rlm@23: #include <stdio.h>
rlm@23: #include <assert.h>
rlm@23: #include <string.h>
rlm@23: #include "SndfileWavUtil.h"
rlm@23: 
rlm@23: const  int Taps = 9;
rlm@23: static int newest;
rlm@23: static short int x[Taps] = {0,0,0,0,0,0,0,0,0};
rlm@23: static short int fir(short int);
rlm@23: const  int short_sz = sizeof(short);
rlm@23: 
rlm@23: // lifted from the bluespec code
rlm@23: static double h[Taps] =  {-0.0124,
rlm@23: 			  0.0,
rlm@23: 			  -0.0133,
rlm@23: 			  0.0,
rlm@23: 			  0.8181,
rlm@23: 			  0.0,
rlm@23: 			  -0.0133,
rlm@23: 			  0.0,
rlm@23: 			  -0.0124};
rlm@23: 
rlm@23: 
rlm@23: int
rlm@23: main (int argc, char * argv [])
rlm@23: {
rlm@23:   const char* inputWavFileName;
rlm@23:   const char* outputWavFileName;
rlm@23: 
rlm@23:   FILE *inputPcmFile;
rlm@23:   FILE *outputPcmFile;
rlm@23: 
rlm@23:   short int sample;
rlm@23: 
rlm@23:   inputWavFileName = argv[1];
rlm@23:   outputWavFileName = argv[2];
rlm@23: 
rlm@23:   // Convert input wav to pcm
rlm@23:   generate_pcm(inputWavFileName, "input.pcm");
rlm@23: 
rlm@23:   inputPcmFile = fopen("input.pcm", "r");
rlm@23:   outputPcmFile = fopen("output.pcm", "w");
rlm@23: 
rlm@23:   assert(inputPcmFile);
rlm@23:   assert(outputPcmFile);
rlm@23: 
rlm@23:   newest = 0;
rlm@23:   memset(x, 0, sizeof(x));
rlm@23: 
rlm@23:   while(fread(&sample, short_sz, 1, inputPcmFile)) {
rlm@23:     sample = fir(sample);
rlm@23:     assert(fwrite(&sample,short_sz,1,outputPcmFile));
rlm@23:   } 
rlm@23: 
rlm@23:   fclose(inputPcmFile);
rlm@23:   fclose(outputPcmFile);
rlm@23: 
rlm@23:   generate_wav("output.pcm", inputWavFileName, outputWavFileName);
rlm@23: }
rlm@23: 
rlm@23: short int
rlm@23: fir(short int sample)
rlm@23: {
rlm@23: 
rlm@23:   x[newest] = sample; 
rlm@23:   double y = 0;
rlm@23: 
rlm@23:   for (int k = 0; k < Taps; k++) { 
rlm@23: 
rlm@23:     short int bits = x[(newest+k)%Taps];
rlm@23:     double x = (double)bits;
rlm@23:     y += h[k] * x; 
rlm@23: 
rlm@23:   }
rlm@23: 
rlm@23:   newest = (newest == 0) ? (Taps-1) : (newest-1);
rlm@23: 
rlm@23:   short int rv = ((short int)y)&0x0000FFFF;
rlm@23:   return rv;
rlm@23: }
rlm@23: