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
  29 #ifdef HAVE_CONFIG_H
  30 # include "config.h"
  31 #endif
  32
  33 #include <math.h>                                        /* sqrt */
  34
  35 #include <vlc_common.h>
  36 #include <vlc_plugin.h>
  37 #include <vlc_aout.h>
  38 #include <vlc_filter.h>
  39 #include <vlc_block.h>
  40
  41 /*****************************************************************************
  42  * Local prototypes
  43  *****************************************************************************/
  44 static int  Create    ( vlc_object_t * );
  45 static void Destroy   ( vlc_object_t * );
  46
  47 static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  48                         aout_buffer_t * );
  49
  50 /* Audio filter2 */
  51 static int  OpenFilter ( vlc_object_t * );
  52 static void CloseFilter( vlc_object_t * );
  53 static block_t *Convert( filter_t *, block_t * );
  54
  55 /*****************************************************************************
  56  * Module descriptor
  57  *****************************************************************************/
  58 #define MODULE_DESCRIPTION N_ ( \
  59      "This effect gives you the feeling that you are standing in a room " \
  60      "with a complete 7.1 speaker set when using only a headphone, " \
  61      "providing a more realistic sound experience. It should also be " \
  62      "more comfortable and less tiring when listening to music for " \
  63      "long periods of time.\nIt works with any source format from mono " \
  64      "to 7.1.")
  65
  66 #define HEADPHONE_DIM_TEXT N_("Characteristic dimension")
  67 #define HEADPHONE_DIM_LONGTEXT N_( \
  68      "Distance between front left speaker and listener in meters.")
  69
  70 #define HEADPHONE_COMPENSATE_TEXT N_("Compensate delay")
  71 #define HEADPHONE_COMPENSATE_LONGTEXT N_( \
  72      "The delay which is introduced by the physical algorithm may "\
  73      "sometimes be disturbing for the synchronization between lips-movement "\
  74      "and speech. In case, turn this on to compensate.")
  75
  76 #define HEADPHONE_DOLBY_TEXT N_("No decoding of Dolby Surround")
  77 #define HEADPHONE_DOLBY_LONGTEXT N_( \
  78      "Dolby Surround encoded streams won't be decoded before being " \
  79      "processed by this filter. Enabling this setting is not recommended.")
  80
  81 vlc_module_begin ()
  82     set_description( N_("Headphone virtual spatialization effect") )
  83     set_shortname( N_("Headphone effect") )
  84     set_help( MODULE_DESCRIPTION )
  85     set_category( CAT_AUDIO )
  86     set_subcategory( SUBCAT_AUDIO_AFILTER )
  87
  88     add_integer( "headphone-dim", 10, NULL, HEADPHONE_DIM_TEXT,
  89                  HEADPHONE_DIM_LONGTEXT, false );
  90     add_bool( "headphone-compensate", 0, NULL, HEADPHONE_COMPENSATE_TEXT,
  91               HEADPHONE_COMPENSATE_LONGTEXT, true );
  92     add_bool( "headphone-dolby", 0, NULL, HEADPHONE_DOLBY_TEXT,
  93               HEADPHONE_DOLBY_LONGTEXT, true );
  94
  95     set_capability( "audio filter", 0 )
  96     set_callbacks( Create, Destroy )
  97     add_shortcut( "headphone" )
  98
  99     /* Audio filter 2 */
 100     add_submodule ()
 101     set_description( N_("Headphone virtual spatialization effect") )
 102     set_capability( "audio filter2", 0 )
 103     set_callbacks( OpenFilter, CloseFilter )
 104 vlc_module_end ()
 105
 106
 107 /*****************************************************************************
 108  * Internal data structures
 109  *****************************************************************************/
 110 struct atomic_operation_t
 111 {
 112     int i_source_channel_offset;
 113     int i_dest_channel_offset;
 114     unsigned int i_delay;/* in sample unit */
 115     double d_amplitude_factor;
 116 };
 117
