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 VideoLAN
   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., 59 Temple Place - Suite 330, Boston, MA  02111, 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 5.1 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 5.1.")
  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 vlc_module_begin();
  61     set_description( N_("headphone channel mixer with virtual spatialization effect") );
  62     set_category( CAT_AUDIO );
  63     set_subcategory( SUBCAT_AUDIO_AFILTER );
  64
  65     add_integer( "headphone-dim", 10, NULL, HEADPHONE_DIM_TEXT,
  66                  HEADPHONE_DIM_LONGTEXT, VLC_FALSE );
  67
  68     set_capability( "audio filter", 0 );
  69     set_callbacks( Create, Destroy );
  70     add_shortcut( "headphone" );
  71 vlc_module_end();
  72
  73
  74 /*****************************************************************************
  75  * Internal data structures
  76  *****************************************************************************/
  77 struct atomic_operation_t
  78 {
  79     int i_source_channel_offset;
  80     int i_dest_channel_offset;
  81     unsigned int i_delay;/* in sample unit */
  82     double d_amplitude_factor;
  83 };
  84
  85 struct aout_filter_sys_t
  86 {
  87     size_t i_overflow_buffer_size;/* in bytes */
  88     byte_t * p_overflow_buffer;
  89     unsigned int i_nb_atomic_operations;
  90     struct atomic_operation_t * p_atomic_operations;
  91 };
  92
  93 /*****************************************************************************
  94  * Init: initialize internal data structures
  95  * and computes the needed atomic operations
  96  *****************************************************************************/
  97 /* x and z represent the coordinates of the virtual speaker
  98  *  relatively to the center of the listener's head, measured in meters :
  99  *
 100  *  left              right
 101  *Z
 102  *-
 103  *a          head
 104  *x
 105  *i
 106  *s
 107  *  rear left    rear right
 108  *
 109  *          x-axis
 110  *  */
 111 static void ComputeChannelOperations ( struct aout_filter_sys_t * p_data
 112         , unsigned int i_rate , unsigned int i_next_atomic_operation
 113         , int i_source_channel_offset , double d_x , double d_z
 114         , double d_channel_amplitude_factor )
 115 {
 116     double d_c = 340; /*sound celerity (unit: m/s)*/
 117
 118     /* Left ear */
 119     p_data->p_atomic_operations[i_next_atomic_operation]
 120         .i_source_channel_offset = i_source_channel_offset;
 121     p_data->p_atomic_operations[i_next_atomic_operation]
 122         .i_dest_channel_offset = 0;/* left */
 123     p_data->p_atomic_operations[i_next_atomic_operation]
 124         .i_delay = (int)( sqrt( (-0.1-d_x)*(-0.1-d_x) + (0-d_z)*(0-d_z) )
 125                           / d_c * i_rate );
 126     if ( d_x < 0 )
 127     {
 128         p_data->p_atomic_operations[i_next_atomic_operation]
 129             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 130     }
 131     else if ( d_x > 0 )
 132     {
 133         p_data->p_atomic_operations[i_next_atomic_operation]
 134             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 135     }
 136     else
 137     {
 138         p_data->p_atomic_operations[i_next_atomic_operation]
 139             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 140     }
 141
 142     /* Right ear */
 143     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 144         .i_source_channel_offset = i_source_channel_offset;
 145     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 146         .i_dest_channel_offset = 1;/* right */
 147     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 148         .i_delay = (int)( sqrt( (0.1-d_x)*(0.1-d_x) + (0-d_z)*(0-d_z) )
 149                           / d_c * i_rate );
 150     if ( d_x < 0 )
 151     {
 152         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 153             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 154     }
 155     else if ( d_x > 0 )
 156     {
 157         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 158             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 159     }
 160     else
