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

   1 /*****************************************************************************
   2  * filters.c : audio output filters management
   3  *****************************************************************************
   4  * Copyright (C) 2002-2004 VideoLAN
   5  * $Id: filters.c,v 1.20 2004/03/03 20:39:52 gbazin 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, 0 );
  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     p_filter->b_continuity = VLC_FALSE;
  64
  65     return p_filter;
  66 }
  67
  68 /*****************************************************************************
  69  * SplitConversion: split a conversion in two parts
  70  *****************************************************************************
  71  * Returns the number of conversions required by the first part - 0 if only
  72  * one conversion was asked.
  73  * Beware : p_output_format can be modified during this function if the
  74  * developer passed SplitConversion( toto, titi, titi, ... ). That is legal.
  75  * SplitConversion( toto, titi, toto, ... ) isn't.
  76  *****************************************************************************/
  77 static int SplitConversion( const audio_sample_format_t * p_input_format,
  78                             const audio_sample_format_t * p_output_format,
  79                             audio_sample_format_t * p_middle_format )
  80 {
  81     vlc_bool_t b_format =
  82              (p_input_format->i_format != p_output_format->i_format);
  83     vlc_bool_t b_rate = (p_input_format->i_rate != p_output_format->i_rate);
  84     vlc_bool_t b_channels =
  85         (p_input_format->i_physical_channels
  86           != p_output_format->i_physical_channels)
  87      || (p_input_format->i_original_channels
  88           != p_output_format->i_original_channels);
  89     int i_nb_conversions = b_format + b_rate + b_channels;
  90
  91     if ( i_nb_conversions <= 1 ) return 0;
  92
  93     memcpy( p_middle_format, p_output_format, sizeof(audio_sample_format_t) );
  94
  95     if ( i_nb_conversions == 2 )
  96     {
  97         if ( !b_format || !b_channels )
  98         {
  99             p_middle_format->i_rate = p_input_format->i_rate;
 100             aout_FormatPrepare( p_middle_format );
 101             return 1;
 102         }
 103
 104         /* !b_rate */
 105         p_middle_format->i_physical_channels
 106              = p_input_format->i_physical_channels;
 107         p_middle_format->i_original_channels
 108              = p_input_format->i_original_channels;
 109         aout_FormatPrepare( p_middle_format );
 110         return 1;
 111     }
 112
 113     /* i_nb_conversion == 3 */
 114     p_middle_format->i_rate = p_input_format->i_rate;
 115     aout_FormatPrepare( p_middle_format );
 116     return 2;
 117 }
 118
 119 /*****************************************************************************
 120  * aout_FiltersCreatePipeline: create a filters pipeline to transform a sample
 121  *                             format to another
 122  *****************************************************************************
 123  * TODO : allow the user to add/remove specific filters
 124  *****************************************************************************/
 125 int aout_FiltersCreatePipeline( aout_instance_t * p_aout,
 126                                 aout_filter_t ** pp_filters,
 127                                 int * pi_nb_filters,
 128                                 const audio_sample_format_t * p_input_format,
 129                                 const audio_sample_format_t * p_output_format )
 130 {
 131     audio_sample_format_t temp_format;
 132     int i_nb_conversions;
 133
 134     if ( AOUT_FMTS_IDENTICAL( p_input_format, p_output_format ) )
 135     {
 136         msg_Dbg( p_aout, "no need for any filter" );
 137         *pi_nb_filters = 0;
 138         return 0;
 139     }
 140
 141     aout_FormatsPrint( p_aout, "filter(s)", p_input_format, p_output_format );
 142
 143     /* Try to find a filter to do the whole conversion. */
 144     pp_filters[0] = FindFilter( p_aout, p_input_format, p_output_format );
 145     if ( pp_filters[0] != NULL )
 146     {
 147         msg_Dbg( p_aout, "found a filter for the whole conversion" );
 148         *pi_nb_filters = 1;
 149         return 0;
 150     }
 151
 152     /* We'll have to split the conversion. We always do the downmixing
 153      * before the resampling, because the audio decoder can probably do it
 154      * for us. */
 155     i_nb_conversions = SplitConversion( p_input_format,
 156                                         p_output_format, &temp_format );
 157     if ( !i_nb_conversions )
 158     {
 159         /* There was only one conversion to do, and we already failed. */
 160         msg_Err( p_aout, "couldn't find a filter for the conversion" );
 161         return -1;
 162     }
 163
 164     pp_filters[0] = FindFilter( p_aout, p_input_format, &temp_format );
 165     if ( pp_filters[0] == NULL && i_nb_conversions == 2 )
 166     {
 167         /* Try with only one conversion. */
 168         SplitConversion( p_input_format, &temp_format, &temp_format );
 169         pp_filters[0] = FindFilter( p_aout, p_input_format, &temp_format );
 170     }
 171     if ( pp_filters[0] == NULL )
 172     {
 173         msg_Err( p_aout,
 174               "couldn't find a filter for the first part of the conversion" );
 175         return -1;
 176     }
 177
 178     /* We have the first stage of the conversion. Find a filter for
 179      * the rest. */
 180     pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
 181                                 p_output_format );
 182     if ( pp_filters[1] == NULL )
 183     {
 184         /* Try to split the conversion. */
 185         i_nb_conversions = SplitConversion( &pp_filters[0]->output,
