1 /*****************************************************************************
2 * aout_alsa.c : Alsa functions library
3 *****************************************************************************
4 * Copyright (C) 2000 VideoLAN
5 * $Id: aout_alsa.c,v 1.16 2001/05/30 17:03:11 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_ErrMsg( "Aout_alsa: error opening alsa device in aout_probe(%d)"
98 " : %s", i_open_return, snd_strerror( i_open_return ) );
99 intf_WarnMsg( 1, "Aout_alsa : module scored 0" );
104 i_close_return = snd_pcm_close( local_sys.p_alsa_handle );
108 intf_ErrMsg( "Aout_alsa: error closing alsa device in aout_probe(%d)"
109 " : %s", i_close_return, snd_strerror( i_close_return ) );
110 intf_WarnMsg( 1, "Aout_alsa : module scored 0" );
114 if( TestMethod( AOUT_METHOD_VAR, "alsa" ) )
116 intf_WarnMsg( 1, "Aout_alsa : module scored 999" );
120 /* And return score */
124 /*****************************************************************************
125 * aout_Open : creates a handle and opens an alsa device
126 *****************************************************************************
127 * This function opens an alsa device, through the alsa API
128 *****************************************************************************/
129 static int aout_Open( aout_thread_t *p_aout )
134 /* Allocate structures */
135 p_aout->p_sys = malloc( sizeof( aout_sys_t ) );
136 if( p_aout->p_sys == NULL )
138 intf_ErrMsg( "Aout_alsa : Could not allocate memory : %s",
143 p_aout->i_format = AOUT_FORMAT_DEFAULT;
144 p_aout->i_channels = 1 + main_GetIntVariable( AOUT_STEREO_VAR,
145 AOUT_STEREO_DEFAULT );
146 p_aout->l_rate = main_GetIntVariable( AOUT_RATE_VAR,
150 if( ( i_open_returns = snd_pcm_open(&(p_aout->p_sys->p_alsa_handle),
152 SND_PCM_STREAM_PLAYBACK, 0) ) )
154 intf_ErrMsg( "Could not open alsa device; exit = %i",
156 intf_ErrMsg( "This means : %s", snd_strerror(i_open_returns) );
160 intf_DbgMsg( "Aout_alsa : Alsa device successfully opened" );
165 /*****************************************************************************
166 * aout_SetFormat : sets the alsa output format
167 *****************************************************************************
168 * This function prepares the device, sets the rate, format, the mode
169 * ( "play as soon as you have data" ), and buffer information.
170 *****************************************************************************/
171 static int aout_SetFormat( aout_thread_t *p_aout )
177 snd_pcm_hw_params_t *p_hw;
178 snd_pcm_sw_params_t *p_sw;
180 snd_pcm_hw_params_alloca(&p_hw);
181 snd_pcm_sw_params_alloca(&p_sw);
183 switch (p_aout->i_format) {
184 case AOUT_FMT_S16_LE:
185 i_format = SND_PCM_FORMAT_S16_LE;
186 p_aout->p_sys->bytes_per_sample = 2;
190 i_format = SND_PCM_FORMAT_S16_BE;
191 p_aout->p_sys->bytes_per_sample = 2;
195 p_aout->p_sys->samples_per_frame = p_aout->i_channels;
196 p_aout->p_sys->bytes_per_frame = p_aout->p_sys->samples_per_frame *
197 p_aout->p_sys->bytes_per_sample;
199 i_rv = snd_pcm_hw_params_any( p_aout->p_sys->p_alsa_handle, p_hw );
202 intf_ErrMsg( "Aout_alsa: Unable to retrieve initial parameters." );
206 i_rv = snd_pcm_hw_params_set_access( p_aout->p_sys->p_alsa_handle, p_hw,
207 SND_PCM_ACCESS_RW_INTERLEAVED );
210 intf_ErrMsg( "Aout_alsa: Unable to set interleaved stream format." );
214 i_rv = snd_pcm_hw_params_set_format( p_aout->p_sys->p_alsa_handle,
218 intf_ErrMsg( "Aout_alsa: Unable to set stream sample size and word"
223 i_rv = snd_pcm_hw_params_set_channels( p_aout->p_sys->p_alsa_handle, p_hw,
224 p_aout->i_channels );
227 intf_ErrMsg( "Aout_alsa: Unable to set number of output channels." );
231 i_rv = snd_pcm_hw_params_set_rate_near( p_aout->p_sys->p_alsa_handle, p_hw,
235 intf_ErrMsg( "Aout_alsa: Unable to set sample rate." );
239 p_aout->p_sys->rate = i_rv;
241 i_rv = snd_pcm_hw_params_set_buffer_time_near( p_aout->p_sys->p_alsa_handle,
242 p_hw, AOUT_BUFFER_DURATION,
246 intf_ErrMsg( "Aout_alsa: Unable to set buffer time." );
250 p_aout->p_sys->buffer_time = i_rv;
252 i_rv = snd_pcm_hw_params_set_period_time_near( p_aout->p_sys->p_alsa_handle,
253 p_hw, p_aout->p_sys->buffer_time / p_aout->p_sys->bytes_per_frame, 0 );
256 intf_ErrMsg( "Aout_alsa: Unable to set period time." );
260 p_aout->p_sys->period_time = i_rv;
262 i_rv = snd_pcm_hw_params(p_aout->p_sys->p_alsa_handle, p_hw);
265 intf_ErrMsg( "Aout_alsa: Unable to set hardware configuration." );
269 p_aout->p_sys->chunk_size = snd_pcm_hw_params_get_period_size( p_hw, 0 );
270 p_aout->p_sys->buffer_size = snd_pcm_hw_params_get_buffer_size( p_hw );
272 snd_pcm_sw_params_current( p_aout->p_sys->p_alsa_handle, p_sw );
273 i_rv = snd_pcm_sw_params_set_sleep_min( p_aout->p_sys->p_alsa_handle, p_sw,
276 i_rv = snd_pcm_sw_params_set_avail_min( p_aout->p_sys->p_alsa_handle, p_sw,
