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 <stdlib.h>                                      /* malloc(), free() */
  29 #include <string.h>
  30 #include <math.h>                                        /* sqrt */
  31
  32 #include <vlc/vlc.h>
  33 #include <audio_output.h>
  34 #include <aout_internal.h>
  35 #include <vlc_filter.h>
  36 #include <vlc_block.h>
  37
  38 /*****************************************************************************
  39  * Local prototypes
  40  *****************************************************************************/
  41 static int  Create    ( vlc_object_t * );
  42 static void Destroy   ( vlc_object_t * );
  43
  44 static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  45                         aout_buffer_t * );
  46
  47 /* Audio filter2 */
  48 static int  OpenFilter ( vlc_object_t * );
  49 static void CloseFilter( vlc_object_t * );
  50 static block_t *Convert( filter_t *, block_t * );
  51
  52 /*****************************************************************************
  53  * Module descriptor
  54  *****************************************************************************/
  55 #define MODULE_DESCRIPTION N_ ( \
  56      "This effect gives you the feeling that you are standing in a room " \
  57      "with a complete 7.1 speaker set when using only a headphone, " \
  58      "providing a more realistic sound experience. It should also be " \
  59      "more comfortable and less tiring when listening to music for " \
  60      "long periods of time.\nIt works with any source format from mono " \
  61      "to 7.1.")
  62
  63 #define HEADPHONE_DIM_TEXT N_("Characteristic dimension")
  64 #define HEADPHONE_DIM_LONGTEXT N_( \
  65      "Distance between front left speaker and listener in meters.")
  66
  67 #define HEADPHONE_COMPENSATE_TEXT N_("Compensate delay")
  68 #define HEADPHONE_COMPENSATE_LONGTEXT N_( \
  69      "The delay which is introduced by the physical algorithm may "\
  70      "sometimes be disturbing for the synchronization between lips-movement "\
  71      "and speech. In case, turn this on to compensate.")
  72
  73 #define HEADPHONE_DOLBY_TEXT N_("No decoding of Dolby Surround")
  74 #define HEADPHONE_DOLBY_LONGTEXT N_( \
  75      "Dolby Surround encoded streams won't be decoded before being " \
  76      "processed by this filter. Enabling this setting is not recommended.")
  77
  78 vlc_module_begin();
  79     set_description( N_("Headphone virtual spatialization effect") );
  80     set_shortname( _("Headphone effect") );
  81     set_help( MODULE_DESCRIPTION );
  82     set_category( CAT_AUDIO );
  83     set_subcategory( SUBCAT_AUDIO_AFILTER );
  84
  85     add_integer( "headphone-dim", 10, NULL, HEADPHONE_DIM_TEXT,
  86                  HEADPHONE_DIM_LONGTEXT, VLC_FALSE );
  87     add_bool( "headphone-compensate", 0, NULL, HEADPHONE_COMPENSATE_TEXT,
  88               HEADPHONE_COMPENSATE_LONGTEXT, VLC_TRUE );
  89     add_bool( "headphone-dolby", 0, NULL, HEADPHONE_DOLBY_TEXT,
  90               HEADPHONE_DOLBY_LONGTEXT, VLC_TRUE );
  91
  92     set_capability( "audio filter", 0 );
  93     set_callbacks( Create, Destroy );
  94     add_shortcut( "headphone" );
  95
  96     /* Audio filter 2 */
  97     add_submodule();
  98     set_description( _("Headphone virtual spatialization effect") );
  99     set_capability( "audio filter2", 0 );
 100     set_callbacks( OpenFilter, CloseFilter );
 101 vlc_module_end();
 102
 103
 104 /*****************************************************************************
 105  * Internal data structures
 106  *****************************************************************************/
 107 struct atomic_operation_t
 108 {
 109     int i_source_channel_offset;
 110     int i_dest_channel_offset;
 111     unsigned int i_delay;/* in sample unit */
 112     double d_amplitude_factor;
 113 };
 114
 115 struct aout_filter_sys_t
 116 {
 117     size_t i_overflow_buffer_size;/* in bytes */
 118     byte_t * p_overflow_buffer;
 119     unsigned int i_nb_atomic_operations;
