git.sesse.net Git - vlc/blob - src/audio_output/filters.c

   1 /*****************************************************************************
   2  * filters.c : audio output filters management
   3  *****************************************************************************
   4  * Copyright (C) 2002 VideoLAN
   5  * $Id: filters.c,v 1.10 2002/09/22 14:53:52 massiot Exp $
   6  *
   7  * Authors: Christophe Massiot <massiot@via.ecp.fr>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #include <stdlib.h>                            /* calloc(), malloc(), free() */
  28 #include <string.h>
  29
  30 #include <vlc/vlc.h>
  31
  32 #ifdef HAVE_ALLOCA_H
  33 #   include <alloca.h>
  34 #endif
  35
  36 #include "audio_output.h"
  37 #include "aout_internal.h"
  38
  39 /*****************************************************************************
  40  * FindFilter: find an audio filter for a specific transformation
  41  *****************************************************************************/
  42 static aout_filter_t * FindFilter( aout_instance_t * p_aout,
  43                              const audio_sample_format_t * p_input_format,
  44                              const audio_sample_format_t * p_output_format )
  45 {
  46     aout_filter_t * p_filter = vlc_object_create( p_aout,
  47                                                   sizeof(aout_filter_t) );
  48
  49     if ( p_filter == NULL ) return NULL;
  50     vlc_object_attach( p_filter, p_aout );
  51
  52     memcpy( &p_filter->input, p_input_format, sizeof(audio_sample_format_t) );
  53     memcpy( &p_filter->output, p_output_format,
  54             sizeof(audio_sample_format_t) );
  55     p_filter->p_module = module_Need( p_filter, "audio filter", NULL );
  56     if ( p_filter->p_module == NULL )
  57     {
  58         vlc_object_detach( p_filter );
  59         vlc_object_destroy( p_filter );
  60         return NULL;
  61     }
  62
  63     return p_filter;
  64 }
  65
  66 /*****************************************************************************
  67  * SplitConversion: split a conversion in two parts
  68  *****************************************************************************
  69  * Returns the number of conversions required by the first part - 0 if only
  70  * one conversion was asked.
  71  * Beware : p_output_format can be modified during this function if the
  72  * developer passed SplitConversion( toto, titi, titi, ... ). That is legal.
  73  * SplitConversion( toto, titi, toto, ... ) isn't.
  74  *****************************************************************************/
  75 static int SplitConversion( aout_instance_t * p_aout,
  76                              const audio_sample_format_t * p_input_format,
  77                              const audio_sample_format_t * p_output_format,
  78                              audio_sample_format_t * p_middle_format )
  79 {
  80     vlc_bool_t b_format =
  81              (p_input_format->i_format != p_output_format->i_format);
  82     vlc_bool_t b_rate = (p_input_format->i_rate != p_output_format->i_rate);
  83     vlc_bool_t b_channels =
  84              (p_input_format->i_channels != p_output_format->i_channels);
  85     int i_nb_conversions = b_format + b_rate + b_channels;
  86
  87     if ( i_nb_conversions <= 1 ) return 0;
  88
  89     memcpy( p_middle_format, p_output_format, sizeof(audio_sample_format_t) );
  90
  91     if ( i_nb_conversions == 2 )
  92     {
  93         if ( !b_format || !b_channels )
  94         {
  95             p_middle_format->i_rate = p_input_format->i_rate;
  96             return 1;
  97         }
  98
  99         /* !b_rate */
 100         p_middle_format->i_channels = p_input_format->i_channels;
 101         return 1;
 102     }
 103
 104     /* i_nb_conversion == 3 */
 105     p_middle_format->i_rate = p_input_format->i_rate;
 106     return 2;
 107 }
 108
 109 /*****************************************************************************
 110  * aout_FiltersCreatePipeline: create a filters pipeline to transform a sample
 111  *                             format to another
 112  *****************************************************************************
 113  * TODO : allow the user to add/remove specific filters
 114  *****************************************************************************/
