git.sesse.net Git - vlc/blob - modules/audio_filter/channel_mixer/headphone.c

   1 /*****************************************************************************
   2  * headphone.c : headphone virtual spatialization channel mixer module
   3  *               -> gives the feeling of a real room with a simple headphone
   4  *****************************************************************************
   5  * Copyright (C) 2002-2006 the VideoLAN team
   6  * $Id$
   7  *
   8  * Authors: Boris Dorès <babal@via.ecp.fr>
   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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 /*****************************************************************************
  26  * Preamble
  27  *****************************************************************************/
  28 #include <math.h>                                        /* sqrt */
  29
  30 #include <vlc/vlc.h>
  31 #include <vlc_aout.h>
  32 #include <vlc_filter.h>
  33 #include <vlc_block.h>
  34
  35 /*****************************************************************************
  36  * Local prototypes
  37  *****************************************************************************/
  38 static int  Create    ( vlc_object_t * );
  39 static void Destroy   ( vlc_object_t * );
  40
  41 static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  42                         aout_buffer_t * );
  43
  44 /* Audio filter2 */
  45 static int  OpenFilter ( vlc_object_t * );
  46 static void CloseFilter( vlc_object_t * );
  47 static block_t *Convert( filter_t *, block_t * );
  48
  49 /*****************************************************************************
  50  * Module descriptor
  51  *****************************************************************************/
  52 #define MODULE_DESCRIPTION N_ ( \
  53      "This effect gives you the feeling that you are standing in a room " \
  54      "with a complete 7.1 speaker set when using only a headphone, " \
  55      "providing a more realistic sound experience. It should also be " \
  56      "more comfortable and less tiring when listening to music for " \
  57      "long periods of time.\nIt works with any source format from mono " \
  58      "to 7.1.")
  59
  60 #define HEADPHONE_DIM_TEXT N_("Characteristic dimension")
  61 #define HEADPHONE_DIM_LONGTEXT N_( \
  62      "Distance between front left speaker and listener in meters.")
  63
  64 #define HEADPHONE_COMPENSATE_TEXT N_("Compensate delay")
  65 #define HEADPHONE_COMPENSATE_LONGTEXT N_( \
  66      "The delay which is introduced by the physical algorithm may "\
  67      "sometimes be disturbing for the synchronization between lips-movement "\
  68      "and speech. In case, turn this on to compensate.")
  69
  70 #define HEADPHONE_DOLBY_TEXT N_("No decoding of Dolby Surround")
  71 #define HEADPHONE_DOLBY_LONGTEXT N_( \
  72      "Dolby Surround encoded streams won't be decoded before being " \
  73      "processed by this filter. Enabling this setting is not recommended.")
  74
  75 vlc_module_begin();
  76     set_description( _("Headphone virtual spatialization effect") );
  77     set_shortname( _("Headphone effect") );
  78     set_help( MODULE_DESCRIPTION );
  79     set_category( CAT_AUDIO );
  80     set_subcategory( SUBCAT_AUDIO_AFILTER );
  81
  82     add_integer( "headphone-dim", 10, NULL, HEADPHONE_DIM_TEXT,
  83                  HEADPHONE_DIM_LONGTEXT, VLC_FALSE );
  84     add_bool( "headphone-compensate", 0, NULL, HEADPHONE_COMPENSATE_TEXT,
  85               HEADPHONE_COMPENSATE_LONGTEXT, VLC_TRUE );
  86     add_bool( "headphone-dolby", 0, NULL, HEADPHONE_DOLBY_TEXT,
  87               HEADPHONE_DOLBY_LONGTEXT, VLC_TRUE );
  88
  89     set_capability( "audio filter", 0 );
  90     set_callbacks( Create, Destroy );
  91     add_shortcut( "headphone" );
  92
  93     /* Audio filter 2 */
  94     add_submodule();
  95     set_description( _("Headphone virtual spatialization effect") );
  96     set_capability( "audio filter2", 0 );
  97     set_callbacks( OpenFilter, CloseFilter );
  98 vlc_module_end();
  99
 100
 101 /*****************************************************************************