 161     {
 162         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 163             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 164     }
 165 }
 166
 167 static int Init ( aout_filter_t * p_filter , struct aout_filter_sys_t * p_data
 168         , unsigned int i_nb_channels , uint32_t i_physical_channels
 169         , unsigned int i_rate )
 170 {
 171     double d_x = config_GetInt ( p_filter , "headphone-dim" );
 172     double d_z = d_x;
 173     double d_z_rear = -d_x/3;
 174     unsigned int i_next_atomic_operation;
 175     int i_source_channel_offset;
 176     unsigned int i;
 177
 178     if ( p_data == NULL )
 179     {
 180         msg_Dbg ( p_filter, "passing a null pointer as argument" );
 181         return 0;
 182     }
 183
 184     /* Number of elementary operations */
 185     p_data->i_nb_atomic_operations = i_nb_channels * 2;
 186     p_data->p_atomic_operations = malloc ( sizeof(struct atomic_operation_t)
 187             * p_data->i_nb_atomic_operations );
 188     if ( p_data->p_atomic_operations == NULL )
 189     {
 190         msg_Err( p_filter, "out of memory" );
 191         return -1;
 192     }
 193
 194     /* For each virtual speaker, computes elementary wave propagation time
 195      * to each ear */
 196     i_next_atomic_operation = 0;
 197     i_source_channel_offset = 0;
 198     if ( i_physical_channels & AOUT_CHAN_LEFT )
 199     {
 200         ComputeChannelOperations ( p_data , i_rate
 201                 , i_next_atomic_operation , i_source_channel_offset
 202                 , -d_x , d_z , 2.0 / i_nb_channels );
 203         i_next_atomic_operation += 2;
 204         i_source_channel_offset++;
 205     }
 206     if ( i_physical_channels & AOUT_CHAN_RIGHT )
 207     {
 208         ComputeChannelOperations ( p_data , i_rate
 209                 , i_next_atomic_operation , i_source_channel_offset
 210                 , d_x , d_z , 2.0 / i_nb_channels );
 211         i_next_atomic_operation += 2;
 212         i_source_channel_offset++;
 213     }
 214     if ( i_physical_channels & AOUT_CHAN_REARLEFT )
 215     {
 216         ComputeChannelOperations ( p_data , i_rate
 217                 , i_next_atomic_operation , i_source_channel_offset
 218                 , -d_x , d_z_rear , 1.5 / i_nb_channels );
 219         i_next_atomic_operation += 2;
 220         i_source_channel_offset++;
 221     }
 222     if ( i_physical_channels & AOUT_CHAN_REARRIGHT )
 223     {
 224         ComputeChannelOperations ( p_data , i_rate
 225                 , i_next_atomic_operation , i_source_channel_offset
 226                 , d_x , d_z_rear , 1.5 / i_nb_channels );
 227         i_next_atomic_operation += 2;
 228         i_source_channel_offset++;
 229     }
 230     if ( i_physical_channels & AOUT_CHAN_REARCENTER )
 231     {
 232         ComputeChannelOperations ( p_data , i_rate
 233                 , i_next_atomic_operation , i_source_channel_offset
 234                 , 0 , -d_z , 1.5 / i_nb_channels );
 235         i_next_atomic_operation += 2;
 236         i_source_channel_offset++;
 237     }
 238     if ( i_physical_channels & AOUT_CHAN_CENTER )
 239     {
 240         ComputeChannelOperations ( p_data , i_rate
 241                 , i_next_atomic_operation , i_source_channel_offset
 242                 , 0 , d_z , 1.5 / i_nb_channels );
 243         i_next_atomic_operation += 2;
 244         i_source_channel_offset++;
 245     }
 246     if ( i_physical_channels & AOUT_CHAN_LFE )
 247     {
 248         ComputeChannelOperations ( p_data , i_rate
 249                 , i_next_atomic_operation , i_source_channel_offset
 250                 , 0 , d_z_rear , 5.0 / i_nb_channels );
 251         i_next_atomic_operation += 2;
 252         i_source_channel_offset++;
 253     }
 254     if ( i_physical_channels & AOUT_CHAN_MIDDLELEFT )
 255     {
 256         ComputeChannelOperations ( p_data , i_rate
 257                 , i_next_atomic_operation , i_source_channel_offset
 258                 , -d_x , 0 , 1.5 / i_nb_channels );
 259         i_next_atomic_operation += 2;
 260         i_source_channel_offset++;
 261     }
 262     if ( i_physical_channels & AOUT_CHAN_MIDDLERIGHT )
 263     {
 264         ComputeChannelOperations ( p_data , i_rate
