1 /*****************************************************************************
2 * aout_alsa.c : Alsa functions library
3 *****************************************************************************
4 * Copyright (C) 2000 VideoLAN
5 * $Id: aout_alsa.c,v 1.17 2001/07/11 02:01:03 sam Exp $
7 * Authors: Henri Fallon <henri@videolan.org> - Original Author
8 * Jeffrey Baker <jwbaker@acm.org> - Port to ALSA 1.0 API
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
23 *****************************************************************************/
25 #define MODULE_NAME alsa
26 #include "modules_inner.h"
28 /*****************************************************************************
30 *****************************************************************************/
34 #include <errno.h> /* ENOMEM */
35 #include <string.h> /* strerror() */
36 #include <stdio.h> /* "intf_msg.h" */
37 #include <stdlib.h> /* calloc(), malloc(), free() */
39 #include <sys/asoundlib.h>
42 #include "common.h" /* boolean_t, byte_t */
47 #include "audio_output.h" /* aout_thread_t */
49 #include "intf_msg.h" /* intf_DbgMsg(), intf_ErrMsg() */
53 #include "modules_export.h"
55 typedef struct alsa_device_s
60 typedef struct alsa_card_s
65 /* here we store plugin dependant informations */
67 typedef struct aout_sys_s
69 snd_pcm_t * p_alsa_handle;
70 unsigned long buffer_time;
71 unsigned long period_time;
72 unsigned long chunk_size;
73 unsigned long buffer_size;
75 unsigned int bytes_per_sample;
76 unsigned int samples_per_frame;
77 unsigned int bytes_per_frame;
81 /*****************************************************************************
82 * aout_Probe: probes the audio device and return a score
83 *****************************************************************************
84 * This function tries to open the dps and returns a score to the plugin
85 * manager so that it can make its choice.
86 *****************************************************************************/
87 static int aout_Probe( probedata_t *p_data )
89 int i_open_return, i_close_return;
93 i_open_return = snd_pcm_open( &(local_sys.p_alsa_handle), "plug:0,0",
94 SND_PCM_STREAM_PLAYBACK, 0 );
97 intf_WarnMsg( 2, "aout info: could not probe ALSA device (%s)",
98 snd_strerror( i_open_return ) );
103 i_close_return = snd_pcm_close( local_sys.p_alsa_handle );
107 intf_ErrMsg( "aout error: could not close ALSA device (%s)",
108 snd_strerror( i_close_return ) );
112 if( TestMethod( AOUT_METHOD_VAR, "alsa" ) )
117 /* And return score */
121 /*****************************************************************************
122 * aout_Open : creates a handle and opens an alsa device
123 *****************************************************************************
124 * This function opens an alsa device, through the alsa API
125 *****************************************************************************/
126 static int aout_Open( aout_thread_t *p_aout )
131 /* Allocate structures */
132 p_aout->p_sys = malloc( sizeof( aout_sys_t ) );
133 if( p_aout->p_sys == NULL )
135 intf_ErrMsg( "aout error: failed allocating memory for ALSA (%s)",
140 p_aout->i_format = AOUT_FORMAT_DEFAULT;
141 p_aout->i_channels = 1 + main_GetIntVariable( AOUT_STEREO_VAR,
142 AOUT_STEREO_DEFAULT );
143 p_aout->l_rate = main_GetIntVariable( AOUT_RATE_VAR,
147 if( ( i_open_returns = snd_pcm_open(&(p_aout->p_sys->p_alsa_handle),
149 SND_PCM_STREAM_PLAYBACK, 0) ) )
151 intf_ErrMsg( "aout error: could not open ALSA device (%s)",
152 snd_strerror(i_open_returns) );
156 intf_DbgMsg( "aout info: ALSA device successfully opened" );
161 /*****************************************************************************
162 * aout_SetFormat : sets the alsa output format
163 *****************************************************************************
164 * This function prepares the device, sets the rate, format, the mode
165 * ( "play as soon as you have data" ), and buffer information.
