Expand Vertical Active Area

Viewing 13 posts - 1 through 13 (of 13 total)
  • Author
  • #23839

    Hi there!

    I’m just trying to figure out how to properly set my PAL Megadrive VA6.5 to OSSC through a CSYNC RGB SCART cable.
    The game I have is th 6 in 1 red cartridge.
    It looks amazing on Lx5 mode, 1920×1080 and I just settle down properly the horizontal image, but, when tryinf to do the same with vertical I realized that the V. Active parameter can’t be changed from 240 since it shows a black screen on my Samsung 4k Q8LED TV…

    I think there are things that I don’t already understand well on the OSSC (just a newby here).
    For my PS1 have a similar problem, the 1600×1200 mode seems to not work on my TV to try different things but my TV should support those modes since I use it for my computer too, so that resolutions should be accepted right?

    Appreciate some help please


    Hi there. For the PAL consoles, try setting the OSSC to 4x and doing what I have just suggested here https://videogameperfection.com/forums/topic/trouble-with-pal-n64/

    Basically in short:
    H Active 1920
    V Active 270
    H Samplerate 2200
    V Backporch 28 (adjust this if the picture is not in the centre)

    Then set your TV’s aspect ratio to 4:3 if you get a stretched image. if it’s too squished horizontally then try

    H Samplerate to 2460
    H Synclen 215
    H Backporch 215


    Thanks I will try but it’s a shame that I cannot use Lx5 mode… It’s just a bit of the down area what doesn’t shows at all…
    Anyway in which dv. Timing resolution do I need to set those Active/Samplerate settings?
    I don’t really understand what Adv. Timing is or how it works… Sometimes some resolutions appears with a “L” at the end also… Thanks!


    This is just in generic 4:3. If you are using a 1080p TV then 4x in PAL is actually 1152p which is more than 1080p already, meaning you don’t even need 5x. What you want to do is set it to 4x and make sure 4x is set to generic 4:3, then just go to sampling options and at advanced timing just press ok on the one that’s there as that’s the one that’s corrently in use, then set those options I mentioned and see if you get a picture.

    EDIT: My mistake, I just seen that you have a 4K set. You’re getting the same vertical resolution in 4x with the settings I have mentioned (1080p) and for 5x PAL, you’re going up to 1340p meaning that 1200 is still going to be missing some detail vertically. I guess it is a bit of a shame but 4x with those settings should look amazing on your TV. I can only get 3x on my Panasonic 4k set in NTSC and can only get 2x PAL 16:9 stretched, so you’re doing much better than me šŸ™‚


    The OSSC chooses a “video mode” automatically based on the input it receives and vertical multiplication mode selected, but it doesn’t matter which one it is because you can still freely change the parameters in Advanced Timing, just go into the one that is preselected for the console (it will be there when you select Sampling Opt -> Advanced Timing). Modes that end with L or LB are 288p modes also. (you can check what the different video modes are in the github file: https://github.com/marqs85/ossc/blob/release/software/sys_controller/tvp7002/video_modes.h )

    Now for x5 mode (set to 1920×1080 mode (default)) it will always reduce V.Active to 216 “under the hood” to fit the v.active area of 1080. It doesn’t do that for the 1200 modes, but if you increase V.Active in that mode, compatibility will probably drop because the output is less standard. Also note that when using PAL consoles, compatibility for higher line modes is reduced because the refresh rate is not the same as for PC modes (which are normally 60Hz). That’s one reason Steos tweak is great, because 4x PAL signal is much closer to 1080p 50Hz standard than 5x mode.

    The increased vertical resolution of PAL is not normally utilized by older consoles anyway, certainly not for the Genesis, it will still just have 224-240 active lines inside the 288. So cutting off vertical area is normally not a problem. Not sure about the PAL PS1 though.

    If you want to display more vertical area, then the tweak Steo gave you is good, because it will display 270 lines (4×270=1080).


    Sorry for the late answer, I just tried the configuration STEO told me at linex4 mode and yes, the fullscreen shows and it looks as good as linex5 mode but with the complete image.

    The only thing is that my PAL megadrive isn’t moded and the game has black bars up and down and I think that the game screen is not intended to be shown at its full, because Streets of Rage (the game I’m testing) shows some strange draws on the above part, I mean like the bushes are so tall, more than it should be xD

    Any way I want to install a 60Hz switchless mod on it and need to know if anyone can advice me a mod kit to install myself that has a dual oscillator too, cause I read that to use with OSSC my console will have some troubles with the frecuency obtained on PAL not being 59,9Hz but 59,3Hz…

    PD: Does some games like Sonic has different resolutions? If I fit my screen at all for Streets of Rage, when I put another game, then its not well centered… There are 2 different ones? Or more than one?

