NES/SNES 240p audio/video stability issues? Read before posting.

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  • March 3, 2018 at 9:10 AM #19787
    marqs
    Participant

      Without going into technical details, NES and SNES generate jittery sync signal in 240p mode. That is a challenge for digitizers which use it in clock generation, and especially for devices like OSSC of which output clock is derived directly from it. While many displays are able to cope with the resulting signal, some are less tolerant, with symptoms ranging from occasional audio/video issues (sync drops, audio cutting) to total incompatibility (rolling / partially missing picture, no sync).

      Before starting new topic about an issue with NES/SNES and OSSC, I suggest making the 2 following simple tests to avoid yet another thread that relates to the same root cause.

      1. Try another 240p source with OSSC. If there are no similar problems, it’s an indication of this issue.
      2. Try another display. If the problem disappears or has different appearance, it’s also an indication of this issue.

      The fix? It is possible to eliminate sync jitter with a console modification. A small mod board is currently in testing with different console revisions – more details are coming soon.

      Update 05/2018: Design files for an add-on board and installation instructions for several models are avaialble on Github. Pre-assembled boards are expected to be available sometime in June.

      Update 07/2018: Pre-assembled boards are now available on the store page, both as standalone and with installation service.

      August 29, 2022 at 10:34 AM #54649
      BuckoA51
      Keymaster

        Do not confuse the SNES jitter issue with another issue, using the wrong RGB cable with your SNES. For whatever reason Nintendo changed the video output on the SNES for Europe compared to the rest of the world. This often trips people up as they try to use a cable for NTSC consoles on a PAL machine, or vice versa.

        If the image is over bright, or displays initially and then quickly fades to black, this is NOT the jitter issue, you simply have the wrong region cable for your console.

        December 25, 2022 at 11:26 PM #56137
        bonna1979
        Participant

          Hi boys
          I’m new so I apologize if I ask a trivial question for you.
          I was trying to record some game sessions , using a Super Famicom , going from Ossc updated with firmware 0.90 . The images of the game, Street fighter 2, I see them correctly and the audio is heard very well. Uses an RGB scart cable which it uses both with OSSC and when plugged directly into my CRT TV. I exit ossc via HDMI and connect to an Aver Media 2 plus card. I start the recording on the micro SD card, she records, without using the pc, as I always do. The game looks very good while I play, but when I stop the recording and import the video file, the video is all black screen, while the audio is heard very well. I also did a recording test using the software, via PC, but a black screen appears and I hear the audio. Before doing this I disabled HDCP protection, but the problem persists. Do you have any idea why I see well on the monitor and can record again, but the video file I record has no images and I only hear the audio?
          Snes Super Famicom Japanese NTSC model, with RGB scart cable.
          Thank you
          Emanuel

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