 102  * Internal data structures
 103  *****************************************************************************/
 104 struct atomic_operation_t
 105 {
 106     int i_source_channel_offset;
 107     int i_dest_channel_offset;
 108     unsigned int i_delay;/* in sample unit */
 109     double d_amplitude_factor;
 110 };
 111
 112 struct aout_filter_sys_t
 113 {
 114     size_t i_overflow_buffer_size;/* in bytes */
 115     byte_t * p_overflow_buffer;
 116     unsigned int i_nb_atomic_operations;
 117     struct atomic_operation_t * p_atomic_operations;
 118 };
 119
 120 struct filter_sys_t
 121 {
 122     size_t i_overflow_buffer_size;/* in bytes */
 123     byte_t * p_overflow_buffer;
 124     unsigned int i_nb_atomic_operations;
 125     struct atomic_operation_t * p_atomic_operations;
 126 };
 127
 128 /*****************************************************************************
 129  * Init: initialize internal data structures
 130  * and computes the needed atomic operations
 131  *****************************************************************************/
 132 /* x and z represent the coordinates of the virtual speaker
 133  *  relatively to the center of the listener's head, measured in meters :
 134  *
 135  *  left              right
 136  *Z
 137  *-
 138  *a          head
 139  *x
 140  *i
 141  *s
 142  *  rear left    rear right
 143  *
 144  *          x-axis
 145  *  */
 146 static void ComputeChannelOperations( struct aout_filter_sys_t * p_data
 147         , unsigned int i_rate, unsigned int i_next_atomic_operation
 148         , int i_source_channel_offset, double d_x, double d_z
 149         , double d_compensation_length, double d_channel_amplitude_factor )
 150 {
 151     double d_c = 340; /*sound celerity (unit: m/s)*/
 152     double d_compensation_delay = (d_compensation_length-0.1) / d_c * i_rate;
 153
 154     /* Left ear */
 155     p_data->p_atomic_operations[i_next_atomic_operation]
 156         .i_source_channel_offset = i_source_channel_offset;
 157     p_data->p_atomic_operations[i_next_atomic_operation]
 158         .i_dest_channel_offset = 0;/* left */
 159     p_data->p_atomic_operations[i_next_atomic_operation]
 160         .i_delay = (int)( sqrt( (-0.1-d_x)*(-0.1-d_x) + (0-d_z)*(0-d_z) )
 161                           / d_c * i_rate - d_compensation_delay );
 162     if( d_x < 0 )
 163     {
 164         p_data->p_atomic_operations[i_next_atomic_operation]
 165             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 166     }
 167     else if( d_x > 0 )
 168     {
 169         p_data->p_atomic_operations[i_next_atomic_operation]
 170             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 171     }
 172     else
 173     {
 174         p_data->p_atomic_operations[i_next_atomic_operation]
 175             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 176     }
 177
 178     /* Right ear */
 179     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 180         .i_source_channel_offset = i_source_channel_offset;
 181     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 182         .i_dest_channel_offset = 1;/* right */
 183     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 184         .i_delay = (int)( sqrt( (0.1-d_x)*(0.1-d_x) + (0-d_z)*(0-d_z) )
 185                           / d_c * i_rate - d_compensation_delay );
 186     if( d_x < 0 )
 187     {
 188         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 189             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 190     }
 191     else if( d_x > 0 )
 192     {
 193         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 194             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 195     }
 196     else
 197     {
 198         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 199             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 200     }
 201 }
 202
 203 static int Init( vlc_object_t *p_this, struct aout_filter_sys_t * p_data
 204         , unsigned int i_nb_channels, uint32_t i_physical_channels
 205         , unsigned int i_rate )
 206 {
 207     double d_x = config_GetInt( p_this, "headphone-dim" );
