8-Bit node.js Buffer Mix

8-bit-mix.js

var length = chA.length,		// A & B must be the same length
 	out = new Buffer(length) 	// faster if you just overwrite one mix channel

for (i=0; i<length; i++) {
	if (chA[i] < 128 && chB[i] < 128) {
		out[i] = chA[i] * chB[i] / 128;
	}
	else {
		out[i] = 2 * (chA[i]+chB[i]) – chA[i] * chB[i] / 128 – 256;
	}
}