delay.c

Ugrás a fájl dokumentációjához.

 
#include <stdio.h>
#include "binary_streams.h"
 
typedef float sample_t;
 
enum
{
    SAMPLE_RATE = 44100,    
    N = SAMPLE_RATE         
};
 
int main(int argc, char **argv)
{
    // delay time
    double T = .2;
    // delay attenuation
    double alpha = .5;
    if (argc >= 3)
    {
        sscanf(argv[1], "%lf", &T);
        sscanf(argv[2], "%lf", &alpha);
    }
 
    int K = SAMPLE_RATE * T;
    sample_t circ_buffer[N][2] = {0};
 
    // reopen streams as binary
    binary_streams();
 
    int cnt = 0;
    sample_t samples[2];
    while (fread(samples, sizeof(sample_t), 2, stdin) == 2)
    {
        int c;
        for (c = 0; c < 2; ++c)
        {
            circ_buffer[cnt][c] *= alpha;       // attenuate past
            circ_buffer[cnt][c] += samples[c];  // add present
        }
 
        // write present + past
        fwrite(circ_buffer[cnt], sizeof(sample_t), 2, stdout);
 
        cnt++;  // circular indexing
        cnt %= K;
    }
 
    return 0;
}