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

   1 /*****************************************************************************
   2  * simple.c : simple channel mixer plug-in
   3  *****************************************************************************
   4  * Copyright (C) 2002, 2004, 2006-2009 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 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #include <vlc_common.h>
  32 #include <vlc_plugin.h>
  33 #include <vlc_aout.h>
  34 #include <vlc_filter.h>
  35 #include <vlc_block.h>
  36 #include <assert.h>
  37
  38 /*****************************************************************************
  39  * Module descriptor
  40  *****************************************************************************/
  41 static int  OpenFilter( vlc_object_t * );
  42
  43 vlc_module_begin ()
  44     set_description( N_("Audio filter for simple channel mixing") )
  45     set_category( CAT_AUDIO )
  46     set_subcategory( SUBCAT_AUDIO_MISC )
  47     set_capability( "audio filter", 10 )
  48     set_callbacks( OpenFilter, NULL )
  49 vlc_module_end ()
  50
  51 /*****************************************************************************
  52  * Local prototypes
  53  *****************************************************************************/
  54 #define AOUT_CHANS_STEREO_FRONT  ( AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT )
  55 #define AOUT_CHANS_STEREO_REAR   ( AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT )
  56 #define AOUT_CHANS_STEREO_MIDDLE (AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT )
  57
  58 #define AOUT_CHANS_2_0          AOUT_CHANS_STEREO_FRONT
  59 #define AOUT_CHANS_3_0          ( AOUT_CHANS_STEREO_FRONT | AOUT_CHAN_CENTER )
  60 #define AOUT_CHANS_4_0          ( AOUT_CHANS_STEREO_FRONT | AOUT_CHANS_STEREO_REAR )
  61 #define AOUT_CHANS_4_0_MIDDLE   ( AOUT_CHANS_STEREO_FRONT | AOUT_CHANS_STEREO_MIDDLE )
  62 #define AOUT_CHANS_4_CENTER_REAR (AOUT_CHANS_STEREO_FRONT | AOUT_CHAN_CENTER | AOUT_CHAN_REARCENTER)
  63 #define AOUT_CHANS_5_0          ( AOUT_CHANS_4_0 | AOUT_CHAN_CENTER )
  64 #define AOUT_CHANS_5_0_MIDDLE   ( AOUT_CHANS_4_0_MIDDLE | AOUT_CHAN_CENTER )
  65 #define AOUT_CHANS_6_0          ( AOUT_CHANS_STEREO_FRONT | AOUT_CHANS_STEREO_REAR | AOUT_CHANS_STEREO_MIDDLE )
  66 #define AOUT_CHANS_7_0          ( AOUT_CHANS_6_0 | AOUT_CHAN_CENTER )
  67
  68 static bool IsSupported( const audio_format_t *p_input, const audio_format_t *p_output );
  69
  70 static block_t *Filter( filter_t *, block_t * );
  71
  72 /*****************************************************************************
  73  * DoWork: convert a buffer
  74  *****************************************************************************/
  75 static void DoWork( filter_t * p_filter,
  76                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
  77 {
  78     const unsigned i_input_physical = p_filter->fmt_in.audio.i_physical_channels;
  79
  80     const bool b_input_7_0 = (i_input_physical & ~AOUT_CHAN_LFE) == AOUT_CHANS_7_0;
  81     const bool b_input_5_0 = !b_input_7_0 &&
  82                              ( (i_input_physical & AOUT_CHANS_5_0) == AOUT_CHANS_5_0 ||
  83                                (i_input_physical & AOUT_CHANS_5_0_MIDDLE) == AOUT_CHANS_5_0_MIDDLE );
  84     const bool b_input_4_center_rear =  !b_input_7_0 && !b_input_5_0 &&
  85                              (i_input_physical & ~AOUT_CHAN_LFE) == AOUT_CHANS_4_CENTER_REAR;
  86     const bool b_input_3_0 = !b_input_7_0 && !b_input_5_0 && !b_input_4_center_rear &&
  87                              (i_input_physical & ~AOUT_CHAN_LFE) == AOUT_CHANS_3_0;
  88
  89     int i_input_nb = aout_FormatNbChannels( &p_filter->fmt_in.audio );
  90     int i_output_nb = aout_FormatNbChannels( &p_filter->fmt_out.audio );
  91     float *p_dest = (float *)p_out_buf->p_buffer;
  92     const float *p_src = (const float *)p_in_buf->p_buffer;
  93     int i;
  94
  95     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