 118 struct aout_filter_sys_t
 119 {
 120     size_t i_overflow_buffer_size;/* in bytes */
 121     uint8_t * p_overflow_buffer;
 122     unsigned int i_nb_atomic_operations;
 123     struct atomic_operation_t * p_atomic_operations;
 124 };
 125
 126 struct filter_sys_t
 127 {
 128     size_t i_overflow_buffer_size;/* in bytes */
 129     uint8_t * p_overflow_buffer;
 130     unsigned int i_nb_atomic_operations;
 131     struct atomic_operation_t * p_atomic_operations;
 132 };
 133
 134 /*****************************************************************************
 135  * Init: initialize internal data structures
 136  * and computes the needed atomic operations
 137  *****************************************************************************/
 138 /* x and z represent the coordinates of the virtual speaker
 139  *  relatively to the center of the listener's head, measured in meters :
 140  *
 141  *  left              right
 142  *Z
 143  *-
 144  *a          head
 145  *x
 146  *i
 147  *s
 148  *  rear left    rear right
 149  *
 150  *          x-axis
 151  *  */
 152 static void ComputeChannelOperations( struct aout_filter_sys_t * p_data
 153         , unsigned int i_rate, unsigned int i_next_atomic_operation
 154         , int i_source_channel_offset, double d_x, double d_z
 155         , double d_compensation_length, double d_channel_amplitude_factor )
 156 {
 157     double d_c = 340; /*sound celerity (unit: m/s)*/
 158     double d_compensation_delay = (d_compensation_length-0.1) / d_c * i_rate;
 159
 160     /* Left ear */
 161     p_data->p_atomic_operations[i_next_atomic_operation]
 162         .i_source_channel_offset = i_source_channel_offset;
 163     p_data->p_atomic_operations[i_next_atomic_operation]
 164         .i_dest_channel_offset = 0;/* left */
 165     p_data->p_atomic_operations[i_next_atomic_operation]
 166         .i_delay = (int)( sqrt( (-0.1-d_x)*(-0.1-d_x) + (0-d_z)*(0-d_z) )
 167                           / d_c * i_rate - d_compensation_delay );
 168     if( d_x < 0 )
 169     {
 170         p_data->p_atomic_operations[i_next_atomic_operation]
 171             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 172     }
 173     else if( d_x > 0 )
 174     {
 175         p_data->p_atomic_operations[i_next_atomic_operation]
 176             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 177     }
 178     else
 179     {
 180         p_data->p_atomic_operations[i_next_atomic_operation]
 181             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 182     }
 183
 184     /* Right ear */
 185     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 186         .i_source_channel_offset = i_source_channel_offset;
 187     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 188         .i_dest_channel_offset = 1;/* right */
 189     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 190         .i_delay = (int)( sqrt( (0.1-d_x)*(0.1-d_x) + (0-d_z)*(0-d_z) )
 191                           / d_c * i_rate - d_compensation_delay );
 192     if( d_x < 0 )
 193     {
 194         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 195             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 196     }
 197     else if( d_x > 0 )
 198     {
 199         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 200             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 201     }
 202     else
 203     {
 204         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 205             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 206     }
 207 }
 208
 209 static int Init( vlc_object_t *p_this, struct aout_filter_sys_t * p_data
 210         , unsigned int i_nb_channels, uint32_t i_physical_channels
 211         , unsigned int i_rate )
 212 {
 213     double d_x = config_GetInt( p_this, "headphone-dim" );
 214     double d_z = d_x;
