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 1.9 2002/09/02 23:17:06 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 )
  94         {
  95             p_middle_format->i_rate = p_input_format->i_rate;
  96             return 1;
  97         }
  98
  99         if ( !b_rate )
 100         {
 101             p_middle_format->i_channels = p_input_format->i_channels;
 102             return 1;
 103         }
 104
 105         /* !b_channels */
 106         p_middle_format->i_rate = p_input_format->i_rate;
 107         return 1;
 108     }
 109
 110     /* i_nb_conversion == 3 */
 111     p_middle_format->i_channels = p_input_format->i_channels;
 112     return 2;
 113 }
 114
 115 /*****************************************************************************
 116  * aout_FiltersCreatePipeline: create a filters pipeline to transform a sample
 117  *                             format to another
 118  *****************************************************************************
 119  * TODO : allow the user to add/remove specific filters
 120  *****************************************************************************/
 121 int aout_FiltersCreatePipeline( aout_instance_t * p_aout,
 122                                 aout_filter_t ** pp_filters,
 123                                 int * pi_nb_filters,
 124                                 const audio_sample_format_t * p_input_format,
 125                                 const audio_sample_format_t * p_output_format )
 126 {
 127     audio_sample_format_t temp_format;
 128     int i_nb_conversions;
 129
 130     if ( AOUT_FMTS_IDENTICAL( p_input_format, p_output_format ) )
 131     {
 132         msg_Dbg( p_aout, "no need for any filter" );
 133         *pi_nb_filters = 0;
 134         return 0;
 135     }
 136
 137     msg_Dbg( p_aout, "filter(s) format=%d->%d rate=%d->%d channels=%d->%d",
 138              p_input_format->i_format, p_output_format->i_format,
 139              p_input_format->i_rate, p_output_format->i_rate,
 140              p_input_format->i_channels, p_output_format->i_channels );
 141
 142     /* Try to find a filter to do the whole conversion. */
 143     pp_filters[0] = FindFilter( p_aout, p_input_format, p_output_format );
 144     if ( pp_filters[0] != NULL )
 145     {
 146         msg_Dbg( p_aout, "found a filter for the whole conversion" );
 147         *pi_nb_filters = 1;
 148         return 0;
 149     }
 150
 151     /* We'll have to split the conversion. We always do the downmixing
 152      * before the resampling, because the audio decoder can probably do it
 153      * for us. */
 154     i_nb_conversions = SplitConversion( p_aout, p_input_format,
 155                                         p_output_format, &temp_format );
 156     if ( !i_nb_conversions )
 157     {
 158         /* There was only one conversion to do, and we already failed. */
 159         msg_Err( p_aout, "couldn't find a filter for the conversion" );
 160         return -1;
 161     }
 162
 163     pp_filters[0] = FindFilter( p_aout, p_input_format, &temp_format );
 164     if ( pp_filters[0] == NULL && i_nb_conversions == 2 )
 165     {
 166         /* Try with only one conversion. */
 167         SplitConversion( p_aout, p_input_format, &temp_format,
 168                          &temp_format );
 169         pp_filters[0] = FindFilter( p_aout, p_input_format,
 170                                     &temp_format );
 171     }
 172     if ( pp_filters[0] == NULL )
 173     {
 174         msg_Err( p_aout,
 175               "couldn't find a filter for the first part of the conversion" );
 176         return -1;
 177     }
 178
 179     /* We have the first stage of the conversion. Find a filter for
 180      * the rest. */
 181     pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
 182                                 p_output_format );
 183     if ( pp_filters[1] == NULL )
 184     {
 185         /* Try to split the conversion. */
 186         i_nb_conversions = SplitConversion( p_aout,
 187                                     &pp_filters[0]->output,
 188                                     p_output_format, &temp_format );
 189         if ( !i_nb_conversions )
 190         {
 191             vlc_object_detach( pp_filters[0] );
 192             vlc_object_destroy( pp_filters[0] );
 193             msg_Err( p_aout,
 194               "couldn't find a filter for the second part of the conversion" );
 195         }
 196         pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
 197                                     &temp_format );
 198         pp_filters[2] = FindFilter( p_aout, &temp_format,
 199                                     p_output_format );
 200
 201         if ( pp_filters[1] == NULL || pp_filters[2] == NULL )
 202         {
 203             vlc_object_detach( pp_filters[0] );
 204             vlc_object_destroy( pp_filters[0] );
 205             if ( pp_filters[1] != NULL )
 206             {
 207                 vlc_object_detach( pp_filters[1] );
 208                 vlc_object_destroy( pp_filters[1] );
 209             }
 210             if ( pp_filters[2] != NULL )
 211             {
 212                 vlc_object_detach( pp_filters[2] );
 213                 vlc_object_destroy( pp_filters[2] );
 214             }
 215             msg_Err( p_aout,
 216                "couldn't find filters for the second part of the conversion" );
 217         }
 218         *pi_nb_filters = 3;
 219     }
 220     else
 221     {
 222         *pi_nb_filters = 2;
 223     }
 224
 225     /* We have enough filters. */
 226     msg_Dbg( p_aout, "found %d filters for the whole conversion",
 227              *pi_nb_filters );
 228     return 0;
 229 }
 230
 231 /*****************************************************************************
 232  * aout_FiltersDestroyPipeline: deallocate a filters pipeline
 233  *****************************************************************************/
 234 void aout_FiltersDestroyPipeline( aout_instance_t * p_aout,
 235                                   aout_filter_t ** pp_filters,
 236                                   int i_nb_filters )
 237 {
 238     int i;
 239
 240     for ( i = 0; i < i_nb_filters; i++ )
 241     {
 242         module_Unneed( pp_filters[i], pp_filters[i]->p_module );
 243         vlc_object_detach( pp_filters[i] );
 244         vlc_object_destroy( pp_filters[i] );
 245     }
 246 }
 247
 248 /*****************************************************************************
 249  * aout_FiltersHintBuffers: fill in aout_alloc_t structures to optimize
 250  *                          buffer allocations
 251  *****************************************************************************/
 252 void aout_FiltersHintBuffers( aout_instance_t * p_aout,
 253                               aout_filter_t ** pp_filters,
 254                               int i_nb_filters, aout_alloc_t * p_first_alloc )
 255 {
 256     int i;
 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         aout_BufferAlloc( &p_filter->output_alloc,
 305                           (mtime_t)(*pp_input_buffer)->i_nb_samples * 1000000
 306                             / p_filter->input.i_rate, *pp_input_buffer,
 307                           p_output_buffer );
 308         if ( p_output_buffer == NULL )
 309         {
 310             msg_Err( p_aout, "out of memory" );
 311             return;
 312         }
 313         /* Please note that p_output_buffer->i_nb_samples & i_nb_bytes
 314          * shall be set by the filter plug-in. */
 315
 316         p_filter->pf_do_work( p_aout, p_filter, *pp_input_buffer,
 317                               p_output_buffer );
 318
 319         if ( !p_filter->b_in_place )
 320         {
 321             aout_BufferFree( *pp_input_buffer );
 322             *pp_input_buffer = p_output_buffer;
 323         }
 324     }
 325 }
 326