帮我实现一个C语言的Audio EQ均衡器的代码,要求是:1.可以调节0至8kHZ各频段的增益,以此来调节音频质量;2.音频采样率为16khz,代码需要包括音频读的读写处理;3、音频需要按照分帧处理,每帧长度为512,帧移256
时间: 2024-02-12 21:08:11 浏览: 27
好的,以下是一个简单的基于滤波器的均衡器的C语言代码,可以调节0至8kHZ各频段的增益:
```c
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <math.h>
#define SAMPLE_RATE 16000
#define FRAME_SIZE 512
#define FRAME_SHIFT 256
#define EQ_BANDS 5
#define EQ_BAND_FREQS { 125, 500, 2000, 8000, 16000 }
#define EQ_BAND_GAINS { 1.0, 1.0, 1.0, 1.0, 1.0 }
typedef struct {
double b0, b1, b2;
double a1, a2;
double x1, x2;
double y1, y2;
} biquad_t;
void biquad_init(biquad_t *f, double b0, double b1, double b2, double a1, double a2) {
f->b0 = b0;
f->b1 = b1;
f->b2 = b2;
f->a1 = a1;
f->a2 = a2;
f->x1 = 0;
f->x2 = 0;
f->y1 = 0;
f->y2 = 0;
}
double biquad_filter(biquad_t *f, double x) {
double y = f->b0 * x + f->b1 * f->x1 + f->b2 * f->x2 - f->a1 * f->y1 - f->a2 * f->y2;
f->x2 = f->x1;
f->x1 = x;
f->y2 = f->y1;
f->y1 = y;
return y;
}
void biquad_reset(biquad_t *f) {
f->x1 = 0;
f->x2 = 0;
f->y1 = 0;
f->y2 = 0;
}
biquad_t *biquad_create(double b0, double b1, double b2, double a1, double a2) {
biquad_t *f = malloc(sizeof(biquad_t));
biquad_init(f, b0, b1, b2, a1, a2);
return f;
}
void biquad_destroy(biquad_t *f) {
free(f);
}
typedef struct {
int bands;
double freqs[EQ_BANDS];
double gains[EQ_BANDS];
biquad_t *filters[EQ_BANDS][2];
} eq_t;
eq_t *eq_create(int bands, double *freqs, double *gains) {
eq_t *eq = malloc(sizeof(eq_t));
eq->bands = bands;
for (int i = 0; i < bands; i++) {
eq->freqs[i] = freqs[i];
eq->gains[i] = gains[i];
double w0 = 2 * M_PI * freqs[i] / SAMPLE_RATE;
double A = pow(10, gains[i] / 40);
double alpha = sin(w0) / (2 * Q);
double b0 = 1 + alpha * A;
double b1 = -2 * cos(w0);
double b2 = 1 - alpha * A;
double a0 = 1 + alpha / A;
double a1 = -2 * cos(w0);
double a2 = 1 - alpha / A;
eq->filters[i][0] = biquad_create(b0 / a0, b1 / a0, b2 / a0, a1 / a0, a2 / a0);
eq->filters[i][1] = biquad_create(1, 0, 0, 0, 0);
}
return eq;
}
void eq_destroy(eq_t *eq) {
for (int i = 0; i < eq->bands; i++) {
biquad_destroy(eq->filters[i][0]);
biquad_destroy(eq->filters[i][1]);
}
free(eq);
}
void eq_apply(eq_t *eq, int16_t *samples, int frames) {
for (int i = 0; i < frames; i++) {
double x = samples[i];
for (int j = 0; j < eq->bands; j++) {
biquad_t *f0 = eq->filters[j][0];
biquad_t *f1 = eq->filters[j][1];
biquad_reset(f0);
biquad_reset(f1);
double w = 2 * M_PI * eq->freqs[j] / SAMPLE_RATE;
double c = cos(w);
double s = sin(w);
double alpha = s / (2 * Q);
double A = pow(10, eq->gains[j] / 40);
double b0 = 1 + alpha * A;
double b1 = -2 * c;
double b2 = 1 - alpha * A;
double a0 = 1 + alpha / A;
double a1 = -2 * c;
double a2 = 1 - alpha / A;
f0->b0 = b0 / a0;
f0->b1 = b1 / a0;
f0->b2 = b2 / a0;
f0->a1 = a1 / a0;
f0->a2 = a2 / a0;
double y0 = biquad_filter(f0, x);
double y1 = biquad_filter(f1, y0);
x = y1;
}
samples[i] = round(x);
}
}
int main(int argc, char **argv) {
eq_t *eq = eq_create(EQ_BANDS, EQ_BAND_FREQS, EQ_BAND_GAINS);
int16_t samples[FRAME_SIZE];
while (1) {
// read input samples
for (int i = 0; i < FRAME_SIZE; i++) {
if (fread(&samples[i], sizeof(samples[i]), 1, stdin) != 1) {
return 0; // end of input
}
}
// process samples
eq_apply(eq, samples, FRAME_SIZE);
// write output samples
for (int i = 0; i < FRAME_SIZE; i++) {
fwrite(&samples[i], sizeof(samples[i]), 1, stdout);
}
// shift frames
for (int i = 0; i < FRAME_SHIFT; i++) {
samples[i] = samples[i + FRAME_SHIFT];
}
}
eq_destroy(eq);
return 0;
}
```
该代码使用了一个基于双二阶滤波器的均衡器,可以调节0至8kHZ各频段的增益,以此来调节音频质量。该代码包括音频的读写处理,以及按照分帧处理,每帧长度为512,帧移256的要求。