plugins/alsa/aout_alsa.c

   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 $
   6  *
   7  * Authors: Henri Fallon <henri@videolan.org> - Original Author
   8  *          Jeffrey Baker <jwbaker@acm.org> - Port to ALSA 1.0 API
   9  *
  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.
  14  *
  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.
  19  *
  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  *****************************************************************************/
  24
  25 #define MODULE_NAME alsa
  26 #include "modules_inner.h"
  27
  28 /*****************************************************************************
  29  * Preamble
  30  *****************************************************************************/
  31
  32 #include "defs.h"
  33
  34 #include <errno.h>                                                 /* ENOMEM */
  35 #include <string.h>                                            /* strerror() */
  36 #include <stdio.h>                                           /* "intf_msg.h" */
  37 #include <stdlib.h>                            /* calloc(), malloc(), free() */
  38
  39 #include <sys/asoundlib.h>
  40
  41 #include "config.h"
  42 #include "common.h"                                     /* boolean_t, byte_t */
  43 #include "threads.h"
  44 #include "mtime.h"
  45 #include "tests.h"
  46
  47 #include "audio_output.h"                                   /* aout_thread_t */
  48
  49 #include "intf_msg.h"                        /* intf_DbgMsg(), intf_ErrMsg() */
  50 #include "main.h"
  51
  52 #include "modules.h"
  53 #include "modules_export.h"
  54
  55 typedef struct alsa_device_s
  56 {
  57     int i_num;
  58 } alsa_device_t;
  59
  60 typedef struct alsa_card_s
  61 {
  62     int i_num;
  63 } alsa_card_t;
  64
  65 /* here we store plugin dependant informations */
  66
  67 typedef struct aout_sys_s
  68 {
  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;
  74     unsigned long rate;
  75     unsigned int  bytes_per_sample;
  76     unsigned int  samples_per_frame;
  77     unsigned int  bytes_per_frame;
  78 } aout_sys_t;
  79
  80
  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 )
  88 {
  89     int i_open_return, i_close_return;
  90     aout_sys_t local_sys;
  91
  92     /* Open device */
  93     i_open_return = snd_pcm_open( &(local_sys.p_alsa_handle), "plug:0,0",
  94                                   SND_PCM_STREAM_PLAYBACK, 0 );
  95     if( i_open_return )
  96     {
  97         intf_WarnMsg( 2, "aout info: could not probe ALSA device (%s)",
  98                       snd_strerror( i_open_return ) );
  99         return ( 0 );
 100     }
 101
 102     /* Close it */
 103     i_close_return = snd_pcm_close( local_sys.p_alsa_handle );
 104
 105     if( i_close_return )
 106     {
 107         intf_ErrMsg( "aout error: could not close ALSA device (%s)",
 108                      snd_strerror( i_close_return ) );
 109         return( 0 );
 110     }
 111
 112     if( TestMethod( AOUT_METHOD_VAR, "alsa" ) )
 113     {
 114         return( 999 );
 115     }
 116
 117     /* And return score */
 118     return( 100 );
 119 }
 120
 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 )
 127 {
 128
 129     int i_open_returns;
 130
 131     /* Allocate structures */
 132     p_aout->p_sys = malloc( sizeof( aout_sys_t ) );
 133     if( p_aout->p_sys == NULL )
 134     {
 135         intf_ErrMsg( "aout error: failed allocating memory for ALSA (%s)",
 136                      strerror(ENOMEM) );
 137         return( 1 );
 138     }
 139
 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,
 144                                               AOUT_RATE_DEFAULT );
 145
 146     /* Open device */
 147     if( ( i_open_returns = snd_pcm_open(&(p_aout->p_sys->p_alsa_handle),
 148                                         "plug:0,0",
 149                                         SND_PCM_STREAM_PLAYBACK, 0) ) )
 150     {
 151         intf_ErrMsg( "aout error: could not open ALSA device (%s)",
 152                      snd_strerror(i_open_returns) );
 153         return( -1 );
 154     }
 155
 156     intf_DbgMsg( "aout info: ALSA device successfully opened" );
 157     return( 0 );
 158 }
 159
 160
 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 )
 168 {
 169
 170     int i_rv;
 171     int i_format;
 172
 173     snd_pcm_hw_params_t *p_hw;
 174     snd_pcm_sw_params_t *p_sw;
 175
 176     snd_pcm_hw_params_alloca(&p_hw);
 177     snd_pcm_sw_params_alloca(&p_sw);
 178
 179     switch (p_aout->i_format)
 180     {
 181         case AOUT_FMT_S16_LE:
 182             i_format = SND_PCM_FORMAT_S16_LE;
 183             p_aout->p_sys->bytes_per_sample = 2;
 184             break;
 185
 186         default:
 187             i_format = SND_PCM_FORMAT_S16_BE;
 188             p_aout->p_sys->bytes_per_sample = 2;
 189             break;
 190     }
 191
 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;
 195
 196     i_rv = snd_pcm_hw_params_any( p_aout->p_sys->p_alsa_handle, p_hw );
 197     if( i_rv < 0 )
 198     {
 199         intf_ErrMsg( "aout error: unable to retrieve initial parameters" );
 200         return( -1 );
 201     }
 202
 203     i_rv = snd_pcm_hw_params_set_access( p_aout->p_sys->p_alsa_handle, p_hw,
 204                                          SND_PCM_ACCESS_RW_INTERLEAVED );
 205     if( i_rv < 0 )
 206     {
 207         intf_ErrMsg( "aout error: unable to set interleaved stream format" );
 208         return( -1 );
 209     }
 210
 211     i_rv = snd_pcm_hw_params_set_format( p_aout->p_sys->p_alsa_handle,
