1 /*****************************************************************************
2 * aout_alsa.c : Alsa functions library
3 *****************************************************************************
4 * Copyright (C) 2000-2001 VideoLAN
5 * $Id: aout_alsa.c,v 1.24 2001/12/30 07:09:54 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 /*****************************************************************************
27 *****************************************************************************/
28 #include <errno.h> /* ENOMEM */
29 #include <string.h> /* strerror() */
30 #include <stdio.h> /* "intf_msg.h" */
31 #include <stdlib.h> /* calloc(), malloc(), free() */
33 #include <alsa/asoundlib.h>
35 #include <videolan/vlc.h>
37 #include "audio_output.h" /* aout_thread_t */
39 typedef struct alsa_device_s
44 typedef struct alsa_card_s
49 /* here we store plugin dependant informations */
51 typedef struct aout_sys_s
53 snd_pcm_t * p_alsa_handle;
54 unsigned long buffer_time;
55 unsigned long period_time;
56 unsigned long chunk_size;
57 unsigned long buffer_size;
59 unsigned int bytes_per_sample;
60 unsigned int samples_per_frame;
61 unsigned int bytes_per_frame;
65 /*****************************************************************************
66 * aout_Probe: probes the audio device and return a score
67 *****************************************************************************
68 * This function tries to open the dps and returns a score to the plugin
69 * manager so that it can make its choice.
70 *****************************************************************************/
71 static int aout_Probe( probedata_t *p_data )
73 int i_open_return, i_close_return;
77 i_open_return = snd_pcm_open( &(local_sys.p_alsa_handle), "default",
78 SND_PCM_STREAM_PLAYBACK, 0 );
81 intf_WarnMsg( 2, "aout info: could not probe ALSA device (%s)",
82 snd_strerror( i_open_return ) );
87 i_close_return = snd_pcm_close( local_sys.p_alsa_handle );
91 intf_ErrMsg( "aout error: could not close ALSA device (%s)",
92 snd_strerror( i_close_return ) );
96 /* And return score */
100 /*****************************************************************************
101 * aout_Open : creates a handle and opens an alsa device
102 *****************************************************************************
103 * This function opens an alsa device, through the alsa API
104 *****************************************************************************/
105 static int aout_Open( aout_thread_t *p_aout )
110 /* Allocate structures */
111 p_aout->p_sys = malloc( sizeof( aout_sys_t ) );
112 if( p_aout->p_sys == NULL )
114 intf_ErrMsg( "aout error: failed allocating memory for ALSA (%s)",
119 p_aout->i_format = AOUT_FORMAT_DEFAULT;
120 p_aout->i_channels = 1 + main_GetIntVariable( AOUT_STEREO_VAR,
121 AOUT_STEREO_DEFAULT );
122 p_aout->l_rate = main_GetIntVariable( AOUT_RATE_VAR,
126 if( ( i_open_returns = snd_pcm_open(&(p_aout->p_sys->p_alsa_handle),
128 SND_PCM_STREAM_PLAYBACK, 0) ) )
130 intf_ErrMsg( "aout error: could not open ALSA device (%s)",
131 snd_strerror(i_open_returns) );
135 intf_DbgMsg( "aout info: ALSA device successfully opened" );
140 /*****************************************************************************
141 * aout_SetFormat : sets the alsa output format
142 *****************************************************************************
143 * This function prepares the device, sets the rate, format, the mode
144 * ( "play as soon as you have data" ), and buffer information.
