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 1.15 2002/12/06 10:10:39 sam 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     p_filter->b_reinit = VLC_TRUE;
  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             return 1;
 101         }
 102
 103         /* !b_rate */
 104         p_middle_format->i_physical_channels
 105              = p_input_format->i_physical_channels;
 106         p_middle_format->i_original_channels
 107              = p_input_format->i_original_channels;
 108         return 1;
 109     }
 110
 111     /* i_nb_conversion == 3 */
 112     p_middle_format->i_rate = p_input_format->i_rate;
 113     return 2;
 114 }
 115
 116 /*****************************************************************************
 117  * aout_FiltersCreatePipeline: create a filters pipeline to transform a sample
 118  *                             format to another
 119  *****************************************************************************
 120  * TODO : allow the user to add/remove specific filters
 121  *****************************************************************************/
 122 int aout_FiltersCreatePipeline( aout_instance_t * p_aout,
 123                                 aout_filter_t ** pp_filters,
 124                                 int * pi_nb_filters,
 125                                 const audio_sample_format_t * p_input_format,
 126                                 const audio_sample_format_t * p_output_format )
 127 {
 128     audio_sample_format_t temp_format;
 129     int i_nb_conversions;
 130
 131     if ( AOUT_FMTS_IDENTICAL( p_input_format, p_output_format ) )
 132     {
 133         msg_Dbg( p_aout, "no need for any filter" );
 134         *pi_nb_filters = 0;
 135         return 0;
 136     }
 137
 138     aout_FormatsPrint( p_aout, "filter(s)", p_input_format, p_output_format );
 139
 140     /* Try to find a filter to do the whole conversion. */
 141     pp_filters[0] = FindFilter( p_aout, p_input_format, p_output_format );
 142     if ( pp_filters[0] != NULL )
 143     {
 144         msg_Dbg( p_aout, "found a filter for the whole conversion" );
 145         *pi_nb_filters = 1;
 146         return 0;
 147     }
 148
 149     /* We'll have to split the conversion. We always do the downmixing
 150      * before the resampling, because the audio decoder can probably do it
 151      * for us. */
 152     i_nb_conversions = SplitConversion( p_input_format,
 153                                         p_output_format, &temp_format );
 154     if ( !i_nb_conversions )
 155     {
 156         /* There was only one conversion to do, and we already failed. */
 157         msg_Err( p_aout, "couldn't find a filter for the conversion" );
 158         return -1;
 159     }
 160
 161     pp_filters[0] = FindFilter( p_aout, p_input_format, &temp_format );
 162     if ( pp_filters[0] == NULL && i_nb_conversions == 2 )
 163     {
 164         /* Try with only one conversion. */
 165         SplitConversion( p_input_format, &temp_format, &temp_format );
 166         pp_filters[0] = FindFilter( p_aout, p_input_format, &temp_format );
 167     }
 168     if ( pp_filters[0] == NULL )
 169     {
 170         msg_Err( p_aout,
 171               "couldn't find a filter for the first part of the conversion" );
 172         return -1;
 173     }
 174
 175     /* We have the first stage of the conversion. Find a filter for
 176      * the rest. */
 177     pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
 178                                 p_output_format );
 179     if ( pp_filters[1] == NULL )
 180     {
 181         /* Try to split the conversion. */
 182         i_nb_conversions = SplitConversion( &pp_filters[0]->output,
 183                                            p_output_format, &temp_format );
 184         if ( !i_nb_conversions )
 185         {
 186             vlc_object_detach( pp_filters[0] );
 187             vlc_object_destroy( pp_filters[0] );
 188             msg_Err( p_aout,
 189               "couldn't find a filter for the second part of the conversion" );
 190         }
 191         pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
 192                                     &temp_format );
 193         pp_filters[2] = FindFilter( p_aout, &temp_format,
 194                                     p_output_format );
 195
 196         if ( pp_filters[1] == NULL || pp_filters[2] == NULL )
 197         {
 198             vlc_object_detach( pp_filters[0] );
 199             vlc_object_destroy( pp_filters[0] );
 200             if ( pp_filters[1] != NULL )
 201             {
 202                 vlc_object_detach( pp_filters[1] );
 203                 vlc_object_destroy( pp_filters[1] );
 204             }
 205             if ( pp_filters[2] != NULL )
 206             {
 207                 vlc_object_detach( pp_filters[2] );
