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 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., 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_shortname( _("Headphone effect") );
  63     set_category( CAT_AUDIO );
  64     set_subcategory( SUBCAT_AUDIO_AFILTER );
  65
  66     add_integer( "headphone-dim", 10, NULL, HEADPHONE_DIM_TEXT,
  67                  HEADPHONE_DIM_LONGTEXT, VLC_FALSE );
  68
  69     set_capability( "audio filter", 0 );
  70     set_callbacks( Create, Destroy );
  71     add_shortcut( "headphone" );
  72 vlc_module_end();
  73
  74
  75 /*****************************************************************************
  76  * Internal data structures
  77  *****************************************************************************/
  78 struct atomic_operation_t
  79 {
  80     int i_source_channel_offset;
  81     int i_dest_channel_offset;
  82     unsigned int i_delay;/* in sample unit */
  83     double d_amplitude_factor;
  84 };
  85
  86 struct aout_filter_sys_t
  87 {
  88     size_t i_overflow_buffer_size;/* in bytes */
  89     byte_t * p_overflow_buffer;
  90     unsigned int i_nb_atomic_operations;
  91     struct atomic_operation_t * p_atomic_operations;
  92 };
  93
  94 /*****************************************************************************
  95  * Init: initialize internal data structures
  96  * and computes the needed atomic operations
  97  *****************************************************************************/
  98 /* x and z represent the coordinates of the virtual speaker
  99  *  relatively to the center of the listener's head, measured in meters :
 100  *
 101  *  left              right
 102  *Z
 103  *-
 104  *a          head
 105  *x
 106  *i
 107  *s
 108  *  rear left    rear right
 109  *
 110  *          x-axis
 111  *  */
 112 static void ComputeChannelOperations ( struct aout_filter_sys_t * p_data
 113         , unsigned int i_rate , unsigned int i_next_atomic_operation
 114         , int i_source_channel_offset , double d_x , double d_z
 115         , double d_channel_amplitude_factor )
 116 {
 117     double d_c = 340; /*sound celerity (unit: m/s)*/
 118
 119     /* Left ear */
 120     p_data->p_atomic_operations[i_next_atomic_operation]
 121         .i_source_channel_offset = i_source_channel_offset;
 122     p_data->p_atomic_operations[i_next_atomic_operation]
 123         .i_dest_channel_offset = 0;/* left */
 124     p_data->p_atomic_operations[i_next_atomic_operation]
 125         .i_delay = (int)( sqrt( (-0.1-d_x)*(-0.1-d_x) + (0-d_z)*(0-d_z) )
 126                           / d_c * i_rate );
 127     if ( d_x < 0 )
 128     {
 129         p_data->p_atomic_operations[i_next_atomic_operation]
 130             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 131     }
 132     else if ( d_x > 0 )
 133     {
 134         p_data->p_atomic_operations[i_next_atomic_operation]
 135             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 136     }
 137     else
 138     {
 139         p_data->p_atomic_operations[i_next_atomic_operation]
 140             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 141     }
 142
 143     /* Right ear */
 144     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 145         .i_source_channel_offset = i_source_channel_offset;
 146     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 147         .i_dest_channel_offset = 1;/* right */
 148     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 149         .i_delay = (int)( sqrt( (0.1-d_x)*(0.1-d_x) + (0-d_z)*(0-d_z) )
 150                           / d_c * i_rate );
 151     if ( d_x < 0 )
 152     {
 153         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 154             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 155     }
 156     else if ( d_x > 0 )
 157     {
 158         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 159             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 160     }
 161     else
 162     {
 163         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 164             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 165     }
 166 }
 167