145 *****************************************************************************/
146 static int aout_SetFormat( aout_thread_t *p_aout )
152 snd_pcm_hw_params_t *p_hw;
153 snd_pcm_sw_params_t *p_sw;
155 snd_pcm_hw_params_alloca(&p_hw);
156 snd_pcm_sw_params_alloca(&p_sw);
158 switch (p_aout->i_format)
160 case AOUT_FMT_S16_LE:
161 i_format = SND_PCM_FORMAT_S16_LE;
162 p_aout->p_sys->bytes_per_sample = 2;
166 i_format = SND_PCM_FORMAT_S16_BE;
167 p_aout->p_sys->bytes_per_sample = 2;
171 p_aout->p_sys->samples_per_frame = p_aout->i_channels;
172 p_aout->p_sys->bytes_per_frame = p_aout->p_sys->samples_per_frame *
173 p_aout->p_sys->bytes_per_sample;
175 i_rv = snd_pcm_hw_params_any( p_aout->p_sys->p_alsa_handle, p_hw );
178 intf_ErrMsg( "aout error: unable to retrieve initial parameters" );
182 i_rv = snd_pcm_hw_params_set_access( p_aout->p_sys->p_alsa_handle, p_hw,
183 SND_PCM_ACCESS_RW_INTERLEAVED );
186 intf_ErrMsg( "aout error: unable to set interleaved stream format" );
190 i_rv = snd_pcm_hw_params_set_format( p_aout->p_sys->p_alsa_handle,
194 intf_ErrMsg( "aout error: unable to set stream sample size and word"
199 i_rv = snd_pcm_hw_params_set_channels( p_aout->p_sys->p_alsa_handle, p_hw,
200 p_aout->i_channels );
203 intf_ErrMsg( "aout error: unable to set number of output channels" );
207 i_rv = snd_pcm_hw_params_set_rate_near( p_aout->p_sys->p_alsa_handle, p_hw,
211 intf_ErrMsg( "aout error: unable to set sample rate" );
214 p_aout->p_sys->rate = i_rv;
216 i_rv = snd_pcm_hw_params_set_buffer_time_near( p_aout->p_sys->p_alsa_handle,
217 p_hw, AOUT_BUFFER_DURATION,
221 intf_ErrMsg( "aout error: unable to set buffer time" );
224 p_aout->p_sys->buffer_time = i_rv;
226 i_rv = snd_pcm_hw_params_set_period_time_near( p_aout->p_sys->p_alsa_handle,
227 p_hw, p_aout->p_sys->buffer_time / p_aout->p_sys->bytes_per_frame, 0 );
230 intf_ErrMsg( "aout error: unable to set period time" );
233 p_aout->p_sys->period_time = i_rv;
235 i_rv = snd_pcm_hw_params(p_aout->p_sys->p_alsa_handle, p_hw);
238 intf_ErrMsg( "aout error: unable to set hardware configuration" );
242 p_aout->p_sys->chunk_size = snd_pcm_hw_params_get_period_size( p_hw, 0 );
243 p_aout->p_sys->buffer_size = snd_pcm_hw_params_get_buffer_size( p_hw );
245 snd_pcm_sw_params_current( p_aout->p_sys->p_alsa_handle, p_sw );
246 i_rv = snd_pcm_sw_params_set_sleep_min( p_aout->p_sys->p_alsa_handle, p_sw,
249 i_rv = snd_pcm_sw_params_set_avail_min( p_aout->p_sys->p_alsa_handle, p_sw,
250 p_aout->p_sys->chunk_size );
252 /* Worked with the CVS version but not with 0.9beta3
253 i_rv = snd_pcm_sw_params_set_start_threshold( p_aout->p_sys->p_alsa_handle,
254 p_sw, p_aout->p_sys->buffer_size );
256 i_rv = snd_pcm_sw_params_set_stop_threshold( p_aout->p_sys->p_alsa_handle,
257 p_sw, p_aout->p_sys->buffer_size);
259 i_rv = snd_pcm_sw_params( p_aout->p_sys->p_alsa_handle, p_sw );
262 intf_ErrMsg( "aout error: unable to set software configuration" );
266 p_aout->i_latency = 0;
271 /*****************************************************************************
272 * aout_HandleXrun : reprepare the output
273 *****************************************************************************
274 * When buffer gets empty, the driver goes in "Xrun" state, where it needs
275 * to be reprepared before playing again
276 *****************************************************************************/
277 static void aout_HandleXrun(aout_thread_t *p_aout)
281 intf_ErrMsg( "aout error: resetting output after buffer underrun" );
283 i_rv = snd_pcm_reset( p_aout->p_sys->p_alsa_handle );
284 i_rv = snd_pcm_prepare( p_aout->p_sys->p_alsa_handle );
287 intf_ErrMsg( "aout error: unable to recover from buffer underrun (%s)",
288 snd_strerror( i_rv ) );
293 /*****************************************************************************
294 * aout_BufInfo: buffer status query
295 *****************************************************************************
296 * This function returns the number of used byte in the queue.
