直接读取wav文件是int数组，但是有一些实现返回的是double数组，还有些输入是double数组；那我们要互相调用的时候还是要看看两者到底有什么关系，其实很简单。
以单身道，16bit为例
/**
* For Mono, 16bit, only!
* @author karl
*
*/
public class BasicIntDoubleConvetor {
private static final float floatScale = 32768;
public double[] arrayIntToDouble (int[] data) {
int numFrames = data.length;
double[] postdata = new double[numFrames];
for (int f=0 ; f<numFrames ; f++)
{
postdata[f] = (double) data[f] / floatScale;
}
return postdata;
}
public int[] arrayDoubleToInt (int[] data) {
int numFrames = data.length;
int[] postdata = new int[numFrames];
for (int f=0 ; f<numFrames ; f++)
{
postdata[f] = (int) (data[f] * floatScale);
}
return postdata;
}
}
对于更广泛的情况来说，floatScale并不是2^16 = 32768
// Calculate the scaling factor for converting to a normalised double
if (wavFile.validBits > 8)
{
// If more than 8 validBits, data is signed
// Conversion required multiplying by magnitude of max positive value
wavFile.floatOffset = 0;
wavFile.floatScale = Long.MAX_VALUE >> (64 - wavFile.validBits);
}
else
{
// Else if 8 or less validBits, data is unsigned
// Conversion required dividing by max positive value
wavFile.floatOffset = 1;
wavFile.floatScale = 0.5 * ((1 << wavFile.validBits) - 1);
}