 120     struct atomic_operation_t * p_atomic_operations;
 121 };
 122
 123 struct filter_sys_t
 124 {
 125     size_t i_overflow_buffer_size;/* in bytes */
 126     byte_t * p_overflow_buffer;
 127     unsigned int i_nb_atomic_operations;
 128     struct atomic_operation_t * p_atomic_operations;
 129 };
 130
 131 /*****************************************************************************
 132  * Init: initialize internal data structures
 133  * and computes the needed atomic operations
 134  *****************************************************************************/
 135 /* x and z represent the coordinates of the virtual speaker
 136  *  relatively to the center of the listener's head, measured in meters :
 137  *
 138  *  left              right
 139  *Z
 140  *-
 141  *a          head
 142  *x
 143  *i
 144  *s
 145  *  rear left    rear right
 146  *
 147  *          x-axis
 148  *  */
 149 static void ComputeChannelOperations( struct aout_filter_sys_t * p_data
 150         , unsigned int i_rate, unsigned int i_next_atomic_operation
 151         , int i_source_channel_offset, double d_x, double d_z
 152         , double d_compensation_length, double d_channel_amplitude_factor )
 153 {
 154     double d_c = 340; /*sound celerity (unit: m/s)*/
 155     double d_compensation_delay = (d_compensation_length-0.1) / d_c * i_rate;
 156
 157     /* Left ear */
 158     p_data->p_atomic_operations[i_next_atomic_operation]
 159         .i_source_channel_offset = i_source_channel_offset;
 160     p_data->p_atomic_operations[i_next_atomic_operation]
 161         .i_dest_channel_offset = 0;/* left */
 162     p_data->p_atomic_operations[i_next_atomic_operation]
 163         .i_delay = (int)( sqrt( (-0.1-d_x)*(-0.1-d_x) + (0-d_z)*(0-d_z) )
 164                           / d_c * i_rate - d_compensation_delay );
 165     if( d_x < 0 )
 166     {
 167         p_data->p_atomic_operations[i_next_atomic_operation]
 168             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 169     }
 170     else if( d_x > 0 )
 171     {
 172         p_data->p_atomic_operations[i_next_atomic_operation]
 173             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 174     }
 175     else
 176     {
 177         p_data->p_atomic_operations[i_next_atomic_operation]
 178             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 179     }
 180
 181     /* Right ear */
 182     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 183         .i_source_channel_offset = i_source_channel_offset;
 184     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 185         .i_dest_channel_offset = 1;/* right */
 186     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 187         .i_delay = (int)( sqrt( (0.1-d_x)*(0.1-d_x) + (0-d_z)*(0-d_z) )
 188                           / d_c * i_rate - d_compensation_delay );
 189     if( d_x < 0 )
 190     {
 191         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 192             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 193     }
 194     else if( d_x > 0 )
 195     {
 196         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 197             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 198     }
 199     else
 200     {
 201         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 202             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 203     }
 204 }
 205
 206 static int Init( vlc_object_t *p_this, struct aout_filter_sys_t * p_data
 207         , unsigned int i_nb_channels, uint32_t i_physical_channels
 208         , unsigned int i_rate )
 209 {
 210     double d_x = config_GetInt( p_this, "headphone-dim" );
 211     double d_z = d_x;
 212     double d_z_rear = -d_x/3;
 213     double d_min = 0;
 214     unsigned int i_next_atomic_operation;
 215     int i_source_channel_offset;
 216     unsigned int i;
 217
 218     if( p_data == NULL )
 219     {
 220         msg_Dbg( p_this, "passing a null pointer as argument" );
 221         return 0;
 222     }
 223
 224     if( config_GetInt( p_this, "headphone-compensate" ) )
 225     {
