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#1 2015-08-10 02:03:29

bbraun
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Registered: 2014-05-29
Posts: 1,064
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840av Video Capture

I've setup my 840av with the intent to capture, or at least play through, video.  I've got the internal video upgraded to 2MB (onboard 1MB does 1152x870@8 and 2MB does it @16bit color.  AFAIK, the builtin video playthrough needs ~1MB of internal video ram, so I've configured it at 1152x870 256 colors, which should make half the video ram available.  I'm using a composite NTSC color video source.  When I playthrough video, the played video is B&W, not color.  Is this a video ram issue, and I should be bumping down the res (which means reconfiguring the stupid dip switches on the video adapter)?  Or is this a logic board issue, since I haven't actually used this for input in forever?

The second part is, I've got a Radius VideoVision Studio Nubus card and input bar, with a 2nd display (this one a standard 640x480 apple hires monitor).  It needs its own display, since to playthrough VV video, it has to be displayed on the VV's output.  Everything works ok, except the VV input is super shoddy.  There's lots of noise, and the left and right edges of the screen seem to vary.  I can grab a screen capture or a video of the display if it'd be useful.  I opened up the VV's input bar, to see if there's any bad caps or whatever but it is pretty simple inside.  There's not much going on there.  The card its self doesn't have any electrolytics either.  This is the same input source as with the builtin video, only the builtin is sharp but b&w and the VV is color, but noisy and not sharp at all.

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#2 2015-08-10 03:08:49

bbraun
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Registered: 2014-05-29
Posts: 1,064
Website

Re: 840av Video Capture

To answer the first part of my question, yes, it was a video ram issue, and the resolution must be <1024x768 to display color video passthrough.  Since my display doesn't support 832x624, putting it to 800x600 works great (other than being 800x600).
I haven't figured out the VV input quality issue yet though...

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#3 2015-08-10 04:45:09

jt
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From: Bermuda Triangle, NC USA
Registered: 2014-05-21
Posts: 1,376

Re: 840av Video Capture

I'm wondering what the output freq. of the VVS card might be? Those Apple Hi-Res monitors are a fixed res horror show in my experience. Have you swapped the displays?

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#4 2015-08-10 16:09:02

bbraun
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Registered: 2014-05-29
Posts: 1,064
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Re: 840av Video Capture

The video output isn't the problem.  The screen and overall picture of the 2nd monitor is acceptable, but the video capture image is pretty bad.

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#5 2015-08-10 16:14:06

ClassicHasClass
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From: Electron Alley
Registered: 2014-05-26
Posts: 1,081
Website

Re: 840av Video Capture

Shielding? EM noise?

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#6 2015-08-10 16:40:55

bbraun
Member
Registered: 2014-05-29
Posts: 1,064
Website

Re: 840av Video Capture

Here's a screenshot of the video capture.  Interestingly, the VVS capture shows up on screenshots, but the builtin video capture doesn't.
VVScap.JPG
That looks like a bad VHS tape or something, but it's from a DVD player and looks fine on the internal video capture.
If it is interference, it seems like it'd be severe and limited to the VVS input block, cable, or card.  The cable looks like it has its own shielding when I disassembled the input block, although the block its self didn't have any.

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#7 2015-08-11 14:35:49

ClassicHasClass
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From: Electron Alley
Registered: 2014-05-26
Posts: 1,081
Website

Re: 840av Video Capture

That really does look like chroma noise.

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