 168 static int Init ( aout_filter_t * p_filter , struct aout_filter_sys_t * p_data
 169         , unsigned int i_nb_channels , uint32_t i_physical_channels
 170         , unsigned int i_rate )
 171 {
 172     double d_x = config_GetInt ( p_filter , "headphone-dim" );
 173     double d_z = d_x;
 174     double d_z_rear = -d_x/3;
 175     unsigned int i_next_atomic_operation;
 176     int i_source_channel_offset;
 177     unsigned int i;
 178
 179     if ( p_data == NULL )
 180     {
 181         msg_Dbg ( p_filter, "passing a null pointer as argument" );
 182         return 0;
 183     }
 184
 185     /* Number of elementary operations */
 186     p_data->i_nb_atomic_operations = i_nb_channels * 2;
 187     p_data->p_atomic_operations = malloc ( sizeof(struct atomic_operation_t)
 188             * p_data->i_nb_atomic_operations );
 189     if ( p_data->p_atomic_operations == NULL )
 190     {
 191         msg_Err( p_filter, "out of memory" );
 192         return -1;
 193     }
 194
 195     /* For each virtual speaker, computes elementary wave propagation time
 196      * to each ear */
 197     i_next_atomic_operation = 0;
 198     i_source_channel_offset = 0;
 199     if ( i_physical_channels & AOUT_CHAN_LEFT )
 200     {
 201         ComputeChannelOperations ( p_data , i_rate
 202                 , i_next_atomic_operation , i_source_channel_offset
 203                 , -d_x , d_z , 2.0 / i_nb_channels );
 204         i_next_atomic_operation += 2;
 205         i_source_channel_offset++;
 206     }
 207     if ( i_physical_channels & AOUT_CHAN_RIGHT )
 208     {
 209         ComputeChannelOperations ( p_data , i_rate
 210                 , i_next_atomic_operation , i_source_channel_offset
 211                 , d_x , d_z , 2.0 / i_nb_channels );
 212         i_next_atomic_operation += 2;
 213         i_source_channel_offset++;
 214     }
 215     if ( i_physical_channels & AOUT_CHAN_REARLEFT )
 216     {
 217         ComputeChannelOperations ( p_data , i_rate
 218                 , i_next_atomic_operation , i_source_channel_offset
 219                 , -d_x , d_z_rear , 1.5 / i_nb_channels );
 220         i_next_atomic_operation += 2;
 221         i_source_channel_offset++;
 222     }
 223     if ( i_physical_channels & AOUT_CHAN_REARRIGHT )
 224     {
 225         ComputeChannelOperations ( p_data , i_rate
 226                 , i_next_atomic_operation , i_source_channel_offset
 227                 , d_x , d_z_rear , 1.5 / i_nb_channels );
 228         i_next_atomic_operation += 2;
 229         i_source_channel_offset++;
 230     }
 231     if ( i_physical_channels & AOUT_CHAN_REARCENTER )
 232     {
 233         ComputeChannelOperations ( p_data , i_rate
 234                 , i_next_atomic_operation , i_source_channel_offset
 235                 , 0 , -d_z , 1.5 / i_nb_channels );
 236         i_next_atomic_operation += 2;
 237         i_source_channel_offset++;
 238     }
 239     if ( i_physical_channels & AOUT_CHAN_CENTER )
 240     {
 241         ComputeChannelOperations ( p_data , i_rate
 242                 , i_next_atomic_operation , i_source_channel_offset
 243                 , 0 , d_z , 1.5 / i_nb_channels );
 244         i_next_atomic_operation += 2;
 245         i_source_channel_offset++;
 246     }
 247     if ( i_physical_channels & AOUT_CHAN_LFE )
 248     {
 249         ComputeChannelOperations ( p_data , i_rate
 250                 , i_next_atomic_operation , i_source_channel_offset
 251                 , 0 , d_z_rear , 5.0 / i_nb_channels );
 252         i_next_atomic_operation += 2;
 253         i_source_channel_offset++;
 254     }
 255     if ( i_physical_channels & AOUT_CHAN_MIDDLELEFT )
 256     {
 257         ComputeChannelOperations ( p_data , i_rate
 258                 , i_next_atomic_operation , i_source_channel_offset
 259                 , -d_x , 0 , 1.5 / i_nb_channels );
 260         i_next_atomic_operation += 2;
 261         i_source_channel_offset++;
 262     }
 263     if ( i_physical_channels & AOUT_CHAN_MIDDLERIGHT )
 264     {
 265         ComputeChannelOperations ( p_data , i_rate
 266                 , i_next_atomic_operation , i_source_channel_offset
 267                 , d_x , 0 , 1.5 / i_nb_channels );
