I have a composite car monitor like this one, but I can't seem to get overscan right on raspbian. By default overscan leaves borders and seems to display 4:3 stretched to 16:9.
To be able to operate properly on this small screen I first set a bigger tty font and set the framebuffer to 720x408, which is 1.5 times the size of the native monitor size. But now I can't adapt that to the borders.
Left and right fit and I figured out top and bottom offset should be -32 and -64 by setting the other to 100 each time, but both do not work. The image is positioned somewhere inbetween instead of stretched like it should. I have no idea why it would output a wrong ratio in the first place.
Thanks for your help!
PS: I already tried to get this done quickly with some automatic tool and without rebooting every time but it failed on me. If someone is interested, this is my question to that matter.
UPDATE: I installed Kodi and found that there actually is a very handy calibration tool like I wished it. I set it up and didn't tried to use the values in the /boot/config.txt yet, but I want to show the values to you already:
left upper corner: 28, 30
right bottom corner: 25, 0
square ratio: 1:196
