1 /*****************************************************************************
2 * oss.c : OSS /dev/dsp module for vlc
3 *****************************************************************************
4 * Copyright (C) 2000-2002 VideoLAN
5 * $Id: oss.c,v 1.2 2002/08/08 00:35:11 sam 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 volatile vlc_bool_t b_die;
66 volatile vlc_bool_t b_initialized;
69 #define DEFAULT_FRAME_SIZE 2048
71 /*****************************************************************************
73 *****************************************************************************/
74 static int Open ( vlc_object_t * );
75 static void Close ( vlc_object_t * );
77 static int SetFormat ( aout_instance_t * );
78 static void Play ( aout_instance_t *, aout_buffer_t * );
79 static int OSSThread ( aout_instance_t * );
81 /*****************************************************************************
83 *****************************************************************************/
85 add_category_hint( N_("Audio"), NULL );
86 add_file( "dspdev", "/dev/dsp", NULL, N_("OSS dsp device"), NULL );
87 set_description( _("Linux OSS /dev/dsp module") );
88 set_capability( "audio output", 100 );
89 set_callbacks( Open, Close );
92 /*****************************************************************************
93 * Open: open the audio device (the digital sound processor)
94 *****************************************************************************
95 * This function opens the dsp as a usual non-blocking write-only file, and
96 * modifies the p_aout->p_sys->i_fd with the file's descriptor.
97 *****************************************************************************/
98 static int Open( vlc_object_t *p_this )
100 aout_instance_t * p_aout = (aout_instance_t *)p_this;
101 struct aout_sys_t * p_sys;
104 /* Allocate structure */
105 p_aout->output.p_sys = p_sys = malloc( sizeof( aout_sys_t ) );
108 msg_Err( p_aout, "out of memory" );
112 /* Initialize some variables */
113 if( (psz_device = config_GetPsz( p_aout, "dspdev" )) == NULL )
115 msg_Err( p_aout, "no audio device given (maybe /dev/dsp ?)" );
120 /* Open the sound device */
121 if( (p_sys->i_fd = open( psz_device, O_WRONLY )) < 0 )
123 msg_Err( p_aout, "cannot open audio device (%s)",
131 /* Create OSS thread and wait for its readiness. */
133 p_sys->b_initialized = VLC_FALSE;
134 if( vlc_thread_create( p_aout, "aout", OSSThread, VLC_FALSE ) )
136 msg_Err( p_aout, "cannot create OSS thread (%s)", strerror(errno) );
142 p_aout->output.pf_setformat = SetFormat;
143 p_aout->output.pf_play = Play;
148 /*****************************************************************************
149 * SetFormat: reset the dsp and set its format
150 *****************************************************************************
151 * This functions resets the DSP device, tries to initialize the output
152 * format with the value contained in the dsp structure, and if this value
153 * could not be set, the default value returned by ioctl is set. It then
154 * does the same for the stereo mode, and for the output rate.
155 *****************************************************************************/
156 static int SetFormat( aout_instance_t *p_aout )
158 struct aout_sys_t * p_sys = p_aout->output.p_sys;
163 p_sys->b_initialized = VLC_FALSE;
165 /* Reset the DSP device */
166 if( ioctl( p_sys->i_fd, SNDCTL_DSP_RESET, NULL ) < 0 )
168 msg_Err( p_aout, "cannot reset OSS audio device" );
172 /* Set the output format */
173 i_format = AOUT_FMT_S16_NE;
174 if( ioctl( p_sys->i_fd, SNDCTL_DSP_SETFMT, &i_format ) < 0
175 || i_format != AOUT_FMT_S16_NE )
177 msg_Err( p_aout, "cannot set audio output format (%i)",
181 p_aout->output.output.i_format = AOUT_FMT_S16_NE;
184 if ( p_aout->output.output.i_channels > 2 )
186 msg_Warn( p_aout, "only two channels are supported at the moment" );
187 /* Trigger downmixing */
188 p_aout->output.output.i_channels = 2;
191 /* Set the number of channels */
192 b_stereo = p_aout->output.output.i_channels - 1;
