git.sesse.net Git - vlc/blob - modules/audio_filter/converter/fixed.c

   1 /*****************************************************************************
   2  * fixed.c: Fixed-point audio format conversions
   3  *****************************************************************************
   4  * Copyright (C) 2002, 2006-2009 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Jean-Paul Saman <jpsaman _at_ videolan _dot_ org>
   8  *          Marc Ariberti <marcari@videolan.org>
   9  *          Samuel Hocevar <sam@zoy.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  24  *****************************************************************************/
  25
  26 /*****************************************************************************
  27  * Preamble
  28  *****************************************************************************/
  29
  30 #ifdef HAVE_CONFIG_H
  31 # include "config.h"
  32 #endif
  33
  34 #include <vlc_common.h>
  35 #include <vlc_plugin.h>
  36 #include <vlc_aout.h>
  37 #include <vlc_filter.h>
  38
  39 static int  CreateTo( vlc_object_t * );
  40 static int  CreateFrom( vlc_object_t * );
  41
  42 /*****************************************************************************
  43  * Module descriptor
  44  *****************************************************************************/
  45 vlc_module_begin ()
  46     set_description( N_("Fixed point audio format conversions") )
  47     set_callbacks( CreateTo, NULL )
  48     set_capability( "audio filter", 15 )
  49     add_submodule ()
  50         set_callbacks( CreateFrom, NULL )
  51         set_capability( "audio filter", 10 )
  52 vlc_module_end ()
  53
  54 /*** Conversion from FI32 to audio output ***/
  55 static block_t *Do_F32ToS16( filter_t *, block_t * );
  56
  57 static int CreateFrom( vlc_object_t *p_this )
  58 {
  59     filter_t * p_filter = (filter_t *)p_this;
  60
  61     if( p_filter->fmt_in.audio.i_format != VLC_CODEC_FI32
  62      || !AOUT_FMTS_SIMILAR( &p_filter->fmt_in.audio,
  63                             &p_filter->fmt_out.audio ) )
  64         return VLC_EGENERIC;
  65
  66     /* In fixed-point builds, audio outputs pretty much all use S16N. */
  67     /* Feel free to add some other format if every needed. */
  68     switch( p_filter->fmt_out.audio.i_format )
  69     {
  70         case VLC_CODEC_S16N:
  71             p_filter->pf_audio_filter = Do_F32ToS16;
  72             break;
  73         default:
  74             return VLC_EGENERIC;
  75     }
  76     return VLC_SUCCESS;;
  77 }
  78
  79 /*****************************************************************************
  80  * F32 to S16
  81  *****************************************************************************/
  82
  83 /*****************************************************************************
  84  * support routines borrowed from mpg321 (file: mad.c), which is distributed
  85  * under GPL license
  86  *
  87  * mpg321 was written by Joe Drew <drew@debian.org>, and based upon 'plaympeg'
  88  * from the smpeg sources, which was written by various people from Loki Software
  89  * (http://www.lokigames.com).
  90  *
  91  * It also incorporates some source from mad, written by Robert Leslie
  92  *****************************************************************************/
  93
  94 /* The following two routines and data structure are from the ever-brilliant
  95      Rob Leslie.
  96 */
  97
  98 #define VLC_F_FRACBITS  28
  99
 100 # if VLC_F_FRACBITS == 28
 101 #  define VLC_F(x) ((vlc_fixed_t) (x##L))
 102 # endif
 103
 104 # define VLC_F_ONE VLC_F(0x10000000)
 105
 106 /*****************************************************************************
 107  * s24_to_s16_pcm: Scale a 24 bit pcm sample to a 16 bit pcm sample.
