screen 'jumps' at capture ATI AIW and JVC SVHS

[lordsmurf]

Sometimes when capturing, most notably with purchased movie tapes, I have recently noticed that the video "bounces" or "jumps" during capture. It does it for about 1 sec every minute or two.

I am using a ATI AIW DDR32, which I'm aware is also known as the ATI AIW 7200 card.

The source is fine. In fact, I have my JVC HRS9800U SVHS VCR setup to play s-video with RCA audio out to the card, with coax on RG6 cable going back to a tv monitor so I may compare the tv to the computer monitor.

Every few seconds, when placed side by side, I can see a minute bounce in the ATI computer image, whereas none exists on the tv. The video signal is being cleaned by the JVC's internal TBC/DNR function.

I have switched cables a few times, and the only noticeable differences are that the effect seems to be minimized by using the s-video cable rather than the RCA video cable.

The video tapes can also be run through an independent TBC, but the effects still exist. On another test, I put the video out from a JVC 3800 and into the TBC whereas it then fed into the ATI card. Same results.

I would normally think: it's the source. But remember, when viewed on the tv set, there are no problems. So the output from the VCRs are fine. So it must be the input on the card. But AHA! I can receive the same results using a cheap AverMedia card. Both cards gone bad? I wouldn't think so.

Where, oh where is this error? Any ideas out there?

This error only seemed to have cropped up in the past few weeks. But I do not remember making any changes to any systems or any video hardware configurations. At least not something that I have not already put back.

[Tommyknocker]

How does the video run once it has been captured?

[Metaluna]

Remember that capture cards can be more sensitive to sync problems than your TV is. That's why you often can't see timebase errors on your TV but they will show up in your capture. The energy stored in the expanding and collapsing magnetic fields in the cathode-ray tube's coils tends to create a sort of "momentum" effect that smooths over some types of problems. Similarly, some capture cards might have different filtering on the analog inputs which might help alleviate the problem.

I have a JVC 9911 VCR and I have a tape that has similar problems. I suspect the tape is wearing out in some way and starting to cause errors. That could be why the problems started only recently. As the tape wears and stretches every so slightly, it finally gets to the point where it's just starting to cause noticeable problems on playback. I don't know about the 9800, but the 9911 has a "Video Stabilizer" function that's supposed to help with shaky tapes. The problem is, you can't have video stabilizer and the TBC on at the same time. So, turn off the TBC, go into the menus and make sure the video stabilizer is on, then see if that helps. In my case it seemed to help a bit but still not enough to make the tape useable.

[lordsmurf]

I have been able to minimize the issue by turning oFF the TBC/DNR function, turning OFF the video stabilization, and removing the standalone TBC. So with all 'correction' devices turned off, it plays better. It's still not perfect, but almost all of the jumping effect has been minimized. Go figure!

Turning on ANY of the functions or adding back the TBC will make it jump again.

And thanks for the other info Metaluna, some of that knowledge helps. Didn't know all that. Explains quite a bit.

And Tommyknocker, the captured file also had the jumping. With the setting I'm using (bitrate, resolution, etc) the output file is pretty much identical to what I see on screen at capture. I wish it would have just been a preview error.

So for anybody with this error too, that's what I've done so far. Sort of fixed it. I no longer get the TBC benefits, but at least there is no jumping in the video.