Random frame - overscan issue

[Nakynaw]

Since I am restarting my Retropie install from scratch, I want to make sure to get it right this time.

I have been having a weird issue : around 20% of the times, when I boot retropie, the image is just a bit out of the frame (too big). The rest of the time, it fits perfectly.

Whether I disable overscan, or set it to minus 50 on every side, it gives the same results : most of the time it boots in the right size, and some of the times it's a bit too big.

I also noticed that the font size of the terminal is bigger when the oversize image happens.

Any idea what is the problem?

I have a Sony Bravia TV with a 1080p resolution. Used to be on automatic resolution detection, which I switched off and chose the «all pixels» options in terms of «zoom».

Canakit extreme package : pi4 8G, plugged in HDMI to the TV, with 5.1V 3.5A power supply.

Nothing has been changed from defaults so far (fresh reset with the official 4.6 image)

Thanks for any help!

[dankcushions]

@Nakynaw i've never heard of such an issue. i would be curious as to the output of

tvservice -m CEA
tvservice -m DMT
tvservice -s

during a time when you have this issue.

[Nakynaw]

I almost thought the many updates I did today discarded the problem, but no.

Here is what you asked (as you can see, I am missing an inch of text on the left side).

I rebooted, and everything was fine, and font size of the terminal became much smaller...

[mitu]

Looks like the change in video output could be because of the resolution change - although the TV says it prefers 1080p, the current resolution is 720p. Do you have any start-up scripts set-up that could cause that ?

Try forcing 1080p in the Raspberry Pi's configuration - modify the /boot/config.txt and add

hdmi_group=1
hdmi_mode=16

then switch set the TV HDMI port to game mode - so the TV doesn't attempt any image post-processing.
See if you get a stable resolution this way (i.e. no changes in font size or image position) and then adjust the overscan if needed.

[Nakynaw]

@mitu You are right, now I get it. It seems like «preferring» a mode is not enough. I will try what you suggested and see if it keeps going back to 720p randomly.

Also, TV was set to «general» but I will put it on fixed «Game mode» and see.

Thanks @dankcushions and @mitu for your time!

[Nakynaw]

Well, 3 days later, no more weird out of frame picture! I think I can safely say that it solved it. Thanks again @mitu !