 108  *****************************************************************************/
 109 static inline int16_t s24_to_s16_pcm(vlc_fixed_t sample)
 110 {
 111   /* round */
 112   sample += (1L << (VLC_F_FRACBITS - 16));
 113
 114   /* clip */
 115   if (sample >= VLC_F_ONE)
 116     sample = VLC_F_ONE - 1;
 117   else if (sample < -VLC_F_ONE)
 118     sample = -VLC_F_ONE;
 119
 120   /* quantize */
 121   return (sample >> (VLC_F_FRACBITS + 1 - 16));
 122 }
 123
 124 static block_t *Do_F32ToS16( filter_t * p_filter, block_t * p_in_buf )
 125 {
 126     int i;
 127     vlc_fixed_t * p_in = (vlc_fixed_t *)p_in_buf->p_buffer;
 128     int16_t * p_out = (int16_t *)p_in_buf->p_buffer;
 129
 130     for ( i = p_in_buf->i_nb_samples
 131                * aout_FormatNbChannels( &p_filter->fmt_in.audio ) ; i-- ; )
 132     {
 133         /* Fast Scaling */
 134         *p_out++ = s24_to_s16_pcm(*p_in++);
 135     }
 136     p_in_buf->i_buffer /= 2;
 137     return p_in_buf;
 138 }
 139
 140 /*** Conversions from decoders to FI32 */
 141 static block_t *Do_S16ToF32( filter_t *, block_t * );
 142 static block_t *Do_U8ToF32( filter_t *, block_t * );
 143
 144 static int CreateTo( vlc_object_t *p_this )
 145 {
 146     filter_t * p_filter = (filter_t *)p_this;
 147
 148     if( p_filter->fmt_out.audio.i_format != VLC_CODEC_FI32
 149      || !AOUT_FMTS_SIMILAR( &p_filter->fmt_in.audio,
 150                             &p_filter->fmt_out.audio ) )
 151         return VLC_EGENERIC;
 152
 153     switch( p_filter->fmt_in.audio.i_format )
 154     {
 155         case VLC_CODEC_S16N:
 156             p_filter->pf_audio_filter = Do_S16ToF32;
 157             break;
 158
 159         case VLC_CODEC_U8:
 160             p_filter->pf_audio_filter = Do_U8ToF32;
 161             break;
 162
 163         default:
 164             return VLC_EGENERIC;
 165     }
 166
 167     return VLC_SUCCESS;
 168 }
 169
 170 /*****************************************************************************
 171  * S16 to F32
 172  *****************************************************************************/
 173 static block_t *Do_S16ToF32( filter_t * p_filter, block_t * p_in_buf )
 174 {
 175     block_t *p_out_buf;
 176     p_out_buf = filter_NewAudioBuffer( p_filter, p_in_buf->i_buffer * 2 );
 177     if( !p_out_buf )
 178         goto out;
 179
 180     int i = p_in_buf->i_nb_samples * aout_FormatNbChannels( &p_filter->fmt_in.audio );
 181     const int16_t * p_in = (int16_t *)p_in_buf->p_buffer;
 182     vlc_fixed_t * p_out = (vlc_fixed_t *)p_out_buf->p_buffer;
 183
 184     while( i-- )
 185     {
 186         *p_out = (vlc_fixed_t)( (int32_t)(*p_in) * (FIXED32_ONE >> 16) );
 187         p_in++; p_out++;
 188     }
 189
 190     p_out_buf->i_pts = p_in_buf->i_pts;
 191     p_out_buf->i_length = p_in_buf->i_length;
 192     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 193 out:
 194     block_Release( p_in_buf );
 195     return p_out_buf;
 196 }
 197
 198
 199 /*****************************************************************************
 200  * U8 to F32
 201  *****************************************************************************/
 202 static block_t *Do_U8ToF32( filter_t * p_filter, block_t * p_in_buf )
 203 {
 204     block_t *p_out_buf;
 205     p_out_buf = filter_NewAudioBuffer( p_filter, 4 * p_in_buf->i_buffer );
 206     if( !p_out_buf )
 207         goto out;
 208
 209     int i = p_in_buf->i_nb_samples * aout_FormatNbChannels( &p_filter->fmt_in.audio );
 210
 211     uint8_t * p_in = (uint8_t *)p_in_buf->p_buffer;
 212     vlc_fixed_t * p_out = (vlc_fixed_t *)p_out_buf->p_buffer;
 213
 214     while( i-- )
 215     {
 216         *p_out = (vlc_fixed_t)( (int32_t)(*p_in - 128) * (FIXED32_ONE / 128) );
 217         p_in++; p_out++;
 218     }
 219     p_out_buf->i_pts = p_in_buf->i_pts;
 220     p_out_buf->i_length = p_in_buf->i_length;
 221     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 222 out:
 223     block_Release( p_in_buf );
 224     return p_out_buf;
 225 }