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 1.12 2002/10/20 12:23:48 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     aout_FormatsPrint( p_aout, "filter(s)", p_input_format, p_output_format );
 132
 133     /* Try to find a filter to do the whole conversion. */
 134     pp_filters[0] = FindFilter( p_aout, p_input_format, p_output_format );
 135     if ( pp_filters[0] != NULL )
 136     {
 137         msg_Dbg( p_aout, "found a filter for the whole conversion" );
 138         *pi_nb_filters = 1;
 139         return 0;
 140     }
 141
 142     /* We'll have to split the conversion. We always do the downmixing
 143      * before the resampling, because the audio decoder can probably do it
 144      * for us. */
 145     i_nb_conversions = SplitConversion( p_aout, p_input_format,
 146                                         p_output_format, &temp_format );
 147     if ( !i_nb_conversions )
 148     {
 149         /* There was only one conversion to do, and we already failed. */
 150         msg_Err( p_aout, "couldn't find a filter for the conversion" );
 151         return -1;
 152     }
 153
 154     pp_filters[0] = FindFilter( p_aout, p_input_format, &temp_format );
 155     if ( pp_filters[0] == NULL && i_nb_conversions == 2 )
 156     {
 157         /* Try with only one conversion. */
 158         SplitConversion( p_aout, p_input_format, &temp_format,
 159                          &temp_format );
 160         pp_filters[0] = FindFilter( p_aout, p_input_format,
 161                                     &temp_format );
 162     }
 163     if ( pp_filters[0] == NULL )
 164     {
 165         msg_Err( p_aout,
 166               "couldn't find a filter for the first part of the conversion" );
 167         return -1;
 168     }
 169
 170     /* We have the first stage of the conversion. Find a filter for
 171      * the rest. */
 172     pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
 173                                 p_output_format );
 174     if ( pp_filters[1] == NULL )
 175     {
 176         /* Try to split the conversion. */
 177         i_nb_conversions = SplitConversion( p_aout,
 178                                     &pp_filters[0]->output,
 179                                     p_output_format, &temp_format );
 180         if ( !i_nb_conversions )
 181         {
 182             vlc_object_detach( pp_filters[0] );
 183             vlc_object_destroy( pp_filters[0] );
 184             msg_Err( p_aout,
 185               "couldn't find a filter for the second part of the conversion" );
 186         }
 187         pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
 188                                     &temp_format );
 189         pp_filters[2] = FindFilter( p_aout, &temp_format,
 190                                     p_output_format );
 191
 192         if ( pp_filters[1] == NULL || pp_filters[2] == NULL )
 193         {
 194             vlc_object_detach( pp_filters[0] );
 195             vlc_object_destroy( pp_filters[0] );
 196             if ( pp_filters[1] != NULL )
 197             {
 198                 vlc_object_detach( pp_filters[1] );
 199                 vlc_object_destroy( pp_filters[1] );
 200             }
 201             if ( pp_filters[2] != NULL )
 202             {
 203                 vlc_object_detach( pp_filters[2] );
 204                 vlc_object_destroy( pp_filters[2] );
 205             }
 206             msg_Err( p_aout,
 207                "couldn't find filters for the second part of the conversion" );
 208         }
 209         *pi_nb_filters = 3;
 210     }
 211     else
 212     {
 213         *pi_nb_filters = 2;
 214     }
 215
 216     /* We have enough filters. */
 217     msg_Dbg( p_aout, "found %d filters for the whole conversion",
 218              *pi_nb_filters );
 219     return 0;
 220 }
 221
 222 /*****************************************************************************
 223  * aout_FiltersDestroyPipeline: deallocate a filters pipeline
 224  *****************************************************************************/
 225 void aout_FiltersDestroyPipeline( aout_instance_t * p_aout,
 226                                   aout_filter_t ** pp_filters,
 227                                   int i_nb_filters )
 228 {
 229     int i;
 230
 231     for ( i = 0; i < i_nb_filters; i++ )
 232     {
 233         module_Unneed( pp_filters[i], pp_filters[i]->p_module );
 234         vlc_object_detach( pp_filters[i] );
 235         vlc_object_destroy( pp_filters[i] );
 236     }
 237 }
 238
 239 /*****************************************************************************
 240  * aout_FiltersHintBuffers: fill in aout_alloc_t structures to optimize
 241  *                          buffer allocations
 242  *****************************************************************************/
 243 void aout_FiltersHintBuffers( aout_instance_t * p_aout,
 244                               aout_filter_t ** pp_filters,
 245                               int i_nb_filters, aout_alloc_t * p_first_alloc )
 246 {
 247     int i;
 248
 249     for ( i = i_nb_filters - 1; i >= 0; i-- )
 250     {
 251         aout_filter_t * p_filter = pp_filters[i];
 252
 253         int i_output_size = p_filter->output.i_bytes_per_frame
 254                              * p_filter->output.i_rate
 255                              / p_filter->output.i_frame_length;
 256         int i_input_size = p_filter->input.i_bytes_per_frame
 257                              * p_filter->input.i_rate
 258                              / p_filter->input.i_frame_length;
 259
 260         p_first_alloc->i_bytes_per_sec = __MAX( p_first_alloc->i_bytes_per_sec,
 261                                                 i_output_size );
 262
 263         if ( p_filter->b_in_place )
 264         {
 265             p_first_alloc->i_bytes_per_sec = __MAX(
 266                                          p_first_alloc->i_bytes_per_sec,
 267                                          i_input_size );
 268             p_filter->output_alloc.i_alloc_type = AOUT_ALLOC_NONE;
 269         }
 270         else
 271         {
 272             /* We're gonna need a buffer allocation. */
 273             memcpy( &p_filter->output_alloc, p_first_alloc,
 274                     sizeof(aout_alloc_t) );
 275             p_first_alloc->i_alloc_type = AOUT_ALLOC_STACK;
 276             p_first_alloc->i_bytes_per_sec = i_input_size;
 277         }
 278     }
 279 }
 280
 281 /*****************************************************************************
 282  * aout_FiltersPlay: play a buffer
 283  *****************************************************************************/
 284 void aout_FiltersPlay( aout_instance_t * p_aout,
 285                        aout_filter_t ** pp_filters,
 286                        int i_nb_filters, aout_buffer_t ** pp_input_buffer )
 287 {
 288     int i;
 289
 290     for ( i = 0; i < i_nb_filters; i++ )
 291     {
 292         aout_filter_t * p_filter = pp_filters[i];
 293         aout_buffer_t * p_output_buffer;
 294
 295         aout_BufferAlloc( &p_filter->output_alloc,
 296                           (mtime_t)(*pp_input_buffer)->i_nb_samples * 1000000
 297                             / p_filter->input.i_rate, *pp_input_buffer,
 298                           p_output_buffer );
 299         if ( p_output_buffer == NULL )
 300         {
 301             msg_Err( p_aout, "out of memory" );
 302             return;
 303         }
 304         /* Please note that p_output_buffer->i_nb_samples & i_nb_bytes
 305          * shall be set by the filter plug-in. */
 306
 307         p_filter->pf_do_work( p_aout, p_filter, *pp_input_buffer,
 308                               p_output_buffer );
 309
 310         if ( !p_filter->b_in_place )
 311         {
 312             aout_BufferFree( *pp_input_buffer );
 313             *pp_input_buffer = p_output_buffer;
 314         }
 315     }
 316 }
 317