Jerky video playback

[Volker Wysk]

Hi, Bret

It seemed like I found the problem, but now I can't reproduce it
(surprise!). I got jerkiness and set the "device decryption"
("Geräteentschlüsselung") to automatic. It was turned off before. That
seemed to solve the problem, but when I turned it off again, it still went
smoothly.

(This should really be called "decoding", not "decryption".)


Am Donnerstag, dem 15.06.2023 um 00:28 +0800 schrieb Bret Busby:
> On 14/6/23 21:01, Volker Wysk wrote:
> > Hi!
> > 
> > I have a problem with my machine. When I play a video, it often occurs that
> > the playback is jerky. It's hard to reproduce. When I stop it for a few
> > seconds, it runs smoothly for a while. The same happens when I "cat" it to
> > /dev/null.
> > 
> > I'm using SMPlayer most of the time. When I tried VLC with a jerky video
> > lately, the video track became smooth. But the audio track became jerky
> > instead.
> > 
> 
> When you get the jerkiness in SMPlayer, what are the video resolution 
> and frame speed?

The resolution was 1920 x 800, the frame speed was 24.0 frames per second.

> Also, what is the file extension? Does it happen for .webm files and 
> .mp4 files?

It's an mp4. And I don't have any .webm files.

> What desktop environment are you using? If you have access to System 
> Monitor, what are the system load average and memory usage like, when 
> you are getting these problems?

I'm using Gnome (from Ubuntu 22.04.2). The system monitor didn't reveal
anything suspicious. The 16 CPUs (eight cores, two hardware threads per
core) were all working below 20% capacity. The memory usage was just below
50% of 16 GiB.

> Also, out of curiosity, because you have not referred (above) to using 
> it, have you tried viewing the problematic videos with Celluloid, and, 
> if so, do you get similar problems?

I can't reproduce it, even when I use SMPlayer. First it is jerky, but when
I try again, it's fine...

I tried it with celluloid, but I get this error when starting it:

/snap/celluloid/38/usr/bin/celluloid: symbol lookup error:
/snap/celluloid/38/usr/lib/x86_64-linux-gnu/libva-x11.so.2: undefined
symbol: va_fool_postp


Cheers,
Volker
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