How to convert a .WAV audio data sample into an double type?

Question

I'm working on an application that processes audio data. I'm using java (I've added MP3SPI, Jlayer, and Tritonus). I'm extracting the audio data from a .wav file to a byte array. The audio data samples I'm working with are 16 bits stereo.

According to what I've read the format for one sample is:

AABBCCDD

where AABB represents left channel and CCDD rigth channel (2 bytes for each channel). I'd need to convert this sample into a double value type. I've reading about data format. Java uses Big endian, .wav files use little endian. I'm a little bit confused. Could you please help me with the conversion process? Thanks you all

Answer 1

Warning: integers and bytes are signed. Maybe you need to mask the low bytes when packing them together:

for (int i =0; i < length; i += 4) {
    double left = (double)((bytes [i] & 0xff) | (bytes[i + 1] << 8));
    double right = (double)((bytes [i + 2] & 0xff) | (bytes[i + 3] << 8));

    ... your code here ...

}

Answer 2

When you use the ByteBuffer (java.nio.ByteBuffer) you can use the method order;

[order]

public final ByteBuffer order(ByteOrder bo)

Modifies this buffer's byte order.

Parameters:
    bo - The new byte order, either BIG_ENDIAN or LITTLE_ENDIAN
Returns:
    This buffer

After this you can get the above mentioned values with;

getChar() getShort() getInt() getFloat() getDouble()

What a great language is Java ;-)