Why is there high cpu usage for no reason?

[Quentin Engles]

I watch a Youtube video for instance. I see high cpu usage in the system monitor around 80 to 90%.

At first I didn't know what was happening. In Firefox I opened the Task Manager, and VDH was shown as the top consumer of resources while watching a Youtube video. No download was active, and the cpu is consistently high while watching the video long after page load. I disabled VDH, and boom, cpu usage dropped to around 10%.

I'm on Linux if that matters. And of course using Firefox as I have already mentioned.

It doesn't seem to happen with every video I watch on Youtube. But when it happens on some video it continues to do high cpu usage on that video page, and does it even if I restart Firefox.

BTW there was one question about something similar, but I don't know if it applies to my particular case.

[Wild Willy]

This thread may or may not be relevant:

https://groups.google.com/g/video-downloadhelper-q-and-a/c/bf_HShpV_pA

I have gotten in the habit of turning VDH off if I'm going to sit & watch something
online from any streaming site. I am also in the habit of stopping playback on something
I am downloading via VDH.

You might post the URL of whatever it was that you were watching. I wouldn't mind
testing your case. I'm on Windows 7 64-bit so I wouldn't be completely replicating your
situation, but I would be using Firefox 96.0.2 64-bit, licensed VDH 7.6.3a1 beta, & CoApp
1.6.3. And in case it becomes a question, I do not work for VDH. I'm just another user,
like you.

[Quentin Engles]

Sorry. I don't remember the last video it happened on. It happens randomly about once a week.

If it happens again maybe I'll try to remember to post a URL here.

[Ga Gu]

When I'm watching a Youtube live stream, CPU is high. Memory occupation is normal though. 
Switching off the Video DownloadHelper extension wil fix the  CPU abnormality.