utils/upsample.c

   1 #include "../../c-flod/backends/wave_format.h"
   2 #include "../../c-flod/flashlib/ByteArray.h"
   3
   4 struct player {
   5         int play_waveslot;
   6         struct ByteArray wave_streams[1];
   7         struct ByteArray out_wave;
   8         WAVE_HEADER_COMPLETE wavhdr;
   9 } playa;
  10
  11 static int handle_overflow(int *sample) {
  12         if(*sample > 32767) {
  13                 *sample = 32767;
  14                 return 1;
  15         } else if (*sample < -32768) {
  16                 *sample = -32768;
  17                 return -1;
  18         }
  19         return 0;
  20 }
  21
  22 void upsample() {
  23         struct ByteArray* mine = &playa.wave_streams[0];
  24         struct ByteArray* out = &playa.out_wave;
  25
  26         if(!mine->bytesAvailable(mine)) return;
  27
  28         size_t i = 0;
  29         size_t upsample_factor = 44100 / playa.wavhdr.wave_hdr.samplerate;
  30         size_t readbytes = playa.wavhdr.wave_hdr.bitwidth == 8 ? 1 : 2;
  31         int chan[2] = { 0, 0 };
  32         int next[2];
  33
  34         while(mine->bytesAvailable(mine)) {
  35                 int16_t sound;
  36                 size_t c, u;
  37                 for(c = 0; c < 2; c++) {
  38                         if(c < playa.wavhdr.wave_hdr.channels) {
  39                                 if(readbytes == 1) next[c] = ((uint8_t) ByteArray_readByte(mine) - 128) * 256;
  40                                 else next[c] = ByteArray_readShort(mine);
  41                                 handle_overflow(&next[c]);
  42                         } else
  43                                 next[c] = next[c - 1];
  44                 }
  45                 for(u = 0; u < upsample_factor; u++) {
  46                         for(c = 0; c < 2; c++) {
  47                                 int interpolated = u == 0 ? chan[c] :
  48                                         chan[c] + ((next[c]-chan[c]) * ((float)u/(float)upsample_factor));
  49                                 ByteArray_writeShort(out, interpolated);
  50                         }
  51                 }
  52                 for (c=0; c<2; c++) chan[c] = next[c];
  53         }
  54
  55         return;
  56 }
  57
  58 static char buf[1024* 1024];
  59
  60 int main(int argc, char ** argv) {
  61         struct ByteArray *ba = &playa.wave_streams[0];
  62         ByteArray_ctor(ba);
  63         if(!ByteArray_open_file(ba, argv[1])) return 1;
  64         ByteArray_set_endian(ba, BAE_LITTLE);
  65         ByteArray_readMultiByte(ba, (void*) &playa.wavhdr, sizeof(WAVE_HEADER_COMPLETE));
  66         struct ByteArray *out = &playa.out_wave;
  67         ByteArray_ctor(out);
  68         ByteArray_set_endian(out, BAE_LITTLE);
  69         ByteArray_open_mem(out, buf, sizeof buf);
  70         upsample();
  71         ByteArray_dump_to_file(out, "test.raw");
  72
  73 }
  74