pcm轉wav的方法及代碼示例

<pre class="cpp" name="code">pcm文件轉wav文件時，主要是在pcm文件加入wav的頭。wav的文件頭包含wav標示及解碼標示。<p>下面的一段代碼爲將8k,16bit,PCM(Intel（LSB,MSB）未加壓縮的轉wav文件。</p>

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

using namespace std;
//讀文件，返回內存指針，記得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轉wav，返回wav內存指針和wav長度
void* pcmToWav(const void *pcm, unsigned int pcmlen, unsigned int *wavlen)
{
	//44字節wav頭
	void *wav = malloc(pcmlen + 44);
	//wav文件多了44個字節
	*wavlen = pcmlen + 44;
	//添加wav文件頭
	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;
	*(int *)((char*)wav + 28) = 16000;
	*(short *)((char*)wav + 32) = 16 / 8;
	*(short *)((char*)wav + 34) = 16;
	strcpy((char*)((char*)wav + 36), "data");
	*(int *)((char*)wav + 40) = pcmlen;

	//拷貝pcm數據到wav中
	memcpy((char*)wav + 44, pcm, pcmlen);
	return wav;
}

//pcm文件轉wav文件，pcmfilePath:pcm文件路勁，wavfilePath:生成的wav路勁
int pcmfileToWavfile(const char *pcmfilePath, const char *wavfilePath)
{
	unsigned int pcmlen;
	//讀取文件獲得pcm流，也可以從其他方式獲得
	void *pcm = ReadFile(pcmfilePath, &pcmlen);
	if (pcm == NULL)
	{
		printf("not found file\n");
		return 1;
	}

	//pcm轉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");
	}
}

比如將這段代碼複製到一個文件中，該文件名字爲pcm2wav.cpp。將其編譯。 

g++ pcm2wav.cpp -o pcm2wav

./pcm2wav /home/20160630102824.pcm  /20160630102824.wav