 208     double d_z = d_x;
 209     double d_z_rear = -d_x/3;
 210     double d_min = 0;
 211     unsigned int i_next_atomic_operation;
 212     int i_source_channel_offset;
 213     unsigned int i;
 214
 215     if( p_data == NULL )
 216     {
 217         msg_Dbg( p_this, "passing a null pointer as argument" );
 218         return 0;
 219     }
 220
 221     if( config_GetInt( p_this, "headphone-compensate" ) )
 222     {
 223         /* minimal distance to any speaker */
 224         if( i_physical_channels & AOUT_CHAN_REARCENTER )
 225         {
 226             d_min = d_z_rear;
 227         }
 228         else
 229         {
 230             d_min = d_z;
 231         }
 232     }
 233
 234     /* Number of elementary operations */
 235     p_data->i_nb_atomic_operations = i_nb_channels * 2;
 236     if( i_physical_channels & AOUT_CHAN_CENTER )
 237     {
 238         p_data->i_nb_atomic_operations += 2;
 239     }
 240     p_data->p_atomic_operations = malloc( sizeof(struct atomic_operation_t)
 241             * p_data->i_nb_atomic_operations );
 242     if( p_data->p_atomic_operations == NULL )
 243     {
 244         msg_Err( p_this, "out of memory" );
 245         return -1;
 246     }
 247
 248     /* For each virtual speaker, computes elementary wave propagation time
 249      * to each ear */
 250     i_next_atomic_operation = 0;
 251     i_source_channel_offset = 0;
 252     if( i_physical_channels & AOUT_CHAN_LEFT )
 253     {
 254         ComputeChannelOperations( p_data , i_rate
 255                 , i_next_atomic_operation , i_source_channel_offset
 256                 , -d_x , d_z , d_min , 2.0 / i_nb_channels );
 257         i_next_atomic_operation += 2;
 258         i_source_channel_offset++;
 259     }
 260     if( i_physical_channels & AOUT_CHAN_RIGHT )
 261     {
 262         ComputeChannelOperations( p_data , i_rate
 263                 , i_next_atomic_operation , i_source_channel_offset
 264                 , d_x , d_z , d_min , 2.0 / i_nb_channels );
 265         i_next_atomic_operation += 2;
 266         i_source_channel_offset++;
 267     }
 268     if( i_physical_channels & AOUT_CHAN_MIDDLELEFT )
 269     {
 270         ComputeChannelOperations( p_data , i_rate
 271                 , i_next_atomic_operation , i_source_channel_offset
 272                 , -d_x , 0 , d_min , 1.5 / i_nb_channels );
 273         i_next_atomic_operation += 2;
 274         i_source_channel_offset++;
 275     }
 276     if( i_physical_channels & AOUT_CHAN_MIDDLERIGHT )
 277     {
 278         ComputeChannelOperations( p_data , i_rate
 279                 , i_next_atomic_operation , i_source_channel_offset
 280                 , d_x , 0 , d_min , 1.5 / i_nb_channels );
 281         i_next_atomic_operation += 2;
 282         i_source_channel_offset++;
 283     }
 284     if( i_physical_channels & AOUT_CHAN_REARLEFT )
 285     {
 286         ComputeChannelOperations( p_data , i_rate
 287                 , i_next_atomic_operation , i_source_channel_offset
 288                 , -d_x , d_z_rear , d_min , 1.5 / i_nb_channels );
 289         i_next_atomic_operation += 2;
 290         i_source_channel_offset++;
 291     }
 292     if( i_physical_channels & AOUT_CHAN_REARRIGHT )
 293     {
 294         ComputeChannelOperations( p_data , i_rate
 295                 , i_next_atomic_operation , i_source_channel_offset
 296                 , d_x , d_z_rear , d_min , 1.5 / i_nb_channels );
 297         i_next_atomic_operation += 2;
 298         i_source_channel_offset++;
 299     }
 300     if( i_physical_channels & AOUT_CHAN_REARCENTER )
 301     {
 302         ComputeChannelOperations( p_data , i_rate
 303                 , i_next_atomic_operation , i_source_channel_offset
 304                 , 0 , -d_z , d_min , 1.5 / i_nb_channels );
 305         i_next_atomic_operation += 2;
 306         i_source_channel_offset++;
 307     }
 308     if( i_physical_channels & AOUT_CHAN_CENTER )
 309     {
 310         /* having two center channels increases the spatialization effect */
 311         ComputeChannelOperations( p_data , i_rate
 312                 , i_next_atomic_operation , i_source_channel_offset
