Using -K breaks the display output

[bloopiy]

Please read the prerequisites to run scrcpy.

Also read the FAQ and check if your issue already exists.

Environment

• OS: WIndows
• Scrcpy version: 3.1
• Installation method: Windows release
• Device model: Samsung S24 Ultra (SM-S928B)
• Android version: 14

Describe the bug

Using the -K parameter breaks the output of the screen displayed on the computer. Tested both wired and wireless.

First screenshot is scrcpy and second screenshot is scrcpy -K

[rom1v]

Are you sure this is related to -K? It looks like an unrelated (random) capture issue.

If you run multiple times with and without -K, is it always only broken with -K?

Is it solved by pressing Alt+r Alt+Shift+r?

[bloopiy]

Yes I'm sure, works fine with any other arguments. I tested multiple times. No it's not solved it Alt + r. It temporarily fixes itself only to revert back to the broken output. It's weird that -K does it so I checked multiple times. This is scrcpy -dK --record=file.mp4 with me rotating the screen with Alt+r

file.mp4

[bloopiy]

file.mp4

Okay nevermind it's now broken without -K as well. The difference is though when I run -K, it immediately breaks the output, but when running with no arguments, it only breaks when I force a rotation.

[rom1v]

I have the same problem on a Galaxy Tab A8. Indeed, -K makes the problem occur immediately (I had never noticed).

However, Alt+Shift+r fixes it (it's not Alt+r as I said earlier).

It seems there is a race condition between size changes and capture on these Samsung devices. I had debugged this some time ago, IIRC there were duplicated size change events (sizeA → sizeB → sizeA → sizeB) which did not occur on other devices, so I concluded it was a bug in the ROM.