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 the VideoLAN team
   5  * $Id: headphone.c 11664 2005-07-09 06:17:09Z courmisch $
   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., 59 Temple Place - Suite 330, Boston, MA  02111, 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_original_channels
  85                     != (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT|AOUT_CHAN_DOLBYSTEREO )
  86           || aout_FormatNbChannels( &p_filter->output ) <= 2
  87           || p_filter->output.i_physical_channels
  88                 != ( p_filter->output.i_original_channels & AOUT_CHAN_PHYSMASK )
  89           || p_filter->input.i_physical_channels
  90                 != ( p_filter->input.i_original_channels & AOUT_CHAN_PHYSMASK ))
  91     {
  92         return VLC_EGENERIC;
  93     }
  94
  95     if ( p_filter->input.i_rate != p_filter->output.i_rate )
  96     {
  97         return VLC_EGENERIC;
  98     }
  99
 100     if ( p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
 101           || p_filter->output.i_format != VLC_FOURCC('f','l','3','2') )
 102     {
 103         return VLC_EGENERIC;
 104     }
 105
 106     /* Allocate the memory needed to store the module's structure */
 107     p_filter->p_sys = malloc( sizeof(struct aout_filter_sys_t) );
 108     if ( p_filter->p_sys == NULL )
 109     {
 110         msg_Err( p_filter, "Out of memory" );
 111         return VLC_EGENERIC;
 112     }
 113     p_filter->p_sys->i_left = -1;
 114     p_filter->p_sys->i_center = -1;
 115     p_filter->p_sys->i_right = -1;
 116     p_filter->p_sys->i_rear_left = -1;
 117     p_filter->p_sys->i_rear_center = -1;
 118     p_filter->p_sys->i_rear_right = -1;
 119
 120     while ( pi_channels[i] )
 121     {
 122         if ( p_filter->output.i_physical_channels & pi_channels[i] )
 123         {
 124             switch ( pi_channels[i] )
 125             {
 126                 case AOUT_CHAN_LEFT:
 127                     p_filter->p_sys->i_left = i_offset;
 128                     break;
 129                 case AOUT_CHAN_CENTER:
 130                     p_filter->p_sys->i_center = i_offset;
 131                     break;
 132                 case AOUT_CHAN_RIGHT:
 133                     p_filter->p_sys->i_right = i_offset;
 134                     break;
 135                 case AOUT_CHAN_REARLEFT:
 136                     p_filter->p_sys->i_rear_left = i_offset;
 137                     break;
 138                 case AOUT_CHAN_REARCENTER:
 139                     p_filter->p_sys->i_rear_center = i_offset;
 140                     break;
 141                 case AOUT_CHAN_REARRIGHT:
 142                     p_filter->p_sys->i_rear_right = i_offset;
 143                     break;
 144             }
 145             ++i_offset;
 146         }
 147         ++i;
 148     }
 149
 150     p_filter->pf_do_work = DoWork;
 151     p_filter->b_in_place = 0;
 152
 153     return VLC_SUCCESS;
 154 }
 155
 156 /*****************************************************************************
 157  * Destroy: deallocate resources associated with headphone downmixer
 158  *****************************************************************************/
 159 static void Destroy( vlc_object_t *p_this )
 160 {
 161     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 162
 163     if ( p_filter->p_sys != NULL )
 164     {
 165         free ( p_filter->p_sys );
 166         p_filter->p_sys = NULL;
 167     }
 168 }
 169
 170 /*****************************************************************************
 171  * DoWork: convert a buffer
 172  *****************************************************************************/
 173 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 174                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 175 {
 176     float * p_in = (float*) p_in_buf->p_buffer;
 177     float * p_out = (float*) p_out_buf->p_buffer;
 178     size_t i_nb_samples = p_in_buf->i_nb_samples;
 179     size_t i_nb_channels = aout_FormatNbChannels( &p_filter->output );
 180
 181     p_out_buf->i_nb_samples = i_nb_samples;
 182     p_out_buf->i_nb_bytes = sizeof(float) * i_nb_samples
 183                             * aout_FormatNbChannels( &p_filter->output );
 184     memset ( p_out , 0 , p_out_buf->i_nb_bytes );
 185
 186     if ( p_filter->p_sys != NULL )
 187     {
 188         struct aout_filter_sys_t * p_sys = p_filter->p_sys;
 189         size_t i_nb_rear = 0;
 190         size_t i;
 191
 192         if ( p_sys->i_rear_left >= 0 )
 193         {
 194             ++i_nb_rear;
 195         }
 196         if ( p_sys->i_rear_center >= 0 )
 197         {
 198             ++i_nb_rear;
 199         }
 200         if ( p_sys->i_rear_right >= 0 )
 201         {
 202             ++i_nb_rear;
 203         }
 204
 205         for ( i = 0; i < i_nb_samples; ++i )
 206         {
 207             float f_left = p_in[ i * 2 ];
 208             float f_right = p_in[ i * 2 + 1 ];
 209             float f_rear = ( f_left - f_right ) / i_nb_rear;
 210
 211             if ( p_sys->i_center >= 0 )
 212             {
 213                 float f_center = f_left + f_right;
 214                 f_left -= f_center / 2;
 215                 f_right -= f_center / 2;
 216
 217                 p_out[ i * i_nb_channels + p_sys->i_center ] = f_center;
 218             }
 219
 220             if ( p_sys->i_left >= 0 )
 221             {
 222                 p_out[ i * i_nb_channels + p_sys->i_left ] = f_left;
 223             }
 224             if ( p_sys->i_right >= 0 )
 225             {
 226                 p_out[ i * i_nb_channels + p_sys->i_right ] = f_right;
 227             }
 228             if ( p_sys->i_rear_left >= 0 )
 229             {
 230                 p_out[ i * i_nb_channels + p_sys->i_rear_left ] = f_rear;
 231             }
 232             if ( p_sys->i_rear_center >= 0 )
 233             {
 234                 p_out[ i * i_nb_channels + p_sys->i_rear_center ] = f_rear;
 235             }
 236             if ( p_sys->i_rear_right >= 0 )
 237             {
 238                 p_out[ i * i_nb_channels + p_sys->i_rear_right ] = f_rear;
 239             }
 240         }
 241     }
 242 }