  96     p_out_buf->i_buffer = p_in_buf->i_buffer * i_output_nb / i_input_nb;
  97
  98     if( p_filter->fmt_out.audio.i_physical_channels == AOUT_CHANS_2_0 )
  99     {
 100         if( b_input_7_0 )
 101         for( i = p_in_buf->i_nb_samples; i--; )
 102         {
 103             *p_dest = p_src[6] + 0.5 * p_src[0] + p_src[2] / 4 + p_src[4] / 4;
 104             p_dest++;
 105             *p_dest = p_src[6] + 0.5 * p_src[1] + p_src[3] / 4 + p_src[5] / 4;
 106             p_dest++;
 107
 108             p_src += 7;
 109
 110             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 111         }
 112         else if( b_input_5_0 )
 113         for( i = p_in_buf->i_nb_samples; i--; )
 114         {
 115             *p_dest = p_src[4] + 0.5 * p_src[0] + 0.33 * p_src[2];
 116             p_dest++;
 117             *p_dest = p_src[4] + 0.5 * p_src[1] + 0.33 * p_src[3];
 118             p_dest++;
 119
 120             p_src += 5;
 121
 122             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 123         }
 124         else if( b_input_3_0 )
 125         for( i = p_in_buf->i_nb_samples; i--; )
 126         {
 127             *p_dest = p_src[2] + 0.5 * p_src[0];
 128             p_dest++;
 129             *p_dest = p_src[2] + 0.5 * p_src[1];
 130             p_dest++;
 131
 132             p_src += 3;
 133
 134             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 135         }
 136         else if (b_input_4_center_rear)
 137         for( i = p_in_buf->i_nb_samples; i--; )
 138         {
 139           *p_dest = p_src[2] + p_src[3] + 0.5 * p_src[0];
 140           p_dest++;
 141           *p_dest = p_src[2] + p_src[3] + 0.5 * p_src[1];
 142           p_dest++;
 143           p_src += 4;
 144         }
 145     }
 146     else if( p_filter->fmt_out.audio.i_physical_channels == AOUT_CHAN_CENTER )
 147     {
 148         if( b_input_7_0 )
 149         for( i = p_in_buf->i_nb_samples; i--; )
 150         {
 151             *p_dest = p_src[6] + p_src[0] / 4 + p_src[1] / 4 + p_src[2] / 8 + p_src[3] / 8 + p_src[4] / 8 + p_src[5] / 8;
 152             p_dest++;
 153
 154             p_src += 7;
 155
 156             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 157         }
 158         else if( b_input_5_0 )
 159         for( i = p_in_buf->i_nb_samples; i--; )
 160         {
 161             *p_dest = p_src[4] + p_src[0] / 4 + p_src[1] / 4 + p_src[2] / 6 + p_src[3] / 6;
 162             p_dest++;
 163
 164             p_src += 5;
 165
 166             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 167         }
 168         else if( b_input_3_0 )
 169         for( i = p_in_buf->i_nb_samples; i--; )
 170         {
 171             *p_dest = p_src[2] + p_src[0] / 4 + p_src[1] / 4;
 172             p_dest++;
 173
 174             p_src += 3;
 175
 176             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 177         }
 178         else
 179         for( i = p_in_buf->i_nb_samples; i--; )
 180         {
 181             *p_dest = p_src[0] / 2 + p_src[1] / 2;
 182             p_dest++;
 183
 184             p_src += 2;
 185         }
 186     }
 187     else
 188     {
 189         assert( p_filter->fmt_out.audio.i_physical_channels == AOUT_CHANS_4_0 );
 190         assert( b_input_7_0 || b_input_5_0 );
 191
 192         if( b_input_7_0 )
 193         for( i = p_in_buf->i_nb_samples; i--; )
 194         {
 195             *p_dest = p_src[6] + 0.5 * p_src[0] + p_src[2] / 6;
 196             p_dest++;
 197             *p_dest = p_src[6] + 0.5 * p_src[1] + p_src[3] / 6;
 198             p_dest++;
 199             *p_dest = p_src[2] / 6 +  p_src[4];
 200             p_dest++;
 201             *p_dest = p_src[3] / 6 +  p_src[5];
 202             p_dest++;
 203
 204             p_src += 7;
 205
 206             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 207         }
 208         else
 209         for( i = p_in_buf->i_nb_samples; i--; )
 210         {
 211             *p_dest = p_src[4] + 0.5 * p_src[0];
 212             p_dest++;
