Set video mode
The video mode menu allows to choose whether the display is fullscreen or windowed, which 
aspect ratio to use, and a list of possible resolutions automatically built from what ZDoom detects to be compatible with your hardware and graphic drivers. Its MENUDEF name is VideoModeMenu and it can be summoned with the menu_video console command.
If you are unsure a video mode would display correctly, you can use the T key to test it for five seconds then return to the previous mode. If you are sure, however, the Enter key selects it normally.
Note: in 16:9 and 16:10 aspect ratios, the LB tag may appear next to some screen resolutions; this means that these modes are 
letterboxed.
- Fullscreen (Yes/No)
- fullscreen
- Chooses between windowed and fullscreen mode.
- Aspect ratio (4:3/16:9/16:10/All)
- menu_screenratios
- Selects which subset of screen resolutions is displayed below.
- Force aspect ratio (Off/4:3/16:9/16:10/5:4)
- vid_aspect
- Forces the chosen screen resolution to be considered as the selected aspect ratio, rather than the actual ratio.
- Enable 5:4 aspect ratio (Yes/No)
- vid_tft
- Enables the use of 5:4 aspect ratio.
Note that some aspect ratios are not what they mathematically should be. 320x200 are logically 16:10 ratios, not 4:3, but they are displayed as 4:3 ratios nonetheless. If 5:4 ratios are not enabled, resolutions such as 1280x1024 will be treated as 4:3 ratios as well. The explanation for these exception is that historical, to emulate CRT monitors which offered such resolutions with a physical 4:3 ratio by using non-square pixels.
