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Tweak compensator ramp up + add slight ramp down

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Gabe Kangas 2022-04-04 21:00:07 -07:00
parent d4e2412893
commit d0bd511101
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GPG key ID: 9A56337728BC81EA
1 changed files with 52 additions and 40 deletions
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92
webroot/js/components/latencyCompensator.js
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@ -15,10 +15,10 @@ It will:
const REBUFFER_EVENT_LIMIT = 5; // Max number of buffering events before we stop compensating for latency.
const MIN_BUFFER_DURATION = 500; // Min duration a buffer event must last to be counted.
const MAX_SPEEDUP_RATE = 1.07; // The playback rate when compensating for latency.
const MAX_SPEEDUP_RAMP = 0.005; // The max amount we will increase the playback rate at once.
const MAX_SPEEDUP_RATE = 1.08; // The playback rate when compensating for latency.
const MAX_SPEEDUP_RAMP = 0.02; // The max amount we will increase the playback rate at once.
const TIMEOUT_DURATION = 30 * 1000; // The amount of time we stop handling latency after certain events.
const CHECK_TIMER_INTERVAL = 5_000; // How often we check if we should be compensating for latency.
const CHECK_TIMER_INTERVAL = 5 * 1000; // How often we check if we should be compensating for latency.
const BUFFERING_AMNESTY_DURATION = 3 * 1000 * 60; // How often until a buffering event expires.
const REQUIRED_BANDWIDTH_RATIO = 2.0; // The player:bitrate ratio required to enable compensating for latency.
const HIGHEST_LATENCY_SEGMENT_LENGTH_MULTIPLIER = 2.5; // Segment length * this value is when we start compensating.
@ -46,20 +46,13 @@ class LatencyCompensator {
// This is run on a timer to check if we should be compensating for latency.
check() {
console.log(
'playback rate',
this.playbackRate,
'enabled:',
this.enabled,
'running: ',
this.running,
'timeout: ',
this.inTimeout,
'buffer count:',
this.bufferingCounter
);
if (this.inTimeout) {
console.log('in timeout...');
return;
}
if (!this.enabled) {
console.log('not enabled...');
return;
}
@ -102,25 +95,6 @@ class LatencyCompensator {
return;
}
// Using our bandwidth ratio determine a wide guess at how fast we can play.
let proposedPlaybackRate = bandwidthRatio * 0.33;
console.log('proposed rate', proposedPlaybackRate);
// But limit the playback rate to a max value.
proposedPlaybackRate = Math.max(
Math.min(proposedPlaybackRate, MAX_SPEEDUP_RATE),
1.0
);
// If this proposed speed is substantially faster than the current rate,
// then allow us to ramp up by using a slower value for now.
if (proposedPlaybackRate > this.playbackRate + MAX_SPEEDUP_RAMP) {
proposedPlaybackRate = this.playbackRate + MAX_SPEEDUP_RAMP;
}
proposedPlaybackRate =
Math.round(proposedPlaybackRate * Math.pow(10, 3)) / Math.pow(10, 3);
try {
const segment = getCurrentlyPlayingSegment(tech);
if (!segment) {
@ -143,6 +117,35 @@ class LatencyCompensator {
const now = new Date().getTime();
const latency = now - segmentTime;
// Using our bandwidth ratio determine a wide guess at how fast we can play.
var proposedPlaybackRate = bandwidthRatio * 0.33;
// But limit the playback rate to a max value.
proposedPlaybackRate = Math.max(
Math.min(proposedPlaybackRate, MAX_SPEEDUP_RATE),
1.0
);
if (latency < minLatencyThreshold * 1.2) {
// If nearing the end of our latency compensation window, then ramp down
// the speed.
proposedPlaybackRate = proposedPlaybackRate - 0.01;
} else if (proposedPlaybackRate > this.playbackRate + MAX_SPEEDUP_RAMP) {
// If this proposed speed is substantially faster than the current rate,
// then allow us to ramp up by using a slower value for now.
proposedPlaybackRate = this.playbackRate + MAX_SPEEDUP_RAMP;
}
// Limit to 3 decimal places of precision.
proposedPlaybackRate =
Math.round(proposedPlaybackRate * Math.pow(10, 3)) / Math.pow(10, 3);
if (latency > maxLatencyThreshold) {
this.start(proposedPlaybackRate);
} else if (latency < minLatencyThreshold) {
this.stop();
}
console.log(
'latency',
latency / 1000,
@ -152,11 +155,18 @@ class LatencyCompensator {
maxLatencyThreshold / 1000
);
if (latency > maxLatencyThreshold) {
this.start(proposedPlaybackRate);
} else if (latency < minLatencyThreshold) {
this.stop();
}
console.log(
'playback rate',
this.playbackRate,
'enabled:',
this.enabled,
'running: ',
this.running,
'timeout: ',
this.inTimeout,
'buffer count:',
this.bufferingCounter
);
} catch (err) {
// console.warn(err);
}
@ -177,6 +187,8 @@ class LatencyCompensator {
}
stop() {
console.log('stopping latency compensator...');
this.running = false;
this.setPlaybackRate(1.0);
}