16inch MacBook Pro blurry motion with ProMotion ON

[MGLXP]

I was wondering if someone else is having the same problem. When I watch video on YouTube in Safari on my 16inch MacBook Pro with ProMotion in full screen, the motion is blurry/jittering. For example, I was watching this video

The motion is NOT blurry when not in full screen or when I disable ProMotion and lock the refresh rate to 60Hz. I also don't have this problem on my other older Macs.

Thanks!

 

[jeznav]

I'm glad I'm not the only one. I've been comparing 4K HDR 60FPS YouTube videos between the M1 Max MBP and a 2017 MBP and I have noticed that the 2017 has a consistent smoother playback, whereas the M1 with Promotion has jitters from time to time. Disabling Promotion and switching to 60hz refresh eliminates this random jitters in playback.

Now this was running on the latest Safari. I did not see jitters when I was playing back the video in MS Edge with ProMotion on.

My guess is that its Safari is causing the problem or isn't supporting 120hz yet whereas Chromium browsers do.
Here's the video I've been comparing with:

Notice the dip in refresh rate during slow-mo paints scenes and closeups of musician's faces.

UPDATE: Ok it's happening in Edge browser too... I wonder if this is because of Adaptive Refresh Rate dipping the framerates down to conserve power, and if there's anyway to disable it.

 

[Sanpete]

The first video looks smooth and sharp to me, playing in Safari (though this is a Youtube video, so I don't know how much Safari enters into it). The Rockets look a little jittery. (That's a joke.)

The second one is fine played at auto Youtube settings, not so sharp but smooth. That's because it's playing at 720p. If I run it at max resolution, it pauses every couple seconds to buffer because I have that kind of internet connection. That may affect playback for others with better connections too.