8Kpcm转16K、32K、44.1K等

下面函数ChangePcm8KTo16K简单的实现了8K转16K。
8K转44.1K是比较特殊的，因为44.1K不是8K的倍数，是介于40K和48K之间的。40K是8K的5倍，48K是6倍。因此需要进行nSkipByte进行区分。
所以先写5个原始数据，接着再写6个，即5-6–5--6…这样循环，就是下面代码的这几句：


还有一个注意点是单声道转双声道问题。

这是单声道的代码

int ChangePcm8KTo44_1K(char *p8K, int i8KLen, char *p44_1K, int i44_1KLen)
{
	int i = 0;
	int iInx = 0;
	int nSkipByte = 5;

	if (p8K == NULL || p44_1K == NULL || i8KLen == 0 || i44_1KLen < (i8KLen * 10))
	{
		return -1;
	}

	for (i = 1, iInx = 0; i < i8KLen;)
	{
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		if (nSkipByte == 5)
		{
			nSkipByte = 6;
			p44_1K[iInx++] = p8K[i - 1];
			p44_1K[iInx++] = p8K[i];
		}
		else
		{
			nSkipByte = 5;
		}
		i += 2;
	}
	return iInx;
}

这是双声道的代码

int ChangePcm8KTo44_1K(char *p8K, int i8KLen, char *p44_1K, int i44_1KLen)
{
	int i = 0;
	int iInx = 0;
	int nSkipByte = 5;

	if (p8K == NULL || p44_1K == NULL || i8KLen == 0 || i44_1KLen < (i8KLen * 10))
	{
		return -1;
	}

	for (i = 1, iInx = 0; i < i8KLen;)
	{
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		//双声道需要多复制一份，单声道不需要
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		//双声道结束
		if (nSkipByte == 5)
		{
			nSkipByte = 6;
			p44_1K[iInx++] = p8K[i - 1];
			p44_1K[iInx++] = p8K[i];
			//双声道需要多复制一份，单声道不需要
			p44_1K[iInx++] = p8K[i - 1];
			p44_1K[iInx++] = p8K[i];
			//双声道结束
		}
		else
		{
			nSkipByte = 5;
		}	
		i += 2;
	}
	return iInx;
}

总体代码如下：

/*******************************************************************
** 函数名:     		ChangePcm8KTo32K
** 函数描述:   	采样率转换函数
** 参数:       		16k,16k_len,32k,32k_len
** 返回:       		32k_len
********************************************************************/
int ChangePcm8KTo16K(char *p8K, int i8KLen, char *p16K, int i16KLen)
{
	int i = 0;
	int iInx = 0;

	if (p8K == NULL || p16K == NULL || i8KLen == 0 || i16KLen < (i8KLen * 2))
	{
		return -1;
	}

	for (i = 1, iInx = 0; i < i8KLen;)
	{
		p16K[iInx++] = p8K[i - 1];
		p16K[iInx++] = p8K[i];
		p16K[iInx++] = p8K[i - 1];
		p16K[iInx++] = p8K[i];

		i += 2;
	}

	return iInx;
}

/*******************************************************************
** 函数名:     		ChangePcm8KTo44_1K
** 函数描述:   	采样率转换函数8K转44.1K
** 参数:       		16k,16k_len,p44_1K,i44_1KLen
** 返回:       		44_1k_len
********************************************************************/
int ChangePcm8KTo44_1K(char *p8K, int i8KLen, char *p44_1K, int i44_1KLen)
{
	int i = 0;
	int iInx = 0;
	int nSkipByte = 5;

	if (p8K == NULL || p44_1K == NULL || i8KLen == 0 || i44_1KLen < (i8KLen * 10))
	{
		return -1;
	}

	for (i = 1, iInx = 0; i < i8KLen;)
	{
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		//双声道需要多复制一份，单声道不需要
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		p44_1K[iInx++] = p8K[i - 1];
		p44_1K[iInx++] = p8K[i];
		//双声道结束
		if (nSkipByte == 5)
		{
			nSkipByte = 6;
			p44_1K[iInx++] = p8K[i - 1];
			p44_1K[iInx++] = p8K[i];
			//双声道需要多复制一份，单声道不需要
			p44_1K[iInx++] = p8K[i - 1];
			p44_1K[iInx++] = p8K[i];
			//双声道结束
		}
		else
		{
			nSkipByte = 5;
		}
		

		i += 2;
	}

	return iInx;
}