How to merge the raw pcm data of two channels?

Question

I have two Float32Arrays containing the raw pcm data of the left and right channel. Is it possible to create a Float32Array that combines both channel? If so, how would I do that? Can I simply concatenate the arrays?

Cheers!

Answer 1

To merge two PCM files (right and left channels) into one, you need to interleave them:

(L,1),(R,1),(L,2),(R,2),...,(L,n),(R,n)

The codes looks something like this:

const interleavedChannelData = new Float32Array(leftChannelData.length + rightChannelData.length);

for (let i = 0; i < interleavedChannelData.length; i += 1) {
    if (i % 2 === 0) {
        interleavedChannelData[i] = leftChannelData[i / 2];
    } else {
        interleavedChannelData[i] = rightChannelData[(i - 1) / 2];
    }
}