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 VLC authors and VideoLAN
   5  * $Id$
   6  *
   7  * Authors: Gildas Bazin <gbazin@videolan.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software Foundation,
  21  * 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 converter", 10 )
  48     set_callbacks( OpenFilter, NULL )
  49 vlc_module_end ()
  50
  51 /*****************************************************************************
  52  * Local prototypes
  53  *****************************************************************************/
  54 static bool IsSupported( const audio_format_t *p_input, const audio_format_t *p_output );
  55
  56 static block_t *Filter( filter_t *, block_t * );
  57
  58 /*****************************************************************************
  59  * DoWork: convert a buffer
  60  *****************************************************************************/
  61 static void DoWork( filter_t * p_filter,
  62                     block_t * p_in_buf, block_t * p_out_buf )
  63 {
  64     const unsigned i_input_physical = p_filter->fmt_in.audio.i_physical_channels;
  65
  66     const bool b_input_7_0 = (i_input_physical & ~AOUT_CHAN_LFE) == AOUT_CHANS_7_0;
  67     const bool b_input_5_0 = !b_input_7_0 &&
  68                              ( (i_input_physical & AOUT_CHANS_5_0) == AOUT_CHANS_5_0 ||
  69                                (i_input_physical & AOUT_CHANS_5_0_MIDDLE) == AOUT_CHANS_5_0_MIDDLE );
  70     const bool b_input_4_center_rear =  !b_input_7_0 && !b_input_5_0 &&
  71                              (i_input_physical & ~AOUT_CHAN_LFE) == AOUT_CHANS_4_CENTER_REAR;
  72     const bool b_input_3_0 = !b_input_7_0 && !b_input_5_0 && !b_input_4_center_rear &&
  73                              (i_input_physical & ~AOUT_CHAN_LFE) == AOUT_CHANS_3_0;
  74
  75     int i_input_nb = aout_FormatNbChannels( &p_filter->fmt_in.audio );
  76     int i_output_nb = aout_FormatNbChannels( &p_filter->fmt_out.audio );
  77     float *p_dest = (float *)p_out_buf->p_buffer;
  78     const float *p_src = (const float *)p_in_buf->p_buffer;
  79     int i;
  80
  81     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
  82     p_out_buf->i_buffer = p_in_buf->i_buffer * i_output_nb / i_input_nb;
  83
  84     if( p_filter->fmt_out.audio.i_physical_channels == AOUT_CHANS_2_0 )
  85     {
  86         if( b_input_7_0 )
  87         for( i = p_in_buf->i_nb_samples; i--; )
  88         {
  89             *p_dest = p_src[6] + 0.5 * p_src[0] + p_src[2] / 4 + p_src[4] / 4;
  90             p_dest++;
  91             *p_dest = p_src[6] + 0.5 * p_src[1] + p_src[3] / 4 + p_src[5] / 4;
  92             p_dest++;
  93
  94             p_src += 7;
  95
  96             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
  97         }
  98         else if( b_input_5_0 )
  99         for( i = p_in_buf->i_nb_samples; i--; )
 100         {
 101             *p_dest = p_src[4] + 0.5 * p_src[0] + 0.33 * p_src[2];
 102             p_dest++;
 103             *p_dest = p_src[4] + 0.5 * p_src[1] + 0.33 * p_src[3];
 104             p_dest++;
 105
 106             p_src += 5;
 107
 108             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 109         }
 110         else if( b_input_3_0 )
 111         for( i = p_in_buf->i_nb_samples; i--; )
 112         {
 113             *p_dest = p_src[2] + 0.5 * p_src[0];
 114             p_dest++;
 115             *p_dest = p_src[2] + 0.5 * p_src[1];
 116             p_dest++;
 117
 118             p_src += 3;
 119
 120             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 121         }
 122         else if (b_input_4_center_rear)
 123         for( i = p_in_buf->i_nb_samples; i--; )
 124         {
 125           *p_dest = p_src[2] + p_src[3] + 0.5 * p_src[0];
 126           p_dest++;
 127           *p_dest = p_src[2] + p_src[3] + 0.5 * p_src[1];
 128           p_dest++;
 129           p_src += 4;
 130         }
 131     }
 132     else if( p_filter->fmt_out.audio.i_physical_channels == AOUT_CHAN_CENTER )
 133     {
 134         if( b_input_7_0 )
 135         for( i = p_in_buf->i_nb_samples; i--; )
 136         {
 137             *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;
 138             p_dest++;
 139
 140             p_src += 7;
 141
 142             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 143         }
 144         else if( b_input_5_0 )
 145         for( i = p_in_buf->i_nb_samples; i--; )
 146         {
 147             *p_dest = p_src[4] + p_src[0] / 4 + p_src[1] / 4 + p_src[2] / 6 + p_src[3] / 6;
 148             p_dest++;
 149
 150             p_src += 5;
 151
 152             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 153         }
 154         else if( b_input_3_0 )
 155         for( i = p_in_buf->i_nb_samples; i--; )
 156         {
 157             *p_dest = p_src[2] + p_src[0] / 4 + p_src[1] / 4;
 158             p_dest++;
 159
 160             p_src += 3;
 161
 162             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 163         }
 164         else
 165         for( i = p_in_buf->i_nb_samples; i--; )
