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) 2002-2005 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
  36 /*****************************************************************************
  37  * Local prototypes
  38  *****************************************************************************/
  39 static int  Create    ( vlc_object_t * );
  40 static void Destroy   ( vlc_object_t * );
  41
  42 static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  43                         aout_buffer_t * );
  44
  45 /*****************************************************************************
  46  * Module descriptor
  47  *****************************************************************************/
  48 #define MODULE_DESCRIPTION N_ ( \
  49      "This effect gives you the feeling that you are standing in a room " \
  50      "with a complete 7.1 speaker set when using only a headphone, " \
  51      "providing a more realistic sound experience. It should also be " \
  52      "more comfortable and less tiring when listening to music for " \
  53      "long periods of time.\nIt works with any source format from mono " \
  54      "to 7.1.")
  55
  56 #define HEADPHONE_DIM_TEXT N_("Characteristic dimension")
  57 #define HEADPHONE_DIM_LONGTEXT N_( \
  58      "Distance between front left speaker and listener in meters.")
  59
  60 #define HEADPHONE_COMPENSATE_TEXT N_("Compensate delay")
  61 #define HEADPHONE_COMPENSATE_LONGTEXT N_( \
  62      "The delay which is introduced by the physical algorithm may "\
  63      "sometimes be disturbing for the lipsync. In that case, turn "\
  64      "this on to compensate.")
  65
  66 #define HEADPHONE_DOLBY_TEXT N_("No decoding of Dolby Surround")
  67 #define HEADPHONE_DOLBY_LONGTEXT N_( \
  68      "If this option is turned on (not recommended), Dolby Surround "\
  69      "encoded streams won't be decoded before being processed by this "\
  70      "filter.")
  71
  72 vlc_module_begin();
  73     set_description( N_("Headphone channel mixer with virtual spatialization effect") );
  74     set_shortname( _("Headphone effect") );
  75     set_category( CAT_AUDIO );
  76     set_subcategory( SUBCAT_AUDIO_AFILTER );
  77
  78     add_integer( "headphone-dim", 10, NULL, HEADPHONE_DIM_TEXT,
  79                  HEADPHONE_DIM_LONGTEXT, VLC_FALSE );
  80     add_bool( "headphone-compensate", 0, NULL, HEADPHONE_COMPENSATE_TEXT,
  81               HEADPHONE_COMPENSATE_LONGTEXT, VLC_TRUE );
  82     add_bool( "headphone-dolby", 0, NULL, HEADPHONE_DOLBY_TEXT,
  83               HEADPHONE_DOLBY_LONGTEXT, VLC_TRUE );
  84
  85     set_capability( "audio filter", 0 );
  86     set_callbacks( Create, Destroy );
  87     add_shortcut( "headphone" );
  88 vlc_module_end();
  89
  90
  91 /*****************************************************************************
  92  * Internal data structures
  93  *****************************************************************************/
  94 struct atomic_operation_t
  95 {
  96     int i_source_channel_offset;
  97     int i_dest_channel_offset;
  98     unsigned int i_delay;/* in sample unit */
  99     double d_amplitude_factor;
 100 };
 101
 102 struct aout_filter_sys_t
 103 {
 104     size_t i_overflow_buffer_size;/* in bytes */
 105     byte_t * p_overflow_buffer;
 106     unsigned int i_nb_atomic_operations;
 107     struct atomic_operation_t * p_atomic_operations;
 108 };
 109
 110 /*****************************************************************************
 111  * Init: initialize internal data structures
 112  * and computes the needed atomic operations
 113  *****************************************************************************/
 114 /* x and z represent the coordinates of the virtual speaker
 115  *  relatively to the center of the listener's head, measured in meters :
 116  *
 117  *  left              right
 118  *Z
 119  *-
 120  *a          head
 121  *x
 122  *i
 123  *s
 124  *  rear left    rear right
 125  *
 126  *          x-axis
 127  *  */
 128 static void ComputeChannelOperations ( struct aout_filter_sys_t * p_data
 129         , unsigned int i_rate , unsigned int i_next_atomic_operation
