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     add_shortcut( "headphone" )
 105 vlc_module_end ()
 106
 107
 108 /*****************************************************************************
 109  * Internal data structures
 110  *****************************************************************************/
 111 struct atomic_operation_t
 112 {
 113     int i_source_channel_offset;
 114     int i_dest_channel_offset;
 115     unsigned int i_delay;/* in sample unit */
 116     double d_amplitude_factor;
 117 };
 118
 119 struct aout_filter_sys_t
 120 {
 121     size_t i_overflow_buffer_size;/* in bytes */
 122     uint8_t * p_overflow_buffer;
 123     unsigned int i_nb_atomic_operations;
 124     struct atomic_operation_t * p_atomic_operations;
 125 };
 126
 127 struct filter_sys_t
 128 {
 129     size_t i_overflow_buffer_size;/* in bytes */
 130     uint8_t * p_overflow_buffer;
 131     unsigned int i_nb_atomic_operations;
 132     struct atomic_operation_t * p_atomic_operations;
 133 };
 134
 135 /*****************************************************************************
 136  * Init: initialize internal data structures
 137  * and computes the needed atomic operations
 138  *****************************************************************************/
 139 /* x and z represent the coordinates of the virtual speaker
 140  *  relatively to the center of the listener's head, measured in meters :
 141  *
 142  *  left              right
 143  *Z
 144  *-
 145  *a          head
 146  *x
 147  *i
 148  *s
 149  *  rear left    rear right
 150  *
 151  *          x-axis
 152  *  */
 153 static void ComputeChannelOperations( struct aout_filter_sys_t * p_data
 154         , unsigned int i_rate, unsigned int i_next_atomic_operation
 155         , int i_source_channel_offset, double d_x, double d_z
 156         , double d_compensation_length, double d_channel_amplitude_factor )
 157 {
 158     double d_c = 340; /*sound celerity (unit: m/s)*/
 159     double d_compensation_delay = (d_compensation_length-0.1) / d_c * i_rate;
 160
 161     /* Left ear */
 162     p_data->p_atomic_operations[i_next_atomic_operation]
 163         .i_source_channel_offset = i_source_channel_offset;
 164     p_data->p_atomic_operations[i_next_atomic_operation]
 165         .i_dest_channel_offset = 0;/* left */
 166     p_data->p_atomic_operations[i_next_atomic_operation]
 167         .i_delay = (int)( sqrt( (-0.1-d_x)*(-0.1-d_x) + (0-d_z)*(0-d_z) )
 168                           / d_c * i_rate - d_compensation_delay );
 169     if( d_x < 0 )
 170     {
 171         p_data->p_atomic_operations[i_next_atomic_operation]
 172             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 173     }
 174     else if( d_x > 0 )
 175     {
 176         p_data->p_atomic_operations[i_next_atomic_operation]
 177             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 178     }
 179     else
 180     {
 181         p_data->p_atomic_operations[i_next_atomic_operation]
 182             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 183     }
 184
 185     /* Right ear */
 186     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 187         .i_source_channel_offset = i_source_channel_offset;
 188     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 189         .i_dest_channel_offset = 1;/* right */
 190     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 191         .i_delay = (int)( sqrt( (0.1-d_x)*(0.1-d_x) + (0-d_z)*(0-d_z) )
 192                           / d_c * i_rate - d_compensation_delay );
 193     if( d_x < 0 )
 194     {
 195         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 196             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 197     }
 198     else if( d_x > 0 )
 199     {
 200         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 201             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 202     }
 203     else
 204     {
 205         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 206             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 207     }