 208                 vlc_object_destroy( pp_filters[2] );
 209             }
 210             msg_Err( p_aout,
 211                "couldn't find filters for the second part of the conversion" );
 212         }
 213         *pi_nb_filters = 3;
 214     }
 215     else
 216     {
 217         *pi_nb_filters = 2;
 218     }
 219
 220     /* We have enough filters. */
 221     msg_Dbg( p_aout, "found %d filters for the whole conversion",
 222              *pi_nb_filters );
 223     return 0;
 224 }
 225
 226 /*****************************************************************************
 227  * aout_FiltersDestroyPipeline: deallocate a filters pipeline
 228  *****************************************************************************/
 229 void aout_FiltersDestroyPipeline( aout_instance_t * p_aout,
 230                                   aout_filter_t ** pp_filters,
 231                                   int i_nb_filters )
 232 {
 233     int i;
 234
 235     for ( i = 0; i < i_nb_filters; i++ )
 236     {
 237         module_Unneed( pp_filters[i], pp_filters[i]->p_module );
 238         vlc_object_detach( pp_filters[i] );
 239         vlc_object_destroy( pp_filters[i] );
 240     }
 241 }
 242
 243 /*****************************************************************************
 244  * aout_FiltersHintBuffers: fill in aout_alloc_t structures to optimize
 245  *                          buffer allocations
 246  *****************************************************************************/
 247 void aout_FiltersHintBuffers( aout_instance_t * p_aout,
 248                               aout_filter_t ** pp_filters,
 249                               int i_nb_filters, aout_alloc_t * p_first_alloc )
 250 {
 251     int i;
 252
 253     (void)p_aout; /* unused */
 254
 255     for ( i = i_nb_filters - 1; i >= 0; i-- )
 256     {
 257         aout_filter_t * p_filter = pp_filters[i];
 258
 259         int i_output_size = p_filter->output.i_bytes_per_frame
 260                              * p_filter->output.i_rate
 261                              / p_filter->output.i_frame_length;
 262         int i_input_size = p_filter->input.i_bytes_per_frame
 263                              * p_filter->input.i_rate
 264                              / p_filter->input.i_frame_length;
 265
 266         p_first_alloc->i_bytes_per_sec = __MAX( p_first_alloc->i_bytes_per_sec,
 267                                                 i_output_size );
 268
 269         if ( p_filter->b_in_place )
 270         {
 271             p_first_alloc->i_bytes_per_sec = __MAX(
 272                                          p_first_alloc->i_bytes_per_sec,
 273                                          i_input_size );
 274             p_filter->output_alloc.i_alloc_type = AOUT_ALLOC_NONE;
 275         }
 276         else
 277         {
 278             /* We're gonna need a buffer allocation. */
 279             memcpy( &p_filter->output_alloc, p_first_alloc,
 280                     sizeof(aout_alloc_t) );
 281             p_first_alloc->i_alloc_type = AOUT_ALLOC_STACK;
 282             p_first_alloc->i_bytes_per_sec = i_input_size;
 283         }
 284     }
 285 }
 286
 287 /*****************************************************************************
 288  * aout_FiltersPlay: play a buffer
 289  *****************************************************************************/
 290 void aout_FiltersPlay( aout_instance_t * p_aout,
 291                        aout_filter_t ** pp_filters,
 292                        int i_nb_filters, aout_buffer_t ** pp_input_buffer )
 293 {
 294     int i;
 295
 296     for ( i = 0; i < i_nb_filters; i++ )
 297     {
 298         aout_filter_t * p_filter = pp_filters[i];
 299         aout_buffer_t * p_output_buffer;
 300
 301         /* We need this because resamplers can produce more samples than
 302            (i_in_nb * p_filter->output.i_rate / p_filter->input.i_rate) */
 303         int i_compensate_rounding = 2 * p_filter->input.i_rate
 304             / p_filter->output.i_rate;
 305
 306         aout_BufferAlloc( &p_filter->output_alloc,
 307             ((mtime_t)(*pp_input_buffer)->i_nb_samples + i_compensate_rounding)
 308             * 1000000 / p_filter->input.i_rate,
 309             *pp_input_buffer, p_output_buffer );
 310         if ( p_output_buffer == NULL )
 311         {
 312             msg_Err( p_aout, "out of memory" );
 313             return;
 314         }
 315         /* Please note that p_output_buffer->i_nb_samples & i_nb_bytes
 316          * shall be set by the filter plug-in. */
 317
 318         p_filter->pf_do_work( p_aout, p_filter, *pp_input_buffer,
 319                               p_output_buffer );
 320
 321         if ( !p_filter->b_in_place )
 322         {
 323             aout_BufferFree( *pp_input_buffer );
 324             *pp_input_buffer = p_output_buffer;
 325         }
 326     }
 327 }
 328