166 *****************************************************************************/
167 static int aout_SetFormat( aout_thread_t *p_aout )
173 snd_pcm_hw_params_t *p_hw;
174 snd_pcm_sw_params_t *p_sw;
176 snd_pcm_hw_params_alloca(&p_hw);
177 snd_pcm_sw_params_alloca(&p_sw);
179 switch (p_aout->i_format)
181 case AOUT_FMT_S16_LE:
182 i_format = SND_PCM_FORMAT_S16_LE;
183 p_aout->p_sys->bytes_per_sample = 2;
187 i_format = SND_PCM_FORMAT_S16_BE;
188 p_aout->p_sys->bytes_per_sample = 2;
192 p_aout->p_sys->samples_per_frame = p_aout->i_channels;
193 p_aout->p_sys->bytes_per_frame = p_aout->p_sys->samples_per_frame *
194 p_aout->p_sys->bytes_per_sample;
196 i_rv = snd_pcm_hw_params_any( p_aout->p_sys->p_alsa_handle, p_hw );
199 intf_ErrMsg( "aout error: unable to retrieve initial parameters" );
203 i_rv = snd_pcm_hw_params_set_access( p_aout->p_sys->p_alsa_handle, p_hw,
204 SND_PCM_ACCESS_RW_INTERLEAVED );
207 intf_ErrMsg( "aout error: unable to set interleaved stream format" );
211 i_rv = snd_pcm_hw_params_set_format( p_aout->p_sys->p_alsa_handle,
215 intf_ErrMsg( "aout error: unable to set stream sample size and word"
220 i_rv = snd_pcm_hw_params_set_channels( p_aout->p_sys->p_alsa_handle, p_hw,
221 p_aout->i_channels );
224 intf_ErrMsg( "aout error: unable to set number of output channels" );
228 i_rv = snd_pcm_hw_params_set_rate_near( p_aout->p_sys->p_alsa_handle, p_hw,
232 intf_ErrMsg( "aout error: unable to set sample rate" );
235 p_aout->p_sys->rate = i_rv;
237 i_rv = snd_pcm_hw_params_set_buffer_time_near( p_aout->p_sys->p_alsa_handle,
238 p_hw, AOUT_BUFFER_DURATION,
242 intf_ErrMsg( "aout error: unable to set buffer time" );
245 p_aout->p_sys->buffer_time = i_rv;
247 i_rv = snd_pcm_hw_params_set_period_time_near( p_aout->p_sys->p_alsa_handle,
248 p_hw, p_aout->p_sys->buffer_time / p_aout->p_sys->bytes_per_frame, 0 );
251 intf_ErrMsg( "aout error: unable to set period time" );
254 p_aout->p_sys->period_time = i_rv;
256 i_rv = snd_pcm_hw_params(p_aout->p_sys->p_alsa_handle, p_hw);
259 intf_ErrMsg( "aout error: unable to set hardware configuration" );
263 p_aout->p_sys->chunk_size = snd_pcm_hw_params_get_period_size( p_hw, 0 );
264 p_aout->p_sys->buffer_size = snd_pcm_hw_params_get_buffer_size( p_hw );
266 snd_pcm_sw_params_current( p_aout->p_sys->p_alsa_handle, p_sw );
267 i_rv = snd_pcm_sw_params_set_sleep_min( p_aout->p_sys->p_alsa_handle, p_sw,
270 i_rv = snd_pcm_sw_params_set_avail_min( p_aout->p_sys->p_alsa_handle, p_sw,
271 p_aout->p_sys->chunk_size );
273 /* Worked with the CVS version but not with 0.9beta3
274 i_rv = snd_pcm_sw_params_set_start_threshold( p_aout->p_sys->p_alsa_handle,
275 p_sw, p_aout->p_sys->buffer_size );
277 i_rv = snd_pcm_sw_params_set_stop_threshold( p_aout->p_sys->p_alsa_handle,
278 p_sw, p_aout->p_sys->buffer_size);
280 i_rv = snd_pcm_sw_params( p_aout->p_sys->p_alsa_handle, p_sw );
283 intf_ErrMsg( "aout error: unable to set software configuration" );
290 /*****************************************************************************
291 * aout_HandleXrun : reprepare the output
292 *****************************************************************************
293 * When buffer gets empty, the driver goes in "Xrun" state, where it needs
294 * to be reprepared before playing again
295 *****************************************************************************/
296 static void aout_HandleXrun(aout_thread_t *p_aout)
300 intf_ErrMsg( "aout error: resetting output after buffer underrun" );
302 i_rv = snd_pcm_reset( p_aout->p_sys->p_alsa_handle );
303 i_rv = snd_pcm_prepare( p_aout->p_sys->p_alsa_handle );
306 intf_ErrMsg( "aout error: unable to recover from buffer underrun (%s)",
307 snd_strerror( i_rv ) );
312 /*****************************************************************************
313 * aout_BufInfo: buffer status query
314 *****************************************************************************
315 * This function returns the number of used byte in the queue.
