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      "Headphone virtual spatialization effect parameter: "\
  59      "distance between front left speaker and listener in meters.")
  60
  61 vlc_module_begin();
  62     set_description( N_("headphone channel mixer with virtual spatialization effect") );
  63
  64     add_integer( "headphone-dim", 10, NULL, HEADPHONE_DIM_TEXT,
  65                  HEADPHONE_DIM_LONGTEXT, VLC_FALSE );
  66
  67     set_capability( "audio filter", 0 );
  68     set_callbacks( Create, Destroy );
  69     add_shortcut( "headphone" );
  70 vlc_module_end();
  71
  72
  73 /*****************************************************************************
  74  * Internal data structures
  75  *****************************************************************************/
  76 struct atomic_operation_t
  77 {
  78     int i_source_channel_offset;
  79     int i_dest_channel_offset;
  80     unsigned int i_delay;/* in sample unit */
  81     double d_amplitude_factor;
  82 };
  83
  84 struct aout_filter_sys_t
  85 {
  86     size_t i_overflow_buffer_size;/* in bytes */
  87     byte_t * p_overflow_buffer;
  88     unsigned int i_nb_atomic_operations;
  89     struct atomic_operation_t * p_atomic_operations;
  90 };
  91
  92 /*****************************************************************************
  93  * Init: initialize internal data structures
  94  * and computes the needed atomic operations
  95  *****************************************************************************/
  96 /* x and z represent the coordinates of the virtual speaker
  97  *  relatively to the center of the listener's head, measured in meters :
  98  *
  99  *  left              right
 100  *Z
 101  *-
 102  *a          head
 103  *x
 104  *i
 105  *s
 106  *  rear left    rear right
 107  *
 108  *          x-axis
 109  *  */
 110 static void ComputeChannelOperations ( struct aout_filter_sys_t * p_data
 111         , unsigned int i_rate , unsigned int i_next_atomic_operation
 112         , int i_source_channel_offset , double d_x , double d_z
 113         , double d_channel_amplitude_factor )
 114 {
 115     double d_c = 340; /*sound celerity (unit: m/s)*/
 116
 117     /* Left ear */
 118     p_data->p_atomic_operations[i_next_atomic_operation]
 119         .i_source_channel_offset = i_source_channel_offset;
 120     p_data->p_atomic_operations[i_next_atomic_operation]
 121         .i_dest_channel_offset = 0;/* left */
 122     p_data->p_atomic_operations[i_next_atomic_operation]
 123         .i_delay = (int)( sqrt( (-0.1-d_x)*(-0.1-d_x) + (0-d_z)*(0-d_z) )
 124                           / d_c * i_rate );
 125     if ( d_x < 0 )
 126     {
 127         p_data->p_atomic_operations[i_next_atomic_operation]
 128             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 129     }
 130     else if ( d_x > 0 )
 131     {
 132         p_data->p_atomic_operations[i_next_atomic_operation]
 133             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 134     }
 135     else
 136     {
 137         p_data->p_atomic_operations[i_next_atomic_operation]
 138             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 139     }
 140
 141     /* Right ear */
 142     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 143         .i_source_channel_offset = i_source_channel_offset;
 144     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 145         .i_dest_channel_offset = 1;/* right */
 146     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 147         .i_delay = (int)( sqrt( (0.1-d_x)*(0.1-d_x) + (0-d_z)*(0-d_z) )
 148                           / d_c * i_rate );
 149     if ( d_x < 0 )
 150     {
 151         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 152             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 153     }
 154     else if ( d_x > 0 )
 155     {
 156         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 157             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 158     }
 159     else
 160     {
 161         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 162             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 163     }
 164 }
 165
