git.sesse.net Git - vlc/blob - modules/audio_filter/channel_mixer/dolby.c

   1 /*****************************************************************************
   2  * dolby.c : simple decoder for dolby surround encoded streams
   3  *****************************************************************************
   4  * Copyright (C) 2005, 2006 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Boris Dorès <babal@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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #include <stdlib.h>                                      /* malloc(), free() */
  28 #include <string.h>
  29
  30 #include <vlc/vlc.h>
  31 #include "audio_output.h"
  32 #include "aout_internal.h"
  33
  34 /*****************************************************************************
  35  * Local prototypes
  36  *****************************************************************************/
  37 static int  Create    ( vlc_object_t * );
  38 static void Destroy   ( vlc_object_t * );
  39
  40 static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  41                         aout_buffer_t * );
  42
  43 /*****************************************************************************
  44  * Module descriptor
  45  *****************************************************************************/
  46 vlc_module_begin();
  47     set_description( N_("Simple decoder for Dolby Surround encoded streams") );
  48     set_shortname( _("Dolby Surround decoder") );
  49     set_category( CAT_INPUT );
  50     set_subcategory( SUBCAT_INPUT_ACODEC );
  51     set_capability( "audio filter", 5 );
  52     set_callbacks( Create, Destroy );
  53 vlc_module_end();
  54
  55 /*****************************************************************************
  56  * Internal data structures
  57  *****************************************************************************/
  58 struct aout_filter_sys_t
  59 {
  60     int i_left;
  61     int i_center;
  62     int i_right;
  63     int i_rear_left;
  64     int i_rear_center;
  65     int i_rear_right;
  66 };
  67
  68 /* our internal channel order (WG-4 order) */
  69 static const uint32_t pi_channels[] =
  70 { AOUT_CHAN_LEFT, AOUT_CHAN_RIGHT, AOUT_CHAN_MIDDLELEFT, AOUT_CHAN_MIDDLERIGHT,
  71   AOUT_CHAN_REARLEFT, AOUT_CHAN_REARRIGHT, AOUT_CHAN_REARCENTER,
  72   AOUT_CHAN_CENTER, AOUT_CHAN_LFE, 0 };
  73
  74 /*****************************************************************************
  75  * Create: allocate headphone downmixer
  76  *****************************************************************************/
  77 static int Create( vlc_object_t *p_this )
  78 {
  79     int i = 0;
  80     int i_offset = 0;
  81     aout_filter_t * p_filter = (aout_filter_t *)p_this;
  82
  83     /* Validate audio filter format */
  84     if ( p_filter->input.i_physical_channels != (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT)
  85        || ! ( p_filter->input.i_original_channels & AOUT_CHAN_DOLBYSTEREO )
  86        || aout_FormatNbChannels( &p_filter->output ) <= 2
  87        || ( p_filter->input.i_original_channels & ~AOUT_CHAN_DOLBYSTEREO )
  88           != ( p_filter->output.i_original_channels & ~AOUT_CHAN_DOLBYSTEREO ) )
  89     {
  90         return VLC_EGENERIC;
  91     }
  92
  93     if ( p_filter->input.i_rate != p_filter->output.i_rate )
  94     {
  95         return VLC_EGENERIC;
  96     }
  97
  98     if ( p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
  99           || p_filter->output.i_format != VLC_FOURCC('f','l','3','2') )
 100     {
 101         return VLC_EGENERIC;
 102     }
 103
 104     /* Allocate the memory needed to store the module's structure */
 105     p_filter->p_sys = malloc( sizeof(struct aout_filter_sys_t) );
 106     if ( p_filter->p_sys == NULL )
 107     {
 108         msg_Err( p_filter, "out of memory" );
 109         return VLC_EGENERIC;
 110     }
 111     p_filter->p_sys->i_left = -1;
 112     p_filter->p_sys->i_center = -1;
 113     p_filter->p_sys->i_right = -1;
 114     p_filter->p_sys->i_rear_left = -1;
 115     p_filter->p_sys->i_rear_center = -1;
 116     p_filter->p_sys->i_rear_right = -1;
 117
 118     while ( pi_channels[i] )
 119     {
 120         if ( p_filter->output.i_physical_channels & pi_channels[i] )
 121         {
 122             switch ( pi_channels[i] )