 215     double d_z_rear = -d_x/3;
 216     double d_min = 0;
 217     unsigned int i_next_atomic_operation;
 218     int i_source_channel_offset;
 219     unsigned int i;
 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         return -1;
 244
 245     /* For each virtual speaker, computes elementary wave propagation time
 246      * to each ear */
 247     i_next_atomic_operation = 0;
 248     i_source_channel_offset = 0;
 249     if( i_physical_channels & AOUT_CHAN_LEFT )
 250     {
 251         ComputeChannelOperations( p_data , i_rate
 252                 , i_next_atomic_operation , i_source_channel_offset
 253                 , -d_x , d_z , d_min , 2.0 / i_nb_channels );
 254         i_next_atomic_operation += 2;
 255         i_source_channel_offset++;
 256     }
 257     if( i_physical_channels & AOUT_CHAN_RIGHT )
 258     {
 259         ComputeChannelOperations( p_data , i_rate
 260                 , i_next_atomic_operation , i_source_channel_offset
 261                 , d_x , d_z , d_min , 2.0 / i_nb_channels );
 262         i_next_atomic_operation += 2;
 263         i_source_channel_offset++;
 264     }
 265     if( i_physical_channels & AOUT_CHAN_MIDDLELEFT )
 266     {
 267         ComputeChannelOperations( p_data , i_rate
 268                 , i_next_atomic_operation , i_source_channel_offset
 269                 , -d_x , 0 , d_min , 1.5 / i_nb_channels );
 270         i_next_atomic_operation += 2;
 271         i_source_channel_offset++;
 272     }
 273     if( i_physical_channels & AOUT_CHAN_MIDDLERIGHT )
 274     {
 275         ComputeChannelOperations( p_data , i_rate
 276                 , i_next_atomic_operation , i_source_channel_offset
 277                 , d_x , 0 , d_min , 1.5 / i_nb_channels );
 278         i_next_atomic_operation += 2;
 279         i_source_channel_offset++;
 280     }
 281     if( i_physical_channels & AOUT_CHAN_REARLEFT )
 282     {
 283         ComputeChannelOperations( p_data , i_rate
 284                 , i_next_atomic_operation , i_source_channel_offset
 285                 , -d_x , d_z_rear , d_min , 1.5 / i_nb_channels );
 286         i_next_atomic_operation += 2;
 287         i_source_channel_offset++;
 288     }
 289     if( i_physical_channels & AOUT_CHAN_REARRIGHT )
 290     {
 291         ComputeChannelOperations( p_data , i_rate
 292                 , i_next_atomic_operation , i_source_channel_offset
 293                 , d_x , d_z_rear , d_min , 1.5 / i_nb_channels );
 294         i_next_atomic_operation += 2;
 295         i_source_channel_offset++;
 296     }
 297     if( i_physical_channels & AOUT_CHAN_REARCENTER )
 298     {
 299         ComputeChannelOperations( p_data , i_rate
 300                 , i_next_atomic_operation , i_source_channel_offset
 301                 , 0 , -d_z , d_min , 1.5 / i_nb_channels );
 302         i_next_atomic_operation += 2;
 303         i_source_channel_offset++;
 304     }
 305     if( i_physical_channels & AOUT_CHAN_CENTER )
 306     {
 307         /* having two center channels increases the spatialization effect */
 308         ComputeChannelOperations( p_data , i_rate
 309                 , i_next_atomic_operation , i_source_channel_offset
 310                 , d_x / 5.0 , d_z , d_min , 0.75 / i_nb_channels );
 311         i_next_atomic_operation += 2;
 312         ComputeChannelOperations( p_data , i_rate
 313                 , i_next_atomic_operation , i_source_channel_offset
 314                 , -d_x / 5.0 , d_z , d_min , 0.75 / i_nb_channels );
 315         i_next_atomic_operation += 2;
 316         i_source_channel_offset++;
 317     }
 318     if( i_physical_channels & AOUT_CHAN_LFE )
 319     {
 320         ComputeChannelOperations( p_data , i_rate
 321                 , i_next_atomic_operation , i_source_channel_offset
 322                 , 0 , d_z_rear , d_min , 5.0 / i_nb_channels );