 166 static int Init ( aout_filter_t * p_filter , struct aout_filter_sys_t * p_data
 167         , unsigned int i_nb_channels , uint32_t i_physical_channels
 168         , unsigned int i_rate )
 169 {
 170     double d_x = config_GetInt ( p_filter , "headphone-dim" );
 171     double d_z = d_x;
 172     double d_z_rear = -d_x/3;
 173     unsigned int i_next_atomic_operation;
 174     int i_source_channel_offset;
 175     unsigned int i;
 176
 177     if ( p_data == NULL )
 178     {
 179         msg_Dbg ( p_filter, "passing a null pointer as argument" );
 180         return 0;
 181     }
 182
 183     /* Number of elementary operations */
 184     p_data->i_nb_atomic_operations = i_nb_channels * 2;
 185     p_data->p_atomic_operations = malloc ( sizeof(struct atomic_operation_t)
 186             * p_data->i_nb_atomic_operations );
 187     if ( p_data->p_atomic_operations == NULL )
 188     {
 189         msg_Err( p_filter, "out of memory" );
 190         return -1;
 191     }
 192
 193     /* For each virtual speaker, computes elementary wave propagation time
 194      * to each ear */
 195     i_next_atomic_operation = 0;
 196     i_source_channel_offset = 0;
 197     if ( i_physical_channels & AOUT_CHAN_LEFT )
 198     {
 199         ComputeChannelOperations ( p_data , i_rate
 200                 , i_next_atomic_operation , i_source_channel_offset
 201                 , -d_x , d_z , 2.0 / i_nb_channels );
 202         i_next_atomic_operation += 2;
 203         i_source_channel_offset++;
 204     }
 205     if ( i_physical_channels & AOUT_CHAN_RIGHT )
 206     {
 207         ComputeChannelOperations ( p_data , i_rate
 208                 , i_next_atomic_operation , i_source_channel_offset
 209                 , d_x , d_z , 2.0 / i_nb_channels );
 210         i_next_atomic_operation += 2;
 211         i_source_channel_offset++;
 212     }
 213     if ( i_physical_channels & AOUT_CHAN_REARLEFT )
 214     {
 215         ComputeChannelOperations ( p_data , i_rate
 216                 , i_next_atomic_operation , i_source_channel_offset
 217                 , -d_x , d_z_rear , 1.5 / i_nb_channels );
 218         i_next_atomic_operation += 2;
 219         i_source_channel_offset++;
 220     }
 221     if ( i_physical_channels & AOUT_CHAN_REARRIGHT )
 222     {
 223         ComputeChannelOperations ( p_data , i_rate
 224                 , i_next_atomic_operation , i_source_channel_offset
 225                 , d_x , d_z_rear , 1.5 / i_nb_channels );
 226         i_next_atomic_operation += 2;
 227         i_source_channel_offset++;
 228     }
 229     if ( i_physical_channels & AOUT_CHAN_REARCENTER )
 230     {
 231         ComputeChannelOperations ( p_data , i_rate
 232                 , i_next_atomic_operation , i_source_channel_offset
 233                 , 0 , -d_z , 1.5 / i_nb_channels );
 234         i_next_atomic_operation += 2;
 235         i_source_channel_offset++;
 236     }
 237     if ( i_physical_channels & AOUT_CHAN_CENTER )
 238     {
 239         ComputeChannelOperations ( p_data , i_rate
 240                 , i_next_atomic_operation , i_source_channel_offset
 241                 , 0 , d_z , 1.5 / i_nb_channels );
 242         i_next_atomic_operation += 2;
 243         i_source_channel_offset++;
 244     }
 245     if ( i_physical_channels & AOUT_CHAN_LFE )
 246     {
 247         ComputeChannelOperations ( p_data , i_rate
 248                 , i_next_atomic_operation , i_source_channel_offset
 249                 , 0 , d_z_rear , 5.0 / i_nb_channels );
 250         i_next_atomic_operation += 2;
 251         i_source_channel_offset++;
 252     }
 253     if ( i_physical_channels & AOUT_CHAN_MIDDLELEFT )
 254     {
 255         ComputeChannelOperations ( p_data , i_rate
 256                 , i_next_atomic_operation , i_source_channel_offset
 257                 , -d_x , 0 , 1.5 / i_nb_channels );
 258         i_next_atomic_operation += 2;
 259         i_source_channel_offset++;
 260     }
 261     if ( i_physical_channels & AOUT_CHAN_MIDDLERIGHT )
 262     {
 263         ComputeChannelOperations ( p_data , i_rate
 264                 , i_next_atomic_operation , i_source_channel_offset
 265                 , d_x , 0 , 1.5 / i_nb_channels );