 208 }
 209
 210 static int Init( vlc_object_t *p_this, struct aout_filter_sys_t * p_data
 211         , unsigned int i_nb_channels, uint32_t i_physical_channels
 212         , unsigned int i_rate )
 213 {
 214     double d_x = config_GetInt( p_this, "headphone-dim" );
 215     double d_z = d_x;
 216     double d_z_rear = -d_x/3;
 217     double d_min = 0;
 218     unsigned int i_next_atomic_operation;
 219     int i_source_channel_offset;
 220     unsigned int i;
 221
 222     if( config_GetInt( p_this, "headphone-compensate" ) )
 223     {
 224         /* minimal distance to any speaker */
 225         if( i_physical_channels & AOUT_CHAN_REARCENTER )
 226         {
 227             d_min = d_z_rear;
 228         }
 229         else
 230         {
 231             d_min = d_z;
 232         }
 233     }
 234
 235     /* Number of elementary operations */
 236     p_data->i_nb_atomic_operations = i_nb_channels * 2;
 237     if( i_physical_channels & AOUT_CHAN_CENTER )
 238     {
 239         p_data->i_nb_atomic_operations += 2;
 240     }
 241     p_data->p_atomic_operations = malloc( sizeof(struct atomic_operation_t)
 242             * p_data->i_nb_atomic_operations );
 243     if( p_data->p_atomic_operations == NULL )
 244         return -1;
 245
 246     /* For each virtual speaker, computes elementary wave propagation time
 247      * to each ear */
 248     i_next_atomic_operation = 0;
 249     i_source_channel_offset = 0;
 250     if( i_physical_channels & AOUT_CHAN_LEFT )
 251     {
 252         ComputeChannelOperations( p_data , i_rate
 253                 , i_next_atomic_operation , i_source_channel_offset
 254                 , -d_x , d_z , d_min , 2.0 / i_nb_channels );
 255         i_next_atomic_operation += 2;
 256         i_source_channel_offset++;
 257     }
 258     if( i_physical_channels & AOUT_CHAN_RIGHT )
 259     {
 260         ComputeChannelOperations( p_data , i_rate
 261                 , i_next_atomic_operation , i_source_channel_offset
 262                 , d_x , d_z , d_min , 2.0 / i_nb_channels );
 263         i_next_atomic_operation += 2;
 264         i_source_channel_offset++;
 265     }
 266     if( i_physical_channels & AOUT_CHAN_MIDDLELEFT )
 267     {
 268         ComputeChannelOperations( p_data , i_rate
 269                 , i_next_atomic_operation , i_source_channel_offset
 270                 , -d_x , 0 , d_min , 1.5 / i_nb_channels );
 271         i_next_atomic_operation += 2;
 272         i_source_channel_offset++;
 273     }
 274     if( i_physical_channels & AOUT_CHAN_MIDDLERIGHT )
 275     {
 276         ComputeChannelOperations( p_data , i_rate
 277                 , i_next_atomic_operation , i_source_channel_offset
 278                 , d_x , 0 , d_min , 1.5 / i_nb_channels );
 279         i_next_atomic_operation += 2;
 280         i_source_channel_offset++;
 281     }
 282     if( i_physical_channels & AOUT_CHAN_REARLEFT )
 283     {
 284         ComputeChannelOperations( p_data , i_rate
 285                 , i_next_atomic_operation , i_source_channel_offset
 286                 , -d_x , d_z_rear , d_min , 1.5 / i_nb_channels );
 287         i_next_atomic_operation += 2;
 288         i_source_channel_offset++;
 289     }
 290     if( i_physical_channels & AOUT_CHAN_REARRIGHT )
 291     {
 292         ComputeChannelOperations( p_data , i_rate
 293                 , i_next_atomic_operation , i_source_channel_offset
 294                 , d_x , d_z_rear , d_min , 1.5 / i_nb_channels );
 295         i_next_atomic_operation += 2;
 296         i_source_channel_offset++;
 297     }
 298     if( i_physical_channels & AOUT_CHAN_REARCENTER )
 299     {
 300         ComputeChannelOperations( p_data , i_rate
 301                 , i_next_atomic_operation , i_source_channel_offset
 302                 , 0 , -d_z , d_min , 1.5 / i_nb_channels );
 303         i_next_atomic_operation += 2;
 304         i_source_channel_offset++;
 305     }
 306     if( i_physical_channels & AOUT_CHAN_CENTER )
 307     {
 308         /* having two center channels increases the spatialization effect */