 226         /* minimal distance to any speaker */
 227         if( i_physical_channels & AOUT_CHAN_REARCENTER )
 228         {
 229             d_min = d_z_rear;
 230         }
 231         else
 232         {
 233             d_min = d_z;
 234         }
 235     }
 236
 237     /* Number of elementary operations */
 238     p_data->i_nb_atomic_operations = i_nb_channels * 2;
 239     if( i_physical_channels & AOUT_CHAN_CENTER )
 240     {
 241         p_data->i_nb_atomic_operations += 2;
 242     }
 243     p_data->p_atomic_operations = malloc( sizeof(struct atomic_operation_t)
 244             * p_data->i_nb_atomic_operations );
 245     if( p_data->p_atomic_operations == NULL )
 246     {
 247         msg_Err( p_this, "out of memory" );
 248         return -1;
 249     }
 250
 251     /* For each virtual speaker, computes elementary wave propagation time
 252      * to each ear */
 253     i_next_atomic_operation = 0;
 254     i_source_channel_offset = 0;
 255     if( i_physical_channels & AOUT_CHAN_LEFT )
 256     {
 257         ComputeChannelOperations( p_data , i_rate
 258                 , i_next_atomic_operation , i_source_channel_offset
 259                 , -d_x , d_z , d_min , 2.0 / i_nb_channels );
 260         i_next_atomic_operation += 2;
 261         i_source_channel_offset++;
 262     }
 263     if( i_physical_channels & AOUT_CHAN_RIGHT )
 264     {
 265         ComputeChannelOperations( p_data , i_rate
 266                 , i_next_atomic_operation , i_source_channel_offset
 267                 , d_x , d_z , d_min , 2.0 / i_nb_channels );
 268         i_next_atomic_operation += 2;
 269         i_source_channel_offset++;
 270     }
 271     if( i_physical_channels & AOUT_CHAN_MIDDLELEFT )
 272     {
 273         ComputeChannelOperations( p_data , i_rate
 274                 , i_next_atomic_operation , i_source_channel_offset
 275                 , -d_x , 0 , d_min , 1.5 / i_nb_channels );
 276         i_next_atomic_operation += 2;
 277         i_source_channel_offset++;
 278     }
 279     if( i_physical_channels & AOUT_CHAN_MIDDLERIGHT )
 280     {
 281         ComputeChannelOperations( p_data , i_rate
 282                 , i_next_atomic_operation , i_source_channel_offset
 283                 , d_x , 0 , d_min , 1.5 / i_nb_channels );
 284         i_next_atomic_operation += 2;
 285         i_source_channel_offset++;
 286     }
 287     if( i_physical_channels & AOUT_CHAN_REARLEFT )
 288     {
 289         ComputeChannelOperations( p_data , i_rate
 290                 , i_next_atomic_operation , i_source_channel_offset
 291                 , -d_x , d_z_rear , d_min , 1.5 / i_nb_channels );
 292         i_next_atomic_operation += 2;
 293         i_source_channel_offset++;
 294     }
 295     if( i_physical_channels & AOUT_CHAN_REARRIGHT )
 296     {
 297         ComputeChannelOperations( p_data , i_rate
 298                 , i_next_atomic_operation , i_source_channel_offset
 299                 , d_x , d_z_rear , d_min , 1.5 / i_nb_channels );
 300         i_next_atomic_operation += 2;
 301         i_source_channel_offset++;
 302     }
 303     if( i_physical_channels & AOUT_CHAN_REARCENTER )
 304     {
 305         ComputeChannelOperations( p_data , i_rate
 306                 , i_next_atomic_operation , i_source_channel_offset
 307                 , 0 , -d_z , d_min , 1.5 / i_nb_channels );
 308         i_next_atomic_operation += 2;
 309         i_source_channel_offset++;
 310     }
 311     if( i_physical_channels & AOUT_CHAN_CENTER )
 312     {
 313         /* having two center channels increases the spatialization effect */
 314         ComputeChannelOperations( p_data , i_rate
 315                 , i_next_atomic_operation , i_source_channel_offset
 316                 , d_x / 5.0 , d_z , d_min , 0.75 / i_nb_channels );
 317         i_next_atomic_operation += 2;
 318         ComputeChannelOperations( p_data , i_rate
 319                 , i_next_atomic_operation , i_source_channel_offset
 320                 , -d_x / 5.0 , d_z , d_min , 0.75 / i_nb_channels );
 321         i_next_atomic_operation += 2;