 266         i_next_atomic_operation += 2;
 267         i_source_channel_offset++;
 268     }
 269
 270     /* Initialize the overflow buffer
 271      * we need it because the process induce a delay in the samples */
 272     p_data->i_overflow_buffer_size = 0;
 273     for ( i = 0 ; i < p_data->i_nb_atomic_operations ; i++ )
 274     {
 275         if ( p_data->i_overflow_buffer_size
 276                 < p_data->p_atomic_operations[i].i_delay * i_nb_channels
 277                 * sizeof (float) )
 278         {
 279             p_data->i_overflow_buffer_size
 280                 = p_data->p_atomic_operations[i].i_delay * i_nb_channels
 281                 * sizeof (float);
 282         }
 283     }
 284     p_data->p_overflow_buffer = malloc ( p_data->i_overflow_buffer_size );
 285     if ( p_data->p_atomic_operations == NULL )
 286     {
 287         msg_Err( p_filter, "out of memory" );
 288         return -1;
 289     }
 290     memset ( p_data->p_overflow_buffer , 0 , p_data->i_overflow_buffer_size );
 291
 292     /* end */
 293     return 0;
 294 }
 295
 296 /*****************************************************************************
 297  * Create: allocate headphone downmixer
 298  *****************************************************************************/
 299 static int Create( vlc_object_t *p_this )
 300 {
 301     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 302
 303     if ( p_filter->output.i_physical_channels != ( AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT )
 304           || p_filter->input.i_format != p_filter->output.i_format
 305           || p_filter->input.i_rate != p_filter->output.i_rate
 306           || (p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
 307                && p_filter->input.i_format != VLC_FOURCC('f','i','3','2')) )
 308     {
 309         msg_Dbg( p_filter, "Filter discarded (invalid format)" );
 310         return -1;
 311     }
 312
 313     /* Allocate the memory needed to store the module's structure */
 314     p_filter->p_sys = malloc( sizeof(struct aout_filter_sys_t) );
 315     if ( p_filter->p_sys == NULL )
 316     {
 317         msg_Err( p_filter, "out of memory" );
 318         return -1;
 319     }
 320     p_filter->p_sys->i_overflow_buffer_size = 0;
 321     p_filter->p_sys->p_overflow_buffer = NULL;
 322     p_filter->p_sys->i_nb_atomic_operations = 0;
 323     p_filter->p_sys->p_atomic_operations = NULL;
 324
 325     if ( Init( p_filter , p_filter->p_sys
 326                 , aout_FormatNbChannels ( &p_filter->input )
 327                 , p_filter->input.i_physical_channels
 328                 ,  p_filter->input.i_rate ) < 0 )
 329     {
 330         return -1;
 331     }
 332
 333     p_filter->pf_do_work = DoWork;
 334     p_filter->b_in_place = 0;
 335
 336     return 0;
 337 }
 338
 339 /*****************************************************************************
 340  * Destroy: deallocate resources associated with headphone downmixer
 341  *****************************************************************************/
 342 static void Destroy( vlc_object_t *p_this )
 343 {
 344     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 345
 346     if ( p_filter->p_sys != NULL )
 347     {
 348         if ( p_filter->p_sys->p_overflow_buffer != NULL )
 349         {
 350             free ( p_filter->p_sys->p_overflow_buffer );
 351         }
 352         if ( p_filter->p_sys->p_atomic_operations != NULL )
 353         {
 354             free ( p_filter->p_sys->p_atomic_operations );
 355         }
 356         free ( p_filter->p_sys );
 357         p_filter->p_sys = NULL;
 358     }
 359 }
 360
 361 /*****************************************************************************
 362  * DoWork: convert a buffer
 363  *****************************************************************************/
 364 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 365                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 366 {
 367     int i_input_nb = aout_FormatNbChannels( &p_filter->input );
 368     int i_output_nb = aout_FormatNbChannels( &p_filter->output );
 369
 370     float * p_in = (float*) p_in_buf->p_buffer;