 186                                            p_output_format, &temp_format );
 187         if ( !i_nb_conversions )
 188         {
 189             vlc_object_detach( pp_filters[0] );
 190             vlc_object_destroy( pp_filters[0] );
 191             msg_Err( p_aout,
 192               "couldn't find a filter for the second part of the conversion" );
 193         }
 194         pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
 195                                     &temp_format );
 196         pp_filters[2] = FindFilter( p_aout, &temp_format,
 197                                     p_output_format );
 198
 199         if ( pp_filters[1] == NULL || pp_filters[2] == NULL )
 200         {
 201             vlc_object_detach( pp_filters[0] );
 202             vlc_object_destroy( pp_filters[0] );
 203             if ( pp_filters[1] != NULL )
 204             {
 205                 vlc_object_detach( pp_filters[1] );
 206                 vlc_object_destroy( pp_filters[1] );
 207             }
 208             if ( pp_filters[2] != NULL )
 209             {
 210                 vlc_object_detach( pp_filters[2] );
 211                 vlc_object_destroy( pp_filters[2] );
 212             }
 213             msg_Err( p_aout,
 214                "couldn't find filters for the second part of the conversion" );
 215         }
 216         *pi_nb_filters = 3;
 217     }
 218     else
 219     {
 220         *pi_nb_filters = 2;
 221     }
 222
 223     /* We have enough filters. */
 224     msg_Dbg( p_aout, "found %d filters for the whole conversion",
 225              *pi_nb_filters );
 226     return 0;
 227 }
 228
 229 /*****************************************************************************
 230  * aout_FiltersDestroyPipeline: deallocate a filters pipeline
 231  *****************************************************************************/
 232 void aout_FiltersDestroyPipeline( aout_instance_t * p_aout,
 233                                   aout_filter_t ** pp_filters,
 234                                   int i_nb_filters )
 235 {
 236     int i;
 237
 238     for ( i = 0; i < i_nb_filters; i++ )
 239     {
 240         module_Unneed( pp_filters[i], pp_filters[i]->p_module );
 241         vlc_object_detach( pp_filters[i] );
 242         vlc_object_destroy( pp_filters[i] );
 243     }
 244 }
 245
 246 /*****************************************************************************
 247  * aout_FiltersHintBuffers: fill in aout_alloc_t structures to optimize
 248  *                          buffer allocations
 249  *****************************************************************************/
 250 void aout_FiltersHintBuffers( aout_instance_t * p_aout,
 251                               aout_filter_t ** pp_filters,
 252                               int i_nb_filters, aout_alloc_t * p_first_alloc )
 253 {
 254     int i;
 255
 256     (void)p_aout; /* unused */
 257
 258     for ( i = i_nb_filters - 1; i >= 0; i-- )
 259     {
 260         aout_filter_t * p_filter = pp_filters[i];
 261
 262         int i_output_size = p_filter->output.i_bytes_per_frame
 263                              * p_filter->output.i_rate
 264                              / p_filter->output.i_frame_length;
 265         int i_input_size = p_filter->input.i_bytes_per_frame
 266                              * p_filter->input.i_rate
 267                              / p_filter->input.i_frame_length;
 268
 269         p_first_alloc->i_bytes_per_sec = __MAX( p_first_alloc->i_bytes_per_sec,
 270                                                 i_output_size );
 271
 272         if ( p_filter->b_in_place )
 273         {
 274             p_first_alloc->i_bytes_per_sec = __MAX(
 275                                          p_first_alloc->i_bytes_per_sec,
 276                                          i_input_size );
 277             p_filter->output_alloc.i_alloc_type = AOUT_ALLOC_NONE;
 278         }
 279         else
 280         {
 281             /* We're gonna need a buffer allocation. */
 282             memcpy( &p_filter->output_alloc, p_first_alloc,
 283                     sizeof(aout_alloc_t) );
 284             p_first_alloc->i_alloc_type = AOUT_ALLOC_STACK;
 285             p_first_alloc->i_bytes_per_sec = i_input_size;
 286         }
 287     }
 288 }
 289
 290 /*****************************************************************************
 291  * aout_FiltersPlay: play a buffer
 292  *****************************************************************************/
 293 void aout_FiltersPlay( aout_instance_t * p_aout,
 294                        aout_filter_t ** pp_filters,
 295                        int i_nb_filters, aout_buffer_t ** pp_input_buffer )
 296 {
 297     int i;
 298
 299     for ( i = 0; i < i_nb_filters; i++ )
 300     {
 301         aout_filter_t * p_filter = pp_filters[i];
 302         aout_buffer_t * p_output_buffer;
 303
 304         /* Resamplers can produce slightly more samples than (i_in_nb *
 305          * p_filter->output.i_rate / p_filter->input.i_rate) so we need
 306          * slightly bigger buffers. */
 307         aout_BufferAlloc( &p_filter->output_alloc,
 308             ((mtime_t)(*pp_input_buffer)->i_nb_samples + 2)
 309             * 1000000 / p_filter->input.i_rate,
 310             *pp_input_buffer, p_output_buffer );
 311         if ( p_output_buffer == NULL )
 312         {
 313             msg_Err( p_aout, "out of memory" );
 314             return;
 315         }
 316         /* Please note that p_output_buffer->i_nb_samples & i_nb_bytes
 317          * shall be set by the filter plug-in. */
 318
 319         p_filter->pf_do_work( p_aout, p_filter, *pp_input_buffer,
 320                               p_output_buffer );
 321
 322         if ( !p_filter->b_in_place )
 323         {
 324             aout_BufferFree( *pp_input_buffer );
 325             *pp_input_buffer = p_output_buffer;
 326         }
 327     }
 328 }
 329