 213             *p_dest = p_src[4] + 0.5 * p_src[1];
 214             p_dest++;
 215             *p_dest = p_src[2];
 216             p_dest++;
 217             *p_dest = p_src[3];
 218             p_dest++;
 219
 220             p_src += 5;
 221
 222             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 223         }
 224     }
 225 }
 226
 227 /*****************************************************************************
 228  * OpenFilter:
 229  *****************************************************************************/
 230 static int OpenFilter( vlc_object_t *p_this )
 231 {
 232     filter_t *p_filter = (filter_t *)p_this;
 233
 234     audio_format_t fmt_in  = p_filter->fmt_in.audio;
 235     audio_format_t fmt_out = p_filter->fmt_out.audio;
 236
 237     fmt_in.i_format = p_filter->fmt_in.i_codec;
 238     fmt_out.i_format = p_filter->fmt_out.i_codec;
 239
 240     if( !IsSupported( &fmt_in, &fmt_out ) )
 241         return -1;
 242
 243     p_filter->pf_audio_filter = Filter;
 244
 245     return 0;
 246 }
 247
 248 /*****************************************************************************
 249  * Filter:
 250  *****************************************************************************/
 251 static block_t *Filter( filter_t *p_filter, block_t *p_block )
 252 {
 253     if( !p_block || !p_block->i_nb_samples )
 254     {
 255         if( p_block )
 256             block_Release( p_block );
 257         return NULL;
 258     }
 259
 260     size_t i_out_size = p_block->i_nb_samples *
 261       p_filter->fmt_out.audio.i_bitspersample *
 262         p_filter->fmt_out.audio.i_channels / 8;
 263
 264     block_t *p_out = filter_NewAudioBuffer( p_filter, i_out_size );
 265     if( !p_out )
 266     {
 267         msg_Warn( p_filter, "can't get output buffer" );
 268         block_Release( p_block );
 269         return NULL;
 270     }
 271
 272     p_out->i_nb_samples = p_block->i_nb_samples;
 273     p_out->i_dts = p_block->i_dts;
 274     p_out->i_pts = p_block->i_pts;
 275     p_out->i_length = p_block->i_length;
 276
 277     DoWork( p_filter, p_block, p_out );
 278
 279     block_Release( p_block );
 280
 281     return p_out;
 282 }
 283
 284 /*****************************************************************************
 285  * Helpers:
 286  *****************************************************************************/
 287 static bool IsSupported( const audio_format_t *p_input, const audio_format_t *p_output )
 288 {
 289     if( p_input->i_format != VLC_CODEC_FL32 ||
 290           p_input->i_format != p_output->i_format ||
 291           p_input->i_rate != p_output->i_rate )
 292         return false;
 293
 294     if( p_input->i_physical_channels == p_output->i_physical_channels &&
 295         p_input->i_original_channels == p_output->i_original_channels )
 296     {
 297         return false;
 298     }
 299
 300     /* Only conversion to Mono, Stereo and 4.0 right now */
 301     if( p_output->i_physical_channels != AOUT_CHAN_CENTER &&
 302         p_output->i_physical_channels != AOUT_CHANS_2_0 &&
 303         p_output->i_physical_channels != AOUT_CHANS_4_0 )
 304     {
 305         return false;
 306     }
 307
 308     /* Only from 7/7.1/5/5.1/3/3.1/2.0
 309      * XXX 5.X rear and middle are handled the same way */
 310     if( (p_input->i_physical_channels & ~AOUT_CHAN_LFE) != AOUT_CHANS_7_0 &&
 311         (p_input->i_physical_channels & ~AOUT_CHAN_LFE) != AOUT_CHANS_5_0 &&
 312         (p_input->i_physical_channels & ~AOUT_CHAN_LFE) != AOUT_CHANS_5_0_MIDDLE &&
 313         (p_input->i_physical_channels & ~AOUT_CHAN_LFE) != AOUT_CHANS_3_0 &&
 314         (p_input->i_physical_channels & ~AOUT_CHAN_LFE) != AOUT_CHANS_4_CENTER_REAR &&
 315          p_input->i_physical_channels != AOUT_CHANS_2_0 )
 316     {
 317         return false;
 318     }
 319
 320     /* Only if we downmix */
 321     if( aout_FormatNbChannels( p_input ) <= aout_FormatNbChannels( p_output ) )
 322         return false;
 323
 324     return true;
 325 }
 326