 322         i_source_channel_offset++;
 323     }
 324     if( i_physical_channels & AOUT_CHAN_LFE )
 325     {
 326         ComputeChannelOperations( p_data , i_rate
 327                 , i_next_atomic_operation , i_source_channel_offset
 328                 , 0 , d_z_rear , d_min , 5.0 / i_nb_channels );
 329         i_next_atomic_operation += 2;
 330         i_source_channel_offset++;
 331     }
 332
 333     /* Initialize the overflow buffer
 334      * we need it because the process induce a delay in the samples */
 335     p_data->i_overflow_buffer_size = 0;
 336     for( i = 0 ; i < p_data->i_nb_atomic_operations ; i++ )
 337     {
 338         if( p_data->i_overflow_buffer_size
 339                 < p_data->p_atomic_operations[i].i_delay * 2 * sizeof (float) )
 340         {
 341             p_data->i_overflow_buffer_size
 342                 = p_data->p_atomic_operations[i].i_delay * 2 * sizeof (float);
 343         }
 344     }
 345     p_data->p_overflow_buffer = malloc( p_data->i_overflow_buffer_size );
 346     if( p_data->p_atomic_operations == NULL )
 347     {
 348         msg_Err( p_this, "out of memory" );
 349         return -1;
 350     }
 351     memset( p_data->p_overflow_buffer, 0 , p_data->i_overflow_buffer_size );
 352
 353     /* end */
 354     return 0;
 355 }
 356
 357 /*****************************************************************************
 358  * Create: allocate headphone downmixer
 359  *****************************************************************************/
 360 static int Create( vlc_object_t *p_this )
 361 {
 362     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 363     vlc_bool_t b_fit = VLC_TRUE;
 364
 365     /* Activate this filter only with stereo devices */
 366     if( p_filter->output.i_physical_channels
 367             != (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT) )
 368     {
 369         msg_Dbg( p_filter, "filter discarded (incompatible format)" );
 370         return VLC_EGENERIC;
 371     }
 372
 373     /* Request a specific format if not already compatible */
 374     if( p_filter->input.i_original_channels
 375             != p_filter->output.i_original_channels )
 376     {
 377         b_fit = VLC_FALSE;
 378         p_filter->input.i_original_channels =
 379                                         p_filter->output.i_original_channels;
 380     }
 381     if( p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
 382           || p_filter->output.i_format != VLC_FOURCC('f','l','3','2') )
 383     {
 384         b_fit = VLC_FALSE;
 385         p_filter->input.i_format = VLC_FOURCC('f','l','3','2');
 386         p_filter->output.i_format = VLC_FOURCC('f','l','3','2');
 387     }
 388     if( p_filter->input.i_rate != p_filter->output.i_rate )
 389     {
 390         b_fit = VLC_FALSE;
 391         p_filter->input.i_rate = p_filter->output.i_rate;
 392     }
 393     if( p_filter->input.i_physical_channels == (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT)
 394           && ( p_filter->input.i_original_channels & AOUT_CHAN_DOLBYSTEREO )
 395           && ! config_GetInt ( p_filter , "headphone-dolby" ) )
 396     {
 397         b_fit = VLC_FALSE;
 398         p_filter->input.i_physical_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
 399                                               AOUT_CHAN_CENTER |
 400                                               AOUT_CHAN_REARLEFT |
 401                                               AOUT_CHAN_REARRIGHT;
 402     }
 403     if( ! b_fit )
 404     {
 405         msg_Dbg( p_filter, "requesting specific format" );
 406         return VLC_EGENERIC;
 407     }
 408
 409     /* Allocate the memory needed to store the module's structure */
 410     p_filter->p_sys = malloc( sizeof(struct aout_filter_sys_t) );
 411     if( p_filter->p_sys == NULL )
 412     {
 413         msg_Err( p_filter, "out of memory" );
 414         return VLC_EGENERIC;
 415     }
 416     p_filter->p_sys->i_overflow_buffer_size = 0;
 417     p_filter->p_sys->p_overflow_buffer = NULL;