194 if( ioctl( p_sys->i_fd, SNDCTL_DSP_STEREO, &b_stereo ) < 0 )
196 msg_Err( p_aout, "cannot set number of audio channels (%i)",
197 p_aout->output.output.i_channels );
201 if ( b_stereo + 1 != p_aout->output.output.i_channels )
203 msg_Warn( p_aout, "driver forced up/downmixing %li->%li",
204 p_aout->output.output.i_channels,
206 p_aout->output.output.i_channels = b_stereo + 1;
209 /* Set the output rate */
210 i_rate = p_aout->output.output.i_rate;
211 if( ioctl( p_sys->i_fd, SNDCTL_DSP_SPEED, &i_rate ) < 0 )
213 msg_Err( p_aout, "cannot set audio output rate (%i)",
214 p_aout->output.output.i_rate );
218 if( i_rate != p_aout->output.output.i_rate )
220 msg_Warn( p_aout, "driver forced resampling %li->%li",
221 p_aout->output.output.i_rate, i_rate );
222 p_aout->output.output.i_rate = i_rate;
225 p_aout->output.i_nb_samples = DEFAULT_FRAME_SIZE;
227 p_sys->b_initialized = VLC_TRUE;
232 /*****************************************************************************
233 * Play: queue a buffer for playing by OSSThread
234 *****************************************************************************/
235 static void Play( aout_instance_t *p_aout, aout_buffer_t * p_buffer )
237 aout_FifoPush( p_aout, &p_aout->output.fifo, p_buffer );
240 /*****************************************************************************
241 * Close: close the dsp audio device
242 *****************************************************************************/
243 static void Close( vlc_object_t * p_this )
245 aout_instance_t *p_aout = (aout_instance_t *)p_this;
246 struct aout_sys_t * p_sys = p_aout->output.p_sys;
249 vlc_thread_join( p_aout );
251 close( p_sys->i_fd );
256 /*****************************************************************************
257 * GetBufInfo: buffer status query
258 *****************************************************************************
259 * This function fills in the audio_buf_info structure :
260 * - returns : number of available fragments (not partially used ones)
261 * - int fragstotal : total number of fragments allocated
262 * - int fragsize : size of a fragment in bytes
263 * - int bytes : available space in bytes (includes partially used fragments)
264 * Note! 'bytes' could be more than fragments*fragsize
265 *****************************************************************************/
266 static int GetBufInfo( aout_instance_t * p_aout )
268 struct aout_sys_t * p_sys = p_aout->output.p_sys;
269 audio_buf_info audio_buf;
271 ioctl( p_sys->i_fd, SNDCTL_DSP_GETOSPACE, &audio_buf );
273 /* returns the allocated space in bytes */
274 return ( (audio_buf.fragstotal * audio_buf.fragsize) - audio_buf.bytes );
277 /*****************************************************************************
278 * OSSThread: asynchronous thread used to DMA the data to the device
279 *****************************************************************************/
280 static int OSSThread( aout_instance_t * p_aout )
282 struct aout_sys_t * p_sys = p_aout->output.p_sys;
284 while ( !p_sys->b_die )
286 int i_bytes_per_sample;
287 aout_buffer_t * p_buffer;
292 /* Get the presentation date of the next write() operation. It
293 * is equal to the current date + duration of buffered samples.
294 * Order is important here, since GetBufInfo is believed to take
295 * more time than mdate(). */
296 if( !p_sys->b_initialized )
298 msleep( THREAD_SLEEP );
302 i_bytes_per_sample = aout_FormatToBytes( &p_aout->output.output );
303 next_date = (mtime_t)GetBufInfo( p_aout ) * 1000000
305 / p_aout->output.output.i_rate;
306 next_date += mdate();
308 p_buffer = aout_OutputNextBuffer( p_aout, next_date );
310 if ( p_buffer != NULL )
312 p_bytes = p_buffer->p_buffer;
316 p_bytes = alloca( DEFAULT_FRAME_SIZE * i_bytes_per_sample );
317 memset( p_bytes, 0, DEFAULT_FRAME_SIZE * i_bytes_per_sample );
320 i_tmp = write( p_sys->i_fd, p_bytes,
321 DEFAULT_FRAME_SIZE * i_bytes_per_sample );
325 msg_Err( p_aout, "write failed (%s)", strerror(errno) );
328 if ( p_buffer != NULL )
330 aout_BufferFree( p_buffer );