Solution for Odd Scaling Behaviour

[Razor54672]

I have a 2880 x 1800 Laptop Screen and was trying to play 1080p video file.

However, even after supplying the dimension via -w 2880x, I was getting cropped video. For some reason, it scaled right with -w 1440x, but with visible pixelation. As such, I figured it was the scaling behavior problem mentioned in readme.md but I couldn't find a setting for "disallow high DPI mode".

You need to do the following for it to work well :

Go to video-compare.exe, right-click and select its Properties. Navigate to the Compatibility tab, select Change high-DPI settings > High DPI scaling override Select the Override high DPI scaling behaviour option and choose Application in the menu.

This should solve this issue.

[jonfryd]

Hi @Razor54672,

Thanks for sharing your workaround.

I'll see if there is something we can do to auto-detect the current high-DPI setting via SDL2 so this extra step won't be necessary in the future.

[jonfryd]

@Razor54672: Did passing -d to the program produce a correctly scaled image on your laptop screen (i.e. without applying your workaround)?

[woshitoutouge]

@Razor54672 Thanks a lot! The unexpectd scaling really bothers me, and now it is good.

[pldavid2]

Thanks @Razor54672, you trick works

@jonfryd, the -d parameter didn't work for me.

[jonfryd]

@pldavid2: OK, interesting. Thanks!

I guess you use some sort of high DPI display, as well?

[pldavid2]

@jonfryd I was testing the player in a 4k monitor to compare two files, one in 1080p and the other 4k. Without the tweak, video compare was showing a smaller windows using the -d flag.

Something related, would it be possible to add some kind of launch parameter to make video-compare open in specific display instead of main one in a multi monitor setup?

I never use SDL directly and have almost zero knowledge of C. But did a quick check on the SDL repository and found this comment https://github.com/libsdl-org/SDL/issues/1176 So it seems that the display can be tweaked on the _SDLCreateWindow call using for example _SDL_WINDOWPOS_UNDEFINEDDISPLAY(1) for a secondary monitor, instead of the default _SDL_WINDOWPOS_UNDEFINEDDISPLAY

[jonfryd]

@pldavid2: Sure, this looks trivial to do. I can't tell when the next updates are out, but I'll your suggestion to my TODO list for now.

Cheers!

[jonfryd]

@pldavid2: Check out the -n option in the latest release which allows you to open video-compare on a specific display. Numbering starts at 0.

[pldavid2]

@pldavid2: Check out the -n option in the latest release which allows you to open video-compare on a specific display. Numbering starts at 0.

working great, very useful thank you!

[jonfryd]

@pldavid2 and @woshitoutouge,

I have released a new version just now (20230713), which I believe resolves the scaling issue on high DPI displays in Windows, eliminating the need for the workaround provided by @Razor54672 above. Could you kindly test it out and let me know if it works for you?

If it doesn't work, I would appreciate it if you could provide me with the output values of SDL GL drawable size and SDL window size. These values are displayed in the console when the tool is launched.

Thanks.

[pldavid2]

@jonfryd, it's weird, but on my system the old version having this odd behaviour, is now working fine without the tweak/trick. Not sure if some other windows update change something on my system, so I can't confirm if was really a video-compare problem or not. You may wait @woshitoutouge or @Razor54672 or just close the issue. Thanks

[jonfryd]

OK, thanks for getting back to me, @pldavid2. Much appreciated.