 313                 , d_x / 5.0 , d_z , d_min , 0.75 / i_nb_channels );
 314         i_next_atomic_operation += 2;
 315         ComputeChannelOperations( p_data , i_rate
 316                 , i_next_atomic_operation , i_source_channel_offset
 317                 , -d_x / 5.0 , d_z , d_min , 0.75 / i_nb_channels );
 318         i_next_atomic_operation += 2;
 319         i_source_channel_offset++;
 320     }
 321     if( i_physical_channels & AOUT_CHAN_LFE )
 322     {
 323         ComputeChannelOperations( p_data , i_rate
 324                 , i_next_atomic_operation , i_source_channel_offset
 325                 , 0 , d_z_rear , d_min , 5.0 / i_nb_channels );
 326         i_next_atomic_operation += 2;
 327         i_source_channel_offset++;
 328     }
 329
 330     /* Initialize the overflow buffer
 331      * we need it because the process induce a delay in the samples */
 332     p_data->i_overflow_buffer_size = 0;
 333     for( i = 0 ; i < p_data->i_nb_atomic_operations ; i++ )
 334     {
 335         if( p_data->i_overflow_buffer_size
 336                 < p_data->p_atomic_operations[i].i_delay * 2 * sizeof (float) )
 337         {
 338             p_data->i_overflow_buffer_size
 339                 = p_data->p_atomic_operations[i].i_delay * 2 * sizeof (float);
 340         }
 341     }
 342     p_data->p_overflow_buffer = malloc( p_data->i_overflow_buffer_size );
 343     if( p_data->p_atomic_operations == NULL )
 344     {
 345         msg_Err( p_this, "out of memory" );
 346         return -1;
 347     }
 348     memset( p_data->p_overflow_buffer, 0 , p_data->i_overflow_buffer_size );
 349
 350     /* end */
 351     return 0;
 352 }
 353
 354 /*****************************************************************************
 355  * Create: allocate headphone downmixer
 356  *****************************************************************************/
 357 static int Create( vlc_object_t *p_this )
 358 {
 359     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 360     vlc_bool_t b_fit = VLC_TRUE;
 361
 362     /* Activate this filter only with stereo devices */
 363     if( p_filter->output.i_physical_channels
 364             != (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT) )
 365     {
 366         msg_Dbg( p_filter, "filter discarded (incompatible format)" );
 367         return VLC_EGENERIC;
 368     }
 369
 370     /* Request a specific format if not already compatible */
 371     if( p_filter->input.i_original_channels
 372             != p_filter->output.i_original_channels )
 373     {
 374         b_fit = VLC_FALSE;
 375         p_filter->input.i_original_channels =
 376                                         p_filter->output.i_original_channels;
 377     }
 378     if( p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
 379           || p_filter->output.i_format != VLC_FOURCC('f','l','3','2') )
 380     {
 381         b_fit = VLC_FALSE;
 382         p_filter->input.i_format = VLC_FOURCC('f','l','3','2');
 383         p_filter->output.i_format = VLC_FOURCC('f','l','3','2');
 384     }
 385     if( p_filter->input.i_rate != p_filter->output.i_rate )
 386     {
 387         b_fit = VLC_FALSE;
 388         p_filter->input.i_rate = p_filter->output.i_rate;
 389     }
 390     if( p_filter->input.i_physical_channels == (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT)
 391           && ( p_filter->input.i_original_channels & AOUT_CHAN_DOLBYSTEREO )
 392           && ! config_GetInt ( p_filter , "headphone-dolby" ) )
 393     {
 394         b_fit = VLC_FALSE;
 395         p_filter->input.i_physical_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
 396                                               AOUT_CHAN_CENTER |
 397                                               AOUT_CHAN_REARLEFT |
 398                                               AOUT_CHAN_REARRIGHT;
 399     }
 400     if( ! b_fit )
 401     {
 402         msg_Dbg( p_filter, "requesting specific format" );
 403         return VLC_EGENERIC;
 404     }
 405
 406     /* Allocate the memory needed to store the module's structure */
 407     p_filter->p_sys = malloc( sizeof(struct aout_filter_sys_t) );