 323         i_next_atomic_operation += 2;
 324         i_source_channel_offset++;
 325     }
 326
 327     /* Initialize the overflow buffer
 328      * we need it because the process induce a delay in the samples */
 329     p_data->i_overflow_buffer_size = 0;
 330     for( i = 0 ; i < p_data->i_nb_atomic_operations ; i++ )
 331     {
 332         if( p_data->i_overflow_buffer_size
 333                 < p_data->p_atomic_operations[i].i_delay * 2 * sizeof (float) )
 334         {
 335             p_data->i_overflow_buffer_size
 336                 = p_data->p_atomic_operations[i].i_delay * 2 * sizeof (float);
 337         }
 338     }
 339     p_data->p_overflow_buffer = malloc( p_data->i_overflow_buffer_size );
 340     if( p_data->p_overflow_buffer == NULL )
 341     {
 342         free( p_data->p_atomic_operations );
 343         return -1;
 344     }
 345     memset( p_data->p_overflow_buffer, 0 , p_data->i_overflow_buffer_size );
 346
 347     return 0;
 348 }
 349
 350 /*****************************************************************************
 351  * Create: allocate headphone downmixer
 352  *****************************************************************************/
 353 static int Create( vlc_object_t *p_this )
 354 {
 355     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 356     bool b_fit = true;
 357
 358     /* Activate this filter only with stereo devices */
 359     if( p_filter->output.i_physical_channels
 360             != (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT) )
 361     {
 362         msg_Dbg( p_filter, "filter discarded (incompatible format)" );
 363         return VLC_EGENERIC;
 364     }
 365
 366     /* Request a specific format if not already compatible */
 367     if( p_filter->input.i_original_channels
 368             != p_filter->output.i_original_channels )
 369     {
 370         b_fit = false;
 371         p_filter->input.i_original_channels =
 372                                         p_filter->output.i_original_channels;
 373     }
 374     if( p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
 375           || p_filter->output.i_format != VLC_FOURCC('f','l','3','2') )
 376     {
 377         b_fit = false;
 378         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     if( p_filter->input.i_rate != p_filter->output.i_rate )
 382     {
 383         b_fit = false;
 384         p_filter->input.i_rate = p_filter->output.i_rate;
 385     }
 386     if( p_filter->input.i_physical_channels == (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT)
 387           && ( p_filter->input.i_original_channels & AOUT_CHAN_DOLBYSTEREO )
 388           && ! config_GetInt ( p_filter , "headphone-dolby" ) )
 389     {
 390         b_fit = false;
 391         p_filter->input.i_physical_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
 392                                               AOUT_CHAN_CENTER |
 393                                               AOUT_CHAN_REARLEFT |
 394                                               AOUT_CHAN_REARRIGHT;
 395     }
 396
 397     if( !b_fit )
 398     {
 399         msg_Dbg( p_filter, "requesting specific format" );
 400         return VLC_EGENERIC;
 401     }
 402
 403     /* Allocate the memory needed to store the module's structure */
 404     p_filter->p_sys = malloc( sizeof(struct aout_filter_sys_t) );
 405     if( p_filter->p_sys == NULL )
 406         return VLC_ENOMEM;
 407     p_filter->p_sys->i_overflow_buffer_size = 0;
 408     p_filter->p_sys->p_overflow_buffer = NULL;
 409     p_filter->p_sys->i_nb_atomic_operations = 0;
 410     p_filter->p_sys->p_atomic_operations = NULL;
 411
 412     if( Init( VLC_OBJECT(p_filter), p_filter->p_sys
 413                 , aout_FormatNbChannels ( &p_filter->input )
 414                 , p_filter->input.i_physical_channels
