Hi Maxime, W dniu 5.09.2022 o 15:37, Maxime Ripard pisze: >>> + vfp = vfp_min + (porches_rem / 2); >>> + vbp = porches - vfp; >> >> Relative position of the vertical sync within the VBI effectively moves the >> image up and down. Adding that (porches_rem / 2) moves the image up off center >> by that many pixels. I'd keep the VFP always at minimum to keep the image >> centered. > > And you would increase the back porch only then? Well, increasing vbp only gives a centered image with the default 480i/576i resolutions. However, only ever changing vbp will cause the image to be always at the bottom of the screen when the active line count is decreased (e.g. setting the resolution to 720x480 but for 50Hz "PAL" - like many game consoles did back in the day). I believe that the perfect solution would: - Use the canonical / standard-defined blanking line counts for the standard vertical resolutions (480/486/576) - Increase vfp and vbp from there by the same number if a smaller number of active lines is specified, so that the resulting image is centered - Likewise, decrease vfp and vbp by the same number if the active line number is larger and there is still leeway (this should allow for seamless handling of 480i vs. 486i for 60 Hz "NTSC") - If even more active lines are specified, once the limit for vfp is hit, then decrease vbp only - the resulting image will definitely be off-center, but there's no other way I hope this makes sense for you as well. Best regards, Mateusz Kwiatkowski