 408     if( p_filter->p_sys == NULL )
 409     {
 410         msg_Err( p_filter, "out of memory" );
 411         return VLC_EGENERIC;
 412     }
 413     p_filter->p_sys->i_overflow_buffer_size = 0;
 414     p_filter->p_sys->p_overflow_buffer = NULL;
 415     p_filter->p_sys->i_nb_atomic_operations = 0;
 416     p_filter->p_sys->p_atomic_operations = NULL;
 417
 418     if( Init( VLC_OBJECT(p_filter), p_filter->p_sys
 419                 , aout_FormatNbChannels ( &p_filter->input )
 420                 , p_filter->input.i_physical_channels
 421                 , p_filter->input.i_rate ) < 0 )
 422     {
 423         return VLC_EGENERIC;
 424     }
 425
 426     p_filter->pf_do_work = DoWork;
 427     p_filter->b_in_place = 0;
 428
 429     return VLC_SUCCESS;
 430 }
 431
 432 /*****************************************************************************
 433  * Destroy: deallocate resources associated with headphone downmixer
 434  *****************************************************************************/
 435 static void Destroy( vlc_object_t *p_this )
 436 {
 437     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 438
 439     if( p_filter->p_sys != NULL )
 440     {
 441         if( p_filter->p_sys->p_overflow_buffer != NULL )
 442         {
 443             free( p_filter->p_sys->p_overflow_buffer );
 444         }
 445         if( p_filter->p_sys->p_atomic_operations != NULL )
 446         {
 447             free( p_filter->p_sys->p_atomic_operations );
 448         }
 449         free( p_filter->p_sys );
 450         p_filter->p_sys = NULL;
 451     }
 452 }
 453
 454 /*****************************************************************************
 455  * DoWork: convert a buffer
 456  *****************************************************************************/
 457 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 458                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 459 {
 460     int i_input_nb = aout_FormatNbChannels( &p_filter->input );
 461     int i_output_nb = aout_FormatNbChannels( &p_filter->output );
 462
 463     float * p_in = (float*) p_in_buf->p_buffer;
 464     byte_t * p_out;
 465     byte_t * p_overflow;
 466     byte_t * p_slide;
 467
 468     size_t i_overflow_size;     /* in bytes */
 469     size_t i_out_size;          /* in bytes */
 470
 471     unsigned int i, j;
 472
 473     int i_source_channel_offset;
 474     int i_dest_channel_offset;
 475     unsigned int i_delay;
 476     double d_amplitude_factor;
 477
 478     /* out buffer characterisitcs */
 479     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 480     p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * i_output_nb / i_input_nb;
 481     p_out = p_out_buf->p_buffer;
 482     i_out_size = p_out_buf->i_nb_bytes;
 483
 484     if( p_filter->p_sys != NULL )
 485     {
 486         /* Slide the overflow buffer */
 487         p_overflow = p_filter->p_sys->p_overflow_buffer;
 488         i_overflow_size = p_filter->p_sys->i_overflow_buffer_size;
 489
 490         memset( p_out, 0, i_out_size );
 491         if ( i_out_size > i_overflow_size )
 492             memcpy( p_out, p_overflow, i_overflow_size );
 493         else
 494             memcpy( p_out, p_overflow, i_out_size );
 495
 496         p_slide = p_filter->p_sys->p_overflow_buffer;
 497         while( p_slide < p_overflow + i_overflow_size )
 498         {
 499             if( p_slide + i_out_size < p_overflow + i_overflow_size )
 500             {
 501                 memset( p_slide, 0, i_out_size );
 502                 if( p_slide + 2 * i_out_size < p_overflow + i_overflow_size )
 503                     memcpy( p_slide, p_slide + i_out_size, i_out_size );
 504                 else
 505                     memcpy( p_slide, p_slide + i_out_size,
 506                             p_overflow + i_overflow_size - ( p_slide + i_out_size ) );
 507             }
 508             else
 509             {
 510                 memset( p_slide, 0, p_overflow + i_overflow_size - p_slide );
 511             }
 512             p_slide += i_out_size;
 513         }
 514
 515         /* apply the atomic operations */