 130         , int i_source_channel_offset , double d_x , double d_z
 131         , double d_compensation_length , double d_channel_amplitude_factor )
 132 {
 133     double d_c = 340; /*sound celerity (unit: m/s)*/
 134     double d_compensation_delay = (d_compensation_length-0.1) / d_c * i_rate;
 135
 136     /* Left ear */
 137     p_data->p_atomic_operations[i_next_atomic_operation]
 138         .i_source_channel_offset = i_source_channel_offset;
 139     p_data->p_atomic_operations[i_next_atomic_operation]
 140         .i_dest_channel_offset = 0;/* left */
 141     p_data->p_atomic_operations[i_next_atomic_operation]
 142         .i_delay = (int)( sqrt( (-0.1-d_x)*(-0.1-d_x) + (0-d_z)*(0-d_z) )
 143                           / d_c * i_rate - d_compensation_delay );
 144     if ( d_x < 0 )
 145     {
 146         p_data->p_atomic_operations[i_next_atomic_operation]
 147             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 148     }
 149     else if ( d_x > 0 )
 150     {
 151         p_data->p_atomic_operations[i_next_atomic_operation]
 152             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 153     }
 154     else
 155     {
 156         p_data->p_atomic_operations[i_next_atomic_operation]
 157             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 158     }
 159
 160     /* Right ear */
 161     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 162         .i_source_channel_offset = i_source_channel_offset;
 163     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 164         .i_dest_channel_offset = 1;/* right */
 165     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 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 + 1]
 171             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 172     }
 173     else if ( d_x > 0 )
 174     {
 175         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 176             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 177     }
 178     else
 179     {
 180         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 181             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 182     }
 183 }
 184
 185 static int Init ( aout_filter_t * p_filter , struct aout_filter_sys_t * p_data
 186         , unsigned int i_nb_channels , uint32_t i_physical_channels
 187         , unsigned int i_rate )
 188 {
 189     double d_x = config_GetInt ( p_filter , "headphone-dim" );
 190     double d_z = d_x;
 191     double d_z_rear = -d_x/3;
 192     double d_min = 0;
 193     unsigned int i_next_atomic_operation;
 194     int i_source_channel_offset;
 195     unsigned int i;
 196
 197     if ( p_data == NULL )
 198     {
 199         msg_Dbg ( p_filter, "passing a null pointer as argument" );
 200         return 0;
 201     }
 202
 203     if ( config_GetInt ( p_filter , "headphone-compensate" ) )
 204     {
 205         /* minimal distance to any speaker */
 206         if ( i_physical_channels & AOUT_CHAN_REARCENTER )
 207         {
 208             d_min = d_z_rear;
 209         }
 210         else
 211         {
 212             d_min = d_z;
 213         }
 214     }
 215
 216     /* Number of elementary operations */
 217     p_data->i_nb_atomic_operations = i_nb_channels * 2;
 218     if ( i_physical_channels & AOUT_CHAN_CENTER )
 219     {
 220         p_data->i_nb_atomic_operations += 2;
 221     }
 222     p_data->p_atomic_operations = malloc ( sizeof(struct atomic_operation_t)
 223             * p_data->i_nb_atomic_operations );
 224     if ( p_data->p_atomic_operations == NULL )
 225     {
 226         msg_Err( p_filter, "out of memory" );
 227         return -1;
 228     }
 229
 230     /* For each virtual speaker, computes elementary wave propagation time
 231      * to each ear */
 232     i_next_atomic_operation = 0;
 233     i_source_channel_offset = 0;
 234     if ( i_physical_channels & AOUT_CHAN_LEFT )
 235     {
 236         ComputeChannelOperations ( p_data , i_rate
 237                 , i_next_atomic_operation , i_source_channel_offset
 238                 , -d_x , d_z , d_min , 2.0 / i_nb_channels );
 239         i_next_atomic_operation += 2;