 415                 , p_filter->input.i_rate ) < 0 )
 416     {
 417         free( p_filter->p_sys );
 418         return VLC_EGENERIC;
 419     }
 420
 421     p_filter->pf_do_work = DoWork;
 422     p_filter->b_in_place = 0;
 423
 424     return VLC_SUCCESS;
 425 }
 426
 427 /*****************************************************************************
 428  * Destroy: deallocate resources associated with headphone downmixer
 429  *****************************************************************************/
 430 static void Destroy( vlc_object_t *p_this )
 431 {
 432     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 433
 434     if( p_filter->p_sys != NULL )
 435     {
 436         free( p_filter->p_sys->p_overflow_buffer );
 437         free( p_filter->p_sys->p_atomic_operations );
 438         free( p_filter->p_sys );
 439         p_filter->p_sys = NULL;
 440     }
 441 }
 442
 443 /*****************************************************************************
 444  * DoWork: convert a buffer
 445  *****************************************************************************/
 446 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 447                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 448 {
 449     VLC_UNUSED(p_aout);
 450     int i_input_nb = aout_FormatNbChannels( &p_filter->input );
 451     int i_output_nb = aout_FormatNbChannels( &p_filter->output );
 452
 453     float * p_in = (float*) p_in_buf->p_buffer;
 454     uint8_t * p_out;
 455     uint8_t * p_overflow;
 456     uint8_t * p_slide;
 457
 458     size_t i_overflow_size;     /* in bytes */
 459     size_t i_out_size;          /* in bytes */
 460
 461     unsigned int i, j;
 462
 463     int i_source_channel_offset;
 464     int i_dest_channel_offset;
 465     unsigned int i_delay;
 466     double d_amplitude_factor;
 467
 468     /* out buffer characterisitcs */
 469     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 470     p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * i_output_nb / i_input_nb;
 471     p_out = p_out_buf->p_buffer;
 472     i_out_size = p_out_buf->i_nb_bytes;
 473
 474     if( p_filter->p_sys != NULL )
 475     {
 476         /* Slide the overflow buffer */
 477         p_overflow = p_filter->p_sys->p_overflow_buffer;
 478         i_overflow_size = p_filter->p_sys->i_overflow_buffer_size;
 479
 480         memset( p_out, 0, i_out_size );
 481         if ( i_out_size > i_overflow_size )
 482             memcpy( p_out, p_overflow, i_overflow_size );
 483         else
 484             memcpy( p_out, p_overflow, i_out_size );
 485
 486         p_slide = p_filter->p_sys->p_overflow_buffer;
 487         while( p_slide < p_overflow + i_overflow_size )
 488         {
 489             if( p_slide + i_out_size < p_overflow + i_overflow_size )
 490             {
 491                 memset( p_slide, 0, i_out_size );
 492                 if( p_slide + 2 * i_out_size < p_overflow + i_overflow_size )
 493                     memcpy( p_slide, p_slide + i_out_size, i_out_size );
 494                 else
 495                     memcpy( p_slide, p_slide + i_out_size,
 496                             p_overflow + i_overflow_size - ( p_slide + i_out_size ) );
 497             }
 498             else
 499             {
 500                 memset( p_slide, 0, p_overflow + i_overflow_size - p_slide );
 501             }
 502             p_slide += i_out_size;
 503         }
 504
 505         /* apply the atomic operations */
 506         for( i = 0; i < p_filter->p_sys->i_nb_atomic_operations; i++ )
 507         {
 508             /* shorter variable names */
 509             i_source_channel_offset
 510                 = p_filter->p_sys->p_atomic_operations[i].i_source_channel_offset;
 511             i_dest_channel_offset
