liba52/resample_c.c

   1 // this code is based on a52dec/libao/audio_out_oss.c
   2
   3 static inline int16_t convert (int32_t i)
   4 {
   5     if (i > 0x43c07fff)
   6         return 32767;
   7     else if (i < 0x43bf8000)
   8         return -32768;
   9     else
  10         return i - 0x43c00000;
  11 }
  12
  13 static int a52_resample_MONO_to_5_C(float * _f, int16_t * s16){
  14     int i;
  15     int32_t * f = (int32_t *) _f;
  16         for (i = 0; i < 256; i++) {
  17             s16[5*i] = s16[5*i+1] = s16[5*i+2] = s16[5*i+3] = 0;
  18             s16[5*i+4] = convert (f[i]);
  19         }
  20     return 5*256;
  21 }
  22
  23 static int a52_resample_MONO_to_1_C(float * _f, int16_t * s16){
  24     int i;
  25     int32_t * f = (int32_t *) _f;
  26         for (i = 0; i < 256; i++) {
  27             s16[i] = convert (f[i]);
  28         }
  29     return 1*256;
  30 }
  31
  32 static int a52_resample_STEREO_to_2_C(float * _f, int16_t * s16){
  33     int i;
  34     int32_t * f = (int32_t *) _f;
  35         for (i = 0; i < 256; i++) {
  36             s16[2*i] = convert (f[i]);
  37             s16[2*i+1] = convert (f[i+256]);
  38         }
  39     return 2*256;
  40 }
  41
  42 static int a52_resample_3F_to_5_C(float * _f, int16_t * s16){
  43     int i;
  44     int32_t * f = (int32_t *) _f;
  45         for (i = 0; i < 256; i++) {
  46             s16[5*i] = convert (f[i]);
  47             s16[5*i+1] = convert (f[i+512]);
  48             s16[5*i+2] = s16[5*i+3] = 0;
  49             s16[5*i+4] = convert (f[i+256]);
  50         }
  51     return 5*256;
  52 }
  53
  54 static int a52_resample_2F_2R_to_4_C(float * _f, int16_t * s16){
  55     int i;
  56     int32_t * f = (int32_t *) _f;
  57         for (i = 0; i < 256; i++) {
  58             s16[4*i] = convert (f[i]);
  59             s16[4*i+1] = convert (f[i+256]);
  60             s16[4*i+2] = convert (f[i+512]);
  61             s16[4*i+3] = convert (f[i+768]);
  62         }
  63     return 4*256;
  64 }
  65
  66 static int a52_resample_3F_2R_to_5_C(float * _f, int16_t * s16){
  67     int i;
  68     int32_t * f = (int32_t *) _f;
  69         for (i = 0; i < 256; i++) {
  70             s16[5*i] = convert (f[i]);
  71             s16[5*i+1] = convert (f[i+512]);
  72             s16[5*i+2] = convert (f[i+768]);
  73             s16[5*i+3] = convert (f[i+1024]);
  74             s16[5*i+4] = convert (f[i+256]);
  75         }
  76     return 5*256;
  77 }
  78
  79 static int a52_resample_MONO_LFE_to_6_C(float * _f, int16_t * s16){
  80     int i;
  81     int32_t * f = (int32_t *) _f;
  82         for (i = 0; i < 256; i++) {
  83             s16[6*i] = s16[6*i+1] = s16[6*i+2] = s16[6*i+3] = 0;
  84             s16[6*i+4] = convert (f[i+256]);
  85             s16[6*i+5] = convert (f[i]);
  86         }
  87     return 6*256;
  88 }
  89
  90 static int a52_resample_STEREO_LFE_to_6_C(float * _f, int16_t * s16){
  91     int i;
  92     int32_t * f = (int32_t *) _f;
  93         for (i = 0; i < 256; i++) {
  94             s16[6*i] = convert (f[i+256]);
  95             s16[6*i+1] = convert (f[i+512]);
  96             s16[6*i+2] = s16[6*i+3] = s16[6*i+4] = 0;
  97             s16[6*i+5] = convert (f[i]);
  98         }
  99     return 6*256;
 100 }
 101
 102 static int a52_resample_3F_LFE_to_6_C(float * _f, int16_t * s16){
 103     int i;
 104     int32_t * f = (int32_t *) _f;
 105         for (i = 0; i < 256; i++) {
 106             s16[6*i] = convert (f[i+256]);
 107             s16[6*i+1] = convert (f[i+768]);
 108             s16[6*i+2] = s16[6*i+3] = 0;
 109             s16[6*i+4] = convert (f[i+512]);
 110             s16[6*i+5] = convert (f[i]);
 111         }
 112     return 6*256;
 113 }
 114
 115 static int a52_resample_2F_2R_LFE_to_6_C(float * _f, int16_t * s16){
 116     int i;
 117     int32_t * f = (int32_t *) _f;
 118         for (i = 0; i < 256; i++) {
 119             s16[6*i] = convert (f[i+256]);
 120             s16[6*i+1] = convert (f[i+512]);
 121             s16[6*i+2] = convert (f[i+768]);
 122             s16[6*i+3] = convert (f[i+1024]);
 123             s16[6*i+4] = 0;
 124             s16[6*i+5] = convert (f[i]);
 125         }
 126     return 6*256;
 127 }
 128
 129 static int a52_resample_3F_2R_LFE_to_6_C(float * _f, int16_t * s16){
 130     int i;
 131     int32_t * f = (int32_t *) _f;
 132         for (i = 0; i < 256; i++) {
 133             s16[6*i] = convert (f[i+256]);
 134             s16[6*i+1] = convert (f[i+768]);
 135             s16[6*i+2] = convert (f[i+1024]);
 136             s16[6*i+3] = convert (f[i+1280]);
 137             s16[6*i+4] = convert (f[i+512]);
 138             s16[6*i+5] = convert (f[i]);
 139         }
 140     return 6*256;
 141 }
 142
 143
 144 static void* a52_resample_C(int flags, int ch){
 145     switch (flags) {
 146     case A52_MONO:
 147         if(ch==5) return a52_resample_MONO_to_5_C;
 148         if(ch==1) return a52_resample_MONO_to_1_C;
 149         break;
 150     case A52_CHANNEL:
 151     case A52_STEREO:
 152     case A52_DOLBY:
 153         if(ch==2) return a52_resample_STEREO_to_2_C;
 154         break;
 155     case A52_3F:
 156         if(ch==5) return a52_resample_3F_to_5_C;
 157         break;
 158     case A52_2F2R:
 159         if(ch==4) return a52_resample_2F_2R_to_4_C;
 160         break;
 161     case A52_3F2R:
 162         if(ch==5) return a52_resample_3F_2R_to_5_C;
 163         break;
 164     case A52_MONO | A52_LFE:
 165         if(ch==6) return a52_resample_MONO_LFE_to_6_C;
 166         break;
 167     case A52_CHANNEL | A52_LFE:
 168     case A52_STEREO | A52_LFE:
 169     case A52_DOLBY | A52_LFE:
 170         if(ch==6) return a52_resample_STEREO_LFE_to_6_C;
 171         break;
 172     case A52_3F | A52_LFE:
 173         if(ch==6) return a52_resample_3F_LFE_to_6_C;
 174         break;
 175     case A52_2F2R | A52_LFE:
 176         if(ch==6) return a52_resample_2F_2R_LFE_to_6_C;
 177         break;
 178     case A52_3F2R | A52_LFE:
 179         if(ch==6) return a52_resample_3F_2R_LFE_to_6_C;
 180         break;
 181     }
 182     return NULL;
 183 }