20180827 qzd

pcm文件转wav文件时，主要是在pcm文件加入wav的头。wav的文件头包含wav标示及解码标示。
下面的一段代码为将8k,16bit,PCM(Intel（LSB,MSB）未加压缩的转wav文件。

代码：pcm2wav.cpp

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
using namespace std;
//读文件，返回内存指针，记得free
void* ReadFile(const char *path, unsigned int *len)
{
    FILE *f = fopen(path, "rb");
    if (f == NULL)
        return NULL;
    fseek(f, 0, SEEK_END);
    *len = ftell(f);
    fseek(f, 0, SEEK_SET);
    void *buffer = malloc(*len);
    *len = fread(buffer, 1, *len, f);
    fclose(f);
    return buffer;
}
 
//pcm转wav，返回wav内存指针和wav长度
void* pcmToWav(const void *pcm, unsigned int pcmlen, unsigned int *wavlen)
{
    //44字节wav头
    void *wav = malloc(pcmlen + 44);
    //wav文件多了44个字节
    *wavlen = pcmlen + 44;
    //添加wav文件头
    memcpy(wav, "RIFF", 4);
    *(int *)((char*)wav + 4) = pcmlen + 36;
    memcpy(((char*)wav + 8), "WAVEfmt ", 8);
    *(int *)((char*)wav + 16) = 16;
    *(short *)((char*)wav + 20) = 1;
    *(short *)((char*)wav + 22) = 1;
    *(int *)((char*)wav + 24) = 8000;  //16khz时16000
    *(int *)((char*)wav + 28) = 16000;  //16khz时32000(总改2)
    *(short *)((char*)wav + 32) = 16 / 8;
    *(short *)((char*)wav + 34) = 16;
    strcpy((char*)((char*)wav + 36), "data");
    *(int *)((char*)wav + 40) = pcmlen;
 
    //拷贝pcm数据到wav中
    memcpy((char*)wav + 44, pcm, pcmlen);
    return wav;
}
 
//pcm文件转wav文件，pcmfilePath:pcm文件路劲，wavfilePath:生成的wav路劲
int pcmfileToWavfile(const char *pcmfilePath, const char *wavfilePath)
{
    unsigned int pcmlen;
    //读取文件获得pcm流，也可以从其他方式获得
    void *pcm = ReadFile(pcmfilePath, &pcmlen);
    if (pcm == NULL)
    {
        printf("not found file\n");
        return 1;
    }
 
    //pcm转wav
    unsigned int wavLen;
    void *wav = pcmToWav(pcm, pcmlen, &wavLen);
 
    FILE *fwav = fopen(wavfilePath, "wb");
    fwrite(wav, 1, wavLen, fwav);
    fclose(fwav);
    free(pcm);
    free(wav);
    return 0;
}
 
int main(int argc,char *argv[])
{
    if(argc<3) return 1; 
    if(strstr(argv[1],".pcm")==NULL) return 1;
    if(strstr(argv[2],".wav")==NULL) return 1;
    int ret = pcmfileToWavfile(argv[1],argv[2]);
    if (ret != 0)
    {
        printf("error pcm to wav\n");
    }
    else
    {
        printf("succ");
    }
}

编译：

g++ pcm2wav.cpp -o pcm2wav

运行：

./pcm2wav 1.pcm  1.wav