[分享] WAV文件格式的详细解析 + 代码

37°男人 2013-4-17 21:44 楼主

WAV文件格式
WAVE文件是非常简单的一种RIFF文件，它的格式类型为"WAVE"。RIFF块包含两个子块，这两个子块的ID分别是"fmt"和"data",其中"fmt"子块由结构PCMWAVEFORMAT所组成，其子块的大小就是sizeofof(PCMWAVEFORMAT),数据组成就是PCMWAVEFORMAT结构中的数据。

标志符（RIFF）

数据大小

格式类型（"WAVE"）

"fmt"

Sizeof(PCMWAVEFORMAT)

PCMWAVEFORMAT

"data"

声音数据大小

声音数据

typedef struct _TWavHeader
{
      int rId; //标志符（RIFF）
      int rLen; //数据大小,包括数据头的大小和音频文件的大小
      int wId; //格式类型（"WAVE"）
      int fId; //"fmt"

int fLen; //Sizeof(WAVEFORMATEX)

      short wFormatTag;    //编码格式，包括WAVE_FORMAT_PCM，WAVEFORMAT_ADPCM等
      short nChannels;       //声道数，单声道为1，双声道为2
      int nSamplesPerSec; //采样频率
      int nAvgBytesPerSec;  //每秒的数据量
      short nBlockAlign;    //块对齐
      short wBitsPerSample; //WAVE文件的采样大小
      int dId;             //"data"
      int wSampleLength; //音频数据的大小
}TWavHeader;

/*
* File name: resolving.c
* Author: xubinbin (xubbwd@gmail.com)
* Version: ver.1.0
* Date: 2013.04.17
* Description: The type wav file header parameter parsing.
*/
#include
#include
#define SIZE_LONG 4
#define SIZE_SHORT 2
#define SIZE_ID 4
#define BITS_PER_BYTE 8
#define WAVE_FORMAT_PCM (0x0001)
#define FILE_NAME "aplay_test.wav"
typedef struct _fa_wavfmt_t
{
unsigned short format;
unsigned short channels; //音频通道数 1：单声道 2：立体声
unsigned long samplerate; //声音采样频率
unsigned short bytes_per_sample; //每帧数据大小（单声道）
unsigned short block_align;
unsigned long data_size; //数据总长度
}fa_wavfmt_t;
/*
* Function: fa_read_u32
* Description: read from the file stream 4 bytes data
*/
static unsigned long fa_read_u32(FILE *fp)
{
unsigned long cx;
unsigned char temp[SIZE_LONG];
fread(temp, sizeof(*temp), SIZE_LONG, fp);
cx = (unsigned long)temp[0];
cx |= (unsigned long)temp[1] << 8;
cx |= (unsigned long)temp[2] << 16;
cx |= (unsigned long)temp[3] << 24;
return cx;
}
/*
* Function: fa_read_u16
* Description: read from the file stream 2 bytes data
*/
static unsigned short fa_read_u16(FILE *fp)
{
unsigned short cx;
unsigned char temp[SIZE_SHORT];
fread(temp, sizeof(*temp), SIZE_SHORT, fp);
cx = temp[0] | (temp[1] * 256);
return cx;
}
void printf_fun(fa_wavfmt_t *fmt)
{
printf("************************************************************\n");
printf("* *\n");
printf("* Copyright (C) 2013 xubinbin 徐彬彬 (Beijing China) *\n");
printf("* Free Software *\n");
printf("* Email: xubbwd@gmail.com *\n");
printf("* *\n");
printf("************************************************************\n\n");
printf("##############################################################\n");
printf("###### format = %d ######\n",fmt->format);
printf("###### channels = %d ######\n",fmt->channels);
printf("###### samplerate = %ld ######\n",fmt->samplerate);
printf("###### bytes_per_sample = %d ######\n",fmt->bytes_per_sample);
printf("###### block_align = %d ######\n",fmt->block_align);
printf("###### data_size = %ld ######\n",fmt->data_size);
printf("##############################################################\n");
return;
}
int main()
{
long nskip, x_size;
unsigned short format;
unsigned short channels, block_align;
unsigned long samplerate;
unsigned long bits_per_sample;
unsigned long bytes_per_sample;
unsigned long data_size;
unsigned char temp[SIZE_ID];
fa_wavfmt_t fmt;
FILE * fp = NULL;
if ((fp = fopen(FILE_NAME, "rb")) == NULL) {
printf("input file can not be opened;\n");
return 0;
}
/*wav的文件标识符为RIFF，对标识符进行判断*/
fread(temp, sizeof(*temp), SIZE_ID, fp);
if (memcmp(temp, "RIFF", (size_t)SIZE_ID)!=0) {
fprintf(stderr, "file is not WAVE format!\n");
return -1;
}
fread(temp, sizeof(*temp), SIZE_LONG, fp);
/*文件的格式类型为WAVE*/
fread(temp, sizeof(*temp), SIZE_ID, fp);
if (memcmp(temp, "WAVE", (size_t)SIZE_ID)!=0) {
fprintf(stderr, "file is not WAVE format!\n");
return -1;
}
/* fmt标志，最后一位为空 */
fread(temp, sizeof(*temp), SIZE_ID, fp);
/* skip chunks except for "fmt " or "data" */
while (memcmp(temp, "fmt ", (size_t)SIZE_ID)!=0) {
nskip = fa_read_u32(fp);
if (nskip!=0) {
fseek(fp, nskip, SEEK_CUR);
}
}
/*sizeof(PCMWAVEFORMAT)*/
x_size = fa_read_u32(fp);
// printf("LINE[%d]#### %ld\n",__LINE__,x_size);
/* 1（WAVE_FORMAT_PCM）格式类别，1表示为PCM形式的声音数据*/
format = fa_read_u16(fp);
x_size -= SIZE_SHORT;
if (WAVE_FORMAT_PCM != format) {
fprintf(stderr, "error! unsupported WAVE file format.\n");
return -1;
}
/*声音通道数*/
channels = fa_read_u16(fp);
x_size -= SIZE_SHORT;
/*声音采样率*/
samplerate = fa_read_u32(fp);
x_size -= SIZE_LONG;
fa_read_u32(fp); /* skip bytes/s 每秒数据量 */
block_align = fa_read_u16(fp); /* skip block align 数据块的调整数 */
bits_per_sample = fa_read_u16(fp); /* bits/sample 每样本的数据位数 */
bytes_per_sample= (bits_per_sample + BITS_PER_BYTE - 1)/BITS_PER_BYTE;
block_align = bytes_per_sample * channels;
x_size -= SIZE_LONG + SIZE_SHORT + SIZE_SHORT; /* skip additional part of "fmt " header */
// printf("LINE[%d]#### %ld\n",__LINE__,x_size);
if (x_size!=0) {
fseek(fp, x_size, SEEK_CUR);
}
/* skip chunks except for "data" */
fread(temp, sizeof(*temp), SIZE_ID, fp);
while (memcmp(temp, "data", SIZE_ID)!=0) {
nskip = fa_read_u32(fp); /* read chunk size */
fseek(fp, nskip, SEEK_CUR);
fread(temp, sizeof(*temp), SIZE_ID, fp);
}
data_size = fa_read_u32(fp); /*语音数据大小*/
fmt.format = format;
fmt.channels = channels;
fmt.samplerate = samplerate;
fmt.bytes_per_sample = bytes_per_sample;
fmt.block_align = block_align;
fmt.data_size = data_size / block_align; /* byte to short */
printf_fun(&fmt);
return 0;
}