 309         ComputeChannelOperations( p_data , i_rate
 310                 , i_next_atomic_operation , i_source_channel_offset
 311                 , d_x / 5.0 , d_z , d_min , 0.75 / i_nb_channels );
 312         i_next_atomic_operation += 2;
 313         ComputeChannelOperations( p_data , i_rate
 314                 , i_next_atomic_operation , i_source_channel_offset
 315                 , -d_x / 5.0 , d_z , d_min , 0.75 / i_nb_channels );
 316         i_next_atomic_operation += 2;
 317         i_source_channel_offset++;
 318     }
 319     if( i_physical_channels & AOUT_CHAN_LFE )
 320     {
 321         ComputeChannelOperations( p_data , i_rate
 322                 , i_next_atomic_operation , i_source_channel_offset
 323                 , 0 , d_z_rear , d_min , 5.0 / i_nb_channels );
 324         i_next_atomic_operation += 2;
 325         i_source_channel_offset++;
 326     }
 327
 328     /* Initialize the overflow buffer
 329      * we need it because the process induce a delay in the samples */
 330     p_data->i_overflow_buffer_size = 0;
 331     for( i = 0 ; i < p_data->i_nb_atomic_operations ; i++ )
 332     {
 333         if( p_data->i_overflow_buffer_size
 334                 < p_data->p_atomic_operations[i].i_delay * 2 * sizeof (float) )
 335         {
 336             p_data->i_overflow_buffer_size
 337                 = p_data->p_atomic_operations[i].i_delay * 2 * sizeof (float);
 338         }
 339     }
 340     p_data->p_overflow_buffer = malloc( p_data->i_overflow_buffer_size );
 341     if( p_data->p_overflow_buffer == NULL )
 342     {
 343         free( p_data->p_atomic_operations );
 344         return -1;
 345     }
 346     memset( p_data->p_overflow_buffer, 0 , p_data->i_overflow_buffer_size );
 347
 348     return 0;
 349 }
 350
 351 /*****************************************************************************
 352  * Create: allocate headphone downmixer
 353  *****************************************************************************/
 354 static int Create( vlc_object_t *p_this )
 355 {
 356     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 357     bool b_fit = true;
 358
 359     /* Activate this filter only with stereo devices */
 360     if( p_filter->output.i_physical_channels
 361             != (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT) )
 362     {
 363         msg_Dbg( p_filter, "filter discarded (incompatible format)" );
 364         return VLC_EGENERIC;
 365     }
 366
 367     /* Request a specific format if not already compatible */
 368     if( p_filter->input.i_original_channels
 369             != p_filter->output.i_original_channels )
 370     {
 371         b_fit = false;
 372         p_filter->input.i_original_channels =
 373                                         p_filter->output.i_original_channels;
 374     }
 375     if( p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
 376           || p_filter->output.i_format != VLC_FOURCC('f','l','3','2') )
 377     {
 378         b_fit = false;
 379         p_filter->input.i_format = VLC_FOURCC('f','l','3','2');
 380         p_filter->output.i_format = VLC_FOURCC('f','l','3','2');
 381     }
 382     if( p_filter->input.i_rate != p_filter->output.i_rate )
 383     {
 384         b_fit = false;
 385         p_filter->input.i_rate = p_filter->output.i_rate;
 386     }
 387     if( p_filter->input.i_physical_channels == (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT)
 388           && ( p_filter->input.i_original_channels & AOUT_CHAN_DOLBYSTEREO )
 389           && ! config_GetInt ( p_filter , "headphone-dolby" ) )
 390     {
 391         b_fit = false;
 392         p_filter->input.i_physical_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
 393                                               AOUT_CHAN_CENTER |
 394                                               AOUT_CHAN_REARLEFT |
 395                                               AOUT_CHAN_REARRIGHT;
 396     }
 397
 398     if( !b_fit )
 399     {
 400         msg_Dbg( p_filter, "requesting specific format" );
