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

下面是一个使用 C 语言读取 WAV 文件并计算其 WVD 的示例代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

#define PI 3.14159265358979323846

typedef struct {
    char chunkId[4];
    unsigned int chunkSize;
    char format[4];
    char subchunk1Id[4];
    unsigned int subchunk1Size;
    unsigned short audioFormat;
    unsigned short numChannels;
    unsigned int sampleRate;
    unsigned int byteRate;
    unsigned short blockAlign;
    unsigned short bitsPerSample;
    char subchunk2Id[4];
    unsigned int subchunk2Size;
} WavHeader;

int main() {
    FILE *fp;
    WavHeader header;
    char filename[256];
    double **data;
    int i, j, k;
    double *window;
    int windowSize = 1024;
    int hopSize = 256;
    int numWindows;
    double **wvd;

    // Read WAV file header
    printf("Enter WAV file name: ");
    scanf("%s", filename);
    if (fopen_s(&fp, filename, "rb") != 0) {
        printf("Cannot open file.\n");
        return 1;
    }
    fread(&header, sizeof(WavHeader), 1, fp);
    printf("Sample rate: %u Hz\n", header.sampleRate);
    printf("Number of channels: %hu\n", header.numChannels);
    printf("Bits per sample: %hu\n", header.bitsPerSample);

    // Allocate memory for audio data
    data = (double **) malloc(header.numChannels * sizeof(double *));
    for (i = 0; i < header.numChannels; i++) {
        data[i] = (double *) malloc(header.subchunk2Size / header.blockAlign * sizeof(double));
    }

    // Read audio data
    for (i = 0; i < header.subchunk2Size / header.blockAlign; i++) {
        for (j = 0; j < header.numChannels; j++) {
            switch (header.bitsPerSample) {
                case 8:
                    data[j][i] = (double) ((int16_t) fgetc(fp) - 128) / 128.0;
                    break;
                case 16:
                    data[j][i] = (double) ((int16_t) fgetc(fp)) / 32768.0;
                    data[j][i] += (double) ((int16_t) fgetc(fp)) / 32768.0 / 256.0;
                    break;
                case 24:
                    data[j][i] = (double) ((int16_t) fgetc(fp)) / 8388608.0;
                    data[j][i] += (double) ((int16_t) fgetc(fp)) / 32768.0 / 256.0;
                    data[j][i] += (double) ((int16_t) fgetc(fp)) / 32768.0 / 65536.0;
                    break;
                case 32:
                    data[j][i] = (double) ((int16_t) fgetc(fp)) / 2147483648.0;
                    data[j][i] += (double) ((int16_t) fgetc(fp)) / 32768.0 / 65536.0;
                    data[j][i] += (double) ((int16_t) fgetc(fp)) / 32768.0 / 4294967296.0;
                    data[j][i] += (double) ((int16_t) fgetc(fp)) / 32768.0 / 1099511627776.0;
                    break;
            }
        }
    }

    // Calculate WVD
    numWindows = (header.subchunk2Size / header.blockAlign - windowSize) / hopSize + 1;
    window = (double *) malloc(windowSize * sizeof(double));
    wvd = (double **) malloc(numWindows * sizeof(double *));
    for (i = 0; i < numWindows; i++) {
        wvd[i] = (double *) malloc(windowSize * windowSize * sizeof(double));
    }
    for (i = 0; i < windowSize; i++) {
        window[i] = 0.5 - 0.5 * cos(2.0 * PI * i / (windowSize - 1));
    }
    for (i = 0; i < numWindows; i++) {
        for (j = 0; j < windowSize; j++) {
            for (k = 0; k < windowSize; k++) {
                double sum = 0.0;
                int n;
                for (n = 0; n < windowSize; n++) {
                    int m = i * hopSize + n;
                    if (m >= 0 && m < header.subchunk2Size / header.blockAlign) {
                        sum += data[0][m] * data[0][m - k] * window[n];
                    }
                }
                wvd[i][j * windowSize + k] = sum;
            }
        }
    }

    // Output WVD
    FILE *fpOut;
    char filenameOut[256];
    sprintf(filenameOut, "%s.wvd", filename);
    if (fopen_s(&fpOut, filenameOut, "wb") != 0) {
        printf("Cannot open file for writing.\n");
        return 1;
    }
    fwrite(&header, sizeof(WavHeader), 1, fpOut);
    for (i = 0; i < numWindows; i++) {
        fwrite(wvd[i], sizeof(double), windowSize * windowSize, fpOut);
    }
    fclose(fpOut);

    // Free memory
    free(window);
    for (i = 0; i < numWindows; i++) {
        free(wvd[i]);
    }
    free(wvd);
    for (i = 0; i < header.numChannels; i++) {
        free(data[i]);
    }
    free(data);
    fclose(fp);
    return 0;
}

这段代码中，我们首先定义了一个结构体 `WavHeader` 来存储 WAV 文件头信息。然后使用 `fopen_s` 函数打开 WAV 文件，读取文件头信息并打印出来。接着分配内存用来存储音频数据，读取 WAV 文件中的音频数据并存储到内存中。接下来计算 WVD，这里使用了固定大小的窗口和重叠方式来分割音频信号，并在每个窗口上计算 WVD。最后将 WVD 结果写入到一个新的 WAV 文件中。

值得注意的是，这段代码只支持 16、24、32 位的 WAV 文件，如果需要支持其他格式的 WAV 文件需要相应地修改代码。