Output 240p at 120Hz on the regular OSSC?

NewHome Forums OSSC & OSSC Pro OSSC – Feature Requests Output 240p at 120Hz on the regular OSSC?

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  • #46714
    Analog Dude
    Participant

    Would it be possible for the OSSC to ever take a 240p 60Hz signal and convert it to 240p 120Hz so that we can have true 240P on a PC CRT monitor? Maybe on a custom firmware or something?

    #46844
    Zacabeb
    Participant

    Since the OSSC doesn’t have a frame buffer, it can’t repeat entire frames but only individual lines and samples. There is probably not enough RAM available onboard the FPGA to buffer more than a few lines of video at a time. Maybe the OSSC Pro might be able to repeat frames.

    #47715
    RoberMC
    Participant

    AFAIK to get the correct effect you don’t have to repeat the frames, just inserting a black one in between.

    #47801
    Zacabeb
    Participant

    Even a 120 Hz mode to simulate CRT flicker would require a buffer since the fields get output twice as fast. The OSSC would need to buffer a full field (224 to 240 lines) while it outputs the picture. As it runs through the buffer, it gradually catches up with real time.

    Depending on the captured resolution, it would require buffering between 215 kiB (320 x 224 x 24 bpp) and 461 kiB (640 x 240 x 24 bpp).

    120 Hz with black frame insertion might also not create the desired effect, but a more flickery picture than CRT TVs have.

    The OSSC Pro might be able to do it if the HDMI Tx permits, I guess. Hopefully @marqs or someone else involved in the design could clarify this.

    • This reply was modified 2 weeks, 3 days ago by Zacabeb.
    • This reply was modified 2 weeks ago by Zacabeb.
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