kaank-react-audio-recorder
Version:
52 lines (51 loc) • 1.83 kB
JavaScript
function writeUTFBytes(dataview, offset, string) {
for (var i = 0; i < string.length; i++) {
dataview.setUint8(offset + i, string.charCodeAt(i));
}
}
function mergeBuffers(buffer, length) {
var result = new Float64Array(length);
var offset = 0;
for (var i = 0; i < buffer.length; i++) {
var inner = buffer[i];
result.set(inner, offset);
offset += inner.length;
}
return result;
}
function interleave(left, right) {
var length = left.length + right.length;
var result = new Float64Array(length);
var inputIndex = 0;
for (var i = 0; i < length;) {
result[i++] = left[inputIndex];
result[i++] = right[inputIndex];
inputIndex++;
}
return result;
}
export default function encodeWAV(buffers, bufferLength, sampleRate, volume) {
if (volume === void 0) { volume = 1; }
var left = mergeBuffers(buffers[0], bufferLength);
var right = mergeBuffers(buffers[1], bufferLength);
var interleaved = interleave(left, right);
var buffer = new ArrayBuffer(44 + interleaved.length * 2);
var view = new DataView(buffer);
writeUTFBytes(view, 0, 'RIFF');
view.setUint32(4, 44 + interleaved.length * 2, true);
writeUTFBytes(view, 8, 'WAVE');
writeUTFBytes(view, 12, 'fmt ');
view.setUint32(16, 16, true);
view.setUint16(20, 1, true);
view.setUint16(22, 2, true);
view.setUint32(24, sampleRate, true);
view.setUint32(28, sampleRate * 4, true);
view.setUint16(32, 4, true);
view.setUint16(34, 16, true);
writeUTFBytes(view, 36, 'data');
view.setUint32(40, interleaved.length * 2, true);
interleaved.forEach(function (sample, index) {
view.setInt16(44 + (index * 2), sample * (0x7fff * volume), true);
});
return new Blob([view], { type: 'audio/wav' });
}