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: headphone.c,v 1.5 2003/05/15 22:27:37 massiot Exp $
   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 HEADPHONE_DIM_TEXT N_("Characteristic dimension")
  49 #define HEADPHONE_DIM_LONGTEXT N_( \
  50      "Headphone virtual spatialization effect parameter: "\
  51      "distance between front left speaker and listener in meters.")
  52
  53 vlc_module_begin();
  54     add_category_hint( N_("headphone"), NULL, VLC_FALSE );
  55     add_integer( "headphone-dim", 5, NULL, HEADPHONE_DIM_TEXT,
  56                  HEADPHONE_DIM_LONGTEXT, VLC_TRUE );
  57     set_description( _("headphone channel mixer with virtual spatialization effect") );
  58     set_capability( "audio filter", 0 );
  59     set_callbacks( Create, Destroy );
  60     add_shortcut( "headphone" );
  61 vlc_module_end();
  62
  63
  64 /*****************************************************************************
  65  * Internal data structures
  66  *****************************************************************************/
  67 struct atomic_operation_t
  68 {
  69     int i_source_channel_offset;
  70     int i_dest_channel_offset;
  71     unsigned int i_delay;/* in sample unit */
  72     double d_amplitude_factor;
  73 };
  74
  75 struct aout_filter_sys_t
  76 {
  77     size_t i_overflow_buffer_size;/* in bytes */
  78     byte_t * p_overflow_buffer;
  79     unsigned int i_nb_atomic_operations;
  80     struct atomic_operation_t * p_atomic_operations;
  81 };
  82
  83 /*****************************************************************************
  84  * Init: initialize internal data structures
  85  * and computes the needed atomic operations
  86  *****************************************************************************/
  87 /* x and z represent the coordinates of the virtual speaker
  88  *  relatively to the center of the listener's head, measured in meters :
  89  *
  90  *  left              right
  91  *Z
  92  *-
  93  *a          head
  94  *x
  95  *i
  96  *s
  97  *  rear left    rear right
  98  *
  99  *          x-axis
 100  *  */
 101 static void ComputeChannelOperations ( struct aout_filter_sys_t * p_data
 102         , unsigned int i_rate , unsigned int i_next_atomic_operation
 103         , int i_source_channel_offset , double d_x , double d_z
 104         , double d_channel_amplitude_factor )
 105 {
 106     double d_c = 340; /*sound celerity (unit: m/s)*/
 107
 108     /* Left ear */
 109     p_data->p_atomic_operations[i_next_atomic_operation]
 110         .i_source_channel_offset = i_source_channel_offset;
 111     p_data->p_atomic_operations[i_next_atomic_operation]
 112         .i_dest_channel_offset = 0;/* left */
 113     p_data->p_atomic_operations[i_next_atomic_operation]
 114         .i_delay = (int)( sqrt( (-0.1-d_x)*(-0.1-d_x) + (0-d_z)*(0-d_z) )
 115                           / d_c * i_rate );
 116     if ( d_x < 0 )
 117     {
 118         p_data->p_atomic_operations[i_next_atomic_operation]
 119             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 120     }
 121     else if ( d_x > 0 )
 122     {
 123         p_data->p_atomic_operations[i_next_atomic_operation]
 124             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 125     }
 126     else
 127     {
 128         p_data->p_atomic_operations[i_next_atomic_operation]
 129             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 130     }
 131
 132     /* Right ear */
 133     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 134         .i_source_channel_offset = i_source_channel_offset;
 135     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 136         .i_dest_channel_offset = 1;/* right */
 137     p_data->p_atomic_operations[i_next_atomic_operation + 1]
 138         .i_delay = (int)( sqrt( (0.1-d_x)*(0.1-d_x) + (0-d_z)*(0-d_z) )
 139                           / d_c * i_rate );
 140     if ( d_x < 0 )
 141     {
 142         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 143             .d_amplitude_factor = d_channel_amplitude_factor * 0.9 / 2;
 144     }
 145     else if ( d_x > 0 )
 146     {
 147         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 148             .d_amplitude_factor = d_channel_amplitude_factor * 1.1 / 2;
