fspecii
131 lines
3.5 KiB
JavaScript
131 lines
3.5 KiB
JavaScript
// FLAC worker for encoding audio using libflac.js
|
|
|
|
importScripts('libflac.js');
|
|
|
|
var flacEncoder;
|
|
var FLAC_INITIALIZED = false;
|
|
var sample_rate = 44100;
|
|
var compression = 5; // Default compression (0-8)
|
|
var channels = 1;
|
|
var buffers = [];
|
|
var bufIndex = 0;
|
|
var first_buffer = true;
|
|
var samples_left = null;
|
|
var samples_right = null;
|
|
|
|
function convert(n) {
|
|
var v = n < 0 ? n * 32768 : n * 32767;
|
|
return Math.max(-32768, Math.min(32768, v));
|
|
}
|
|
|
|
function initFLAC() {
|
|
if (FLAC_INITIALIZED) return true;
|
|
|
|
// SAMPLERATE, CHANNELS, BPS, COMPRESSION, 0, VERIFY, BLOCK_SIZE);
|
|
flacEncoder = Flac.create_libflac_encoder(sample_rate, channels, 16, compression, 0, true, 0);
|
|
if (flacEncoder != 0) {
|
|
var status = Flac.init_encoder_stream(flacEncoder, function(buffer, bytes) {
|
|
buffers.push(new Uint8Array(buffer));
|
|
bufIndex += buffer.byteLength;
|
|
});
|
|
|
|
FLAC_INITIALIZED = true;
|
|
return status == 0;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
function interleave(inputL, inputR) {
|
|
var length = inputL.length + inputR.length;
|
|
var result = new Int32Array(length);
|
|
|
|
var index = 0,
|
|
inputIndex = 0;
|
|
|
|
while (index < length) {
|
|
result[index++] = inputL[inputIndex];
|
|
result[index++] = inputR[inputIndex];
|
|
++inputIndex;
|
|
}
|
|
return result;
|
|
}
|
|
|
|
onmessage = function(ev) {
|
|
if (!ev.data) return;
|
|
|
|
if (ev.data.sample_rate) {
|
|
sample_rate = ev.data.sample_rate / 1;
|
|
compression = ev.data.flac_compression;
|
|
channels = ev.data.channels / 1;
|
|
|
|
initFLAC();
|
|
return;
|
|
}
|
|
|
|
if (first_buffer) {
|
|
samples_left = new Int16Array(ev.data, 0);
|
|
first_buffer = false;
|
|
|
|
if (channels > 1) return;
|
|
}
|
|
|
|
if (ev.data && channels > 1) {
|
|
samples_right = new Int16Array(ev.data, 0);
|
|
}
|
|
|
|
if (!FLAC_INITIALIZED) {
|
|
postMessage({percentage: 0});
|
|
return;
|
|
}
|
|
|
|
// Progress update
|
|
postMessage({percentage: 50});
|
|
|
|
// Process the audio data
|
|
var interleaved = null;
|
|
var samples = null;
|
|
|
|
if (channels > 1) {
|
|
// Create interleaved buffer for stereo
|
|
interleaved = interleave(samples_left, samples_right);
|
|
samples = interleaved;
|
|
} else {
|
|
// Use mono buffer directly
|
|
samples = samples_left;
|
|
}
|
|
|
|
// Encode the audio data
|
|
if (channels > 1) {
|
|
Flac.FLAC__stream_encoder_process_interleaved(flacEncoder, samples, samples_left.length);
|
|
} else {
|
|
var tmp_samples = new Int32Array(samples_left.length);
|
|
var tmp_index = 0;
|
|
while (tmp_index < samples_left.length) {
|
|
tmp_samples[tmp_index] = samples_left[tmp_index];
|
|
++tmp_index;
|
|
}
|
|
Flac.FLAC__stream_encoder_process(flacEncoder, [tmp_samples], samples_left.length);
|
|
}
|
|
|
|
// Finish encoding
|
|
Flac.FLAC__stream_encoder_finish(flacEncoder);
|
|
|
|
// Combine all buffers into a single Uint8Array
|
|
var outputData = new Uint8Array(bufIndex);
|
|
var offset = 0;
|
|
for (var i = 0; i < buffers.length; i++) {
|
|
outputData.set(buffers[i], offset);
|
|
offset += buffers[i].length;
|
|
}
|
|
|
|
// Create blob and return
|
|
var blob = new Blob([outputData], {type: 'audio/flac'});
|
|
postMessage(blob);
|
|
|
|
// Clean up
|
|
Flac.FLAC__stream_encoder_delete(flacEncoder);
|
|
FLAC_INITIALIZED = false;
|
|
buffers = [];
|
|
bufIndex = 0;
|
|
} |