RPi4 LibreELEC-RPi4.aarch64-12.0-nightly-20230510 jerky playback

I'm doing the initial testing of my RPi4 using a BENQ monitor since it was to disruptive using the TV (Panasonic) and it was looking worth checking out on the TV so moved it and connected everything up.

I wanted to compare the picture quality with what I get from the RPi3 running LE9.2.8. If I didn't have that as a comparison I'd probably be happy with the RPi4. I used "Looper" to test with. About 2:30 in there's a bit where a tractor is pulling a large yellow trailer along a dirt road. On the RPi3 (or my PC using VLC) its nice and smooth. With the RPi4 its a little jerky. Its not enough to stop me watching but it is enough for my brain to think something's wrong. I've tried turning off deinterlacing with no discernible difference.

Is there another setting I should be trying or do I need to bite the bullet and buy different equipment?

<<A debug log would help.>>

I can dig out one for the RPi3 & the RPi4. Is there a quick way of turning it on and off or do I have to go through the menu each time.

<<Obvious question is what is the framerate of the video.>>

No idea, but 1) exactly the same as when played on the RPi3 and 2) pretty much the same as all of my videos since they have all been through Handbrake with the same settings.

<<Do you have "adjust display refresh rate to match video" enabled.>>

I don't think so but I'll have a look and if not set it. Since the RPi3 is my daily driver and its easy I just had a look and its set to always. I'll be back after fighting with cables

<<Does the BENQ monitor support that framerate?>>

Immaterial. The BENQ 21" was only being used until I was reasonably happy with the RPi4 running LE12 and I didn't look to closely. Its when I try it on the 40" Panasonic and look closely that the problem emerges. There are other issues which I didn't care about/notice on the BENQ monitor that I do care about on the TV, one of which I've posted about.

<<Obvious question is what is the framerate of the video.>>

If I'm interpretting the ctrl-shift-o display correctly fr: 25

<<Do you have "adjust display refresh rate to match video" enabled.>>

It was set off, I changed it to always but it didn't seem to make a difference.

I then thought what happens if I set the display rate to 25fps and its almost perfect. I reset the refresh rate to 30 and rebooted but still jerky. Blundering about the wiki I manage to track down the entry for this and it says always isn't recommended - which of the two remaining is the best choice?

I'll give that a try

Is there a better description of what whitelist does. I found the wiki and its left me baffled.

Thanks - I now have a nice smooth playback. I copied the display settings from the RPi3 - 1920x1080. Why they are that I have no idea since the TV is 3480x2160 but it works so I'm leaving it alone.

Next stage - how to test out my Hauppage & TVHeadend when I don't have a spare adapter - I shall have to negotiate to not recording stuff

The whole point of moving to the RPi4 was to simplify my rats nest of 2 x RPi3Bs (1 for TVHeadend sever and 1 as client/video playback) which meant extra extension leads, a mini hub for ethernet connection etc.