 265                 , i_next_atomic_operation , i_source_channel_offset
 266                 , d_x , 0 , 1.5 / i_nb_channels );
 267         i_next_atomic_operation += 2;
 268         i_source_channel_offset++;
 269     }
 270
 271     /* Initialize the overflow buffer
 272      * we need it because the process induce a delay in the samples */
 273     p_data->i_overflow_buffer_size = 0;
 274     for ( i = 0 ; i < p_data->i_nb_atomic_operations ; i++ )
 275     {
 276         if ( p_data->i_overflow_buffer_size
 277                 < p_data->p_atomic_operations[i].i_delay * i_nb_channels
 278                 * sizeof (float) )
 279         {
 280             p_data->i_overflow_buffer_size
 281                 = p_data->p_atomic_operations[i].i_delay * i_nb_channels
 282                 * sizeof (float);
 283         }
 284     }
 285     p_data->p_overflow_buffer = malloc ( p_data->i_overflow_buffer_size );
 286     if ( p_data->p_atomic_operations == NULL )
 287     {
 288         msg_Err( p_filter, "out of memory" );
 289         return -1;
 290     }
 291     memset ( p_data->p_overflow_buffer , 0 , p_data->i_overflow_buffer_size );
 292
 293     /* end */
 294     return 0;
 295 }
 296
 297 /*****************************************************************************
 298  * Create: allocate headphone downmixer
 299  *****************************************************************************/
 300 static int Create( vlc_object_t *p_this )
 301 {
 302     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 303
 304     if ( p_filter->output.i_physical_channels != ( AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT )
 305           || p_filter->input.i_format != p_filter->output.i_format
 306           || p_filter->input.i_rate != p_filter->output.i_rate
 307           || (p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
 308                && p_filter->input.i_format != VLC_FOURCC('f','i','3','2')) )
 309     {
 310         msg_Dbg( p_filter, "Filter discarded (invalid format)" );
 311         return -1;
 312     }
 313
 314     /* Allocate the memory needed to store the module's structure */
 315     p_filter->p_sys = malloc( sizeof(struct aout_filter_sys_t) );
 316     if ( p_filter->p_sys == NULL )
 317     {
 318         msg_Err( p_filter, "out of memory" );
 319         return -1;
 320     }
 321     p_filter->p_sys->i_overflow_buffer_size = 0;
 322     p_filter->p_sys->p_overflow_buffer = NULL;
 323     p_filter->p_sys->i_nb_atomic_operations = 0;
 324     p_filter->p_sys->p_atomic_operations = NULL;
 325
 326     if ( Init( p_filter , p_filter->p_sys
 327                 , aout_FormatNbChannels ( &p_filter->input )
 328                 , p_filter->input.i_physical_channels
 329                 ,  p_filter->input.i_rate ) < 0 )
 330     {
 331         return -1;
 332     }
 333
 334     p_filter->pf_do_work = DoWork;
 335     p_filter->b_in_place = 0;
 336
 337     return 0;
 338 }
 339
 340 /*****************************************************************************
 341  * Destroy: deallocate resources associated with headphone downmixer
 342  *****************************************************************************/
 343 static void Destroy( vlc_object_t *p_this )
 344 {
 345     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 346
 347     if ( p_filter->p_sys != NULL )
 348     {
 349         if ( p_filter->p_sys->p_overflow_buffer != NULL )
 350         {
 351             free ( p_filter->p_sys->p_overflow_buffer );
 352         }
 353         if ( p_filter->p_sys->p_atomic_operations != NULL )
 354         {
 355             free ( p_filter->p_sys->p_atomic_operations );
 356         }
 357         free ( p_filter->p_sys );
 358         p_filter->p_sys = NULL;
 359     }
 360 }
 361
 362 /*****************************************************************************
 363  * DoWork: convert a buffer
 364  *****************************************************************************/
 365 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 366                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 367 {
 368     int i_input_nb = aout_FormatNbChannels( &p_filter->input );
 369     int i_output_nb = aout_FormatNbChannels( &p_filter->output );
