need help in capturing video from bnc

[mahmoud]

hi all
i try to capture the video from old medical device has a bnc out put
i used a bnc male to male coaxial cable, lifeview lr138 tv tuner in my pc and adaptor bnc female to rca male attached to rca in the lifeview tv card but the result is not the same as the monitor






the second image is from monitor
the first is the captured with my lifeview tv card

n.b that the original image is 1024 spatical resolution

what is wrong ??? sorry for my bad english

[Cornucopia]

BNC-to-RCA is about as simple & common an adapter as you can get in the video world, so I'm positive it has nothing to do with that.

Unless there is something wrong with your capture card (which could be possible, because it sounds like a knock-off consumer card - but if you've used it before OK then that probably isn't it), my best guess is that the Medical device does not put out a standard video signal. Is the monitor that it is hooked up to a "standard" TV? or is it a special "Medical" monitor. If so, it likely has some proprietary H/V sync. (BTW, this is a COMMON occurrence with medical industry devices)
If that is the case, you won't be able to get an appropriate signal into your card without some type of converter. IIWY, I'd check to see what Secondary outputs (or accessories) are available for that device's output that ARE standard.

Barring that, you could always just cap them as they appear and then clean them up (as well as possible) in AVISynth/Virtualdub later.

Scott

[mahmoud]

thank you for your interest

-the tv card is ok
-the monitor is a medical monitor

please inform me if you know a secondry outputs that convert the signal to standard





thank you

[Cornucopia]

Well, that all depends on the Medical equipment's brand and how it all works in their proprietary format, doesn't it? And we still don't know the brand/model of anything except your TV card. You cannot fix something if you don't know HOW it's broken.

However, as I said, your "broken" image doesn't at a glance seem to be that far off. I'm guessing a simple crop+resize might be all you need (though that might lose motion if it is some weird interlacing).

Scott

[hech54]

Looks like he is capturing as HalfD1 or worse.

[2Bdecided]

I bet it's a monochrome 1024x768p60 (approximately) PC/VGA-like output but with composite syncs. It's amazing that a normal SD video capture card is getting anything at all, but many SD (interlaced) video devices will give you double images like that with progressive sources.

I'm sure there are devices that let you capture PC outputs properly, but I don't know the name of any. It may still be a challenge, as this isn't a standard modern PC output either.

It is possible to process what you have, but you'll only get about 1/3rd of the original resolution.

Hope this helps.

Cheers,
David.

[Rawit]

You could try to use a scan converter device. But if you scan convert it to SD resolution, you will loose detail. Is the signal stable? Perhaps the two halves can be combined into one, giving you an image with increased vertical resolution.

[jagabo]

The medical device is probably 640x480p60. That's why there are two image side by side -- twice the scan rate of NTSC 30i so there are two scan lines of the source on each scan line of the cap.

ImageSource("attachment.jpg") 
PointResize(width,height/2)
left=Crop(0,0,360,-0).Crop(0,0,-72,0).AddBorders(72,0,0,0)
right=Crop(360,0,-0,-0)

Interleave(left,right)
Sharpen(0.5, 0.0)
AssumeFieldBased()
AssumeTFF()
Weave()
BicubicResize(width*2,height)

[Cornucopia]

Touché! jagabo wins the prize.

Scott