297 * It also deals with errors : indeed if the device comes to run out
298 * of data to play, it switches to the "underrun" status. It has to
299 * be flushed and re-prepared
300 *****************************************************************************/
301 static long aout_GetBufInfo( aout_thread_t *p_aout, long l_buffer_limit )
303 snd_pcm_status_t *p_status;
304 int i_alsa_get_status_returns;
306 snd_pcm_status_alloca( &p_status );
308 i_alsa_get_status_returns = snd_pcm_status( p_aout->p_sys->p_alsa_handle,
311 if( i_alsa_get_status_returns )
313 intf_ErrMsg ( "aout error: failed getting alsa buffer info (%s)",
314 snd_strerror ( i_alsa_get_status_returns ) );
318 switch( snd_pcm_status_get_state( p_status ) )
320 case SND_PCM_STATE_XRUN :
321 aout_HandleXrun( p_aout );
324 case SND_PCM_STATE_OPEN:
325 case SND_PCM_STATE_PREPARED:
326 case SND_PCM_STATE_RUNNING:
330 intf_ErrMsg( "aout error: unhandled condition %i",
331 snd_pcm_status_get_state( p_status ) );
335 return( snd_pcm_status_get_avail(p_status) *
336 p_aout->p_sys->bytes_per_frame );
339 /*****************************************************************************
340 * aout_Play : plays a sample
341 *****************************************************************************
342 * Plays a sample using the snd_pcm_writei function from the alsa API
343 *****************************************************************************/
344 static void aout_Play( aout_thread_t *p_aout, byte_t *buffer, int i_size )
346 snd_pcm_uframes_t tot_frames;
347 snd_pcm_uframes_t frames_left;
348 snd_pcm_uframes_t rv;
350 tot_frames = i_size / p_aout->p_sys->bytes_per_frame;
351 frames_left = tot_frames;
353 while( frames_left > 0 )
355 rv = snd_pcm_writei( p_aout->p_sys->p_alsa_handle, buffer +
356 (tot_frames - frames_left) *
357 p_aout->p_sys->bytes_per_frame, frames_left );
359 if( (signed int) rv < 0 )
361 intf_ErrMsg( "aout error: failed writing to output (%s)",
362 snd_strerror( rv ) );
370 /*****************************************************************************
371 * aout_Close : close the Alsa device
372 *****************************************************************************/
373 static void aout_Close( aout_thread_t *p_aout )
377 i_close_returns = snd_pcm_close( p_aout->p_sys->p_alsa_handle );
379 if( i_close_returns )
381 intf_ErrMsg( "aout error: failed closing ALSA device (%s)",
382 i_close_returns, snd_strerror( i_close_returns ) );
385 free( p_aout->p_sys );
387 intf_DbgMsg( "aout: ALSA device closed" );
390 /*****************************************************************************
391 * Functions exported as capabilities. They are declared as static so that
392 * we don't pollute the namespace too much.
393 *****************************************************************************/
394 void _M( aout_getfunctions )( function_list_t * p_function_list )
396 p_function_list->pf_probe = aout_Probe;
397 p_function_list->functions.aout.pf_open = aout_Open;
398 p_function_list->functions.aout.pf_setformat = aout_SetFormat;
399 p_function_list->functions.aout.pf_getbufinfo = aout_GetBufInfo;
400 p_function_list->functions.aout.pf_play = aout_Play;
401 p_function_list->functions.aout.pf_close = aout_Close;