 401         return VLC_EGENERIC;
 402     }
 403
 404     /* Allocate the memory needed to store the module's structure */
 405     p_filter->p_sys = malloc( sizeof(struct aout_filter_sys_t) );
 406     if( p_filter->p_sys == NULL )
 407         return VLC_ENOMEM;
 408     p_filter->p_sys->i_overflow_buffer_size = 0;
 409     p_filter->p_sys->p_overflow_buffer = NULL;
 410     p_filter->p_sys->i_nb_atomic_operations = 0;
 411     p_filter->p_sys->p_atomic_operations = NULL;
 412
 413     if( Init( VLC_OBJECT(p_filter), p_filter->p_sys
 414                 , aout_FormatNbChannels ( &p_filter->input )
 415                 , p_filter->input.i_physical_channels
 416                 , p_filter->input.i_rate ) < 0 )
 417     {
 418         free( p_filter->p_sys );
 419         return VLC_EGENERIC;
 420     }
 421
 422     p_filter->pf_do_work = DoWork;
 423     p_filter->b_in_place = 0;
 424
 425     return VLC_SUCCESS;
 426 }
 427
 428 /*****************************************************************************
 429  * Destroy: deallocate resources associated with headphone downmixer
 430  *****************************************************************************/
 431 static void Destroy( vlc_object_t *p_this )
 432 {
 433     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 434
 435     if( p_filter->p_sys != NULL )
 436     {
 437         free( p_filter->p_sys->p_overflow_buffer );
 438         free( p_filter->p_sys->p_atomic_operations );
 439         free( p_filter->p_sys );
 440         p_filter->p_sys = NULL;
 441     }
 442 }
 443
 444 /*****************************************************************************
 445  * DoWork: convert a buffer
 446  *****************************************************************************/
 447 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 448                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 449 {
 450     VLC_UNUSED(p_aout);
 451     int i_input_nb = aout_FormatNbChannels( &p_filter->input );
 452     int i_output_nb = aout_FormatNbChannels( &p_filter->output );
 453
 454     float * p_in = (float*) p_in_buf->p_buffer;
 455     uint8_t * p_out;
 456     uint8_t * p_overflow;
 457     uint8_t * p_slide;
 458
 459     size_t i_overflow_size;     /* in bytes */
 460     size_t i_out_size;          /* in bytes */
 461
 462     unsigned int i, j;
 463
 464     int i_source_channel_offset;
 465     int i_dest_channel_offset;
 466     unsigned int i_delay;
 467     double d_amplitude_factor;
 468
 469     /* out buffer characterisitcs */
 470     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 471     p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * i_output_nb / i_input_nb;
 472     p_out = p_out_buf->p_buffer;
 473     i_out_size = p_out_buf->i_nb_bytes;
 474
 475     if( p_filter->p_sys != NULL )
 476     {
 477         /* Slide the overflow buffer */
 478         p_overflow = p_filter->p_sys->p_overflow_buffer;
 479         i_overflow_size = p_filter->p_sys->i_overflow_buffer_size;
 480
 481         memset( p_out, 0, i_out_size );
 482         if ( i_out_size > i_overflow_size )
 483             memcpy( p_out, p_overflow, i_overflow_size );
 484         else
 485             memcpy( p_out, p_overflow, i_out_size );
 486
 487         p_slide = p_filter->p_sys->p_overflow_buffer;
 488         while( p_slide < p_overflow + i_overflow_size )
 489         {
 490             if( p_slide + i_out_size < p_overflow + i_overflow_size )
 491             {
 492                 memset( p_slide, 0, i_out_size );
 493                 if( p_slide + 2 * i_out_size < p_overflow + i_overflow_size )
 494                     memcpy( p_slide, p_slide + i_out_size, i_out_size );
 495                 else
 496                     memcpy( p_slide, p_slide + i_out_size,
 497                             p_overflow + i_overflow_size - ( p_slide + i_out_size ) );
 498             }
 499             else
 500             {
 501                 memset( p_slide, 0, p_overflow + i_overflow_size - p_slide );
 502             }
