio_buf.fragstotal * audio_buf.fragsize) - audio_buf.bytes;
435 /* Return the fragment duration */
436 return (mtime_t)i_bytes * 1000000
437 / p_aout->output.output.i_bytes_per_frame
438 / p_aout->output.output.i_rate
439 * p_aout->output.output.i_frame_length;
442 /*****************************************************************************
443 * OSSThread: asynchronous thread used to DMA the data to the device
444 *****************************************************************************/
445 static int OSSThread( aout_instance_t * p_aout )
447 struct aout_sys_t * p_sys = p_aout->output.p_sys;
448 mtime_t next_date = 0;
450 while ( !p_aout->b_die )
452 aout_buffer_t * p_buffer = NULL;
456 if ( p_aout->output.output.i_format != VLC_FOURCC('s','p','d','i') )
458 mtime_t buffered = BufferDuration( p_aout );
460 if( p_aout->output.p_sys->b_workaround_buggy_driver )
462 #define i_fragstotal p_aout->output.p_sys->i_fragstotal
463 /* Wait a bit - we don't want our buffer to be full */
464 if( buffered > (p_aout->output.p_sys->max_buffer_duration
465 / i_fragstotal * (i_fragstotal - 1)) )
467 msleep((p_aout->output.p_sys->max_buffer_duration
469 buffered = BufferDuration( p_aout );
476 /* This is the _real_ presentation date */
477 next_date = mdate() + buffered;
481 /* Give a hint to the audio output about our drift, but
482 * not too much because we want to make it happy with our
483 * nicely calculated dates. */
484 next_date = ( (next_date * 7) + (mdate() + buffered) ) / 8;
487 /* Next buffer will be played at mdate()+buffered */
488 p_buffer = aout_OutputNextBuffer( p_aout, next_date, VLC_FALSE );
492 /* emu10k1 driver does not report Buffer Duration correctly in
493 * passthrough mode so we have to cheat */
500 mtime_t delay = next_date - mdate();
501 if( delay > AOUT_PTS_TOLERANCE )
507 while( !p_aout->b_die && ! ( p_buffer =
508 aout_OutputNextBuffer( p_aout, next_date, VLC_TRUE ) ) )
515 if ( p_buffer != NULL )
517 p_bytes = p_buffer->p_buffer;
518 i_size = p_buffer->i_nb_bytes;
519 /* This is theoretical ... we'll see next iteration whether
521 next_date += p_buffer->end_date - p_buffer->start_date;
525 i_size = FRAME_SIZE / p_aout->output.output.i_frame_length
526 * p_aout->output.output.i_bytes_per_frame;
527 p_bytes = malloc( i_size );
528 memset( p_bytes, 0, i_size );
532 i_tmp = write( p_sys->i_fd, p_bytes, i_size );
536 msg_Err( p_aout, "write failed (%s)", strerror(errno) );
539 if ( p_buffer != NULL )
541 aout_BufferFree( p_buffer );