OSSC and Amiga HiRes Interlaced mode

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    Hi, thanks for the device its great so far but I noticed something odd when I tried to put the Amiga into Hi-res interlaced mode.
    I set the box to do the de-interlacing and I got a solid picture but it seemed squashed.

    The high res (interlaced) mode is 640×512, but on screen it looked closer to 640×256.

    When running it in hi res mode 640×256 it upscales is wonderfully, was just hoping to get something similar with the interlaced mode.


    Hmm, I’ve not had any issues with interlace on my Amiga CD32. Have you tried just passing through the interlace signal to your TV? If you’re using interlace for Workbench your TV will add more lag, but that shouldn’t matter if you’re only using it for Workbench.


    Which input are you using and what are the details on character LCD screen?


    I think this might be a quirk of the Amiga and me not understanding some of the settings.

    640×256 and 640×512 (interlaced) with 480i/576i passtr off both show up on screen as the exact same size, but the 512 hight does have more lines. but I get a lot of flicker in the interlaced mode and no option for scaling.

    The squashed picture was when I let the TV handle the de-interlacing, which gave me a picture with no flickering but oddly proportioned.

    the LCD screen reads as follows:

    AV1: RGBS 313p
    15.62Khz 49.9Mhz

    AV1: RGBS 625i
    15.62Khz 50.00Mhz

    My TV reports 576p @ 50Mhz for both.

    All games run at the lower resolution and I’ve always used workbench at the lower res (as the monitor’s I’ve had hasn’t handled the interlaced mode well) so its not a big problem. I was wanting to try out different things on my new box and hi-res mode as always been something that I’ve wanted to see done well.


    Both readings seem to be ok, and your TV reports OSSC output correctly (should be 576i with passthrough, though). Flicker with interlace is normal like it was with CRTs back in the day. If your display has good deinterlacer, you should get more stable picture with passthrough option.


    My Dell U2410 does a poor job of handling PAL interlaced mode. It displays visible interlaced artifacts, but it does well with a handful of other modes, namely DblPAL HIRES NO FLICKER.

    From what I am reading, I should not expect the OSSC to eliminate this problem. There are other problems I have with the U2410 that I do hope it will help with but I won’t be sure until I get my hands on a unit (patiently waiting for pre-orders to open).

    There may have been two or three firmware updates since this post, however, and I know improvements to interlace detection was involved so I am optimistic.

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