Cues not discarded across attachSource calls leading to increased JS heap usage #4427
Comments
I think the idea is not to discard future cues that are likely to be needed soon. |
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@vodlogic Can you share a stream to reproduce this? Typically,
function _isCueActive(cue) {
const currentTime = videoModel.getTime();
return currentTime >= cue.startTime && currentTime <= cue.endTime
} |
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@dsilhavy issue is visible also with https://dash.akamaized.net/akamai/test/caption_test/ElephantsDream/elephants_dream_480p_heaac5_1_https.mpd
So for this stream you need to wait 30s (subtitles are from around 20s after start). I tested also the There is a minimal test scenario where heap is slowly growing: <!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<script src="http://cdn.dashjs.org/v4.7.4/dash.all.min.js"></script>
</head>
<body>
<div>
<video id="videoPlayer" controls></video>
<div id='sub'/>
</div>
<script>
const sleep = s => new Promise(r => setTimeout(r, s * 1000));
const videoElement = document.getElementById('videoPlayer');
const subElement = document.getElementById("sub");
// Initialize the Dash.js player
const player = dashjs.MediaPlayer().create();
// Setup the player
player.initialize(videoElement);
player.attachTTMLRenderingDiv(subElement);
// Set defaultEnabled: true to enable subtitles
player.updateSettings({streaming: {text: {defaultEnabled: true}}});
player.setInitialMediaSettingsFor('text', {
lang: 'eng',
});
async function test() {
while (true) {
player.attachSource('https://dash.akamaized.net/akamai/test/caption_test/ElephantsDream/elephants_dream_480p_heaac5_1_https.mpd');
await sleep(30);
}
}
test();
</script>
</body>
</html> |
We have observed JS Heap increasing at a rate of approximately 1MB every 3 minutes when a new manifest is loaded when
player.attachSource(<new manifest URL>)is called every 15 seconds when subtitles are enabled. We observe this in dash.js 4.7.4 and are yet to try earlier versions of dash.jsWhen subtitles are disabled, JS heap increases only a couple of MB per hour when
attachSource()is called every 15 seconds.This leads us to hypothesise that cues are not being properly cleaned up when a new manifest is loaded by the player.
We can see that the number of cues continues to grow across calls to
attachSource()The fix merged in #4305 resolved a memory leak when soak testing a stream for 24 hours without calling
attachSource()Not sure if this is related, but we also wanted to check the logic that has been implemented for the previous PR to discard outdated cues.
https://github.com/Dash-Industry-Forum/dash.js/pull/4305/files#diff-033321ac6c729cfa349f6ca06067679dc6919fe8fe1023ec6fd990c83e98ac9aR829
Should the expression be
return cue.startTime <= currentTime && cue.endTime >= currentTimeto determine if cue is active?The text was updated successfully, but these errors were encountered: