ffmpeg/libswresample/resample_template.c

   1 /*
   2  * audio resampling
   3  * Copyright (c) 2004-2012 Michael Niedermayer <michaelni@gmx.at>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file
  24  * audio resampling
  25  * @author Michael Niedermayer <michaelni@gmx.at>
  26  */
  27
  28 #if defined(TEMPLATE_RESAMPLE_DBL)
  29
  30 #    define RENAME(N) N ## _double
  31 #    define FILTER_SHIFT 0
  32 #    define DELEM  double
  33 #    define FELEM  double
  34 #    define FELEM2 double
  35 #    define OUT(d, v) d = v
  36
  37 #elif    defined(TEMPLATE_RESAMPLE_FLT)
  38
  39 #    define RENAME(N) N ## _float
  40 #    define FILTER_SHIFT 0
  41 #    define DELEM  float
  42 #    define FELEM  float
  43 #    define FELEM2 float
  44 #    define OUT(d, v) d = v
  45
  46 #elif defined(TEMPLATE_RESAMPLE_S32)
  47
  48 #    define RENAME(N) N ## _int32
  49 #    define FILTER_SHIFT 30
  50 #    define DELEM  int32_t
  51 #    define FELEM  int32_t
  52 #    define FELEM2 int64_t
  53 #    define FELEM_MAX INT32_MAX
  54 #    define FELEM_MIN INT32_MIN
  55 #    define OUT(d, v) v = (v + (1<<(FILTER_SHIFT-1)))>>FILTER_SHIFT;\
  56                       d = (uint64_t)(v + 0x80000000) > 0xFFFFFFFF ? (v>>63) ^ 0x7FFFFFFF : v
  57
  58 #elif    defined(TEMPLATE_RESAMPLE_S16)
  59
  60 #    define RENAME(N) N ## _int16
  61 #    define FILTER_SHIFT 15
  62 #    define DELEM  int16_t
  63 #    define FELEM  int16_t
  64 #    define FELEM2 int32_t
  65 #    define FELEML int64_t
  66 #    define FELEM_MAX INT16_MAX
  67 #    define FELEM_MIN INT16_MIN
  68 #    define OUT(d, v) v = (v + (1<<(FILTER_SHIFT-1)))>>FILTER_SHIFT;\
  69                       d = (unsigned)(v + 32768) > 65535 ? (v>>31) ^ 32767 : v
  70
  71 #endif
  72
  73 static void RENAME(resample_one)(void *dest, const void *source,
  74                                  int dst_size, int64_t index2, int64_t incr)
  75 {
  76     DELEM *dst = dest;
  77     const DELEM *src = source;
  78     int dst_index;
  79
  80     for (dst_index = 0; dst_index < dst_size; dst_index++) {
  81         dst[dst_index] = src[index2 >> 32];
  82         index2 += incr;
  83     }
  84 }
  85
  86 static int RENAME(resample_common)(ResampleContext *c,
  87                                    void *dest, const void *source,
  88                                    int n, int update_ctx)
  89 {
  90     DELEM *dst = dest;
  91     const DELEM *src = source;
  92     int dst_index;
  93     int index= c->index;
  94     int frac= c->frac;
  95     int sample_index = index >> c->phase_shift;
  96
  97     index &= c->phase_mask;
  98     for (dst_index = 0; dst_index < n; dst_index++) {
  99         FELEM *filter = ((FELEM *) c->filter_bank) + c->filter_alloc * index;
 100
 101         FELEM2 val=0;
 102         int i;
 103         for (i = 0; i < c->filter_length; i++) {
 104             val += src[sample_index + i] * (FELEM2)filter[i];
 105         }
 106         OUT(dst[dst_index], val);
 107
 108         frac  += c->dst_incr_mod;
 109         index += c->dst_incr_div;
 110         if (frac >= c->src_incr) {
 111             frac -= c->src_incr;
 112             index++;
 113         }
 114         sample_index += index >> c->phase_shift;
 115         index &= c->phase_mask;
 116     }
 117
 118     if(update_ctx){
 119         c->frac= frac;
 120         c->index= index;
 121     }
 122
 123     return sample_index;
 124 }
 125
 126 static int RENAME(resample_linear)(ResampleContext *c,
 127                                    void *dest, const void *source,
 128                                    int n, int update_ctx)
 129 {
 130     DELEM *dst = dest;
 131     const DELEM *src = source;
 132     int dst_index;
 133     int index= c->index;
 134     int frac= c->frac;
 135     int sample_index = index >> c->phase_shift;
 136 #if FILTER_SHIFT == 0
 137     double inv_src_incr = 1.0 / c->src_incr;
 138 #endif
 139
 140     index &= c->phase_mask;
 141     for (dst_index = 0; dst_index < n; dst_index++) {
 142         FELEM *filter = ((FELEM *) c->filter_bank) + c->filter_alloc * index;
 143         FELEM2 val=0, v2 = 0;
 144
 145         int i;
 146         for (i = 0; i < c->filter_length; i++) {
 147             val += src[sample_index + i] * (FELEM2)filter[i];
 148             v2  += src[sample_index + i] * (FELEM2)filter[i + c->filter_alloc];
 149         }
 150 #ifdef FELEML
 151         val += (v2 - val) * (FELEML) frac / c->src_incr;
 152 #else
 153 #    if FILTER_SHIFT == 0
 154         val += (v2 - val) * inv_src_incr * frac;
 155 #    else
 156         val += (v2 - val) / c->src_incr * frac;
 157 #    endif
 158 #endif
 159         OUT(dst[dst_index], val);
 160
 161         frac += c->dst_incr_mod;
 162         index += c->dst_incr_div;
 163         if (frac >= c->src_incr) {
 164             frac -= c->src_incr;
 165             index++;
 166         }
 167         sample_index += index >> c->phase_shift;
 168         index &= c->phase_mask;
 169     }
 170
 171     if(update_ctx){
 172         c->frac= frac;
 173         c->index= index;
 174     }
 175
 176     return sample_index;
 177 }
 178
 179 #undef RENAME
 180 #undef FILTER_SHIFT
 181 #undef DELEM
 182 #undef FELEM
 183 #undef FELEM2
 184 #undef FELEML
 185 #undef FELEM_MAX
 186 #undef FELEM_MIN
 187 #undef OUT