OSSC VGA interference

[Spbmlb10]

Hi all, I can connect the OSSC via HDMI to my projector but I am very limited to what modes I can use so I decided to get a HDMI to VGA adapter (Tendak) off Amazon that was recommended to use with it and connect to my projectors VGA input as I can utilise every mode available on the OSSC. One problem that I have though is that I have some type of interference when using this adapter. I’ve tried two different brands (Tendak) and one from Hong along and getting the same problem with Audio interference and display interference using the audio out in the adapter it has a ticking sound which just repeats and the screen text seems to move slightly to the ticking sound (see movie attached) Does this sound like AC interference? No issues connecting directly to projector with HDMI but as soon as I try a HDMI adapter to VGA I get the interfernace. Might I add that on Mode 1 straight through does not create interference mode 2-5 does.

Doesn’t matter what source I select, component or scart or Console I use. This was the megadrive for testing purposes.

Video of problem here

[BuckoA51]

Looks like regular image jitter to me rather than powerline interference. I can’t think what you could try to eliminate it sorry.

[Spbmlb10]

Thanks Bucko for your reply mate, mmm Image jitter. I wonder how I can rectify or try to eliminate some of this. It’s doing my head in. I havnt been able to really use the unit properly. Does anyone else have any ideas?? Thanks

[BuckoA51]

You’ve tried different output modes (2x 3x 4x etc) on the OSSC?

[Spbmlb10]

Yeah I have tried 2x 3x 4x 5x all showing it to some degree.

[BuckoA51]

Have you tried DVI and HDMI output mode?

[Spbmlb10]

I think I did try that, but I’ll have to have another look at it to make sure

[Spbmlb10]

It wasn’t on DVI so I switched it but it’s still the same. In passthrough mode it doesn’t have the jitter but in 2X 3X 4X and 5X the jitter is there. This is getting so frustrating, any more ideas?

Please

[BuckoA51]

Passthrough mode works? Perhaps your projector is 15khz then?

[Spbmlb10]

I have attached two images from my projector info. First one is in 2x mode

Second pic is of Passthrough mode, not 15khz. If it was true passthrough wouldn’t it be 15khz or is the projector picking up the signal but processing it as 60khz?

No jitter in this mode but looks quite blurry as the ossc isn’t doing its magic. As soon as I get 2x to 5x it’s there and less prevalent in 5x mode. But still noticeable?

I’ve tried adjusting the tracking and sync menus on my projector and they don’t touch the jitter?

Is it possible the hdmi to vga adapter is causing this? I have tried two different brands and both display the jitter in 2–5 X modes?

Thanks for trying to help, do you suggest anything else I could try??

Picture 1

Yeah Picture 2

[nmalinoski]

Second pic is of Passthrough mode, not 15khz. If it was true passthrough wouldn’t it be 15khz or is the projector picking up the signal but processing it as 60khz?

You’re conflating vertical horizontal refresh rate with frame rate. That 15kHz figure refers to the vertical horizontal refresh rate, or the number of times per second that the monitor writes the frame a line to its screen, and the 60Hz figure (Not 60kHz) refers to the number of frames fed to the monitor per second.

The vertical horizontal refresh rate also hints at which video modes are supported, so when BuckoA51 suggested that your projector is 15kHz, he was suggesting it may be limited to SD modes (240p/288p/480i/576i), though I find that hard to believe when it has HDMI-input.

For troubleshooting, I’d try the HDMI->VGA converter with a different HDMI device, but the same cable and otherwise the same settings on your projector. If you don’t get the interference, then it might be a quirk with either the OSSC or how the converter treats the signal from the OSSC. If you <i>do</i> continue to get the interference, you should try a different VGA cable (preferably a good, beefy one).

You may also want to look into getting a secondary scaler/video processor that can normalize the output from the OSSC, and perhaps upscale it to 1080p or whatever resolution your projector supports, so you can simply feed it to the projector with HDMI.

[Anonymous]

To nmalinoski’s point, I’ve been toying with one of these, which I had from my pre-OSSC days, and it seems to work well for “smoothing” the OSSC output, in those scenarios that I need it. We discussed it in another thread here, but thought it might be helpful in this thread.

https://www.ebay.com/i/152730122282?chn=ps

This device is branded and sold about a thousand different ways online, so wherever you are located, you can probably find one at a relatively inexpensive price point.

Going HDMI to HDMI through this guy, it adds minimal lag and is still a noticeable improvement with all the other benefits of the OSSC. SCART to HDMI adds more lag. I don’t think that’s relevant for what it could be used to solve here, but thought it worth mentioning. I put a quick video together, sending each of the OSSC 480i output modes through this scaler, and finally letting PS1 240p @ line3x play through it: https://www.youtube.com/watch?v=9BGvT6RpyNs&t=1s

Long story short this device could help “smooth” the OSSC output via HDMI and at the price point, it may be worth a try.

[BuckoA51]

I believe the lag is 30ms with those scalers and that they always do a frame rate conversion. Not really what you want.

The vertical refresh rate also hints at which video modes are supported, so when BuckoA51 suggested that your projector is 15kHz, he was suggesting it may be limited to SD modes (240p/288p/480i/576i), though I find that hard to believe when it has HDMI-input.

I thought it only had VGA input hence the need for the converter?

[Harrumph]

That 15kHz figure refers to the vertical refresh rate, or the number of times per second that the monitor writes the frame to its screen

You mean horizontal refresh. It’s the number of times it writes a line, not a frame.

[Anonymous]

I believe the lag is 30ms with those scalers and that they always do a frame rate conversion. Not really what you want.

That’s good to know. I’ve been using it only on the capture side of my setup, not chained ahead of the display I play on. It seems to work well with very minimal degradation to the signal, for capturing purposes. My line of thinking was: test this cheap scaler in the chain to see if it achieves the goal of getting rid of the interference and getting to higher OSSC output modes and resolutions. If it works, then possibly consider something better/higher-end like a DVDO product. But, maybe there’s no value in that approach…just a suggestion at a potential solution.

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