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92 lines
2.2 KiB
JavaScript
92 lines
2.2 KiB
JavaScript
importScripts("Mp3LameEncoder.min.js");
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var NUM_CH = 2, // constant
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sampleRate = 44100,
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options = undefined,
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maxBuffers = undefined,
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encoder = undefined,
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recBuffers = undefined,
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bufferCount = 0;
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function error(message) {
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self.postMessage({ command: "error", message: "mp3: " + message });
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}
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function init(data) {
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if (data.config.numChannels === NUM_CH) {
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sampleRate = data.config.sampleRate;
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options = data.options;
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} else
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error("numChannels must be " + NUM_CH);
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};
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function setOptions(opt) {
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if (encoder || recBuffers)
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error("cannot set options during recording");
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else
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options = opt;
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}
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function start(bufferSize) {
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maxBuffers = Math.ceil(options.timeLimit * sampleRate / bufferSize);
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if (options.encodeAfterRecord)
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recBuffers = [];
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else
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encoder = new Mp3LameEncoder(sampleRate, options.mp3.bitRate);
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}
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function record(buffer) {
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if (bufferCount++ < maxBuffers)
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if (encoder)
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encoder.encode(buffer);
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else
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recBuffers.push(buffer);
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else
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self.postMessage({ command: "timeout" });
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};
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function postProgress(progress) {
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self.postMessage({ command: "progress", progress: progress });
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};
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function finish() {
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if (recBuffers) {
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postProgress(0);
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encoder = new Mp3LameEncoder(sampleRate, options.mp3.bitRate);
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var timeout = Date.now() + options.progressInterval;
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while (recBuffers.length > 0) {
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encoder.encode(recBuffers.shift());
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var now = Date.now();
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if (now > timeout) {
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postProgress((bufferCount - recBuffers.length) / bufferCount);
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timeout = now + options.progressInterval;
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}
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}
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postProgress(1);
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}
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self.postMessage({
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command: "complete",
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blob: encoder.finish(options.mp3.mimeType)
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});
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cleanup();
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};
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function cleanup() {
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encoder = recBuffers = undefined;
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bufferCount = 0;
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}
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self.onmessage = function(event) {
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var data = event.data;
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switch (data.command) {
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case "init": init(data); break;
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case "options": setOptions(data.options); break;
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case "start": start(data.bufferSize); break;
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case "record": record(data.buffer); break;
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case "finish": finish(); break;
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case "cancel": cleanup();
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}
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};
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self.postMessage({ command: "loaded" });
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