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Jitter with HDMI to VGA adapter

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This topic contains 5 replies, has 3 voices, and was last updated by  Hydr0genjukebox 1 month, 2 weeks ago.

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  • #15667

    Hydr0genjukebox
    Participant

    Hello everyone. I just got my OSSC this week. I love it. One issue though…she likes to do the jitterbug when going through an HDMI to VGA adapter. So, here’s what I’m working with:

    – Panasonic TH-P42GT30A
    – OSSC 1.6
    – Consoles plugged in directly via SCART
    – Belkin HDMI to VGA adapter

    So once she arrived, I went directly from console to OSSC to TV via HDMI. Since I have a Panasonic plasma, I was aware that she might not like the signal from the OSSC for anything else other than Line 2x. I was right. 2x worked like a charm with the consoles I tested (PC Engine Duo-R/RGB-modded toploader NES/RGB-modded SNES Jr.) and the lack of lag was a revelation. Ninja Gaiden seems responsive again! All good there. 3x, 4x, and 5x didn’t work, however. So I checked my TVs manual and found that there are a bevy of extra resolutions available via the PC port. So, I picked up an HDMI to VGA adapter at JB HiFi and was off to the races. FANTASTIC! 3x and 4x both worked, with 5x still a no go. The only issue is that there is a small amount of jitter when playing in this manner. The jitter appears to be horizontal in nature (i.e. pixels shifting ever so slightly right to left). When the test pattern is up on startup of the OSSC, there is no jitter. When it is going directly to the Panny via HDMI in Line 2x mode there is no jitter. It is only through the HDMI to VGA adapter that it starts to show itself. This goes for Line 2x, 3x, and 4x. Everything else looks great. Colours are solid, graphics are sharp, and the picture looks healthy.

    So, I was wondering if you guys could give me some advice as to which settings I might give a tweak in order to remedy this jitter situation. If you’d like to have a look at my TV’s manual, it can be found here:

    http://www.panasonic.com/au/support/manual-download/tvs-projectors/plasma-tvs/th-p42gt30a.html

    I’m just looking to remove some variables, so if you recommend changing a setting(s), and an order in which to apply those settings, it would be greatly appreciated. I’ve messed around a bit with the Analogue LPF settings to no avail. I also perused through the Sampling options, but there are so many that I thought I’d try here first and see if I could get put on the right track. Once I try a few settings out, I’ll move on to thinking about trying a different HDMI to VGA adapter and see if that is the culprit.

    Thanks in advance, ya’ll.

    #15726

    BuckoA51
    Keymaster

    Have you tried playing with the low-pass filter settings? Both analogue sync LPF and video LPF.

    #15765

    Hydr0genjukebox
    Participant

    I have played with both, to no avail. Any other ideas, bucko?

    #15778

    BuckoA51
    Keymaster

    Short of buying a HD Fury Nano, no sorry 🙁

    #15854

    marqs
    Participant

    Since you’re converting back to analog RGB, the TV needs to redo sampling and ADC which may well be cause for the jitter. If the set has clock/phase adjustment options, I’d try tweaking those.

    #15859

    Hydr0genjukebox
    Participant

    Thanks, marqs. Indeed my TV does have clock/phase adjustment. I’ll mess around with those a bit more and see what’s what. Thanks again.

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