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 union dw
  80 {
  81     float    f;
  82     int32_t  s;
  83     uint32_t u;
  84 };
  85
  86 /*****************************************************************************
  87  * F32 to S16
  88  *****************************************************************************/
  89
  90 /*****************************************************************************
  91  * support routines borrowed from mpg321 (file: mad.c), which is distributed
  92  * under GPL license
  93  *
  94  * mpg321 was written by Joe Drew <drew@debian.org>, and based upon 'plaympeg'
  95  * from the smpeg sources, which was written by various people from Loki Software
  96  * (http://www.lokigames.com).
  97  *
  98  * It also incorporates some source from mad, written by Robert Leslie
  99  *****************************************************************************/
 100
 101 /* The following two routines and data structure are from the ever-brilliant
 102      Rob Leslie.
 103 */
 104
 105 #define VLC_F_FRACBITS  28
 106
 107 # if VLC_F_FRACBITS == 28
 108 #  define VLC_F(x) ((vlc_fixed_t) (x##L))
 109 # endif
 110
 111 # define VLC_F_ONE VLC_F(0x10000000)
 112
 113 /*****************************************************************************
 114  * s24_to_s16_pcm: Scale a 24 bit pcm sample to a 16 bit pcm sample.
 115  *****************************************************************************/
 116 static inline int16_t s24_to_s16_pcm(vlc_fixed_t sample)
 117 {
 118   /* round */
 119   sample += (1L << (VLC_F_FRACBITS - 16));
 120
 121   /* clip */
 122   if (sample >= VLC_F_ONE)
 123     sample = VLC_F_ONE - 1;
 124   else if (sample < -VLC_F_ONE)
 125     sample = -VLC_F_ONE;
 126
 127   /* quantize */
 128   return (sample >> (VLC_F_FRACBITS + 1 - 16));
 129 }
 130
 131 static block_t *Do_F32ToS16( filter_t * p_filter, block_t * p_in_buf )
 132 {
 133     int i;
 134     vlc_fixed_t * p_in = (vlc_fixed_t *)p_in_buf->p_buffer;
 135     int16_t * p_out = (int16_t *)p_in_buf->p_buffer;
 136
 137     for ( i = p_in_buf->i_nb_samples
 138                * aout_FormatNbChannels( &p_filter->fmt_in.audio ) ; i-- ; )
 139     {
 140         /* Fast Scaling */
 141         *p_out++ = s24_to_s16_pcm(*p_in++);
 142     }
 143     p_in_buf->i_buffer /= 2;
 144     return p_in_buf;
 145 }
 146
 147 /*** Conversions from decoders to FI32 */
 148 static block_t *Do_FL32ToF32( filter_t *, block_t * );
 149 static block_t *Do_S32ToF32( filter_t *, block_t * );
 150 static block_t *Do_S16ToF32( filter_t *, block_t * );
 151 static block_t *Do_U8ToF32( filter_t *, block_t * );
 152
 153 static int CreateTo( vlc_object_t *p_this )
 154 {
 155     filter_t * p_filter = (filter_t *)p_this;
 156
 157     if( p_filter->fmt_out.audio.i_format != VLC_CODEC_FI32
 158      || !AOUT_FMTS_SIMILAR( &p_filter->fmt_in.audio,
 159                             &p_filter->fmt_out.audio ) )
 160         return VLC_EGENERIC;
 161
 162     switch( p_filter->fmt_in.audio.i_format )
 163     {
 164         case VLC_CODEC_FL32:
 165             p_filter->pf_audio_filter = Do_FL32ToF32;
 166             break;
 167
 168         case VLC_CODEC_S32N:
 169             p_filter->pf_audio_filter = Do_S32ToF32;
 170             break;
 171
 172         case VLC_CODEC_S16N:
 173             p_filter->pf_audio_filter = Do_S16ToF32;
