Incorrect video window size on Retina displays

[md]

With the latest 3.0.16 release, VLC plays FullHD and 4K content smoothly on recent 27" iMACs using HW acceleration, however, initially it always opens the video window 2-times bigger than appropriate.

For FullHD, it opens 4K window:

main debug: original format sz 1920x1088, of (0,0), vsz 1920x1080, 4cc CVPI, sar 1:1, msk r0x0 g0x0 b0x0
main debug: VoutDisplayEvent 'resize' 3840x2160

and for 4K it scales the video to all available display space, making it blurry:

main debug: original format sz 3840x2160, of (0,0), vsz 3840x2160, 4cc CVPN, sar 1:1, msk r0x0 g0x0 b0x0
main debug: VoutDisplayEvent 'resize' 5120x2718

Pressing ⌘0 for 'Half size' shrinks the video window to proper size and ensures 1:1 pixel mapping for both FullHD:
main debug: VoutDisplayEvent 'resize' 1920x1080

and also for 4K:
main debug: VoutDisplayEvent 'resize' 3840x2160

Looks like VLC somehow confuses logical display size and physical display size on Retina displays.

[fkuehne]

This behaves as designed and expected. It should also match the behavior of QuickTime Player and further competing players.

This is done on purpose as 1:1 pixel matching of video would look too small to the ordinary user on modern, high resolution screens. When VLC runs on non-hiDPI screens, the mapping is still 1:1.

[md]

Well, just tested with QuickTime and IINA - both open proper 1:1 pixel mapped video window for 4K content, not double-sized windows.

QuickTime opens double-sized window only for lower resolutions. IINA never opens double-sized window.

For 4K, the original, 1:1 pixel mapped window covers 3/4 of the iMAC screen's width/height, so that's clearly the optimal size - if I want bigger picture, I can resize it or go to full screen.

So while for low resolutions, double-sized window might benefit ordinary users, for 4K it's definitely lowering video quality and I believe VLC should follow other players and open original, 1:1 pixel mapped window