 166         {
 167             *p_dest = p_src[0] / 2 + p_src[1] / 2;
 168             p_dest++;
 169
 170             p_src += 2;
 171         }
 172     }
 173     else
 174     {
 175         assert( p_filter->fmt_out.audio.i_physical_channels == AOUT_CHANS_4_0 );
 176         assert( b_input_7_0 || b_input_5_0 );
 177
 178         if( b_input_7_0 )
 179         for( i = p_in_buf->i_nb_samples; i--; )
 180         {
 181             *p_dest = p_src[6] + 0.5 * p_src[0] + p_src[2] / 6;
 182             p_dest++;
 183             *p_dest = p_src[6] + 0.5 * p_src[1] + p_src[3] / 6;
 184             p_dest++;
 185             *p_dest = p_src[2] / 6 +  p_src[4];
 186             p_dest++;
 187             *p_dest = p_src[3] / 6 +  p_src[5];
 188             p_dest++;
 189
 190             p_src += 7;
 191
 192             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 193         }
 194         else
 195         for( i = p_in_buf->i_nb_samples; i--; )
 196         {
 197             *p_dest = p_src[4] + 0.5 * p_src[0];
 198             p_dest++;
 199             *p_dest = p_src[4] + 0.5 * p_src[1];
 200             p_dest++;
 201             *p_dest = p_src[2];
 202             p_dest++;
 203             *p_dest = p_src[3];
 204             p_dest++;
 205
 206             p_src += 5;
 207
 208             if( p_filter->fmt_in.audio.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
 209         }
 210     }
 211 }
 212
 213 /*****************************************************************************
 214  * OpenFilter:
 215  *****************************************************************************/
 216 static int OpenFilter( vlc_object_t *p_this )
 217 {
 218     filter_t *p_filter = (filter_t *)p_this;
 219
 220     audio_format_t fmt_in  = p_filter->fmt_in.audio;
 221     audio_format_t fmt_out = p_filter->fmt_out.audio;
 222
 223     fmt_in.i_format = p_filter->fmt_in.i_codec;
 224     fmt_out.i_format = p_filter->fmt_out.i_codec;
 225
 226     if( !IsSupported( &fmt_in, &fmt_out ) )
 227         return -1;
 228
 229     p_filter->pf_audio_filter = Filter;
 230
 231     return 0;
 232 }
 233
 234 /*****************************************************************************
 235  * Filter:
 236  *****************************************************************************/
 237 static block_t *Filter( filter_t *p_filter, block_t *p_block )
 238 {
 239     if( !p_block || !p_block->i_nb_samples )
 240     {
 241         if( p_block )
 242             block_Release( p_block );
 243         return NULL;
 244     }
 245
 246     size_t i_out_size = p_block->i_nb_samples *
 247       p_filter->fmt_out.audio.i_bitspersample *
 248         p_filter->fmt_out.audio.i_channels / 8;
 249
 250     block_t *p_out = filter_NewAudioBuffer( p_filter, i_out_size );
 251     if( !p_out )
 252     {
 253         msg_Warn( p_filter, "can't get output buffer" );
 254         block_Release( p_block );
 255         return NULL;
 256     }
 257
 258     p_out->i_nb_samples = p_block->i_nb_samples;
 259     p_out->i_dts = p_block->i_dts;
 260     p_out->i_pts = p_block->i_pts;
 261     p_out->i_length = p_block->i_length;
 262
 263     DoWork( p_filter, p_block, p_out );
 264
 265     block_Release( p_block );
 266
 267     return p_out;
 268 }
 269
 270 /*****************************************************************************
 271  * Helpers:
 272  *****************************************************************************/
 273 static bool IsSupported( const audio_format_t *p_input, const audio_format_t *p_output )
 274 {
 275     if( p_input->i_format != VLC_CODEC_FL32 ||
 276           p_input->i_format != p_output->i_format ||
 277           p_input->i_rate != p_output->i_rate )
 278         return false;
 279
 280     if( p_input->i_physical_channels == p_output->i_physical_channels &&
 281         p_input->i_original_channels == p_output->i_original_channels )
 282     {
 283         return false;
 284     }
 285
 286     /* Only conversion to Mono, Stereo and 4.0 right now */
 287     if( p_output->i_physical_channels != AOUT_CHAN_CENTER &&
 288         p_output->i_physical_channels != AOUT_CHANS_2_0 &&
 289         p_output->i_physical_channels != AOUT_CHANS_4_0 )
 290     {
 291         return false;
 292     }
 293
 294     /* Only from 7/7.1/5/5.1/3/3.1/2.0
 295      * XXX 5.X rear and middle are handled the same way */
 296     if( (p_input->i_physical_channels & ~AOUT_CHAN_LFE) != AOUT_CHANS_7_0 &&
 297         (p_input->i_physical_channels & ~AOUT_CHAN_LFE) != AOUT_CHANS_5_0 &&
 298         (p_input->i_physical_channels & ~AOUT_CHAN_LFE) != AOUT_CHANS_5_0_MIDDLE &&
 299         (p_input->i_physical_channels & ~AOUT_CHAN_LFE) != AOUT_CHANS_3_0 &&
 300         (p_input->i_physical_channels & ~AOUT_CHAN_LFE) != AOUT_CHANS_4_CENTER_REAR &&
 301          p_input->i_physical_channels != AOUT_CHANS_2_0 )
 302     {
 303         return false;
 304     }
 305
 306     /* Only if we downmix */
 307     if( aout_FormatNbChannels( p_input ) <= aout_FormatNbChannels( p_output ) )
 308         return false;
 309
 310     return true;
 311 }
 312