 503             p_slide += i_out_size;
 504         }
 505
 506         /* apply the atomic operations */
 507         for( i = 0; i < p_filter->p_sys->i_nb_atomic_operations; i++ )
 508         {
 509             /* shorter variable names */
 510             i_source_channel_offset
 511                 = p_filter->p_sys->p_atomic_operations[i].i_source_channel_offset;
 512             i_dest_channel_offset
 513                 = p_filter->p_sys->p_atomic_operations[i].i_dest_channel_offset;
 514             i_delay = p_filter->p_sys->p_atomic_operations[i].i_delay;
 515             d_amplitude_factor
 516                 = p_filter->p_sys->p_atomic_operations[i].d_amplitude_factor;
 517
 518             if( p_out_buf->i_nb_samples > i_delay )
 519             {
 520                 /* current buffer coefficients */
 521                 for( j = 0; j < p_out_buf->i_nb_samples - i_delay; j++ )
 522                 {
 523                     ((float*)p_out)[ (i_delay+j)*i_output_nb + i_dest_channel_offset ]
 524                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 525                            * d_amplitude_factor;
 526                 }
 527
 528                 /* overflow buffer coefficients */
 529                 for( j = 0; j < i_delay; j++ )
 530                 {
 531                     ((float*)p_overflow)[ j*i_output_nb + i_dest_channel_offset ]
 532                         += p_in[ (p_out_buf->i_nb_samples - i_delay + j)
 533                            * i_input_nb + i_source_channel_offset ]
 534                            * d_amplitude_factor;
 535                 }
 536             }
 537             else
 538             {
 539                 /* overflow buffer coefficients only */
 540                 for( j = 0; j < p_out_buf->i_nb_samples; j++ )
 541                 {
 542                     ((float*)p_overflow)[ (i_delay - p_out_buf->i_nb_samples + j)
 543                         * i_output_nb + i_dest_channel_offset ]
 544                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 545                            * d_amplitude_factor;
 546                 }
 547             }
 548         }
 549     }
 550     else
 551     {
 552         memset( p_out, 0, i_out_size );
 553     }
 554 }
 555
 556 /*
 557  * Audio filter 2
 558  */
 559 /*****************************************************************************
 560  * OpenFilter:
 561  *****************************************************************************/
 562 static int OpenFilter( vlc_object_t *p_this )
 563 {
 564     filter_t *p_filter = (filter_t *)p_this;
 565     bool b_fit = true;
 566
 567     /* Activate this filter only with stereo devices */
 568     if( p_filter->fmt_out.audio.i_physical_channels
 569             != (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT) )
 570     {
 571         msg_Dbg( p_filter, "filter discarded (incompatible format)" );
 572         return VLC_EGENERIC;
 573     }
 574
 575     /* Request a specific format if not already compatible */
 576     if( p_filter->fmt_in.audio.i_original_channels
 577             != p_filter->fmt_out.audio.i_original_channels )
 578     {
 579         b_fit = false;
 580         p_filter->fmt_in.audio.i_original_channels =
 581                                         p_filter->fmt_out.audio.i_original_channels;
 582     }
 583     if( p_filter->fmt_in.audio.i_format != VLC_FOURCC('f','l','3','2')
 584           || p_filter->fmt_out.audio.i_format != VLC_FOURCC('f','l','3','2') )
 585     {
 586         b_fit = false;
 587         p_filter->fmt_in.audio.i_format = VLC_FOURCC('f','l','3','2');
 588         p_filter->fmt_out.audio.i_format = VLC_FOURCC('f','l','3','2');
 589     }
 590     if( p_filter->fmt_in.audio.i_rate != p_filter->fmt_out.audio.i_rate )
 591     {
 592         b_fit = false;
 593         p_filter->fmt_in.audio.i_rate = p_filter->fmt_out.audio.i_rate;
 594     }
 595     if( p_filter->fmt_in.audio.i_physical_channels == (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT)
