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 <stdlib.h>                                      /* malloc(), free() */
  28 #include <string.h>
  29
  30 #include <vlc/vlc.h>
  31 #include <vlc_aout.h>
  32
  33 /*****************************************************************************
  34  * Local prototypes
  35  *****************************************************************************/
  36 static int  Create    ( vlc_object_t * );
  37
  38 static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  39                         aout_buffer_t * );
  40
  41 /*****************************************************************************
  42  * Module descriptor
  43  *****************************************************************************/
  44 vlc_module_begin();
  45     set_description( _("Audio filter for simple channel mixing") );
  46     set_capability( "audio filter", 10 );
  47     set_category( CAT_AUDIO );
  48     set_subcategory( SUBCAT_AUDIO_MISC );
  49     set_callbacks( Create, NULL );
  50 vlc_module_end();
  51
  52 /*****************************************************************************
  53  * Create: allocate trivial channel mixer
  54  *****************************************************************************/
  55 static int Create( vlc_object_t *p_this )
  56 {
  57     aout_filter_t * p_filter = (aout_filter_t *)p_this;
  58
  59     if ( (p_filter->input.i_physical_channels
  60            == p_filter->output.i_physical_channels
  61            && p_filter->input.i_original_channels
  62                == p_filter->output.i_original_channels)
  63           || p_filter->input.i_format != p_filter->output.i_format
  64           || p_filter->input.i_rate != p_filter->output.i_rate
  65           || p_filter->input.i_format != VLC_FOURCC('f','l','3','2') )
  66     {
  67         return -1;
  68     }
  69
  70     /* Only conversion to Stereo and 4.0 right now */
  71     if( p_filter->output.i_physical_channels !=
  72         (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT)
  73         && p_filter->output.i_physical_channels !=
  74         ( AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
  75         AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT) )
  76         {
  77             return -1;
  78         }
  79
  80     /* Only from 7/7.1/5/5.1 */
  81     if( (p_filter->input.i_physical_channels & ~AOUT_CHAN_LFE) !=
  82         (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER |
  83          AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT) &&
  84         (p_filter->input.i_physical_channels & ~AOUT_CHAN_LFE) !=
  85         (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER |
  86          AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT |
  87          AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT) )
  88     {
  89         return -1;
  90     }
  91
  92     p_filter->pf_do_work = DoWork;
  93     p_filter->b_in_place = 0;
  94
  95     return 0;
  96 }
  97
  98 /*****************************************************************************
  99  * DoWork: convert a buffer
 100  *****************************************************************************/
 101 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 102                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 103 {
 104     int i_input_nb = aout_FormatNbChannels( &p_filter->input );
 105     int i_output_nb = aout_FormatNbChannels( &p_filter->output );
 106     float *p_dest = (float *)p_out_buf->p_buffer;
 107     float *p_src = (float *)p_in_buf->p_buffer;
 108     int i;
 109
 110     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 111     p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * i_output_nb / i_input_nb;
 112
 113     if( p_filter->output.i_physical_channels ==
 114                             (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT) )
 115     {
 116         if( p_filter->input.i_physical_channels & AOUT_CHAN_MIDDLELEFT )
 117         for( i = p_in_buf->i_nb_samples; i--; )
 118         {
 119             *p_dest = p_src[6] + 0.5 * p_src[0] + p_src[2] / 4 + p_src[4] / 4;
 120             p_dest++;
 121             *p_dest = p_src[6] + 0.5 * p_src[1] + p_src[3] / 4 + p_src[5] / 4;
 122             p_dest++;
 123
 124             p_src += 7;
 125
 126             if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 127         }
 128         else
 129         for( i = p_in_buf->i_nb_samples; i--; )
 130         {
 131             *p_dest = p_src[4] + 0.5 * p_src[0] + 0.33 * p_src[2];
 132             p_dest++;
 133             *p_dest = p_src[4] + 0.5 * p_src[1] + 0.33 * p_src[3];
 134             p_dest++;
 135
 136             p_src += 5;
 137
 138             if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 139         }
 140     }
 141     else
 142     {
 143         if( p_filter->input.i_physical_channels & AOUT_CHAN_MIDDLELEFT )
 144         for( i = p_in_buf->i_nb_samples; i--; )
 145         {
 146             *p_dest = p_src[6] + 0.5 * p_src[0] + p_src[2] / 6;
 147             p_dest++;
 148             *p_dest = p_src[6] + 0.5 * p_src[1] + p_src[3] / 6;
 149             p_dest++;
 150             *p_dest = p_src[2] / 6 +  p_src[4];
 151             p_dest++;
 152             *p_dest = p_src[3] / 6 +  p_src[5];
 153             p_dest++;
 154
 155             p_src += 7;
 156
 157             if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 158         }
 159         else
 160         for( i = p_in_buf->i_nb_samples; i--; )
 161         {
 162             *p_dest = p_src[4] + 0.5 * p_src[0];
 163             p_dest++;
 164             *p_dest = p_src[4] + 0.5 * p_src[1];
 165             p_dest++;
 166             *p_dest = p_src[2];
 167             p_dest++;
 168             *p_dest = p_src[3];
 169             p_dest++;
 170
 171             p_src += 5;
 172
 173             if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 174         }
 175
 176     }
 177 }