Optional framebuffer

[gruntbuggly]

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?

[marqs]

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.

[gruntbuggly]

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.

[BuckoA51]

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

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