316 * It also deals with errors : indeed if the device comes to run out
317 * of data to play, it switches to the "underrun" status. It has to
318 * be flushed and re-prepared
319 *****************************************************************************/
320 static long aout_GetBufInfo( aout_thread_t *p_aout, long l_buffer_limit )
322 snd_pcm_status_t *p_status;
323 int i_alsa_get_status_returns;
325 snd_pcm_status_alloca( &p_status );
327 i_alsa_get_status_returns = snd_pcm_status( p_aout->p_sys->p_alsa_handle,
330 if( i_alsa_get_status_returns )
332 intf_ErrMsg ( "aout error: failed getting alsa buffer info (%s)",
333 snd_strerror ( i_alsa_get_status_returns ) );
337 switch( snd_pcm_status_get_state( p_status ) )
339 case SND_PCM_STATE_XRUN :
340 aout_HandleXrun( p_aout );
343 case SND_PCM_STATE_OPEN:
344 case SND_PCM_STATE_PREPARED:
345 case SND_PCM_STATE_RUNNING:
349 intf_ErrMsg( "aout error: unhandled condition %i",
350 snd_pcm_status_get_state( p_status ) );
354 return( snd_pcm_status_get_avail(p_status) *
355 p_aout->p_sys->bytes_per_frame );
358 /*****************************************************************************
359 * aout_Play : plays a sample
360 *****************************************************************************
361 * Plays a sample using the snd_pcm_writei function from the alsa API
362 *****************************************************************************/
363 static void aout_Play( aout_thread_t *p_aout, byte_t *buffer, int i_size )
365 snd_pcm_uframes_t tot_frames;
366 snd_pcm_uframes_t frames_left;
367 snd_pcm_uframes_t rv;
369 tot_frames = i_size / p_aout->p_sys->bytes_per_frame;
370 frames_left = tot_frames;
372 while( frames_left > 0 )
374 rv = snd_pcm_writei( p_aout->p_sys->p_alsa_handle, buffer +
375 (tot_frames - frames_left) *
376 p_aout->p_sys->bytes_per_frame, frames_left );
378 if( (signed int) rv < 0 )
380 intf_ErrMsg( "aout error: failed writing to output (%s)",
381 snd_strerror( rv ) );
389 /*****************************************************************************
390 * aout_Close : close the Alsa device
391 *****************************************************************************/
392 static void aout_Close( aout_thread_t *p_aout )
396 i_close_returns = snd_pcm_close( p_aout->p_sys->p_alsa_handle );
398 if( i_close_returns )
400 intf_ErrMsg( "aout error: failed closing ALSA device (%s)",
401 i_close_returns, snd_strerror( i_close_returns ) );
404 free( p_aout->p_sys );
406 intf_DbgMsg( "aout: ALSA device closed" );
409 /*****************************************************************************
410 * Functions exported as capabilities. They are declared as static so that
411 * we don't pollute the namespace too much.
412 *****************************************************************************/
413 void _M( aout_getfunctions )( function_list_t * p_function_list )
415 p_function_list->pf_probe = aout_Probe;
416 p_function_list->functions.aout.pf_open = aout_Open;
417 p_function_list->functions.aout.pf_setformat = aout_SetFormat;
418 p_function_list->functions.aout.pf_getbufinfo = aout_GetBufInfo;
419 p_function_list->functions.aout.pf_play = aout_Play;
420 p_function_list->functions.aout.pf_close = aout_Close;