I am receiving an interleaved 16 bit PCM samples over the wire. Each sample is signed
I read it as Int16bit array, lets call this ALL_DATA. So each of the array entries is a a 16 bit sample.
Because it is interleaved I extract it into 2 channels R-L-R-L I end up with 2 (16 bit) arrays half the size of ALL_DATA array.
After that I go over each sample and normalize it to Float32Array because that is what web audio API uses.
var normalizedSample= (sample > 0) ? sample / 32768 : sample / -32768;
Is this the right way to do it.
I am getting distorted sounds. You can tell what is going on. So literally if you are listening to classic guitar it sounds like it is electric with distortion.
For Arguments sake I am putting down the example code but This code handles
MONO SOUND to make the example simpler, so we don't have to interleave it as well
var startTime = 0;
var fileReader = new FileReader();
fileReader.onload = function (e) {
var data = new DataView(e.target.result);
var audio = new Int16Array(data.byteLength / Int16Array.BYTES_PER_ELEMENT);
var len = audio.length;
for (var jj = 0; jj < len; ++jj) {
audio[jj] = data.getInt16(jj * Int16Array.BYTES_PER_ELEMENT, true);
}
var right = new Float32Array(audio.length);
var channleCounter = 0;
for (var i = 0; i < audio.length; ) {
var normalizedRight = (audio[i] > 0) ? audio[i] / 32768 : audio[i] / -32768;
i = i + 1;
right[channleCounter] = normalizedRight;
channleCounter++;
}
var source = audioContext.createBufferSource();
var audioBuffer = audioContext.createBuffer(1, right.length, 44100);
audioBuffer.getChannelData(0).set(right);
source.buffer = audioBuffer;
source.connect(audioContext.destination);
source.noteOn(startTime);
startTime += audioBuffer.duration;
};
Any suggestions that might be causing the distorted sound will help. I have written the pcm data before I send it on the server side to a file is good and sound is perfect.
Instead of saying
var normalizedSample= (sample > 0) ? sample / 32768 : sample / -32768;
try
var normalizedSample= sample / 32768;
Your calculation, as currently written, will invert the negative portions of your waveform, in a manner similar to a full-wave rectifier (your samples will always be positive numbers).
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