 174             break;
 175
 176         case VLC_CODEC_U8:
 177             p_filter->pf_audio_filter = Do_U8ToF32;
 178             break;
 179
 180         default:
 181             return VLC_EGENERIC;
 182     }
 183
 184     return VLC_SUCCESS;
 185 }
 186
 187 /*****************************************************************************
 188  * S16 to F32
 189  *****************************************************************************/
 190 static block_t *Do_S16ToF32( filter_t * p_filter, block_t * p_in_buf )
 191 {
 192     block_t *p_out_buf;
 193     p_out_buf = filter_NewAudioBuffer( p_filter, p_in_buf->i_buffer * 2 );
 194     if( !p_out_buf )
 195         goto out;
 196
 197     int i = p_in_buf->i_nb_samples * aout_FormatNbChannels( &p_filter->fmt_in.audio );
 198     const int16_t * p_in = (int16_t *)p_in_buf->p_buffer;
 199     vlc_fixed_t * p_out = (vlc_fixed_t *)p_out_buf->p_buffer;
 200
 201     while( i-- )
 202     {
 203         *p_out = (vlc_fixed_t)( (int32_t)(*p_in) * (FIXED32_ONE >> 16) );
 204         p_in++; p_out++;
 205     }
 206
 207     p_out_buf->i_dts = p_in_buf->i_dts;
 208     p_out_buf->i_pts = p_in_buf->i_pts;
 209     p_out_buf->i_length = p_in_buf->i_length;
 210     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 211 out:
 212     block_Release( p_in_buf );
 213     return p_out_buf;
 214 }
 215
 216
 217 /*****************************************************************************
 218  * U8 to F32
 219  *****************************************************************************/
 220 static block_t *Do_U8ToF32( filter_t * p_filter, block_t * p_in_buf )
 221 {
 222     block_t *p_out_buf;
 223     p_out_buf = filter_NewAudioBuffer( p_filter, 4 * p_in_buf->i_buffer );
 224     if( !p_out_buf )
 225         goto out;
 226
 227     int i = p_in_buf->i_nb_samples * aout_FormatNbChannels( &p_filter->fmt_in.audio );
 228
 229     uint8_t * p_in = (uint8_t *)p_in_buf->p_buffer;
 230     vlc_fixed_t * p_out = (vlc_fixed_t *)p_out_buf->p_buffer;
 231
 232     while( i-- )
 233     {
 234         *p_out = (vlc_fixed_t)( (int32_t)(*p_in - 128) * (FIXED32_ONE / 128) );
 235         p_in++; p_out++;
 236     }
 237     p_out_buf->i_dts = p_in_buf->i_dts;
 238     p_out_buf->i_pts = p_in_buf->i_pts;
 239     p_out_buf->i_length = p_in_buf->i_length;
 240     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 241 out:
 242     block_Release( p_in_buf );
 243     return p_out_buf;
 244 }
 245
 246 static block_t *Do_FL32ToF32( filter_t * p_filter, block_t * p_in_buf )
 247 {
 248     unsigned count = p_in_buf->i_nb_samples
 249                    * aout_FormatNbChannels( &p_filter->fmt_in.audio );
 250     union dw *restrict p = (union dw *)p_in_buf->p_buffer, *end = p + count;
 251     const float one = FIXED32_ONE;
 252
 253     while (p < end)
 254     {
 255         p->s = (one * p->f);
 256         p++;
 257     }
 258     return p_in_buf;
 259 }
 260
 261 static block_t *Do_S32ToF32( filter_t * p_filter, block_t * p_in_buf )
 262 {
 263     unsigned count = p_in_buf->i_nb_samples
 264                    * aout_FormatNbChannels( &p_filter->fmt_in.audio );
 265     int32_t *restrict p = (int32_t *)p_in_buf->p_buffer, *end = p + count;
 266
 267     while (p < end)
 268     {
 269         *p = *p >> 3;
 270         p++;
 271     }
 272     return p_in_buf;
 273 }