 240         i_source_channel_offset++;
 241     }
 242     if ( i_physical_channels & AOUT_CHAN_RIGHT )
 243     {
 244         ComputeChannelOperations ( p_data , i_rate
 245                 , i_next_atomic_operation , i_source_channel_offset
 246                 , d_x , d_z , d_min , 2.0 / i_nb_channels );
 247         i_next_atomic_operation += 2;
 248         i_source_channel_offset++;
 249     }
 250     if ( i_physical_channels & AOUT_CHAN_MIDDLELEFT )
 251     {
 252         ComputeChannelOperations ( p_data , i_rate
 253                 , i_next_atomic_operation , i_source_channel_offset
 254                 , -d_x , 0 , d_min , 1.5 / i_nb_channels );
 255         i_next_atomic_operation += 2;
 256         i_source_channel_offset++;
 257     }
 258     if ( i_physical_channels & AOUT_CHAN_MIDDLERIGHT )
 259     {
 260         ComputeChannelOperations ( p_data , i_rate
 261                 , i_next_atomic_operation , i_source_channel_offset
 262                 , d_x , 0 , d_min , 1.5 / i_nb_channels );
 263         i_next_atomic_operation += 2;
 264         i_source_channel_offset++;
 265     }
 266     if ( i_physical_channels & AOUT_CHAN_REARLEFT )
 267     {
 268         ComputeChannelOperations ( p_data , i_rate
 269                 , i_next_atomic_operation , i_source_channel_offset
 270                 , -d_x , d_z_rear , 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_REARRIGHT )
 275     {
 276         ComputeChannelOperations ( p_data , i_rate
 277                 , i_next_atomic_operation , i_source_channel_offset
 278                 , d_x , d_z_rear , 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_REARCENTER )
 283     {
 284         ComputeChannelOperations ( p_data , i_rate
 285                 , i_next_atomic_operation , i_source_channel_offset
 286                 , 0 , -d_z , 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_CENTER )
 291     {
 292         /* having two center channels increases the spatialization effect */
 293         ComputeChannelOperations ( p_data , i_rate
 294                 , i_next_atomic_operation , i_source_channel_offset
 295                 , d_x / 5.0 , d_z , d_min , 0.75 / i_nb_channels );
 296         i_next_atomic_operation += 2;
 297         ComputeChannelOperations ( p_data , i_rate
 298                 , i_next_atomic_operation , i_source_channel_offset
 299                 , -d_x / 5.0 , d_z , d_min , 0.75 / i_nb_channels );
 300         i_next_atomic_operation += 2;
 301         i_source_channel_offset++;
 302     }
 303     if ( i_physical_channels & AOUT_CHAN_LFE )
 304     {
 305         ComputeChannelOperations ( p_data , i_rate
 306                 , i_next_atomic_operation , i_source_channel_offset
 307                 , 0 , d_z_rear , d_min , 5.0 / i_nb_channels );
 308         i_next_atomic_operation += 2;
 309         i_source_channel_offset++;
 310     }
 311
 312     /* Initialize the overflow buffer
 313      * we need it because the process induce a delay in the samples */
 314     p_data->i_overflow_buffer_size = 0;
 315     for ( i = 0 ; i < p_data->i_nb_atomic_operations ; i++ )
 316     {
 317         if ( p_data->i_overflow_buffer_size
 318                 < p_data->p_atomic_operations[i].i_delay * 2 * sizeof (float) )
 319         {
 320             p_data->i_overflow_buffer_size
 321                 = p_data->p_atomic_operations[i].i_delay * 2 * sizeof (float);
 322         }
 323     }
 324     p_data->p_overflow_buffer = malloc ( p_data->i_overflow_buffer_size );
 325     if ( p_data->p_atomic_operations == NULL )
 326     {
 327         msg_Err( p_filter, "out of memory" );
 328         return -1;
 329     }
 330     memset ( p_data->p_overflow_buffer , 0 , p_data->i_overflow_buffer_size );
 331
 332     /* end */
 333     return 0;
 334 }
 335
 336 /*****************************************************************************
 337  * Create: allocate headphone downmixer
 338  *****************************************************************************/
 339 static int Create( vlc_object_t *p_this )
 340 {
 341     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 342     vlc_bool_t b_fit = VLC_TRUE;