 596           && ( p_filter->fmt_in.audio.i_original_channels & AOUT_CHAN_DOLBYSTEREO )
 597           && !config_GetInt( p_filter, "headphone-dolby" ) )
 598     {
 599         b_fit = false;
 600         p_filter->fmt_in.audio.i_physical_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
 601                                               AOUT_CHAN_CENTER |
 602                                               AOUT_CHAN_REARLEFT |
 603                                               AOUT_CHAN_REARRIGHT;
 604     }
 605     if( !b_fit )
 606     {
 607         msg_Dbg( p_filter, "requesting specific format" );
 608         return VLC_EGENERIC;
 609     }
 610
 611     /* Allocate the memory needed to store the module's structure */
 612     p_filter->p_sys = malloc( sizeof(struct filter_sys_t) );
 613     if( p_filter->p_sys == NULL )
 614         return VLC_ENOMEM;
 615     p_filter->p_sys->i_overflow_buffer_size = 0;
 616     p_filter->p_sys->p_overflow_buffer = NULL;
 617     p_filter->p_sys->i_nb_atomic_operations = 0;
 618     p_filter->p_sys->p_atomic_operations = NULL;
 619
 620     if( Init( VLC_OBJECT(p_filter), (struct aout_filter_sys_t *)p_filter->p_sys
 621                 , aout_FormatNbChannels ( &(p_filter->fmt_in.audio) )
 622                 , p_filter->fmt_in.audio.i_physical_channels
 623                 , p_filter->fmt_in.audio.i_rate ) < 0 )
 624     {
 625         free( p_filter->p_sys );
 626         return VLC_EGENERIC;
 627     }
 628
 629     p_filter->pf_audio_filter = Convert;
 630     p_filter->fmt_out.audio.i_rate = p_filter->fmt_in.audio.i_rate;
 631
 632     return VLC_SUCCESS;
 633 }
 634
 635 /*****************************************************************************
 636  * CloseFilter : deallocate data structures
 637  *****************************************************************************/
 638 static void CloseFilter( vlc_object_t *p_this )
 639 {
 640     filter_t *p_filter = (filter_t *)p_this;
 641
 642     if( p_filter->p_sys != NULL )
 643     {
 644         free( p_filter->p_sys->p_overflow_buffer );
 645         free( p_filter->p_sys->p_atomic_operations );
 646         free( p_filter->p_sys );
 647         p_filter->p_sys = NULL;
 648     }
 649 }
 650
 651 static block_t *Convert( filter_t *p_filter, block_t *p_block )
 652 {
 653     aout_filter_t aout_filter;
 654     aout_buffer_t in_buf, out_buf;
 655     block_t *p_out;
 656     int i_out_size;
 657
 658     if( !p_block || !p_block->i_samples )
 659     {
 660         if( p_block )
 661             block_Release( p_block );
 662         return NULL;
 663     }
 664
 665     i_out_size = p_block->i_samples *
 666       p_filter->fmt_out.audio.i_bitspersample/8 *
 667         aout_FormatNbChannels( &(p_filter->fmt_out.audio) );
 668
 669     p_out = p_filter->pf_audio_buffer_new( p_filter, i_out_size );
 670     if( !p_out )
 671     {
 672         msg_Warn( p_filter, "can't get output buffer" );
 673         block_Release( p_block );
 674         return NULL;
 675     }
 676
 677     p_out->i_samples = p_block->i_samples;
 678     p_out->i_dts = p_block->i_dts;
 679     p_out->i_pts = p_block->i_pts;
 680     p_out->i_length = p_block->i_length;
 681
 682     aout_filter.p_sys = (struct aout_filter_sys_t *)p_filter->p_sys;
 683     aout_filter.input = p_filter->fmt_in.audio;
 684     aout_filter.input.i_format = p_filter->fmt_in.i_codec;
 685     aout_filter.output = p_filter->fmt_out.audio;
 686     aout_filter.output.i_format = p_filter->fmt_out.i_codec;
 687     aout_filter.b_in_place = 0;
 688
 689     in_buf.p_buffer = p_block->p_buffer;
 690     in_buf.i_nb_bytes = p_block->i_buffer;
 691     in_buf.i_nb_samples = p_block->i_samples;
 692     out_buf.p_buffer = p_out->p_buffer;
 693     out_buf.i_nb_bytes = p_out->i_buffer;
 694     out_buf.i_nb_samples = p_out->i_samples;
 695
 696     DoWork( (aout_instance_t *)p_filter, &aout_filter, &in_buf, &out_buf );
 697
 698     p_out->i_buffer = out_buf.i_nb_bytes;
 699     p_out->i_samples = out_buf.i_nb_samples;
 700
 701     block_Release( p_block );
 702     return p_out;
 703 }