64 lines
1.9 KiB
JavaScript
64 lines
1.9 KiB
JavaScript
const ytdl = require('ytdl-core');
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const prism = require('prism-media');
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const { pipeline } = require('stream');
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function filter(format) {
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return format.codecs === 'opus' &&
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format.container === 'webm' &&
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format.audioSampleRate == 48000;
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}
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/**
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* Tries to find the highest bitrate audio-only format. Failing that, will use any available audio format.
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* @private
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* @param {Object[]} formats The formats to select from
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* @param {boolean} isLive Whether the content is live or not
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*/
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function nextBestFormat(formats, isLive) {
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let filter = format => format.audioBitrate;
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if (isLive) filter = format => format.audioBitrate && format.isHLS;
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formats = formats
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.filter(filter)
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.sort((a, b) => b.audioBitrate - a.audioBitrate);
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return formats.find(format => !format.bitrate) || formats[0];
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}
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const noop = () => {};
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async function download(url, options = {}) {
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const info = await ytdl.getInfo(url);
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// Prefer opus
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const format = info.formats.find(filter);
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const canDemux = format && info.videoDetails.lengthSeconds != 0;
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if (canDemux) options = { ...options, filter };
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else if (info.videoDetails.lengthSeconds != 0) options = { ...options, filter: 'audioonly' };
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if (canDemux) {
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const demuxer = new prism.opus.WebmDemuxer();
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return pipeline([
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ytdl.downloadFromInfo(info, options),
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demuxer,
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], noop);
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} else {
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const bestFormat = nextBestFormat(info.formats, info.videoDetails.isLiveContent);
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if (!bestFormat) throw new Error('No suitable format found');
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const transcoder = new prism.FFmpeg({
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args: [
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'-reconnect', '1',
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'-reconnect_streamed', '1',
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'-reconnect_delay_max', '5',
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'-i', bestFormat.url,
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'-analyzeduration', '0',
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'-loglevel', '0',
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'-f', 's16le',
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'-ar', '48000',
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'-ac', '2',
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],
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shell: false,
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});
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const opus = new prism.opus.Encoder({ rate: 48000, channels: 2, frameSize: 960 });
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return pipeline([transcoder, opus], noop);
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}
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}
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module.exports = Object.assign(download, ytdl);
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