 418     p_filter->p_sys->i_nb_atomic_operations = 0;
 419     p_filter->p_sys->p_atomic_operations = NULL;
 420
 421     if( Init( VLC_OBJECT(p_filter), p_filter->p_sys
 422                 , aout_FormatNbChannels ( &p_filter->input )
 423                 , p_filter->input.i_physical_channels
 424                 , p_filter->input.i_rate ) < 0 )
 425     {
 426         return VLC_EGENERIC;
 427     }
 428
 429     p_filter->pf_do_work = DoWork;
 430     p_filter->b_in_place = 0;
 431
 432     return VLC_SUCCESS;
 433 }
 434
 435 /*****************************************************************************
 436  * Destroy: deallocate resources associated with headphone downmixer
 437  *****************************************************************************/
 438 static void Destroy( vlc_object_t *p_this )
 439 {
 440     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 441
 442     if( p_filter->p_sys != NULL )
 443     {
 444         if( p_filter->p_sys->p_overflow_buffer != NULL )
 445         {
 446             free( p_filter->p_sys->p_overflow_buffer );
 447         }
 448         if( p_filter->p_sys->p_atomic_operations != NULL )
 449         {
 450             free( p_filter->p_sys->p_atomic_operations );
 451         }
 452         free( p_filter->p_sys );
 453         p_filter->p_sys = NULL;
 454     }
 455 }
 456
 457 /*****************************************************************************
 458  * DoWork: convert a buffer
 459  *****************************************************************************/
 460 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 461                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 462 {
 463     int i_input_nb = aout_FormatNbChannels( &p_filter->input );
 464     int i_output_nb = aout_FormatNbChannels( &p_filter->output );
 465
 466     float * p_in = (float*) p_in_buf->p_buffer;
 467     byte_t * p_out;
 468     byte_t * p_overflow;
 469     byte_t * p_slide;
 470
 471     size_t i_overflow_size;     /* in bytes */
 472     size_t i_out_size;          /* in bytes */
 473
 474     unsigned int i, j;
 475
 476     int i_source_channel_offset;
 477     int i_dest_channel_offset;
 478     unsigned int i_delay;
 479     double d_amplitude_factor;
 480
 481     /* out buffer characterisitcs */
 482     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 483     p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * i_output_nb / i_input_nb;
 484     p_out = p_out_buf->p_buffer;
 485     i_out_size = p_out_buf->i_nb_bytes;
 486
 487     if( p_filter->p_sys != NULL )
 488     {
 489         /* Slide the overflow buffer */
 490         p_overflow = p_filter->p_sys->p_overflow_buffer;
 491         i_overflow_size = p_filter->p_sys->i_overflow_buffer_size;
 492
 493         memset( p_out, 0, i_out_size );
 494         if ( i_out_size > i_overflow_size )
 495             memcpy( p_out, p_overflow, i_overflow_size );
 496         else
 497             memcpy( p_out, p_overflow, i_out_size );
 498
 499         p_slide = p_filter->p_sys->p_overflow_buffer;
 500         while( p_slide < p_overflow + i_overflow_size )
 501         {
 502             if( p_slide + i_out_size < p_overflow + i_overflow_size )
 503             {
 504                 memset( p_slide, 0, i_out_size );
 505                 if( p_slide + 2 * i_out_size < p_overflow + i_overflow_size )
 506                     memcpy( p_slide, p_slide + i_out_size, i_out_size );
 507                 else
 508                     memcpy( p_slide, p_slide + i_out_size,
 509                             p_overflow + i_overflow_size - ( p_slide + i_out_size ) );
 510             }
 511             else
 512             {
 513                 memset( p_slide, 0, p_overflow + i_overflow_size - p_slide );
 514             }
 515             p_slide += i_out_size;
 516         }
 517
 518         /* apply the atomic operations */
 519         for( i = 0; i < p_filter->p_sys->i_nb_atomic_operations; i++ )
 520         {
 521             /* shorter variable names */
 522             i_source_channel_offset