 123             {
 124                 case AOUT_CHAN_LEFT:
 125                     p_filter->p_sys->i_left = i_offset;
 126                     break;
 127                 case AOUT_CHAN_CENTER:
 128                     p_filter->p_sys->i_center = i_offset;
 129                     break;
 130                 case AOUT_CHAN_RIGHT:
 131                     p_filter->p_sys->i_right = i_offset;
 132                     break;
 133                 case AOUT_CHAN_REARLEFT:
 134                     p_filter->p_sys->i_rear_left = i_offset;
 135                     break;
 136                 case AOUT_CHAN_REARCENTER:
 137                     p_filter->p_sys->i_rear_center = i_offset;
 138                     break;
 139                 case AOUT_CHAN_REARRIGHT:
 140                     p_filter->p_sys->i_rear_right = i_offset;
 141                     break;
 142             }
 143             ++i_offset;
 144         }
 145         ++i;
 146     }
 147
 148     p_filter->pf_do_work = DoWork;
 149     p_filter->b_in_place = 0;
 150
 151     return VLC_SUCCESS;
 152 }
 153
 154 /*****************************************************************************
 155  * Destroy: deallocate resources associated with headphone downmixer
 156  *****************************************************************************/
 157 static void Destroy( vlc_object_t *p_this )
 158 {
 159     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 160
 161     if ( p_filter->p_sys != NULL )
 162     {
 163         free ( p_filter->p_sys );
 164         p_filter->p_sys = NULL;
 165     }
 166 }
 167
 168 /*****************************************************************************
 169  * DoWork: convert a buffer
 170  *****************************************************************************/
 171 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 172                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 173 {
 174     float * p_in = (float*) p_in_buf->p_buffer;
 175     float * p_out = (float*) p_out_buf->p_buffer;
 176     size_t i_nb_samples = p_in_buf->i_nb_samples;
 177     size_t i_nb_channels = aout_FormatNbChannels( &p_filter->output );
 178
 179     p_out_buf->i_nb_samples = i_nb_samples;
 180     p_out_buf->i_nb_bytes = sizeof(float) * i_nb_samples
 181                             * aout_FormatNbChannels( &p_filter->output );
 182     memset ( p_out , 0 , p_out_buf->i_nb_bytes );
 183
 184     if ( p_filter->p_sys != NULL )
 185     {
 186         struct aout_filter_sys_t * p_sys = p_filter->p_sys;
 187         size_t i_nb_rear = 0;
 188         size_t i;
 189
 190         if ( p_sys->i_rear_left >= 0 )
 191         {
 192             ++i_nb_rear;
 193         }
 194         if ( p_sys->i_rear_center >= 0 )
 195         {
 196             ++i_nb_rear;
 197         }
 198         if ( p_sys->i_rear_right >= 0 )
 199         {
 200             ++i_nb_rear;
 201         }
 202
 203         for ( i = 0; i < i_nb_samples; ++i )
 204         {
 205             float f_left = p_in[ i * 2 ];
 206             float f_right = p_in[ i * 2 + 1 ];
 207             float f_rear = ( f_left - f_right ) / i_nb_rear;
 208
 209             if ( p_sys->i_center >= 0 )
 210             {
 211                 float f_center = f_left + f_right;
 212                 f_left -= f_center / 2;
 213                 f_right -= f_center / 2;
 214
 215                 p_out[ i * i_nb_channels + p_sys->i_center ] = f_center;
 216             }
 217
 218             if ( p_sys->i_left >= 0 )
 219             {
 220                 p_out[ i * i_nb_channels + p_sys->i_left ] = f_left;
 221             }
 222             if ( p_sys->i_right >= 0 )
 223             {
 224                 p_out[ i * i_nb_channels + p_sys->i_right ] = f_right;
 225             }
 226             if ( p_sys->i_rear_left >= 0 )
 227             {
 228                 p_out[ i * i_nb_channels + p_sys->i_rear_left ] = f_rear;
 229             }
 230             if ( p_sys->i_rear_center >= 0 )
 231             {
 232                 p_out[ i * i_nb_channels + p_sys->i_rear_center ] = f_rear;
 233             }
 234             if ( p_sys->i_rear_right >= 0 )
 235             {
 236                 p_out[ i * i_nb_channels + p_sys->i_rear_right ] = f_rear;
 237             }
 238         }
 239     }
 240 }