 343
 344     /* Activate this filter only with stereo devices */
 345     if ( p_filter->output.i_physical_channels
 346             != (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT) )
 347     {
 348         msg_Dbg( p_filter, "Filter discarded (incompatible format)" );
 349         return VLC_EGENERIC;
 350     }
 351
 352     /* Request a specific format if not already compatible */
 353     if ( p_filter->input.i_original_channels
 354             != p_filter->output.i_original_channels )
 355     {
 356         b_fit = VLC_FALSE;
 357         p_filter->input.i_original_channels =
 358                                         p_filter->output.i_original_channels;
 359     }
 360     if ( p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
 361           || p_filter->output.i_format != VLC_FOURCC('f','l','3','2') )
 362     {
 363         b_fit = VLC_FALSE;
 364         p_filter->input.i_format = VLC_FOURCC('f','l','3','2');
 365         p_filter->output.i_format = VLC_FOURCC('f','l','3','2');
 366     }
 367     if ( p_filter->input.i_rate != p_filter->output.i_rate )
 368     {
 369         b_fit = VLC_FALSE;
 370         p_filter->input.i_rate = p_filter->output.i_rate;
 371     }
 372     if ( p_filter->input.i_physical_channels == (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT)
 373           && ( p_filter->input.i_original_channels & AOUT_CHAN_DOLBYSTEREO )
 374           && ! config_GetInt ( p_filter , "headphone-dolby" ) )
 375     {
 376         b_fit = VLC_FALSE;
 377         p_filter->input.i_physical_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
 378                                               AOUT_CHAN_CENTER |
 379                                               AOUT_CHAN_REARLEFT |
 380                                               AOUT_CHAN_REARRIGHT;
 381     }
 382     if ( ! b_fit )
 383     {
 384         msg_Dbg( p_filter, "Requesting specific format" );
 385         return VLC_EGENERIC;
 386     }
 387
 388     /* Allocate the memory needed to store the module's structure */
 389     p_filter->p_sys = malloc( sizeof(struct aout_filter_sys_t) );
 390     if ( p_filter->p_sys == NULL )
 391     {
 392         msg_Err( p_filter, "Out of memory" );
 393         return VLC_EGENERIC;
 394     }
 395     p_filter->p_sys->i_overflow_buffer_size = 0;
 396     p_filter->p_sys->p_overflow_buffer = NULL;
 397     p_filter->p_sys->i_nb_atomic_operations = 0;
 398     p_filter->p_sys->p_atomic_operations = NULL;
 399
 400     if ( Init( p_filter , p_filter->p_sys
 401                 , aout_FormatNbChannels ( &p_filter->input )
 402                 , p_filter->input.i_physical_channels
 403                 , p_filter->input.i_rate ) < 0 )
 404     {
 405         return VLC_EGENERIC;
 406     }
 407
 408     p_filter->pf_do_work = DoWork;
 409     p_filter->b_in_place = 0;
 410
 411     return VLC_SUCCESS;
 412 }
 413
 414 /*****************************************************************************
 415  * Destroy: deallocate resources associated with headphone downmixer
 416  *****************************************************************************/
 417 static void Destroy( vlc_object_t *p_this )
 418 {
 419     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 420
 421     if ( p_filter->p_sys != NULL )
 422     {
 423         if ( p_filter->p_sys->p_overflow_buffer != NULL )
 424         {
 425             free ( p_filter->p_sys->p_overflow_buffer );
 426         }
 427         if ( p_filter->p_sys->p_atomic_operations != NULL )
 428         {
 429             free ( p_filter->p_sys->p_atomic_operations );
 430         }
 431         free ( p_filter->p_sys );
 432         p_filter->p_sys = NULL;
 433     }
 434 }
 435
 436 /*****************************************************************************
 437  * DoWork: convert a buffer
 438  *****************************************************************************/
 439 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 440                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 441 {
 442     int i_input_nb = aout_FormatNbChannels( &p_filter->input );