 516         for( i = 0; i < p_filter->p_sys->i_nb_atomic_operations; i++ )
 517         {
 518             /* shorter variable names */
 519             i_source_channel_offset
 520                 = p_filter->p_sys->p_atomic_operations[i].i_source_channel_offset;
 521             i_dest_channel_offset
 522                 = p_filter->p_sys->p_atomic_operations[i].i_dest_channel_offset;
 523             i_delay = p_filter->p_sys->p_atomic_operations[i].i_delay;
 524             d_amplitude_factor
 525                 = p_filter->p_sys->p_atomic_operations[i].d_amplitude_factor;
 526
 527             if( p_out_buf->i_nb_samples > i_delay )
 528             {
 529                 /* current buffer coefficients */
 530                 for( j = 0; j < p_out_buf->i_nb_samples - i_delay; j++ )
 531                 {
 532                     ((float*)p_out)[ (i_delay+j)*i_output_nb + i_dest_channel_offset ]
 533                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 534                            * d_amplitude_factor;
 535                 }
 536
 537                 /* overflow buffer coefficients */
 538                 for( j = 0; j < i_delay; j++ )
 539                 {
 540                     ((float*)p_overflow)[ j*i_output_nb + i_dest_channel_offset ]
 541                         += p_in[ (p_out_buf->i_nb_samples - i_delay + j)
 542                            * i_input_nb + i_source_channel_offset ]
 543                            * d_amplitude_factor;
 544                 }
 545             }
 546             else
 547             {
 548                 /* overflow buffer coefficients only */
 549                 for( j = 0; j < p_out_buf->i_nb_samples; j++ )
 550                 {
 551                     ((float*)p_overflow)[ (i_delay - p_out_buf->i_nb_samples + j)
 552                         * i_output_nb + i_dest_channel_offset ]
 553                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 554                            * d_amplitude_factor;
 555                 }
 556             }
 557         }
 558     }
 559     else
 560     {
 561         memset( p_out, 0, i_out_size );
 562     }
 563 }
 564
 565 /*
 566  * Audio filter 2
 567  */
 568 /*****************************************************************************
 569  * OpenFilter:
 570  *****************************************************************************/
 571 static int OpenFilter( vlc_object_t *p_this )
 572 {
 573     filter_t *p_filter = (filter_t *)p_this;
 574     vlc_bool_t b_fit = VLC_TRUE;
 575
 576     /* Activate this filter only with stereo devices */
 577     if( p_filter->fmt_out.audio.i_physical_channels
 578             != (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT) )
 579     {
 580         msg_Dbg( p_filter, "filter discarded (incompatible format)" );
 581         return VLC_EGENERIC;
 582     }
 583
 584     /* Request a specific format if not already compatible */
 585     if( p_filter->fmt_in.audio.i_original_channels
 586             != p_filter->fmt_out.audio.i_original_channels )
 587     {
 588         b_fit = VLC_FALSE;
 589         p_filter->fmt_in.audio.i_original_channels =
 590                                         p_filter->fmt_out.audio.i_original_channels;
 591     }
 592     if( p_filter->fmt_in.audio.i_format != VLC_FOURCC('f','l','3','2')
 593           || p_filter->fmt_out.audio.i_format != VLC_FOURCC('f','l','3','2') )
 594     {
 595         b_fit = VLC_FALSE;
 596         p_filter->fmt_in.audio.i_format = VLC_FOURCC('f','l','3','2');
 597         p_filter->fmt_out.audio.i_format = VLC_FOURCC('f','l','3','2');
 598     }
 599     if( p_filter->fmt_in.audio.i_rate != p_filter->fmt_out.audio.i_rate )
 600     {
 601         b_fit = VLC_FALSE;
 602         p_filter->fmt_in.audio.i_rate = p_filter->fmt_out.audio.i_rate;
 603     }
 604     if( p_filter->fmt_in.audio.i_physical_channels == (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT)
 605           && ( p_filter->fmt_in.audio.i_original_channels & AOUT_CHAN_DOLBYSTEREO )
 606           && !config_GetInt( p_filter, "headphone-dolby" ) )
 607     {
 608         b_fit = VLC_FALSE;