 268         i_next_atomic_operation += 2;
 269         i_source_channel_offset++;
 270     }
 271
 272     /* Initialize the overflow buffer
 273      * we need it because the process induce a delay in the samples */
 274     p_data->i_overflow_buffer_size = 0;
 275     for ( i = 0 ; i < p_data->i_nb_atomic_operations ; i++ )
 276     {
 277         if ( p_data->i_overflow_buffer_size
 278                 < p_data->p_atomic_operations[i].i_delay * i_nb_channels
 279                 * sizeof (float) )
 280         {
 281             p_data->i_overflow_buffer_size
 282                 = p_data->p_atomic_operations[i].i_delay * i_nb_channels
 283                 * sizeof (float);
 284         }
 285     }
 286     p_data->p_overflow_buffer = malloc ( p_data->i_overflow_buffer_size );
 287     if ( p_data->p_atomic_operations == NULL )
 288     {
 289         msg_Err( p_filter, "out of memory" );
 290         return -1;
 291     }
 292     memset ( p_data->p_overflow_buffer , 0 , p_data->i_overflow_buffer_size );
 293
 294     /* end */
 295     return 0;
 296 }
 297
 298 /*****************************************************************************
 299  * Create: allocate headphone downmixer
 300  *****************************************************************************/
 301 static int Create( vlc_object_t *p_this )
 302 {
 303     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 304
 305     if ( p_filter->output.i_physical_channels != ( AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT )
 306           || p_filter->input.i_format != p_filter->output.i_format
 307           || p_filter->input.i_rate != p_filter->output.i_rate
 308           || (p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
 309                && p_filter->input.i_format != VLC_FOURCC('f','i','3','2')) )
 310     {
 311         msg_Dbg( p_filter, "Filter discarded (invalid format)" );
 312         return -1;
 313     }
 314
 315     /* Allocate the memory needed to store the module's structure */
 316     p_filter->p_sys = malloc( sizeof(struct aout_filter_sys_t) );
 317     if ( p_filter->p_sys == NULL )
 318     {
 319         msg_Err( p_filter, "out of memory" );
 320         return -1;
 321     }
 322     p_filter->p_sys->i_overflow_buffer_size = 0;
 323     p_filter->p_sys->p_overflow_buffer = NULL;
 324     p_filter->p_sys->i_nb_atomic_operations = 0;
 325     p_filter->p_sys->p_atomic_operations = NULL;
 326
 327     if ( Init( p_filter , p_filter->p_sys
 328                 , aout_FormatNbChannels ( &p_filter->input )
 329                 , p_filter->input.i_physical_channels
 330                 ,  p_filter->input.i_rate ) < 0 )
 331     {
 332         return -1;
 333     }
 334
 335     p_filter->pf_do_work = DoWork;
 336     p_filter->b_in_place = 0;
 337
 338     return 0;
 339 }
 340
 341 /*****************************************************************************
 342  * Destroy: deallocate resources associated with headphone downmixer
 343  *****************************************************************************/
 344 static void Destroy( vlc_object_t *p_this )
 345 {
 346     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 347
 348     if ( p_filter->p_sys != NULL )
 349     {
 350         if ( p_filter->p_sys->p_overflow_buffer != NULL )
 351         {
 352             free ( p_filter->p_sys->p_overflow_buffer );
 353         }
 354         if ( p_filter->p_sys->p_atomic_operations != NULL )
 355         {
 356             free ( p_filter->p_sys->p_atomic_operations );
 357         }
 358         free ( p_filter->p_sys );
 359         p_filter->p_sys = NULL;
 360     }
 361 }
 362
 363 /*****************************************************************************
 364  * DoWork: convert a buffer
 365  *****************************************************************************/
 366 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 367                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 368 {
 369     int i_input_nb = aout_FormatNbChannels( &p_filter->input );
 370     int i_output_nb = aout_FormatNbChannels( &p_filter->output );
 371
 372     float * p_in = (float*) p_in_buf->p_buffer;