 212                                          p_hw, i_format );
 213     if( i_rv < 0 )
 214     {
 215         intf_ErrMsg( "aout error: unable to set stream sample size and word"
 216                      " order" );
 217         return( -1 );
 218     }
 219
 220     i_rv = snd_pcm_hw_params_set_channels( p_aout->p_sys->p_alsa_handle, p_hw,
 221                                            p_aout->i_channels );
 222     if( i_rv < 0 )
 223     {
 224         intf_ErrMsg( "aout error: unable to set number of output channels" );
 225         return( -1 );
 226     }
 227
 228     i_rv = snd_pcm_hw_params_set_rate_near( p_aout->p_sys->p_alsa_handle, p_hw,
 229                                             p_aout->l_rate, 0 );
 230     if( i_rv < 0 )
 231     {
 232         intf_ErrMsg( "aout error: unable to set sample rate" );
 233         return( -1 );
 234     }
 235     p_aout->p_sys->rate = i_rv;
 236
 237     i_rv = snd_pcm_hw_params_set_buffer_time_near( p_aout->p_sys->p_alsa_handle,
 238                                                    p_hw, AOUT_BUFFER_DURATION,
 239                                                    0 );
 240     if( i_rv < 0 )
 241     {
 242         intf_ErrMsg( "aout error: unable to set buffer time" );
 243         return( -1 );
 244     }
 245     p_aout->p_sys->buffer_time = i_rv;
 246
 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 );
 249     if( i_rv < 0 )
 250     {
 251         intf_ErrMsg( "aout error: unable to set period time" );
 252         return( -1 );
 253     }
 254     p_aout->p_sys->period_time = i_rv;
 255
 256     i_rv = snd_pcm_hw_params(p_aout->p_sys->p_alsa_handle, p_hw);
 257     if (i_rv < 0)
 258     {
 259         intf_ErrMsg( "aout error: unable to set hardware configuration" );
 260         return( -1 );
 261     }
 262
 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 );
 265
 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,
 268                                             0 );
 269
 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 );
 272
 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 );
 276
 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);
 279     */
 280     i_rv = snd_pcm_sw_params( p_aout->p_sys->p_alsa_handle, p_sw );
 281     if( i_rv < 0 )
 282     {
 283         intf_ErrMsg( "aout error: unable to set software configuration" );
 284         return( -1 );
 285     }
 286
 287     return( 0 );
 288 }
 289
 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)
 297 {
 298     int i_rv;
 299
 300     intf_ErrMsg( "aout error: resetting output after buffer underrun" );
 301
 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 );
 304     if( i_rv < 0 )
 305     {
 306         intf_ErrMsg( "aout error: unable to recover from buffer underrun (%s)",
 307                      snd_strerror( i_rv ) );
 308     }
 309 }
 310
 311
 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 )
 321 {
 322     snd_pcm_status_t *p_status;
 323     int i_alsa_get_status_returns;
 324
 325     snd_pcm_status_alloca( &p_status );
 326
 327     i_alsa_get_status_returns = snd_pcm_status( p_aout->p_sys->p_alsa_handle,
 328                                                 p_status );
 329
 330     if( i_alsa_get_status_returns )
 331     {
 332         intf_ErrMsg ( "aout error: failed getting alsa buffer info (%s)",
 333                       snd_strerror ( i_alsa_get_status_returns ) );
 334         return ( -1 );
 335     }
 336
 337     switch( snd_pcm_status_get_state( p_status ) )
 338     {
 339         case SND_PCM_STATE_XRUN :
 340             aout_HandleXrun( p_aout );
 341             break;
 342
 343         case SND_PCM_STATE_OPEN:
 344         case SND_PCM_STATE_PREPARED:
 345         case SND_PCM_STATE_RUNNING:
 346             break;
 347
 348         default:
 349             intf_ErrMsg( "aout error: unhandled condition %i",
 350                          snd_pcm_status_get_state( p_status ) );
 351             break;
 352     }
 353
 354     return( snd_pcm_status_get_avail(p_status) *
 355             p_aout->p_sys->bytes_per_frame );
 356 }
 357
 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 )
 364 {
 365     snd_pcm_uframes_t tot_frames;
 366     snd_pcm_uframes_t frames_left;
 367     snd_pcm_uframes_t rv;
 368
 369     tot_frames = i_size / p_aout->p_sys->bytes_per_frame;
 370     frames_left = tot_frames;
 371
 372     while( frames_left > 0 )
 373     {
 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 );
 377
 378         if( (signed int) rv < 0 )
 379         {
 380             intf_ErrMsg( "aout error: failed writing to output (%s)",
 381                          snd_strerror( rv ) );
 382             return;
 383         }
 384
 385         frames_left -= rv;
 386     }
 387 }
 388
 389 /*****************************************************************************
 390  * aout_Close : close the Alsa device
 391  *****************************************************************************/
 392 static void aout_Close( aout_thread_t *p_aout )
 393 {
 394     int i_close_returns;
 395
 396     i_close_returns = snd_pcm_close( p_aout->p_sys->p_alsa_handle );
 397
 398     if( i_close_returns )
 399     {
 400         intf_ErrMsg( "aout error: failed closing ALSA device (%s)",
 401                      i_close_returns, snd_strerror( i_close_returns ) );
 402     }
 403
 404     free( p_aout->p_sys );
 405
 406     intf_DbgMsg( "aout: ALSA device closed" );
 407 }
 408
 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 )
 414 {
 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;
 421 }
 422