High contrast output from VCR

[solouplay]

I'm trying to capture a VHS-tape but somehow the contrast is very high and it really kills the detail in the picture, for example: lines on the road disappears.

I tried messing with the capture card settings, decreasing the contrast + brightness, gain and everything, but nothing works...

Also I tried capturing the footage with another capture card that isn't very good, but it works alot better and you can clearly see the lines on the road.
However I cannot use that card because it can't capture properly. If there's noise present in the picture (which happens sometimes) it dies on me.

So is there any way to decrease the contrast from the VCR to the capture card? Maybe I can put a variable resistor on the video-cable? Maybe there's a contrast control pot inside the VCR?

Help very much appreciated! :)
/Solouplay

[JVRaines]

There are probably trimmers for black level and gain inside the VCR. You'll need a service manual to identify them. Better capture cards have an adjustable processing amplifier to take care of these problems before the A/D conversion. Sounds like your second card is of this variety. To make it happy with sketchy video, insert a frame synchronizer between VCR and converter.

[solouplay]

There are probably trimmers for black level and gain inside the VCR. You'll need a service manual to identify them. Better capture cards have an adjustable processing amplifier to take care of these problems before the A/D conversion. Sounds like your second card is of this variety. To make it happy with sketchy video, insert a frame synchronizer between VCR and converter.

By frame synchronizer you mean time base corrector? I do want one of those, but I think it's too expensive. The first capture card with the contrast issues have no issues with bad frames, that's why I like it.. I've digitized many tapes with it but this particular tape is kind of difficult... (it's a very edited tape, many generations) maybe the tape is causing the AGC in the VCR to freak out?

But I do have a service manual, and I will try tweaking some pots. Thanks for your answer!

[solouplay]

Here's the variable resistors found in the luma circuit, but I'm not sure which one represents the contrast control?

[Cornucopia]

There is no contrast control, per se.

Contrast in consumer analog video parlance is really a reference to the difference between full black level (but not superblack) and full white level.

Those first 3 adjustments will affect the "contrast". However,
YOU SHOULD NOT MAKE ANY ADJUSTMENTS without proper testing & monitoring equipment, especially in this case a test pattern generator and vectorscope/waveform monitor.

Scott

[JVRaines]

One volt is peak white, so my guess is #2. Please note that I am not a video engineer! Do you have a scope and test tape ready to restore the setting after you've played with it?

[solouplay]

One volt is peak white, so my guess is #2. Please note that I am not a video engineer! Do you have a scope and test tape ready to restore the setting after you've played with it?

There is no contrast control, per se.

Contrast in consumer analog video parlance is really a reference to the difference between full black level (but not superblack) and full white level.

Those first 3 adjustments will affect the "contrast". However,
YOU SHOULD NOT MAKE ANY ADJUSTMENTS without proper testing & monitoring equipment, especially in this case a test pattern generator and vectorscope/waveform monitor.

Scott

I ended putting a potentiometer on the video-cable (RCA). The ground is unchanged, but I can adjust the hot signal. Now it looks great!

Thanks for all the replies! :)

/Solouplay