wav音频文件格式解析

wav是微软开发的一种音频文件格式，注意，wav文件格式是无损音频文件格式，相对于其他音频格式文件数据是没有经过压缩的，通常文件也相对比较大些。
文件格式如图所示：



解析代码如下：

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>

struct WAV_Format {
uint32_t ChunkID;	/* "RIFF" */
uint32_t ChunkSize;	/* 36 + Subchunk2Size */
uint32_t Format;	/* "WAVE" */

/* sub-chunk "fmt" */
uint32_t Subchunk1ID;	/* "fmt " */
uint32_t Subchunk1Size;	/* 16 for PCM */
uint16_t AudioFormat;	/* PCM = 1*/
uint16_t NumChannels;	/* Mono = 1, Stereo = 2, etc. */
uint32_t SampleRate;	/* 8000, 44100, etc. */
uint32_t ByteRate;	/* = SampleRate * NumChannels * BitsPerSample/8 */
uint16_t BlockAlign;	/* = NumChannels * BitsPerSample/8 */
uint16_t BitsPerSample;	/* 8bits, 16bits, etc. */

/* sub-chunk "data" */
uint32_t Subchunk2ID;	/* "data" */
uint32_t Subchunk2Size;	/* data size */
};

int main(void)
{
FILE *fp = NULL;
struct WAV_Format wav;

fp = fopen("test.wav", "rb");
if (!fp) {
printf("can't open audio file\n");
exit(1);
}

fread(&wav, 1, sizeof(struct WAV_Format), fp);

printf("ChunkID \t%x\n", wav.ChunkID);
printf("ChunkSize \t%d\n", wav.ChunkSize);
printf("Format \t\t%x\n", wav.Format);
printf("Subchunk1ID \t%x\n", wav.Subchunk1ID);
printf("Subchunk1Size \t%d\n", wav.Subchunk1Size);
printf("AudioFormat \t%d\n", wav.AudioFormat);
printf("NumChannels \t%d\n", wav.NumChannels);
printf("SampleRate \t%d\n", wav.SampleRate);
printf("ByteRate \t%d\n", wav.ByteRate);
printf("BlockAlign \t%d\n", wav.BlockAlign);
printf("BitsPerSample \t%d\n", wav.BitsPerSample);
printf("Subchunk2ID \t%x\n", wav.Subchunk2ID);
printf("Subchunk2Size \t%d\n", wav.Subchunk2Size);

fclose(fp);

return 0;
}

// 2016-09-22 add

ByteRate计算方法是SampleRate * NumChannels * BitsPerSample/8，那么这个公式计算出来的是1秒钟音频数据大小，单位为Byte，以44100、16bit、2通道为例，那么计算出来值为176400，根据总音频数据大小，可以得出播放时间的计算公式为Subchunk2Size / ByteRate。

参考：http://soundfile.sapp.org/doc/WaveFormat/