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, 2006 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 <string.h>
  28
  29 #include <vlc/vlc.h>
  30 #include <vlc_aout.h>
  31
  32 /*****************************************************************************
  33  * Local prototypes
  34  *****************************************************************************/
  35 static int  Create    ( vlc_object_t * );
  36
  37 static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  38                         aout_buffer_t * );
  39
  40 /*****************************************************************************
  41  * Module descriptor
  42  *****************************************************************************/
  43 vlc_module_begin();
  44     set_description( _("Audio filter for simple channel mixing") );
  45     set_capability( "audio filter", 10 );
  46     set_category( CAT_AUDIO );
  47     set_subcategory( SUBCAT_AUDIO_MISC );
  48     set_callbacks( Create, NULL );
  49 vlc_module_end();
  50
  51 /*****************************************************************************
  52  * Create: allocate trivial channel mixer
  53  *****************************************************************************/
  54 static int Create( vlc_object_t *p_this )
  55 {
  56     aout_filter_t * p_filter = (aout_filter_t *)p_this;
  57
  58     if ( (p_filter->input.i_physical_channels
  59            == p_filter->output.i_physical_channels
  60            && p_filter->input.i_original_channels
  61                == p_filter->output.i_original_channels)
  62           || p_filter->input.i_format != p_filter->output.i_format
  63           || p_filter->input.i_rate != p_filter->output.i_rate
  64           || p_filter->input.i_format != VLC_FOURCC('f','l','3','2') )
  65     {
  66         return -1;
  67     }
  68
  69     /* Only conversion to Stereo and 4.0 right now */
  70     if( p_filter->output.i_physical_channels !=
  71         (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT)
  72         && p_filter->output.i_physical_channels !=
  73         ( AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
  74         AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT) )
  75         {
  76             return -1;
  77         }
  78
  79     /* Only from 7/7.1/5/5.1 */
  80     if( (p_filter->input.i_physical_channels & ~AOUT_CHAN_LFE) !=
  81         (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER |
  82          AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT) &&
  83         (p_filter->input.i_physical_channels & ~AOUT_CHAN_LFE) !=
  84         (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER |
  85          AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT |
  86          AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT) )
  87     {
  88         return -1;
  89     }
  90
  91     p_filter->pf_do_work = DoWork;
  92     p_filter->b_in_place = 0;
  93
  94     return 0;
  95 }
  96
  97 /*****************************************************************************
  98  * DoWork: convert a buffer
  99  *****************************************************************************/
 100 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 101                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 102 {
 103     int i_input_nb = aout_FormatNbChannels( &p_filter->input );
 104     int i_output_nb = aout_FormatNbChannels( &p_filter->output );
 105     float *p_dest = (float *)p_out_buf->p_buffer;
 106     float *p_src = (float *)p_in_buf->p_buffer;
 107     int i;
 108
 109     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 110     p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * i_output_nb / i_input_nb;
 111
 112     if( p_filter->output.i_physical_channels ==
 113                             (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT) )
 114     {
 115         if( p_filter->input.i_physical_channels & AOUT_CHAN_MIDDLELEFT )
 116         for( i = p_in_buf->i_nb_samples; i--; )
 117         {
 118             *p_dest = p_src[6] + 0.5 * p_src[0] + p_src[2] / 4 + p_src[4] / 4;
 119             p_dest++;
 120             *p_dest = p_src[6] + 0.5 * p_src[1] + p_src[3] / 4 + p_src[5] / 4;
 121             p_dest++;
 122
 123             p_src += 7;
 124
 125             if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 126         }
 127         else
 128         for( i = p_in_buf->i_nb_samples; i--; )
 129         {
 130             *p_dest = p_src[4] + 0.5 * p_src[0] + 0.33 * p_src[2];
 131             p_dest++;
 132             *p_dest = p_src[4] + 0.5 * p_src[1] + 0.33 * p_src[3];
 133             p_dest++;
 134
 135             p_src += 5;
 136
 137             if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 138         }
 139     }
 140     else
 141     {
 142         if( p_filter->input.i_physical_channels & AOUT_CHAN_MIDDLELEFT )
 143         for( i = p_in_buf->i_nb_samples; i--; )
 144         {
 145             *p_dest = p_src[6] + 0.5 * p_src[0] + p_src[2] / 6;
 146             p_dest++;
 147             *p_dest = p_src[6] + 0.5 * p_src[1] + p_src[3] / 6;
 148             p_dest++;
 149             *p_dest = p_src[2] / 6 +  p_src[4];
 150             p_dest++;
 151             *p_dest = p_src[3] / 6 +  p_src[5];
 152             p_dest++;
 153
 154             p_src += 7;
 155
 156             if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 157         }
 158         else
 159         for( i = p_in_buf->i_nb_samples; i--; )
 160         {
 161             *p_dest = p_src[4] + 0.5 * p_src[0];
 162             p_dest++;
 163             *p_dest = p_src[4] + 0.5 * p_src[1];
 164             p_dest++;
 165             *p_dest = p_src[2];
 166             p_dest++;
 167             *p_dest = p_src[3];
 168             p_dest++;
 169
 170             p_src += 5;
 171
 172             if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 173         }
 174
 175     }
 176 }