 512                 = p_filter->p_sys->p_atomic_operations[i].i_dest_channel_offset;
 513             i_delay = p_filter->p_sys->p_atomic_operations[i].i_delay;
 514             d_amplitude_factor
 515                 = p_filter->p_sys->p_atomic_operations[i].d_amplitude_factor;
 516
 517             if( p_out_buf->i_nb_samples > i_delay )
 518             {
 519                 /* current buffer coefficients */
 520                 for( j = 0; j < p_out_buf->i_nb_samples - i_delay; j++ )
 521                 {
 522                     ((float*)p_out)[ (i_delay+j)*i_output_nb + i_dest_channel_offset ]
 523                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 524                            * d_amplitude_factor;
 525                 }
 526
 527                 /* overflow buffer coefficients */
 528                 for( j = 0; j < i_delay; j++ )
 529                 {
 530                     ((float*)p_overflow)[ j*i_output_nb + i_dest_channel_offset ]
 531                         += p_in[ (p_out_buf->i_nb_samples - i_delay + j)
 532                            * i_input_nb + i_source_channel_offset ]
 533                            * d_amplitude_factor;
 534                 }
 535             }
 536             else
 537             {
 538                 /* overflow buffer coefficients only */
 539                 for( j = 0; j < p_out_buf->i_nb_samples; j++ )
 540                 {
 541                     ((float*)p_overflow)[ (i_delay - p_out_buf->i_nb_samples + j)
 542                         * i_output_nb + i_dest_channel_offset ]
 543                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 544                            * d_amplitude_factor;
 545                 }
 546             }
 547         }
 548     }
 549     else
 550     {
 551         memset( p_out, 0, i_out_size );
 552     }
 553 }
 554
 555 /*
 556  * Audio filter 2
 557  */
 558 /*****************************************************************************
 559  * OpenFilter:
 560  *****************************************************************************/
 561 static int OpenFilter( vlc_object_t *p_this )
 562 {
 563     filter_t *p_filter = (filter_t *)p_this;
 564     bool b_fit = true;
 565
 566     /* Activate this filter only with stereo devices */
 567     if( p_filter->fmt_out.audio.i_physical_channels
 568             != (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT) )
 569     {
 570         msg_Dbg( p_filter, "filter discarded (incompatible format)" );
 571         return VLC_EGENERIC;
 572     }
 573
 574     /* Request a specific format if not already compatible */
 575     if( p_filter->fmt_in.audio.i_original_channels
 576             != p_filter->fmt_out.audio.i_original_channels )
 577     {
 578         b_fit = false;
 579         p_filter->fmt_in.audio.i_original_channels =
 580                                         p_filter->fmt_out.audio.i_original_channels;
 581     }
 582     if( p_filter->fmt_in.audio.i_format != VLC_FOURCC('f','l','3','2')
 583           || p_filter->fmt_out.audio.i_format != VLC_FOURCC('f','l','3','2') )
 584     {
 585         b_fit = false;
 586         p_filter->fmt_in.audio.i_format = VLC_FOURCC('f','l','3','2');
 587         p_filter->fmt_out.audio.i_format = VLC_FOURCC('f','l','3','2');
 588     }
 589     if( p_filter->fmt_in.audio.i_rate != p_filter->fmt_out.audio.i_rate )
 590     {
 591         b_fit = false;
 592         p_filter->fmt_in.audio.i_rate = p_filter->fmt_out.audio.i_rate;
 593     }
 594     if( p_filter->fmt_in.audio.i_physical_channels == (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT)
 595           && ( p_filter->fmt_in.audio.i_original_channels & AOUT_CHAN_DOLBYSTEREO )
 596           && !config_GetInt( p_filter, "headphone-dolby" ) )
 597     {
 598         b_fit = false;
 599         p_filter->fmt_in.audio.i_physical_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