 370
 371     float * p_in = (float*) p_in_buf->p_buffer;
 372     byte_t * p_out;
 373     byte_t * p_overflow;
 374     byte_t * p_slide;
 375
 376     size_t i_overflow_size;/* in bytes */
 377     size_t i_out_size;/* in bytes */
 378
 379     unsigned int i, j;
 380
 381     int i_source_channel_offset;
 382     int i_dest_channel_offset;
 383     unsigned int i_delay;
 384     double d_amplitude_factor;
 385
 386
 387     /* out buffer characterisitcs */
 388     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 389     p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * i_output_nb / i_input_nb;
 390     p_out = p_out_buf->p_buffer;
 391     i_out_size = p_out_buf->i_nb_bytes;
 392
 393     if ( p_filter->p_sys != NULL )
 394     {
 395         /* Slide the overflow buffer */
 396         p_overflow = p_filter->p_sys->p_overflow_buffer;
 397         i_overflow_size = p_filter->p_sys->i_overflow_buffer_size;
 398
 399         memset ( p_out , 0 , i_out_size );
 400         if ( i_out_size > i_overflow_size )
 401             memcpy ( p_out , p_overflow , i_overflow_size );
 402         else
 403             memcpy ( p_out , p_overflow , i_out_size );
 404
 405         p_slide = p_filter->p_sys->p_overflow_buffer;
 406         while ( p_slide < p_overflow + i_overflow_size )
 407         {
 408             if ( p_slide + i_out_size < p_overflow + i_overflow_size )
 409             {
 410                 memset ( p_slide , 0 , i_out_size );
 411                 if ( p_slide + 2 * i_out_size < p_overflow + i_overflow_size )
 412                     memcpy ( p_slide , p_slide + i_out_size , i_out_size );
 413                 else
 414                     memcpy ( p_slide , p_slide + i_out_size
 415                       , p_overflow + i_overflow_size - ( p_slide + i_out_size ) );
 416             }
 417             else
 418             {
 419                 memset ( p_slide , 0 , p_overflow + i_overflow_size - p_slide );
 420             }
 421             p_slide += i_out_size;
 422         }
 423
 424         /* apply the atomic operations */
 425         for ( i = 0 ; i < p_filter->p_sys->i_nb_atomic_operations ; i++ )
 426         {
 427             /* shorter variable names */
 428             i_source_channel_offset
 429                 = p_filter->p_sys->p_atomic_operations[i].i_source_channel_offset;
 430             i_dest_channel_offset
 431                 = p_filter->p_sys->p_atomic_operations[i].i_dest_channel_offset;
 432             i_delay = p_filter->p_sys->p_atomic_operations[i].i_delay;
 433             d_amplitude_factor
 434                 = p_filter->p_sys->p_atomic_operations[i].d_amplitude_factor;
 435
 436             if ( p_out_buf->i_nb_samples > i_delay )
 437             {
 438                 /* current buffer coefficients */
 439                 for ( j = 0 ; j < p_out_buf->i_nb_samples - i_delay ; j++ )
 440                 {
 441                     ((float*)p_out)[ (i_delay+j)*i_output_nb + i_dest_channel_offset ]
 442                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 443                            * d_amplitude_factor;
 444                 }
 445
 446                 /* overflow buffer coefficients */
 447                 for ( j = 0 ; j < i_delay ; j++ )
 448                 {
 449                     ((float*)p_overflow)[ j*i_output_nb + i_dest_channel_offset ]
 450                         += p_in[ (p_out_buf->i_nb_samples - i_delay + j)
 451                            * i_input_nb + i_source_channel_offset ]
 452                            * d_amplitude_factor;
 453                 }
 454             }
 455             else
 456             {
 457                 /* overflow buffer coefficients only */
 458                 for ( j = 0 ; j < p_out_buf->i_nb_samples ; j++ )
 459                 {
 460                     ((float*)p_overflow)[ (i_delay - p_out_buf->i_nb_samples + j)
 461                         * i_output_nb + i_dest_channel_offset ]
 462                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 463                            * d_amplitude_factor;
 464                 }
 465             }
 466         }
 467     }
 468     else
 469     {
 470         memset ( p_out , 0 , i_out_size );
 471     }
 472 }