Video sink stuttering (xv/gl/auto)

[Nicolas Dufresne]

Le jeudi 19 août 2021 à 21:14 +0200, Zeno Endemann a écrit :
> On 19.08.21 20:23 Nicolas Dufresne wrote:
> > Not certain. I see some stuttering, but it's a side effect of clock drift
> > between display (at 60hz) and render 30hz. At 60hz, it looks better. Note that
> > this pipeline is all sw driven.
> 
> Yes, running at 60fps I still think I can occasionally see a hickup, but 
> it is much better. SW driven should not really matter, as it handles 
> 60fps better than 30fps, so this is not about performance, but rather 
> somehow bad timings of the output plugins. Of course in general 30fps is 
> not that smooth overall, especially in such a synthetic stream, but I am 
> specifically talking about irregular stuttering on top of that.
> 
> I can't imagine clock drift being so bad that this is as noticeable as 
> this. With displaying every frame two times you should get perfect 
> playback on a 60fps display. Ok, clock drift between the rtc and display 
> vsync can happen, but it simply can't be this bad. And as I said, 
> playback of the 30fps video file doesn't show that problem either, or at 
> least it is much less noticeable.
> 
> I suppose I'll report this as a bug...

If you do, please make sure to investigate enough to show that the stutter is
due to GStreamer fault's and not your compositor having small hickups. We don't
have enough bandwidth in this project to store bugs that may not be directly
related to us. Perhaps give i a try without X11/Wayland (with gbm backend).

> 
> Anyway, thanks for the feedback
>