277 p_aout->p_sys->chunk_size );
279 /* Worked with the CVS version but not with 0.9beta3
280 i_rv = snd_pcm_sw_params_set_start_threshold( p_aout->p_sys->p_alsa_handle,
281 p_sw, p_aout->p_sys->buffer_size );
283 i_rv = snd_pcm_sw_params_set_stop_threshold( p_aout->p_sys->p_alsa_handle,
284 p_sw, p_aout->p_sys->buffer_size);
286 i_rv = snd_pcm_sw_params( p_aout->p_sys->p_alsa_handle, p_sw );
289 intf_ErrMsg( "Aout_alsa: Unable to set software configuration." );
297 /*****************************************************************************
298 * static void aout_HandleXrun : reprepare the output
299 *****************************************************************************
300 * When buffer gets empty, the driver goes in "Xrun" state, where it needs
301 * to be reprepared before playing again
302 *****************************************************************************/
303 static void aout_HandleXrun(aout_thread_t *p_aout)
307 intf_ErrMsg( "Aout_alsa: resetting output after buffer underrun." );
309 i_rv = snd_pcm_reset( p_aout->p_sys->p_alsa_handle );
310 i_rv = snd_pcm_prepare( p_aout->p_sys->p_alsa_handle );
312 intf_ErrMsg( "Aout_alsa: Unable to recover from buffer underrun: %s",
313 snd_strerror( i_rv ) );
317 /*****************************************************************************
318 * aout_BufInfo: buffer status query
319 *****************************************************************************
320 * This function returns the number of used byte in the queue.
321 * It also deals with errors : indeed if the device comes to run out
322 * of data to play, it switches to the "underrun" status. It has to
323 * be flushed and re-prepared
324 *****************************************************************************/
325 static long aout_GetBufInfo( aout_thread_t *p_aout, long l_buffer_limit )
327 snd_pcm_status_t *p_status;
328 int i_alsa_get_status_returns;
330 snd_pcm_status_alloca( &p_status );
332 i_alsa_get_status_returns = snd_pcm_status( p_aout->p_sys->p_alsa_handle,
335 if( i_alsa_get_status_returns )
337 intf_ErrMsg ( "Aout_alsa: Error getting alsa buffer info (%d) : %s",
338 i_alsa_get_status_returns,
339 snd_strerror ( i_alsa_get_status_returns ) );
343 switch( snd_pcm_status_get_state( p_status ) )
345 case SND_PCM_STATE_XRUN :
346 aout_HandleXrun( p_aout );
349 case SND_PCM_STATE_OPEN:
350 case SND_PCM_STATE_PREPARED:
351 case SND_PCM_STATE_RUNNING:
355 intf_ErrMsg( "Aout_alsa: Encountered unhandled condition %i!",
356 snd_pcm_status_get_state( p_status ) );
360 return( snd_pcm_status_get_avail(p_status) *
361 p_aout->p_sys->bytes_per_frame );
364 /*****************************************************************************
365 * aout_Play : plays a sample
366 *****************************************************************************
367 * Plays a sample using the snd_pcm_writei function from the alsa API
368 *****************************************************************************/
369 static void aout_Play( aout_thread_t *p_aout, byte_t *buffer, int i_size )
371 snd_pcm_uframes_t tot_frames;
372 snd_pcm_uframes_t frames_left;
373 snd_pcm_uframes_t rv;
375 tot_frames = i_size / p_aout->p_sys->bytes_per_frame;
376 frames_left = tot_frames;
378 while( frames_left > 0 )
380 rv = snd_pcm_writei( p_aout->p_sys->p_alsa_handle, buffer +
381 (tot_frames - frames_left) *
382 p_aout->p_sys->bytes_per_frame, frames_left );
384 if( (signed int) rv < 0 )
386 intf_ErrMsg( "Aout_alsa: error writing to output: %s",
387 snd_strerror( rv ) );
395 /*****************************************************************************
396 * aout_Close : close the Alsa device
397 *****************************************************************************/
398 static void aout_Close( aout_thread_t *p_aout )
402 i_close_returns = snd_pcm_close( p_aout->p_sys->p_alsa_handle );
404 if( i_close_returns )
406 intf_ErrMsg( "Aout_alsa: error closing alsa device (%d): %s",
407 i_close_returns, snd_strerror( i_close_returns ) );
410 free( p_aout->p_sys );
412 intf_DbgMsg( "Aout_alsa : Alsa device closed" );
415 /*****************************************************************************
416 * Functions exported as capabilities. They are declared as static so that
417 * we don't pollute the namespace too much.
418 *****************************************************************************/
419 void _M( aout_getfunctions )( function_list_t * p_function_list )
421 p_function_list->pf_probe = aout_Probe;
422 p_function_list->functions.aout.pf_open = aout_Open;
423 p_function_list->functions.aout.pf_setformat = aout_SetFormat;
424 p_function_list->functions.aout.pf_getbufinfo = aout_GetBufInfo;
425 p_function_list->functions.aout.pf_play = aout_Play;
426 p_function_list->functions.aout.pf_close = aout_Close;