 149     }
 150     else
 151     {
 152         p_data->p_atomic_operations[i_next_atomic_operation + 1]
 153             .d_amplitude_factor = d_channel_amplitude_factor / 2;
 154     }
 155 }
 156
 157 static int Init ( aout_filter_t * p_filter , struct aout_filter_sys_t * p_data
 158         , unsigned int i_nb_channels , uint32_t i_physical_channels
 159         , unsigned int i_rate )
 160 {
 161     double d_x = config_GetInt ( p_filter , "headphone-dim" );
 162     double d_z = d_x;
 163     double d_z_rear = -d_x/3;
 164     unsigned int i_next_atomic_operation;
 165     int i_source_channel_offset;
 166     unsigned int i;
 167
 168     if ( p_data == NULL )
 169     {
 170         msg_Dbg ( p_filter, "passing a null pointer as argument" );
 171         return 0;
 172     }
 173
 174     /* Number of elementary operations */
 175     p_data->i_nb_atomic_operations = i_nb_channels * 2;
 176     p_data->p_atomic_operations = malloc ( sizeof(struct atomic_operation_t)
 177             * p_data->i_nb_atomic_operations );
 178     if ( p_data->p_atomic_operations == NULL )
 179     {
 180         msg_Err( p_filter, "out of memory" );
 181         return -1;
 182     }
 183
 184     /* For each virtual speaker, computes elementary wave propagation time
 185      * to each ear */
 186     i_next_atomic_operation = 0;
 187     i_source_channel_offset = 0;
 188     if ( i_physical_channels & AOUT_CHAN_LEFT )
 189     {
 190         ComputeChannelOperations ( p_data , i_rate
 191                 , i_next_atomic_operation , i_source_channel_offset
 192                 , -d_x , d_z , 2.0 / i_nb_channels );
 193         i_next_atomic_operation += 2;
 194         i_source_channel_offset++;
 195     }
 196     if ( i_physical_channels & AOUT_CHAN_RIGHT )
 197     {
 198         ComputeChannelOperations ( p_data , i_rate
 199                 , i_next_atomic_operation , i_source_channel_offset
 200                 , d_x , d_z , 2.0 / i_nb_channels );
 201         i_next_atomic_operation += 2;
 202         i_source_channel_offset++;
 203     }
 204     if ( i_physical_channels & AOUT_CHAN_REARLEFT )
 205     {
 206         ComputeChannelOperations ( p_data , i_rate
 207                 , i_next_atomic_operation , i_source_channel_offset
 208                 , -d_x , d_z_rear , 1.5 / i_nb_channels );
 209         i_next_atomic_operation += 2;
 210         i_source_channel_offset++;
 211     }
 212     if ( i_physical_channels & AOUT_CHAN_REARRIGHT )
 213     {
 214         ComputeChannelOperations ( p_data , i_rate
 215                 , i_next_atomic_operation , i_source_channel_offset
 216                 , d_x , d_z_rear , 1.5 / i_nb_channels );
 217         i_next_atomic_operation += 2;
 218         i_source_channel_offset++;
 219     }
 220     if ( i_physical_channels & AOUT_CHAN_REARCENTER )
 221     {
 222         ComputeChannelOperations ( p_data , i_rate
 223                 , i_next_atomic_operation , i_source_channel_offset
 224                 , 0 , -d_z , 1.5 / i_nb_channels );
 225         i_next_atomic_operation += 2;
 226         i_source_channel_offset++;
 227     }
 228     if ( i_physical_channels & AOUT_CHAN_CENTER )
 229     {
 230         ComputeChannelOperations ( p_data , i_rate
 231                 , i_next_atomic_operation , i_source_channel_offset
 232                 , 0 , d_z , 1.5 / i_nb_channels );
 233         i_next_atomic_operation += 2;
 234         i_source_channel_offset++;
 235     }
 236     if ( i_physical_channels & AOUT_CHAN_LFE )
 237     {
 238         ComputeChannelOperations ( p_data , i_rate
 239                 , i_next_atomic_operation , i_source_channel_offset
 240                 , 0 , d_z_rear , 5.0 / i_nb_channels );
 241         i_next_atomic_operation += 2;
 242         i_source_channel_offset++;
 243     }
 244     if ( i_physical_channels & AOUT_CHAN_MIDDLELEFT )
 245     {
 246         ComputeChannelOperations ( p_data , i_rate
 247                 , i_next_atomic_operation , i_source_channel_offset
 248                 , -d_x , 0 , 1.5 / i_nb_channels );
 249         i_next_atomic_operation += 2;
 250         i_source_channel_offset++;
 251     }
 252     if ( i_physical_channels & AOUT_CHAN_MIDDLERIGHT )
 253     {
