使用 fopen_s读取一个wav文件并对其求WVD并输出WVD结果不使用库函数C语言并解释代码
时间: 2024-05-07 08:23:39 浏览: 14
首先,需要了解WVD(Wigner-Ville Distribution)的计算方法。WVD是一种时频分析方法,它将信号在时间与频率两个维度上进行分析,得到一个二维的时频分布图。
以下是一个简单的C语言代码示例,用于读取一个wav文件并对其计算WVD:
```c
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define PI 3.14159265358979323846
// 读取wav文件
void read_wav(const char *filename, short **data, int *samples, int *bitrate) {
FILE *fp = NULL;
unsigned char header[44];
int len = 0;
fopen_s(&fp, filename, "rb");
if (fp == NULL) {
return;
}
fread(header, sizeof(unsigned char), 44, fp);
*samples = *(int *)(header + 40);
*bitrate = *(int *)(header + 34);
len = (*samples) * ((*bitrate) / 8);
*data = (short *)malloc(len);
fread(*data, sizeof(short), len/2, fp);
fclose(fp);
}
// 计算WVD
void wvd(short *data, int samples, int bitrate, double **wvd, int *wvd_size) {
int i, j, k;
double t, f, w;
double re, im;
double *tmp = NULL;
*wvd_size = samples * samples;
*wvd = (double *)malloc((*wvd_size) * sizeof(double));
tmp = (double *)malloc(samples * sizeof(double));
for (i = 0; i < samples; i++) {
for (j = 0; j < samples; j++) {
(*wvd)[i*samples+j] = 0.0;
}
}
for (i = 0; i < samples; i++) {
for (j = 0; j < samples; j++) {
for (k = 0; k < samples; k++) {
t = (i - k) * 1.0 / samples;
f = (j - k) * 1.0 / samples;
w = exp(-2 * PI * f * t * bitrate);
tmp[k] = data[k] * w;
}
for (k = 0; k < samples; k++) {
re = tmp[k] * cos(2 * PI * (j - k) * 1.0 / samples * bitrate);
im = tmp[k] * sin(2 * PI * (j - k) * 1.0 / samples * bitrate);
(*wvd)[i*samples+j] += re*re - im*im;
}
}
}
free(tmp);
}
// 输出WVD结果
void print_wvd(double *wvd, int wvd_size) {
int i, j;
for (i = 0; i < wvd_size; i++) {
printf("%f ", wvd[i]);
if ((i+1) % samples == 0) {
printf("\n");
}
}
}
int main(int argc, char *argv[]) {
short *data = NULL;
int samples = 0, bitrate = 0;
double *wvd = NULL;
int wvd_size = 0;
read_wav("test.wav", &data, &samples, &bitrate);
wvd(data, samples, bitrate, &wvd, &wvd_size);
print_wvd(wvd, wvd_size);
free(data);
free(wvd);
return 0;
}
```
需要注意的是,该代码示例并没有进行错误检查和异常处理,仅作为一个简单的参考示例。实际使用中,需要根据具体情况进行修改和完善。