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

   1 /*****************************************************************************
   2  * simple.c : simple channel mixer plug-in (only 7/7.1/5/5.1 -> Stereo for now)
   3  *****************************************************************************
   4  * Copyright (C) 2002 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Gildas Bazin <gbazin@videolan.org>
   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
  39 static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  40                         aout_buffer_t * );
  41
  42 /*****************************************************************************
  43  * Module descriptor
  44  *****************************************************************************/
  45 vlc_module_begin();
  46     set_description( _("audio filter for simple channel mixing") );
  47     set_capability( "audio filter", 10 );
  48     set_category( CAT_AUDIO );
  49     set_subcategory( SUBCAT_AUDIO_MISC );
  50     set_callbacks( Create, NULL );
  51 vlc_module_end();
  52
  53 /*****************************************************************************
  54  * Create: allocate trivial channel mixer
  55  *****************************************************************************/
  56 static int Create( vlc_object_t *p_this )
  57 {
  58     aout_filter_t * p_filter = (aout_filter_t *)p_this;
  59
  60     if ( (p_filter->input.i_physical_channels
  61            == p_filter->output.i_physical_channels
  62            && p_filter->input.i_original_channels
  63                == p_filter->output.i_original_channels)
  64           || p_filter->input.i_format != p_filter->output.i_format
  65           || p_filter->input.i_rate != p_filter->output.i_rate
  66           || p_filter->input.i_format != VLC_FOURCC('f','l','3','2') )
  67     {
  68         return -1;
  69     }
  70
  71     /* Only conversion to Stereo and 4.0 right now */
  72     if( p_filter->output.i_physical_channels !=
  73         (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT)
  74         && p_filter->output.i_physical_channels !=
  75         ( AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
  76         AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT) )
  77         {
  78             return -1;
  79         }
  80
  81     /* Only from 7/7.1/5/5.1 */
  82     if( (p_filter->input.i_physical_channels & ~AOUT_CHAN_LFE) !=
  83         (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER |
  84          AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT) &&
  85         (p_filter->input.i_physical_channels & ~AOUT_CHAN_LFE) !=
  86         (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER |
  87          AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT |
  88          AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT) )
  89     {
  90         return -1;
  91     }
  92
  93     p_filter->pf_do_work = DoWork;
  94     p_filter->b_in_place = 0;
  95
  96     return 0;
  97 }
  98
  99 /*****************************************************************************
 100  * DoWork: convert a buffer
 101  *****************************************************************************/
 102 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 103                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 104 {
 105     int i_input_nb = aout_FormatNbChannels( &p_filter->input );
 106     int i_output_nb = aout_FormatNbChannels( &p_filter->output );
 107     float *p_dest = (float *)p_out_buf->p_buffer;
 108     float *p_src = (float *)p_in_buf->p_buffer;
 109     int i;
 110
 111     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 112     p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * i_output_nb / i_input_nb;
 113
 114     if( p_filter->output.i_physical_channels ==
 115                             (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT) )
 116     {
 117         if( p_filter->input.i_physical_channels & AOUT_CHAN_MIDDLELEFT )
 118         for( i = p_in_buf->i_nb_samples; i--; )
 119         {
 120             *p_dest = p_src[6] + 0.5 * p_src[0] + p_src[2] / 4 + p_src[4] / 4;
 121             p_dest++;
 122             *p_dest = p_src[6] + 0.5 * p_src[1] + p_src[3] / 4 + p_src[5] / 4;
 123             p_dest++;
 124
 125             p_src += 7;
 126
 127             if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 128         }
 129         else
 130         for( i = p_in_buf->i_nb_samples; i--; )
 131         {
 132             *p_dest = p_src[4] + 0.5 * p_src[0] + 0.33 * p_src[2];
 133             p_dest++;
 134             *p_dest = p_src[4] + 0.5 * p_src[1] + 0.33 * p_src[3];
 135             p_dest++;
 136
 137             p_src += 5;
 138
 139             if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 140         }
 141     }
 142     else
 143     {
 144         if( p_filter->input.i_physical_channels & AOUT_CHAN_MIDDLELEFT )
 145         for( i = p_in_buf->i_nb_samples; i--; )
 146         {
 147             *p_dest = p_src[6] + 0.5 * p_src[0] + p_src[2] / 6;
 148             p_dest++;
 149             *p_dest = p_src[6] + 0.5 * p_src[1] + p_src[3] / 6;
 150             p_dest++;
 151             *p_dest = p_src[2] / 6 +  p_src[4];
 152             p_dest++;
 153             *p_dest = p_src[3] / 6 +  p_src[5];
 154             p_dest++;
 155
 156             p_src += 7;
 157
 158             if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 159         }
 160         else
 161         for( i = p_in_buf->i_nb_samples; i--; )
 162         {
 163             *p_dest = p_src[4] + 0.5 * p_src[0];
 164             p_dest++;
 165             *p_dest = p_src[4] + 0.5 * p_src[1];
 166             p_dest++;
 167             *p_dest = p_src[2];
 168             p_dest++;
 169             *p_dest = p_src[3];
 170             p_dest++;
 171
 172             p_src += 5;
 173
 174             if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 175         }
 176
 177     }
 178 }