 443     int i_output_nb = aout_FormatNbChannels( &p_filter->output );
 444
 445     float * p_in = (float*) p_in_buf->p_buffer;
 446     byte_t * p_out;
 447     byte_t * p_overflow;
 448     byte_t * p_slide;
 449
 450     size_t i_overflow_size;/* in bytes */
 451     size_t i_out_size;/* in bytes */
 452
 453     unsigned int i, j;
 454
 455     int i_source_channel_offset;
 456     int i_dest_channel_offset;
 457     unsigned int i_delay;
 458     double d_amplitude_factor;
 459
 460
 461     /* out buffer characterisitcs */
 462     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 463     p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * i_output_nb / i_input_nb;
 464     p_out = p_out_buf->p_buffer;
 465     i_out_size = p_out_buf->i_nb_bytes;
 466
 467     if ( p_filter->p_sys != NULL )
 468     {
 469         /* Slide the overflow buffer */
 470         p_overflow = p_filter->p_sys->p_overflow_buffer;
 471         i_overflow_size = p_filter->p_sys->i_overflow_buffer_size;
 472
 473         memset ( p_out , 0 , i_out_size );
 474         if ( i_out_size > i_overflow_size )
 475             memcpy ( p_out , p_overflow , i_overflow_size );
 476         else
 477             memcpy ( p_out , p_overflow , i_out_size );
 478
 479         p_slide = p_filter->p_sys->p_overflow_buffer;
 480         while ( p_slide < p_overflow + i_overflow_size )
 481         {
 482             if ( p_slide + i_out_size < p_overflow + i_overflow_size )
 483             {
 484                 memset ( p_slide , 0 , i_out_size );
 485                 if ( p_slide + 2 * i_out_size < p_overflow + i_overflow_size )
 486                     memcpy ( p_slide , p_slide + i_out_size , i_out_size );
 487                 else
 488                     memcpy ( p_slide , p_slide + i_out_size
 489                       , p_overflow + i_overflow_size - ( p_slide + i_out_size ) );
 490             }
 491             else
 492             {
 493                 memset ( p_slide , 0 , p_overflow + i_overflow_size - p_slide );
 494             }
 495             p_slide += i_out_size;
 496         }
 497
 498         /* apply the atomic operations */
 499         for ( i = 0 ; i < p_filter->p_sys->i_nb_atomic_operations ; i++ )
 500         {
 501             /* shorter variable names */
 502             i_source_channel_offset
 503                 = p_filter->p_sys->p_atomic_operations[i].i_source_channel_offset;
 504             i_dest_channel_offset
 505                 = p_filter->p_sys->p_atomic_operations[i].i_dest_channel_offset;
 506             i_delay = p_filter->p_sys->p_atomic_operations[i].i_delay;
 507             d_amplitude_factor
 508                 = p_filter->p_sys->p_atomic_operations[i].d_amplitude_factor;
 509
 510             if ( p_out_buf->i_nb_samples > i_delay )
 511             {
 512                 /* current buffer coefficients */
 513                 for ( j = 0 ; j < p_out_buf->i_nb_samples - i_delay ; j++ )
 514                 {
 515                     ((float*)p_out)[ (i_delay+j)*i_output_nb + i_dest_channel_offset ]
 516                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 517                            * d_amplitude_factor;
 518                 }
 519
 520                 /* overflow buffer coefficients */
 521                 for ( j = 0 ; j < i_delay ; j++ )
 522                 {
 523                     ((float*)p_overflow)[ j*i_output_nb + i_dest_channel_offset ]
 524                         += p_in[ (p_out_buf->i_nb_samples - i_delay + j)
 525                            * i_input_nb + i_source_channel_offset ]
 526                            * d_amplitude_factor;
 527                 }
 528             }
 529             else
 530             {
 531                 /* overflow buffer coefficients only */
 532                 for ( j = 0 ; j < p_out_buf->i_nb_samples ; j++ )
 533                 {
 534                     ((float*)p_overflow)[ (i_delay - p_out_buf->i_nb_samples + j)
 535                         * 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         }
 541     }
 542     else
 543     {
 544         memset ( p_out , 0 , i_out_size );
 545     }
 546 }