 373     byte_t * p_out;
 374     byte_t * p_overflow;
 375     byte_t * p_slide;
 376
 377     size_t i_overflow_size;/* in bytes */
 378     size_t i_out_size;/* in bytes */
 379
 380     unsigned int i, j;
 381
 382     int i_source_channel_offset;
 383     int i_dest_channel_offset;
 384     unsigned int i_delay;
 385     double d_amplitude_factor;
 386
 387
 388     /* out buffer characterisitcs */
 389     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 390     p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * i_output_nb / i_input_nb;
 391     p_out = p_out_buf->p_buffer;
 392     i_out_size = p_out_buf->i_nb_bytes;
 393
 394     if ( p_filter->p_sys != NULL )
 395     {
 396         /* Slide the overflow buffer */
 397         p_overflow = p_filter->p_sys->p_overflow_buffer;
 398         i_overflow_size = p_filter->p_sys->i_overflow_buffer_size;
 399
 400         memset ( p_out , 0 , i_out_size );
 401         if ( i_out_size > i_overflow_size )
 402             memcpy ( p_out , p_overflow , i_overflow_size );
 403         else
 404             memcpy ( p_out , p_overflow , i_out_size );
 405
 406         p_slide = p_filter->p_sys->p_overflow_buffer;
 407         while ( p_slide < p_overflow + i_overflow_size )
 408         {
 409             if ( p_slide + i_out_size < p_overflow + i_overflow_size )
 410             {
 411                 memset ( p_slide , 0 , i_out_size );
 412                 if ( p_slide + 2 * i_out_size < p_overflow + i_overflow_size )
 413                     memcpy ( p_slide , p_slide + i_out_size , i_out_size );
 414                 else
 415                     memcpy ( p_slide , p_slide + i_out_size
 416                       , p_overflow + i_overflow_size - ( p_slide + i_out_size ) );
 417             }
 418             else
 419             {
 420                 memset ( p_slide , 0 , p_overflow + i_overflow_size - p_slide );
 421             }
 422             p_slide += i_out_size;
 423         }
 424
 425         /* apply the atomic operations */
 426         for ( i = 0 ; i < p_filter->p_sys->i_nb_atomic_operations ; i++ )
 427         {
 428             /* shorter variable names */
 429             i_source_channel_offset
 430                 = p_filter->p_sys->p_atomic_operations[i].i_source_channel_offset;
 431             i_dest_channel_offset
 432                 = p_filter->p_sys->p_atomic_operations[i].i_dest_channel_offset;
 433             i_delay = p_filter->p_sys->p_atomic_operations[i].i_delay;
 434             d_amplitude_factor
 435                 = p_filter->p_sys->p_atomic_operations[i].d_amplitude_factor;
 436
 437             if ( p_out_buf->i_nb_samples > i_delay )
 438             {
 439                 /* current buffer coefficients */
 440                 for ( j = 0 ; j < p_out_buf->i_nb_samples - i_delay ; j++ )
 441                 {
 442                     ((float*)p_out)[ (i_delay+j)*i_output_nb + i_dest_channel_offset ]
 443                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 444                            * d_amplitude_factor;
 445                 }
 446
 447                 /* overflow buffer coefficients */
 448                 for ( j = 0 ; j < i_delay ; j++ )
 449                 {
 450                     ((float*)p_overflow)[ j*i_output_nb + i_dest_channel_offset ]
 451                         += p_in[ (p_out_buf->i_nb_samples - i_delay + j)
 452                            * i_input_nb + i_source_channel_offset ]
 453                            * d_amplitude_factor;
 454                 }
 455             }
 456             else
 457             {
 458                 /* overflow buffer coefficients only */
 459                 for ( j = 0 ; j < p_out_buf->i_nb_samples ; j++ )
 460                 {
 461                     ((float*)p_overflow)[ (i_delay - p_out_buf->i_nb_samples + j)
 462                         * i_output_nb + i_dest_channel_offset ]
 463                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 464                            * d_amplitude_factor;
 465                 }
 466             }
 467         }
 468     }
 469     else
 470     {
 471         memset ( p_out , 0 , i_out_size );
 472     }
 473 }