 609         p_filter->fmt_in.audio.i_physical_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
 610                                               AOUT_CHAN_CENTER |
 611                                               AOUT_CHAN_REARLEFT |
 612                                               AOUT_CHAN_REARRIGHT;
 613     }
 614     if( !b_fit )
 615     {
 616         msg_Dbg( p_filter, "requesting specific format" );
 617         return VLC_EGENERIC;
 618     }
 619
 620     /* Allocate the memory needed to store the module's structure */
 621     p_filter->p_sys = malloc( sizeof(struct filter_sys_t) );
 622     if( p_filter->p_sys == NULL )
 623     {
 624         msg_Err( p_filter, "out of memory" );
 625         return VLC_EGENERIC;
 626     }
 627     p_filter->p_sys->i_overflow_buffer_size = 0;
 628     p_filter->p_sys->p_overflow_buffer = NULL;
 629     p_filter->p_sys->i_nb_atomic_operations = 0;
 630     p_filter->p_sys->p_atomic_operations = NULL;
 631
 632     if( Init( VLC_OBJECT(p_filter), (struct aout_filter_sys_t *)p_filter->p_sys
 633                 , aout_FormatNbChannels ( &(p_filter->fmt_in.audio) )
 634                 , p_filter->fmt_in.audio.i_physical_channels
 635                 , p_filter->fmt_in.audio.i_rate ) < 0 )
 636     {
 637         return VLC_EGENERIC;
 638     }
 639
 640     p_filter->pf_audio_filter = Convert;
 641     p_filter->fmt_out.audio.i_rate = p_filter->fmt_in.audio.i_rate;
 642
 643     return VLC_SUCCESS;
 644 }
 645
 646 /*****************************************************************************
 647  * CloseFilter : deallocate data structures
 648  *****************************************************************************/
 649 static void CloseFilter( vlc_object_t *p_this )
 650 {
 651     filter_t *p_filter = (filter_t *)p_this;
 652
 653     if( p_filter->p_sys != NULL )
 654     {
 655         if( p_filter->p_sys->p_overflow_buffer != NULL )
 656         {
 657             free ( p_filter->p_sys->p_overflow_buffer );
 658         }
 659         if( p_filter->p_sys->p_atomic_operations != NULL )
 660         {
 661             free ( p_filter->p_sys->p_atomic_operations );
 662         }
 663         free( p_filter->p_sys );
 664         p_filter->p_sys = NULL;
 665     }
 666 }
 667
 668 static block_t *Convert( filter_t *p_filter, block_t *p_block )
 669 {
 670     aout_filter_t aout_filter;
 671     aout_buffer_t in_buf, out_buf;
 672     block_t *p_out;
 673     int i_out_size;
 674
 675     if( !p_block || !p_block->i_samples )
 676     {
 677         if( p_block ) p_block->pf_release( p_block );
 678         return NULL;
 679     }
 680
 681     i_out_size = p_block->i_samples *
 682       p_filter->fmt_out.audio.i_bitspersample/8 *
 683         aout_FormatNbChannels( &(p_filter->fmt_out.audio) );
 684
 685     p_out = p_filter->pf_audio_buffer_new( p_filter, i_out_size );
 686     if( !p_out )
 687     {
 688         msg_Warn( p_filter, "can't get output buffer" );
 689         if( p_block ) p_block->pf_release( p_block );
 690         return NULL;
 691     }
 692
 693     p_out->i_samples = p_block->i_samples;
 694     p_out->i_dts = p_block->i_dts;
 695     p_out->i_pts = p_block->i_pts;
 696     p_out->i_length = p_block->i_length;
 697
 698     aout_filter.p_sys = (struct aout_filter_sys_t *)p_filter->p_sys;
 699     aout_filter.input = p_filter->fmt_in.audio;
 700     aout_filter.input.i_format = p_filter->fmt_in.i_codec;
 701     aout_filter.output = p_filter->fmt_out.audio;
 702     aout_filter.output.i_format = p_filter->fmt_out.i_codec;
 703     aout_filter.b_in_place = 0;
 704
 705     in_buf.p_buffer = p_block->p_buffer;
 706     in_buf.i_nb_bytes = p_block->i_buffer;
 707     in_buf.i_nb_samples = p_block->i_samples;
 708     out_buf.p_buffer = p_out->p_buffer;
 709     out_buf.i_nb_bytes = p_out->i_buffer;
 710     out_buf.i_nb_samples = p_out->i_samples;
 711
 712     DoWork( (aout_instance_t *)p_filter, &aout_filter, &in_buf, &out_buf );
 713
 714     p_out->i_buffer = out_buf.i_nb_bytes;
 715     p_out->i_samples = out_buf.i_nb_samples;
 716
 717     if( p_block ) p_block->pf_release( p_block );
 718     return p_out;
 719 }