 600                                               AOUT_CHAN_CENTER |
 601                                               AOUT_CHAN_REARLEFT |
 602                                               AOUT_CHAN_REARRIGHT;
 603     }
 604     if( !b_fit )
 605     {
 606         msg_Dbg( p_filter, "requesting specific format" );
 607         return VLC_EGENERIC;
 608     }
 609
 610     /* Allocate the memory needed to store the module's structure */
 611     p_filter->p_sys = malloc( sizeof(struct filter_sys_t) );
 612     if( p_filter->p_sys == NULL )
 613         return VLC_ENOMEM;
 614     p_filter->p_sys->i_overflow_buffer_size = 0;
 615     p_filter->p_sys->p_overflow_buffer = NULL;
 616     p_filter->p_sys->i_nb_atomic_operations = 0;
 617     p_filter->p_sys->p_atomic_operations = NULL;
 618
 619     if( Init( VLC_OBJECT(p_filter), (struct aout_filter_sys_t *)p_filter->p_sys
 620                 , aout_FormatNbChannels ( &(p_filter->fmt_in.audio) )
 621                 , p_filter->fmt_in.audio.i_physical_channels
 622                 , p_filter->fmt_in.audio.i_rate ) < 0 )
 623     {
 624         free( p_filter->p_sys );
 625         return VLC_EGENERIC;
 626     }
 627
 628     p_filter->pf_audio_filter = Convert;
 629     p_filter->fmt_out.audio.i_rate = p_filter->fmt_in.audio.i_rate;
 630
 631     return VLC_SUCCESS;
 632 }
 633
 634 /*****************************************************************************
 635  * CloseFilter : deallocate data structures
 636  *****************************************************************************/
 637 static void CloseFilter( vlc_object_t *p_this )
 638 {
 639     filter_t *p_filter = (filter_t *)p_this;
 640
 641     if( p_filter->p_sys != NULL )
 642     {
 643         free( p_filter->p_sys->p_overflow_buffer );
 644         free( p_filter->p_sys->p_atomic_operations );
 645         free( p_filter->p_sys );
 646         p_filter->p_sys = NULL;
 647     }
 648 }
 649
 650 static block_t *Convert( filter_t *p_filter, block_t *p_block )
 651 {
 652     aout_filter_t aout_filter;
 653     aout_buffer_t in_buf, out_buf;
 654     block_t *p_out;
 655     int i_out_size;
 656
 657     if( !p_block || !p_block->i_samples )
 658     {
 659         if( p_block )
 660             block_Release( p_block );
 661         return NULL;
 662     }
 663
 664     i_out_size = p_block->i_samples *
 665       p_filter->fmt_out.audio.i_bitspersample/8 *
 666         aout_FormatNbChannels( &(p_filter->fmt_out.audio) );
 667
 668     p_out = p_filter->pf_audio_buffer_new( p_filter, i_out_size );
 669     if( !p_out )
 670     {
 671         msg_Warn( p_filter, "can't get output buffer" );
 672         block_Release( p_block );
 673         return NULL;
 674     }
 675
 676     p_out->i_samples = p_block->i_samples;
 677     p_out->i_dts = p_block->i_dts;
 678     p_out->i_pts = p_block->i_pts;
 679     p_out->i_length = p_block->i_length;
 680
 681     aout_filter.p_sys = (struct aout_filter_sys_t *)p_filter->p_sys;
 682     aout_filter.input = p_filter->fmt_in.audio;
 683     aout_filter.input.i_format = p_filter->fmt_in.i_codec;
 684     aout_filter.output = p_filter->fmt_out.audio;
 685     aout_filter.output.i_format = p_filter->fmt_out.i_codec;
 686     aout_filter.b_in_place = 0;
 687
 688     in_buf.p_buffer = p_block->p_buffer;
 689     in_buf.i_nb_bytes = p_block->i_buffer;
 690     in_buf.i_nb_samples = p_block->i_samples;
 691     out_buf.p_buffer = p_out->p_buffer;
 692     out_buf.i_nb_bytes = p_out->i_buffer;
 693     out_buf.i_nb_samples = p_out->i_samples;
 694
 695     DoWork( (aout_instance_t *)p_filter, &aout_filter, &in_buf, &out_buf );
 696
 697     p_out->i_buffer = out_buf.i_nb_bytes;
 698     p_out->i_samples = out_buf.i_nb_samples;
 699
 700     block_Release( p_block );
 701     return p_out;
 702 }