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 /*****************************************************************************
  40  * Local prototypes
  41  *****************************************************************************/
  42 static int  Create_F32ToS16    ( vlc_object_t * );
  43 static block_t *Do_F32ToS16( filter_t *, block_t * );
  44
  45 static int  Create_S16ToF32    ( vlc_object_t * );
  46 static block_t *Do_S16ToF32( filter_t *, block_t * );
  47
  48 static int  Create_U8ToF32    ( vlc_object_t * );
  49 static block_t *Do_U8ToF32( filter_t *, block_t * );
  50
  51 /*****************************************************************************
  52  * Module descriptor
  53  *****************************************************************************/
  54 vlc_module_begin ()
  55     set_description( N_("Fixed point audio format conversions") )
  56     add_submodule ()
  57         set_callbacks( Create_F32ToS16, NULL )
  58         set_capability( "audio filter2", 10 )
  59     add_submodule ()
  60         set_callbacks( Create_S16ToF32, NULL )
  61         set_capability( "audio filter2", 15 )
  62     add_submodule ()
  63         set_callbacks( Create_U8ToF32, NULL )
  64         set_capability( "audio filter2", 1 )
  65 vlc_module_end ()
  66
  67 /*****************************************************************************
  68  * F32 to S16
  69  *****************************************************************************/
  70 static int Create_F32ToS16( vlc_object_t *p_this )
  71 {
  72     filter_t * p_filter = (filter_t *)p_this;
  73
  74     if ( p_filter->fmt_in.audio.i_format != VLC_CODEC_FI32
  75           || p_filter->fmt_out.audio.i_format != VLC_CODEC_S16N )
  76     {
  77         return VLC_EGENERIC;
  78     }
  79
  80     if ( !AOUT_FMTS_SIMILAR( &p_filter->fmt_in.audio, &p_filter->fmt_out.audio ) )
  81     {
  82         return VLC_EGENERIC;
  83     }
  84
  85     p_filter->pf_audio_filter = Do_F32ToS16;
  86
  87     return VLC_SUCCESS;;
  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
 148 /*****************************************************************************
 149  * S16 to F32
 150  *****************************************************************************/
 151 static int Create_S16ToF32( vlc_object_t *p_this )
 152 {
 153     filter_t * p_filter = (filter_t *)p_this;
 154
 155     if ( p_filter->fmt_out.audio.i_format != VLC_CODEC_FI32
 156           || p_filter->fmt_in.audio.i_format != VLC_CODEC_S16N )
 157     {
 158         return VLC_EGENERIC;
 159     }
 160
 161     if ( !AOUT_FMTS_SIMILAR( &p_filter->fmt_in.audio, &p_filter->fmt_out.audio ) )
 162     {
 163         return VLC_EGENERIC;
 164     }
 165
 166     p_filter->pf_audio_filter = Do_S16ToF32;
 167
 168     return VLC_SUCCESS;
 169 }
 170
 171 static block_t *Do_S16ToF32( filter_t * p_filter, block_t * p_in_buf )
 172 {
 173     block_t *p_out_buf;
 174     p_out_buf = filter_NewAudioBuffer( p_filter, p_in_buf->i_buffer * 2 );
 175     if( !p_out_buf )
 176         goto out;
 177
 178     int i = p_in_buf->i_nb_samples * aout_FormatNbChannels( &p_filter->fmt_in.audio );
 179     const int16_t * p_in = (int16_t *)p_in_buf->p_buffer;
 180     vlc_fixed_t * p_out = (vlc_fixed_t *)p_out_buf->p_buffer;
 181
 182     while( i-- )
 183     {
 184         *p_out = (vlc_fixed_t)( (int32_t)(*p_in) * (FIXED32_ONE >> 16) );
 185         p_in++; p_out++;
 186     }
 187
 188     p_out_buf->i_pts = p_in_buf->i_pts;
 189     p_out_buf->i_length = p_in_buf->i_length;
 190     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 191 out:
 192     block_Release( p_in_buf );
 193     return p_out_buf;
 194 }
 195
 196
 197 /*****************************************************************************
 198  * U8 to F32
 199  *****************************************************************************/
 200 static int Create_U8ToF32( vlc_object_t *p_this )
 201 {
 202     filter_t * p_filter = (filter_t *)p_this;
 203
 204     if ( p_filter->fmt_in.audio.i_format != VLC_CODEC_U8
 205           || p_filter->fmt_out.audio.i_format != VLC_CODEC_FI32 )
 206     {
 207         return VLC_EGENERIC;
 208     }
 209
 210     if ( !AOUT_FMTS_SIMILAR( &p_filter->fmt_in.audio, &p_filter->fmt_out.audio ) )
 211     {
 212         return VLC_EGENERIC;
 213     }
 214
 215     p_filter->pf_audio_filter = Do_U8ToF32;
 216
 217     return VLC_SUCCESS;
 218 }
 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_pts = p_in_buf->i_pts;
 238     p_out_buf->i_length = p_in_buf->i_length;
 239     p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
 240 out:
 241     block_Release( p_in_buf );
 242     return p_out_buf;
 243 }