 115 int aout_FiltersCreatePipeline( aout_instance_t * p_aout,
 116                                 aout_filter_t ** pp_filters,
 117                                 int * pi_nb_filters,
 118                                 const audio_sample_format_t * p_input_format,
 119                                 const audio_sample_format_t * p_output_format )
 120 {
 121     audio_sample_format_t temp_format;
 122     int i_nb_conversions;
 123
 124     if ( AOUT_FMTS_IDENTICAL( p_input_format, p_output_format ) )
 125     {
 126         msg_Dbg( p_aout, "no need for any filter" );
 127         *pi_nb_filters = 0;
 128         return 0;
 129     }
 130
 131     msg_Dbg( p_aout, "filter(s) format=%d->%d rate=%d->%d channels=%d->%d",
 132              p_input_format->i_format, p_output_format->i_format,
 133              p_input_format->i_rate, p_output_format->i_rate,
 134              p_input_format->i_channels, p_output_format->i_channels );
 135
 136     /* Try to find a filter to do the whole conversion. */
 137     pp_filters[0] = FindFilter( p_aout, p_input_format, p_output_format );
 138     if ( pp_filters[0] != NULL )
 139     {
 140         msg_Dbg( p_aout, "found a filter for the whole conversion" );
 141         *pi_nb_filters = 1;
 142         return 0;
 143     }
 144
 145     /* We'll have to split the conversion. We always do the downmixing
 146      * before the resampling, because the audio decoder can probably do it
 147      * for us. */
 148     i_nb_conversions = SplitConversion( p_aout, p_input_format,
 149                                         p_output_format, &temp_format );
 150     if ( !i_nb_conversions )
 151     {
 152         /* There was only one conversion to do, and we already failed. */
 153         msg_Err( p_aout, "couldn't find a filter for the conversion" );
 154         return -1;
 155     }
 156
 157     pp_filters[0] = FindFilter( p_aout, p_input_format, &temp_format );
 158     if ( pp_filters[0] == NULL && i_nb_conversions == 2 )
 159     {
 160         /* Try with only one conversion. */
 161         SplitConversion( p_aout, p_input_format, &temp_format,
 162                          &temp_format );
 163         pp_filters[0] = FindFilter( p_aout, p_input_format,
 164                                     &temp_format );
 165     }
 166     if ( pp_filters[0] == NULL )
 167     {
 168         msg_Err( p_aout,
 169               "couldn't find a filter for the first part of the conversion" );
 170         return -1;
 171     }
 172
 173     /* We have the first stage of the conversion. Find a filter for
 174      * the rest. */
 175     pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
 176                                 p_output_format );
 177     if ( pp_filters[1] == NULL )
 178     {
 179         /* Try to split the conversion. */
 180         i_nb_conversions = SplitConversion( p_aout,
 181                                     &pp_filters[0]->output,
 182                                     p_output_format, &temp_format );
 183         if ( !i_nb_conversions )
 184         {
 185             vlc_object_detach( pp_filters[0] );
 186             vlc_object_destroy( pp_filters[0] );
 187             msg_Err( p_aout,
 188               "couldn't find a filter for the second part of the conversion" );
 189         }
 190         pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
 191                                     &temp_format );
 192         pp_filters[2] = FindFilter( p_aout, &temp_format,
 193                                     p_output_format );
 194
 195         if ( pp_filters[1] == NULL || pp_filters[2] == NULL )
 196         {
 197             vlc_object_detach( pp_filters[0] );
 198             vlc_object_destroy( pp_filters[0] );
 199             if ( pp_filters[1] != NULL )
 200             {
 201                 vlc_object_detach( pp_filters[1] );
 202                 vlc_object_destroy( pp_filters[1] );
 203             }
 204             if ( pp_filters[2] != NULL )
 205             {
 206                 vlc_object_detach( pp_filters[2] );
 207                 vlc_object_destroy( pp_filters[2] );
 208             }
 209             msg_Err( p_aout,
 210                "couldn't find filters for the second part of the conversion" );
 211         }
 212         *pi_nb_filters = 3;
 213     }
