Adolfo Reyna
43 lines
1.5 KiB
JavaScript
43 lines
1.5 KiB
JavaScript
const TARGET_NUMBER_OF_CHANNELS = 2;
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const TARGET_SAMPLE_RATE = 48000;
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function mixAudio(waves, length) {
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if (waves.length === 1 && waves[0].length === length) {
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return waves[0];
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}
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const mixed = new Int16Array(length);
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if (waves.length === 1) {
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mixed.set(waves[0].subarray(0, length));
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return mixed;
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}
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for (let i = 0; i < length; i++) {
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const sum = waves.reduce((acc, wave) => {
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var _a;
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return acc + ((_a = wave[i]) !== null && _a !== void 0 ? _a : 0);
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}, 0);
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// Clamp to Int16 range
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mixed[i] = Math.max(-32768, Math.min(32767, sum));
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}
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return mixed;
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}
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export const onlyInlineAudio = ({ assets, fps, frame, }) => {
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const inlineAudio = assets.filter((asset) => asset.type === 'inline-audio');
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if (inlineAudio.length === 0) {
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return null;
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}
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const expectedLength = Math.round((TARGET_NUMBER_OF_CHANNELS * TARGET_SAMPLE_RATE) / fps);
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for (const asset of inlineAudio) {
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if (asset.toneFrequency !== 1) {
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throw new Error('Setting the toneFrequency is not supported yet in web rendering.');
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}
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}
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const mixedAudio = mixAudio(inlineAudio.map((asset) => asset.audio), expectedLength);
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return new AudioData({
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data: mixedAudio,
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format: 's16',
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numberOfChannels: TARGET_NUMBER_OF_CHANNELS,
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numberOfFrames: expectedLength / TARGET_NUMBER_OF_CHANNELS,
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sampleRate: TARGET_SAMPLE_RATE,
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timestamp: (frame / fps) * 1000000,
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});
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};
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