 254         ComputeChannelOperations ( p_data , i_rate
 255                 , i_next_atomic_operation , i_source_channel_offset
 256                 , d_x , 0 , 1.5 / i_nb_channels );
 257         i_next_atomic_operation += 2;
 258         i_source_channel_offset++;
 259     }
 260
 261     /* Initialize the overflow buffer
 262      * we need it because the process induce a delay in the samples */
 263     p_data->i_overflow_buffer_size = 0;
 264     for ( i = 0 ; i < p_data->i_nb_atomic_operations ; i++ )
 265     {
 266         if ( p_data->i_overflow_buffer_size
 267                 < p_data->p_atomic_operations[i].i_delay * i_nb_channels
 268                 * sizeof (float) )
 269         {
 270             p_data->i_overflow_buffer_size
 271                 = p_data->p_atomic_operations[i].i_delay * i_nb_channels
 272                 * sizeof (float);
 273         }
 274     }
 275     p_data->p_overflow_buffer = malloc ( p_data->i_overflow_buffer_size );
 276     if ( p_data->p_atomic_operations == NULL )
 277     {
 278         msg_Err( p_filter, "out of memory" );
 279         return -1;
 280     }
 281     memset ( p_data->p_overflow_buffer , 0 , p_data->i_overflow_buffer_size );
 282
 283     /* end */
 284     return 0;
 285 }
 286
 287 /*****************************************************************************
 288  * Create: allocate headphone downmixer
 289  *****************************************************************************/
 290 static int Create( vlc_object_t *p_this )
 291 {
 292     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 293
 294     if ( p_filter->output.i_physical_channels != ( AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT )
 295           || p_filter->input.i_format != p_filter->output.i_format
 296           || p_filter->input.i_rate != p_filter->output.i_rate
 297           || (p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
 298                && p_filter->input.i_format != VLC_FOURCC('f','i','3','2')) )
 299     {
 300         return -1;
 301     }
 302
 303     /* Allocate the memory needed to store the module's structure */
 304     p_filter->p_sys = malloc( sizeof(struct aout_filter_sys_t) );
 305     if ( p_filter->p_sys == NULL )
 306     {
 307         msg_Err( p_filter, "out of memory" );
 308         return -1;
 309     }
 310     p_filter->p_sys->i_overflow_buffer_size = 0;
 311     p_filter->p_sys->p_overflow_buffer = NULL;
 312     p_filter->p_sys->i_nb_atomic_operations = 0;
 313     p_filter->p_sys->p_atomic_operations = NULL;
 314
 315     if ( Init( p_filter , p_filter->p_sys
 316                 , aout_FormatNbChannels ( &p_filter->input )
 317                 , p_filter->input.i_physical_channels
 318                 ,  p_filter->input.i_rate ) < 0 )
 319     {
 320         return -1;
 321     }
 322
 323     p_filter->pf_do_work = DoWork;
 324     p_filter->b_in_place = 0;
 325
 326     return 0;
 327 }
 328
 329 /*****************************************************************************
 330  * Destroy: deallocate resources associated with headphone downmixer
 331  *****************************************************************************/
 332 static void Destroy( vlc_object_t *p_this )
 333 {
 334     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 335
 336     if ( p_filter->p_sys != NULL )
 337     {
 338         if ( p_filter->p_sys->p_overflow_buffer != NULL )
 339         {
 340             free ( p_filter->p_sys->p_overflow_buffer );
 341         }
 342         if ( p_filter->p_sys->p_atomic_operations != NULL )
 343         {
 344             free ( p_filter->p_sys->p_atomic_operations );
 345         }
 346         free ( p_filter->p_sys );
 347         p_filter->p_sys = NULL;
 348     }
 349 }
 350
 351 /*****************************************************************************
 352  * DoWork: convert a buffer
 353  *****************************************************************************/
 354 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 355                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 356 {
 357     int i_input_nb = aout_FormatNbChannels( &p_filter->input );
 358     int i_output_nb = aout_FormatNbChannels( &p_filter->output );
 359