 523                 = p_filter->p_sys->p_atomic_operations[i].i_source_channel_offset;
 524             i_dest_channel_offset
 525                 = p_filter->p_sys->p_atomic_operations[i].i_dest_channel_offset;
 526             i_delay = p_filter->p_sys->p_atomic_operations[i].i_delay;
 527             d_amplitude_factor
 528                 = p_filter->p_sys->p_atomic_operations[i].d_amplitude_factor;
 529
 530             if( p_out_buf->i_nb_samples > i_delay )
 531             {
 532                 /* current buffer coefficients */
 533                 for( j = 0; j < p_out_buf->i_nb_samples - i_delay; j++ )
 534                 {
 535                     ((float*)p_out)[ (i_delay+j)*i_output_nb + i_dest_channel_offset ]
 536                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 537                            * d_amplitude_factor;
 538                 }
 539
 540                 /* overflow buffer coefficients */
 541                 for( j = 0; j < i_delay; j++ )
 542                 {
 543                     ((float*)p_overflow)[ j*i_output_nb + i_dest_channel_offset ]
 544                         += p_in[ (p_out_buf->i_nb_samples - i_delay + j)
 545                            * i_input_nb + i_source_channel_offset ]
 546                            * d_amplitude_factor;
 547                 }
 548             }
 549             else
 550             {
 551                 /* overflow buffer coefficients only */
 552                 for( j = 0; j < p_out_buf->i_nb_samples; j++ )
 553                 {
 554                     ((float*)p_overflow)[ (i_delay - p_out_buf->i_nb_samples + j)
 555                         * i_output_nb + i_dest_channel_offset ]
 556                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 557                            * d_amplitude_factor;
 558                 }
 559             }
 560         }
 561     }
 562     else
 563     {
 564         memset( p_out, 0, i_out_size );
 565     }
 566 }
 567
 568 /*
 569  * Audio filter 2
 570  */
 571 /*****************************************************************************
 572  * OpenFilter:
 573  *****************************************************************************/
 574 static int OpenFilter( vlc_object_t *p_this )
 575 {
 576     filter_t *p_filter = (filter_t *)p_this;
 577     vlc_bool_t b_fit = VLC_TRUE;
 578
 579     /* Activate this filter only with stereo devices */
 580     if( p_filter->fmt_out.audio.i_physical_channels
 581             != (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT) )
 582     {
 583         msg_Dbg( p_filter, "filter discarded (incompatible format)" );
 584         return VLC_EGENERIC;
 585     }
 586
 587     /* Request a specific format if not already compatible */
 588     if( p_filter->fmt_in.audio.i_original_channels
 589             != p_filter->fmt_out.audio.i_original_channels )
 590     {
 591         b_fit = VLC_FALSE;
 592         p_filter->fmt_in.audio.i_original_channels =
 593                                         p_filter->fmt_out.audio.i_original_channels;
 594     }
 595     if( p_filter->fmt_in.audio.i_format != VLC_FOURCC('f','l','3','2')
 596           || p_filter->fmt_out.audio.i_format != VLC_FOURCC('f','l','3','2') )
 597     {
 598         b_fit = VLC_FALSE;
 599         p_filter->fmt_in.audio.i_format = VLC_FOURCC('f','l','3','2');
 600         p_filter->fmt_out.audio.i_format = VLC_FOURCC('f','l','3','2');
 601     }
 602     if( p_filter->fmt_in.audio.i_rate != p_filter->fmt_out.audio.i_rate )
 603     {
 604         b_fit = VLC_FALSE;
 605         p_filter->fmt_in.audio.i_rate = p_filter->fmt_out.audio.i_rate;
 606     }
 607     if( p_filter->fmt_in.audio.i_physical_channels == (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT)
 608           && ( p_filter->fmt_in.audio.i_original_channels & AOUT_CHAN_DOLBYSTEREO )
 609           && !config_GetInt( p_filter, "headphone-dolby" ) )
 610     {
 611         b_fit = VLC_FALSE;
 612         p_filter->fmt_in.audio.i_physical_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
