Optional framebuffer


Viewing 4 posts - 1 through 4 (of 4 total)
  • Author
  • #8250

    I know it goes against the OSSC’s lagless, framebuffer-free design, but I can think of three reasons why a frame buffer would be useful:

    1. Maybe faster switching between 240p and 480i for games like Resident Evil on N64. Almost instantaneous mode switching is the one advantage my cheap Chinese SCART-to-HDMI adapter has over the OSSC on my monitor.
    2. Improved line tripling compatibility.
    3. The possibility of 480i line quadrupling to 960p.

    So I think it would be good if the OSSC had a framebuffer that I could turn on whenever its benefits outweigh the latency it would add. What do you think?


    In my option framebuffer would be required only for nicer looking deinterlace – majority of other improvements could be done with just some additional line buffers and timing circuitry.

    1. I wonder if that adapter implements framelock, because 240p<->480i switch changes refresh rate by around 0.1Hz. That is enough to desync most monitors no matter how fast a video converter follows the input, unless it operates at indenpendent refresh rate without framelock (also resulting to dropped/duplicated frames every now and then).

    2. Doesn’t necessarily need framebuffer.

    3. Doesn’t necessarily need framebuffer unless different deinterlace implementation is used.


    For #1, is there something I could help you do to figure out what the cheap adapter does? I’m testing it with the 240p Test Suite on a Sega Genesis, where it seems to pause the image for a second when it switches between 240p and 480i.


    Sounds like it’s using framebuffer and unlocked (independent) refresh rate.

Viewing 4 posts - 1 through 4 (of 4 total)
  • You must be logged in to reply to this topic.