    Sorry for all the questions, appreciate the answers, thanks!


    You can use a vertical mask in post processing to get rid of all the garbage pixels drawn outside the game window.

    I have a modded Mega Drive 2 that I just put a switch on and it gets 59.3Hz in NTSC. I haven’t tested that in my 4k TV yet, though my Saturn is the same and that keeps frameskipping on my 4K TV because of it, though it works on the Samsung TV with no issues.

    I ended up just importing a Genesis myself since someone was selling one in the UK (I’m Irish). That gets the intended 59.9Hz and you can even hear that the sound is a few cents higher pitched than the PAL Mega Drive.

    I think you’re best off using the second oscillator to avoid problems with certain displays for your own peace of mind.

    Edit: I have a 1 chip SNES and I had to use a second oscillator on that myself.

    Edit 2: Also, Streets Of Rage is amazing šŸ˜›


    The Genesis/MD has two resolutions: a 256 and a 320 mode.

    FBX has a list of 256 games here:



    I’m now just trying to connect my pal Playstation 1 to OSSC to see if the result can be better than the pound HDMI cable, which configuration would be better, the Lx4 that Steos gave me above?



    Iā€™m now just trying to connect my pal Playstation 1 to OSSC to see if the result can be better than the pound HDMI cable, which configuration would be better, the Lx4 that Steos gave me above?

    Your results will depend on your equipment. The Pound cable has a built-in scaler that, as I understand it, will output 720p regardless of the game resolution, and I believe it performs framerate conversion, which will result in a very compatible if potentially jittery signal that few TVs would take issue with.

    The OSSC, on the other hand, does not perform any kind of framerate conversion, so your TV is going to have to like whatever framerate your PS2 is outputting. 288p and 576i line2x (resulting in 576p) shouldn’t be a problem, and, if your TV will accept 576i over HDMI (passthrough), that will immediately look better than the Pound cable. You should absolutely try the 576i line4x instructions above, as that will certainly give you a better image, but I don’t think it’d be a dealbreaker if your TV doesn’t like that mode.

    * Unfortunately, I’m not able to find much about how the Pound cable behaves with PAL sources; could you please confirm whether you get 50Hz or 60Hz output when using this cable with your PAL PS1?


    I just tried the Pound cable only with my PAL PS1, I think the frecuency is 50Hz for sure, but can’t see it anywhere…

    I’ve been today tweaking with the OSSC on my PAL PS1 with the Lx4 configuration recommended here and voila! I can now see the full image on my 65″ Samsung QLED Q8C and is as good as Lx5 mode.

    Image here with my TV forcing the 4:3 mode:

    PAL PS1 OSSC Lx4

    With the zoom options of my TV I filled the screen up/down and the left/right borders with almost success:

    PS1 OSSC Lx4

    Yes, I know it would be great to not stretch all the image but the H. Active parameter can’t go above 1920 so… Anyway it looks bad to you guys?

    The menu image is the one that I don’t know why it looks like this… It is at the same resolution so I can’t understand whats going on:


    For the boot screen, the resolution is different, anyone knows the correct settings for it? 480i/576i I think it is.

    PAL PS1 OSSC 480i/576i

    And last thing I want to comment is about the image trembling on the game, in the game menu is more visible… Is it because of the interlacing? Can be fixed?

    Thanks to everyone for all the information and help! ??


    Yes, the boot screen is in 480i/576i. In order to avoid the vertical shimmering, you need to either use passthrough or line3x (if your display supports it) to let your display perform deinterlacing, or you need to use an interim scaler, like an Extron DSC 301 HD, to do the deinterlacing and bring the image to something standard, like 1080p.

    Unfortunately, there doesn’t appear to be any 2x or 4x interlaced mode for 960i or 1152i output, which a DSC 301 HD could ostensibly support.


    I used passthrough in that Sony boot up image because I’ve noticed that with that mode the image doesn’t trembles…
    So the Lx3 mode is special? Didn’t know that my TV can deinterlace by itself and only in that mode.

    I didn’t know nothing about that scaler… I have Framemeister too if that works… But I think the PS1 looks better on the OSSC right?

    For the game menu screen btw the image position is sooo down don’t know why…


Viewing 13 posts - 1 through 13 (of 13 total)
  • You must be logged in to reply to this topic.