question about advanced timing options

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    Hey guys, setup is:
    Dreamcast > “madness games” VGA box > OSSC (FW is .73) > Samsung LN-46A650 LCD widescreen.

    With the 480p-in sampler set to auto or VESA, I get a small vertical black strip on the right side of the screen. I didn’t count, but probably between 10 and 20 pixels. Not a big deal, but I tried to center the image and fill the screen by adjusting horizontal back porch length and played around with the horizontal active length, but one or both of those seemed to cause some issues when I was testing them, by ultimately displaying a lot of pink snow over the displayed image until I reset the OSSC & Dreamcast.

    I found that I can move the image over and center it on the screen by setting the “synclen” to 90. Furthermore, if I change the “synclen” to 98 and the “H.Samplerate” to 812, I can center it and fill the screen with very little change to aspect ratio (maybe a pixel wider).

    If I run the 480p-in sampler in DTV 480p mode, I get big bars on both sides of the image, but can still center and fill the screen by adjusting the same settings to these numbers: (Synclen-100, H.Samplerate 906). I forget if this stretched the image badly or not.

    If I try to save any of the settings within the advanced timing sub-menus, they don’t save. Should I be able to save them if I want to?
    The picture looks OK after changing the “synclen” and “Horizontal Samplerate” settings in order to center the image or fill the screen.


    In the older firmwares, you save out in the main menu, it’s one of the last items. However, I think you should update your firmare anyway.


    I should have specified that I did save in the main menu, but the settings in advanced timing sub-menu did not stick.

    Should I be able to save them with my loaded firmware? Or is this something that came along in later firmware?

    Also, is it possible that it is not saving due to the OSSC blinking the red light as I adjust through the numbers that I mentioned above? It will blink once as I switch through each number. However, it also does this when I return to the default numbers, so it might be normal. To me the adjusted display looks just as good as what comes up as the default, but I also think that the red light might signify some sort of issue.


    Marqs has added saving of the Advanced timing options together with profiles in firmware 0.75 so not being able to save is expected. The red light just comes on because its resyncing with the new timing options.

    You should set H.samplerate not lower than 858 with the Dreamcast or else you will be losing detail so samplerate 906 should be good.

    Did you try to cycle the input on the tv after changing Sometimes I have to do that on my Samsung monitor after changing to make it stretch properly.


    OK, I will have to buy a 2gb micro SD card & adapter so I can upgrade the FW and save the settings.

    My TV does not seem to alter the image if I cycle the inputs on the TV, but I played around with the OSSC some more while using the DTV 480P input setting instead of “auto”/”VESA”.

    480p Advanced Timing defaults & changes:

    H Samplerate 858 (default) to 910
    H Synclen 62 (default)
    H Active 720 (default)
    VActive 480 (default)
    H Backporch 60 (default) to 100
    V backporch 30 (Default) to 33

    Adjusting the H Samplerate and the H backporch centered and stretched the image out to where the few vertical pixel columns on either side of the screen that the Dreamcast fades just a little are overscanned and are beyond the edge of my screen.
    I adjusted the vertical backporch to raise the very bottom of the “shenmue clock” above the bottom edge of the screen.
    I seemed to notice that adjusting these settings while using the DTV standard seems to re-size things on screen to maintain the aspect ratio, so the “shenmue clock” or shenmues on-screen buttons get larger all around, whereas stretching/re-centering the image though the Advanced Timing settings while using the VESA 640×480 input setting stretches the image horizontally a little.

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