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