 371     byte_t * p_out;
 372     byte_t * p_overflow;
 373     byte_t * p_slide;
 374
 375     size_t i_overflow_size;/* in bytes */
 376     size_t i_out_size;/* in bytes */
 377
 378     unsigned int i, j;
 379
 380     int i_source_channel_offset;
 381     int i_dest_channel_offset;
 382     unsigned int i_delay;
 383     double d_amplitude_factor;
 384
 385
 386     /* out buffer characterisitcs */
 387     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 388     p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * i_output_nb / i_input_nb;
 389     p_out = p_out_buf->p_buffer;
 390     i_out_size = p_out_buf->i_nb_bytes;
 391
 392     if ( p_filter->p_sys != NULL )
 393     {
 394         /* Slide the overflow buffer */
 395         p_overflow = p_filter->p_sys->p_overflow_buffer;
 396         i_overflow_size = p_filter->p_sys->i_overflow_buffer_size;
 397
 398         memset ( p_out , 0 , i_out_size );
 399         if ( i_out_size > i_overflow_size )
 400             memcpy ( p_out , p_overflow , i_overflow_size );
 401         else
 402             memcpy ( p_out , p_overflow , i_out_size );
 403
 404         p_slide = p_filter->p_sys->p_overflow_buffer;
 405         while ( p_slide < p_overflow + i_overflow_size )
 406         {
 407             if ( p_slide + i_out_size < p_overflow + i_overflow_size )
 408             {
 409                 memset ( p_slide , 0 , i_out_size );
 410                 if ( p_slide + 2 * i_out_size < p_overflow + i_overflow_size )
 411                     memcpy ( p_slide , p_slide + i_out_size , i_out_size );
 412                 else
 413                     memcpy ( p_slide , p_slide + i_out_size
 414                       , p_overflow + i_overflow_size - ( p_slide + i_out_size ) );
 415             }
 416             else
 417             {
 418                 memset ( p_slide , 0 , p_overflow + i_overflow_size - p_slide );
 419             }
 420             p_slide += i_out_size;
 421         }
 422
 423         /* apply the atomic operations */
 424         for ( i = 0 ; i < p_filter->p_sys->i_nb_atomic_operations ; i++ )
 425         {
 426             /* shorter variable names */
 427             i_source_channel_offset
 428                 = p_filter->p_sys->p_atomic_operations[i].i_source_channel_offset;
 429             i_dest_channel_offset
 430                 = p_filter->p_sys->p_atomic_operations[i].i_dest_channel_offset;
 431             i_delay = p_filter->p_sys->p_atomic_operations[i].i_delay;
 432             d_amplitude_factor
 433                 = p_filter->p_sys->p_atomic_operations[i].d_amplitude_factor;
 434
 435             if ( p_out_buf->i_nb_samples > i_delay )
 436             {
 437                 /* current buffer coefficients */
 438                 for ( j = 0 ; j < p_out_buf->i_nb_samples - i_delay ; j++ )
 439                 {
 440                     ((float*)p_out)[ (i_delay+j)*i_output_nb + i_dest_channel_offset ]
 441                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 442                            * d_amplitude_factor;
 443                 }
 444
 445                 /* overflow buffer coefficients */
 446                 for ( j = 0 ; j < i_delay ; j++ )
 447                 {
 448                     ((float*)p_overflow)[ j*i_output_nb + i_dest_channel_offset ]
 449                         += p_in[ (p_out_buf->i_nb_samples - i_delay + j)
 450                            * i_input_nb + i_source_channel_offset ]
 451                            * d_amplitude_factor;
 452                 }
 453             }
 454             else
 455             {
 456                 /* overflow buffer coefficients only */
 457                 for ( j = 0 ; j < p_out_buf->i_nb_samples ; j++ )
 458                 {
 459                     ((float*)p_overflow)[ (i_delay - p_out_buf->i_nb_samples + j)
 460                         * i_output_nb + i_dest_channel_offset ]
 461                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 462                            * d_amplitude_factor;
 463                 }
 464             }
 465         }
 466     }
 467     else
 468     {
 469         memset ( p_out , 0 , i_out_size );
 470     }
 471 }