AudioEQ均衡器c代码实现
时间: 2024-02-12 09:05:30 浏览: 25
下面是一个简单的 C 语言实现 AudioEQ 均衡器的代码示例:
```c
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define SAMPLE_RATE 44100
#define BUFFER_SIZE 1024
typedef struct {
double frequency;
double gain;
double Q;
double A;
double alpha;
double beta;
double gamma;
double b0;
double b1;
double b2;
double a0;
double a1;
double a2;
double x1;
double x2;
double y1;
double y2;
} BiquadFilter;
void initFilter(BiquadFilter *filter, double frequency, double gain, double Q) {
filter->frequency = frequency;
filter->gain = gain;
filter->Q = Q;
filter->A = pow(10, gain / 40);
filter->alpha = sin(2 * M_PI * frequency / SAMPLE_RATE) / (2 * Q);
filter->beta = sqrt(filter->A) / Q;
filter->gamma = sin(2 * M_PI * frequency / SAMPLE_RATE) / (2 * filter->beta);
filter->b0 = (1 - filter->gamma) / 2;
filter->b1 = 0;
filter->b2 = -(1 - filter->gamma) / 2;
filter->a0 = 1 + filter->alpha;
filter->a1 = -2 * cos(2 * M_PI * frequency / SAMPLE_RATE);
filter->a2 = 1 - filter->alpha;
filter->x1 = filter->x2 = filter->y1 = filter->y2 = 0;
}
void applyFilter(BiquadFilter *filter, double *buffer, int bufferSize) {
for (int i = 0; i < bufferSize; i++) {
double x0 = buffer[i];
double y0 = filter->b0 * x0 + filter->b1 * filter->x1 + filter->b2 * filter->x2
- filter->a1 * filter->y1 - filter->a2 * filter->y2;
filter->x2 = filter->x1;
filter->x1 = x0;
filter->y2 = filter->y1;
filter->y1 = y0;
buffer[i] = y0;
}
}
int main() {
// create a low-pass filter with cutoff frequency 1000 Hz, gain 0 dB, and Q 1
BiquadFilter filter;
initFilter(&filter, 1000, 0, 1);
// generate a sine wave at 440 Hz
double buffer[BUFFER_SIZE];
double phase = 0;
double deltaPhase = 2 * M_PI * 440 / SAMPLE_RATE;
for (int i = 0; i < BUFFER_SIZE; i++) {
buffer[i] = sin(phase);
phase += deltaPhase;
}
// apply the filter
applyFilter(&filter, buffer, BUFFER_SIZE);
// print the filtered samples
for (int i = 0; i < BUFFER_SIZE; i++) {
printf("%f\n", buffer[i]);
}
return 0;
}
```
该代码实现了一个二阶滤波器,可以通过修改 `initFilter` 函数中的参数创建不同类型的滤波器。在 `applyFilter` 函数中,将输入的音频缓冲区应用滤波器并输出结果。
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