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https://github.com/jellyfin/jellyfin-web
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50 lines
1.4 KiB
JavaScript
50 lines
1.4 KiB
JavaScript
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/*
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* EWMA Bandwidth Estimator
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* - heavily inspired from shaka-player
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* Tracks bandwidth samples and estimates available bandwidth.
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* Based on the minimum of two exponentially-weighted moving averages with
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* different half-lives.
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*/
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import EWMA from '../utils/ewma';
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class EwmaBandWidthEstimator {
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constructor(hls) {
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this.hls = hls;
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this.defaultEstimate_ = 5e5; // 500kbps
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this.minWeight_ = 0.001;
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this.minDelayMs_ = 50;
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this.fast_ = new EWMA(hls.config.abrEwmaFast);
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this.slow_ = new EWMA(hls.config.abrEwmaSlow);
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}
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sample(durationMs,numBytes) {
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durationMs = Math.max(durationMs, this.minDelayMs_);
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var bandwidth = 8000* numBytes / durationMs;
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//console.log('instant bw:'+ Math.round(bandwidth));
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// we weight sample using loading duration....
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var weigth = durationMs / 1000;
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this.fast_.sample(weigth,bandwidth);
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this.slow_.sample(weigth,bandwidth);
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}
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getEstimate() {
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if (this.fast_.getTotalWeight() < this.minWeight_) {
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return this.defaultEstimate_;
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}
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//console.log('slow estimate:'+ Math.round(this.slow_.getEstimate()));
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//console.log('fast estimate:'+ Math.round(this.fast_.getEstimate()));
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// Take the minimum of these two estimates. This should have the effect of
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// adapting down quickly, but up more slowly.
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return Math.min(this.fast_.getEstimate(),this.slow_.getEstimate());
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}
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destroy() {
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}
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}
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export default EwmaBandWidthEstimator;
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