 613                                               AOUT_CHAN_CENTER |
 614                                               AOUT_CHAN_REARLEFT |
 615                                               AOUT_CHAN_REARRIGHT;
 616     }
 617     if( !b_fit )
 618     {
 619         msg_Dbg( p_filter, "requesting specific format" );
 620         return VLC_EGENERIC;
 621     }
 622
 623     /* Allocate the memory needed to store the module's structure */
 624     p_filter->p_sys = malloc( sizeof(struct filter_sys_t) );
 625     if( p_filter->p_sys == NULL )
 626     {
 627         msg_Err( p_filter, "out of memory" );
 628         return VLC_EGENERIC;
 629     }
 630     p_filter->p_sys->i_overflow_buffer_size = 0;
 631     p_filter->p_sys->p_overflow_buffer = NULL;
 632     p_filter->p_sys->i_nb_atomic_operations = 0;
 633     p_filter->p_sys->p_atomic_operations = NULL;
 634
 635     if( Init( VLC_OBJECT(p_filter), (struct aout_filter_sys_t *)p_filter->p_sys
 636                 , aout_FormatNbChannels ( &(p_filter->fmt_in.audio) )
 637                 , p_filter->fmt_in.audio.i_physical_channels
 638                 , p_filter->fmt_in.audio.i_rate ) < 0 )
 639     {
 640         return VLC_EGENERIC;
 641     }
 642
 643     p_filter->pf_audio_filter = Convert;
 644     p_filter->fmt_out.audio.i_rate = p_filter->fmt_in.audio.i_rate;
 645
 646     return VLC_SUCCESS;
 647 }
 648
 649 /*****************************************************************************
 650  * CloseFilter : deallocate data structures
 651  *****************************************************************************/
 652 static void CloseFilter( vlc_object_t *p_this )
 653 {
 654     filter_t *p_filter = (filter_t *)p_this;
 655
 656     if( p_filter->p_sys != NULL )
 657     {
 658         if( p_filter->p_sys->p_overflow_buffer != NULL )
 659         {
 660             free ( p_filter->p_sys->p_overflow_buffer );
 661         }
 662         if( p_filter->p_sys->p_atomic_operations != NULL )
 663         {
 664             free ( p_filter->p_sys->p_atomic_operations );
 665         }
 666         free( p_filter->p_sys );
 667         p_filter->p_sys = NULL;
 668     }
 669 }
 670
 671 static block_t *Convert( filter_t *p_filter, block_t *p_block )
 672 {
 673     aout_filter_t aout_filter;
 674     aout_buffer_t in_buf, out_buf;
 675     block_t *p_out;
 676     int i_out_size;
 677
 678     if( !p_block || !p_block->i_samples )
 679     {
 680         if( p_block ) p_block->pf_release( p_block );
 681         return NULL;
 682     }
 683
 684     i_out_size = p_block->i_samples *
 685       p_filter->fmt_out.audio.i_bitspersample/8 *
 686         aout_FormatNbChannels( &(p_filter->fmt_out.audio) );
 687
 688     p_out = p_filter->pf_audio_buffer_new( p_filter, i_out_size );
 689     if( !p_out )
 690     {
 691         msg_Warn( p_filter, "can't get output buffer" );
 692         if( p_block ) p_block->pf_release( p_block );
 693         return NULL;
 694     }
 695
 696     p_out->i_samples = p_block->i_samples;
 697     p_out->i_dts = p_block->i_dts;
 698     p_out->i_pts = p_block->i_pts;
 699     p_out->i_length = p_block->i_length;
 700
 701     aout_filter.p_sys = (struct aout_filter_sys_t *)p_filter->p_sys;
 702     aout_filter.input = p_filter->fmt_in.audio;
 703     aout_filter.input.i_format = p_filter->fmt_in.i_codec;
 704     aout_filter.output = p_filter->fmt_out.audio;
 705     aout_filter.output.i_format = p_filter->fmt_out.i_codec;
 706     aout_filter.b_in_place = 0;
 707
 708     in_buf.p_buffer = p_block->p_buffer;
 709     in_buf.i_nb_bytes = p_block->i_buffer;
 710     in_buf.i_nb_samples = p_block->i_samples;
 711     out_buf.p_buffer = p_out->p_buffer;
 712     out_buf.i_nb_bytes = p_out->i_buffer;
 713     out_buf.i_nb_samples = p_out->i_samples;
 714
 715     DoWork( (aout_instance_t *)p_filter, &aout_filter, &in_buf, &out_buf );
 716
 717     p_out->i_buffer = out_buf.i_nb_bytes;
 718     p_out->i_samples = out_buf.i_nb_samples;
 719
 720     if( p_block ) p_block->pf_release( p_block );
 721     return p_out;
 722 }