 360     float * p_in = (float*) p_in_buf->p_buffer;
 361     byte_t * p_out;
 362     byte_t * p_overflow;
 363     byte_t * p_slide;
 364
 365     size_t i_overflow_size;/* in bytes */
 366     size_t i_out_size;/* in bytes */
 367
 368     unsigned int i, j;
 369
 370     int i_source_channel_offset;
 371     int i_dest_channel_offset;
 372     unsigned int i_delay;
 373     double d_amplitude_factor;
 374
 375
 376     /* out buffer characterisitcs */
 377     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 378     p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * i_output_nb / i_input_nb;
 379     p_out = p_out_buf->p_buffer;
 380     i_out_size = p_out_buf->i_nb_bytes;
 381
 382     if ( p_filter->p_sys != NULL )
 383     {
 384         /* Slide the overflow buffer */
 385         p_overflow = p_filter->p_sys->p_overflow_buffer;
 386         i_overflow_size = p_filter->p_sys->i_overflow_buffer_size;
 387
 388         memset ( p_out , 0 , i_out_size );
 389         if ( i_out_size > i_overflow_size )
 390             memcpy ( p_out , p_overflow , i_overflow_size );
 391         else
 392             memcpy ( p_out , p_overflow , i_out_size );
 393
 394         p_slide = p_filter->p_sys->p_overflow_buffer;
 395         while ( p_slide < p_overflow + i_overflow_size )
 396         {
 397             if ( p_slide + i_out_size < p_overflow + i_overflow_size )
 398             {
 399                 memset ( p_slide , 0 , i_out_size );
 400                 if ( p_slide + 2 * i_out_size < p_overflow + i_overflow_size )
 401                     memcpy ( p_slide , p_slide + i_out_size , i_out_size );
 402                 else
 403                     memcpy ( p_slide , p_slide + i_out_size
 404                       , p_overflow + i_overflow_size - ( p_slide + i_out_size ) );
 405             }
 406             else
 407             {
 408                 memset ( p_slide , 0 , p_overflow + i_overflow_size - p_slide );
 409             }
 410             p_slide += i_out_size;
 411         }
 412
 413         /* apply the atomic operations */
 414         for ( i = 0 ; i < p_filter->p_sys->i_nb_atomic_operations ; i++ )
 415         {
 416             /* shorter variable names */
 417             i_source_channel_offset
 418                 = p_filter->p_sys->p_atomic_operations[i].i_source_channel_offset;
 419             i_dest_channel_offset
 420                 = p_filter->p_sys->p_atomic_operations[i].i_dest_channel_offset;
 421             i_delay = p_filter->p_sys->p_atomic_operations[i].i_delay;
 422             d_amplitude_factor
 423                 = p_filter->p_sys->p_atomic_operations[i].d_amplitude_factor;
 424
 425             if ( p_out_buf->i_nb_samples > i_delay )
 426             {
 427                 /* current buffer coefficients */
 428                 for ( j = 0 ; j < p_out_buf->i_nb_samples - i_delay ; j++ )
 429                 {
 430                     ((float*)p_out)[ (i_delay+j)*i_output_nb + i_dest_channel_offset ]
 431                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 432                            * d_amplitude_factor;
 433                 }
 434
 435                 /* overflow buffer coefficients */
 436                 for ( j = 0 ; j < i_delay ; j++ )
 437                 {
 438                     ((float*)p_overflow)[ j*i_output_nb + i_dest_channel_offset ]
 439                         += p_in[ (p_out_buf->i_nb_samples - i_delay + j)
 440                            * i_input_nb + i_source_channel_offset ]
 441                            * d_amplitude_factor;
 442                 }
 443             }
 444             else
 445             {
 446                 /* overflow buffer coefficients only */
 447                 for ( j = 0 ; j < p_out_buf->i_nb_samples ; j++ )
 448                 {
 449                     ((float*)p_overflow)[ (i_delay - p_out_buf->i_nb_samples + j)
 450                         * i_output_nb + i_dest_channel_offset ]
 451                         += p_in[ j * i_input_nb + i_source_channel_offset ]
 452                            * d_amplitude_factor;
 453                 }
 454             }
 455         }
 456     }
 457     else
 458     {
 459         memset ( p_out , 0 , i_out_size );
 460     }
 461 }