 214     else
 215     {
 216         *pi_nb_filters = 2;
 217     }
 218
 219     /* We have enough filters. */
 220     msg_Dbg( p_aout, "found %d filters for the whole conversion",
 221              *pi_nb_filters );
 222     return 0;
 223 }
 224
 225 /*****************************************************************************
 226  * aout_FiltersDestroyPipeline: deallocate a filters pipeline
 227  *****************************************************************************/
 228 void aout_FiltersDestroyPipeline( aout_instance_t * p_aout,
 229                                   aout_filter_t ** pp_filters,
 230                                   int i_nb_filters )
 231 {
 232     int i;
 233
 234     for ( i = 0; i < i_nb_filters; i++ )
 235     {
 236         module_Unneed( pp_filters[i], pp_filters[i]->p_module );
 237         vlc_object_detach( pp_filters[i] );
 238         vlc_object_destroy( pp_filters[i] );
 239     }
 240 }
 241
 242 /*****************************************************************************
 243  * aout_FiltersHintBuffers: fill in aout_alloc_t structures to optimize
 244  *                          buffer allocations
 245  *****************************************************************************/
 246 void aout_FiltersHintBuffers( aout_instance_t * p_aout,
 247                               aout_filter_t ** pp_filters,
 248                               int i_nb_filters, aout_alloc_t * p_first_alloc )
 249 {
 250     int i;
 251
 252     for ( i = i_nb_filters - 1; i >= 0; i-- )
 253     {
 254         aout_filter_t * p_filter = pp_filters[i];
 255
 256         int i_output_size = p_filter->output.i_bytes_per_frame
 257                              * p_filter->output.i_rate
 258                              / p_filter->output.i_frame_length;
 259         int i_input_size = p_filter->input.i_bytes_per_frame
 260                              * p_filter->input.i_rate
 261                              / p_filter->input.i_frame_length;
 262
 263         p_first_alloc->i_bytes_per_sec = __MAX( p_first_alloc->i_bytes_per_sec,
 264                                                 i_output_size );
 265
 266         if ( p_filter->b_in_place )
 267         {
 268             p_first_alloc->i_bytes_per_sec = __MAX(
 269                                          p_first_alloc->i_bytes_per_sec,
 270                                          i_input_size );
 271             p_filter->output_alloc.i_alloc_type = AOUT_ALLOC_NONE;
 272         }
 273         else
 274         {
 275             /* We're gonna need a buffer allocation. */
 276             memcpy( &p_filter->output_alloc, p_first_alloc,
 277                     sizeof(aout_alloc_t) );
 278             p_first_alloc->i_alloc_type = AOUT_ALLOC_STACK;
 279             p_first_alloc->i_bytes_per_sec = i_input_size;
 280         }
 281     }
 282 }
 283
 284 /*****************************************************************************
 285  * aout_FiltersPlay: play a buffer
 286  *****************************************************************************/
 287 void aout_FiltersPlay( aout_instance_t * p_aout,
 288                        aout_filter_t ** pp_filters,
 289                        int i_nb_filters, aout_buffer_t ** pp_input_buffer )
 290 {
 291     int i;
 292
 293     for ( i = 0; i < i_nb_filters; i++ )
 294     {
 295         aout_filter_t * p_filter = pp_filters[i];
 296         aout_buffer_t * p_output_buffer;
 297
 298         aout_BufferAlloc( &p_filter->output_alloc,
 299                           (mtime_t)(*pp_input_buffer)->i_nb_samples * 1000000
 300                             / p_filter->input.i_rate, *pp_input_buffer,
 301                           p_output_buffer );
 302         if ( p_output_buffer == NULL )
 303         {
 304             msg_Err( p_aout, "out of memory" );
 305             return;
 306         }
 307         /* Please note that p_output_buffer->i_nb_samples & i_nb_bytes
 308          * shall be set by the filter plug-in. */
 309
 310         p_filter->pf_do_work( p_aout, p_filter, *pp_input_buffer,
 311                               p_output_buffer );
 312
 313         if ( !p_filter->b_in_place )
 314         {
 315             aout_BufferFree( *pp_input_buffer );
 316             *pp_input_buffer = p_output_buffer;
 317         }
 318     }
 319 }
 320