Please help! Problem with using TBC to capture VHS tapes.

[jrodefeld]

Hello everyone,

I am in desperate need of some help with a project I am working on. Some of you may recall I have posted a few threads about this in the past and I have gotten a lot of help from posters here. Basically I am working on capturing VHS tapes to make DVDs from. I am using a Panasonic AG-1970P S-VHS player as the source and a ATI TV Wonder 650 capture card. I am using virtualdub to capture uncompressed avi with the huffyuv codec.

The problem is if I simply connect the S-VHS player to the capture card with S-Video connections everything works fine but if I try to add the CTB-100 (AVT-8710) Time Base Corrector, it doesn't work and I can't capture.

All I am doing is connecting the S-VHS player with S-Video to the TBC and then running a second S-Video cable from the TBC to the capture card. That should be all I need to do but for some reason the computer is not picking up the signal and I cannot capture. I only have a black screen in virtualdub.

Can someone tell me what is going wrong and offer some ideas? I bought the TBC specifically to improve the quality of the tapes and it was by far the most expensive item I bought for this project so if I can't use it that would be extremely disappointing. I have looked at the manual for the TBC but basically all it says is plug it in and it should work. I can't find any other help.

Please help me out if you can. I was all prepared to work through this project for the next week and I can't even start because of this problem. I would really appreciate any assistance you could provide. Thanks.

[jrodefeld]

Hi everyone,

I was able to make it work with the TBC so I've handled that problem. However, I am wondering if anyone could give me any tips to capture in the best quality I possibly can. For those with this model TBC, do you use the "tint, color, bright, contrast, etc" controls and does it improve the PQ significantly? What about the picture controls on the Panasonic S-VHS player? Should I use the Panasonic TBC in addition to the external TBC? What about the "Soft to Sharp" picture slider and the noise filter? For those of you who have used similar hardware, are there any capturing tips you could offer for a newbie to this subject? I would appreciate it.

My current belief is that I should capture with Huffyuv through the TBC and then worry about cleaning up the image with filters etc later. Is that correct? Any help you could offer would be fantastic. Thanks.

[lordsmurf]

You'll find much of this has been covered before here.
Clean up as much as you can pre-digital. Otherwise, it may be too late to fix.

At least you have many of the proper tools.

[sanlyn]

Glad you have it working. I've used the AVT-8710 for years. I seldom use its image controls unless working with a VHS tape that's in really poor shape. As you know by now, the image controls are a bit clunky to use, but I've found them to be frequently useful and the results are very clean, no disturbances added to the output -- unless you push things too far, in which case you're better off making corrections after capture.

Don't use sharpeners when capturing VHS. You sharpen the image all right, but you also sharpen VHS noise and make it tougher to eliminate later.

My understanding of the Panasonic's TBC is that it's a line-level TBC (I could stand some correction on that, but that's what I've heard to date). A line-level TBC does its work by collecting output lines from a single frame in memory, then outputting those lines so that they all "arrive" at the same time within each frame. This avoids the vertical and horizontal wiggles you see on most VHS tapes, and cures a few other problems as well, such as some degree of preventing chroma smearing.

The AVT-8710 and most TBC's like it are frame-level TBC's. They don't do anything to individual lines in a frame, they just transmit them as-is. But they do ensure that your frames are output exactly at the appropriate frame rate for your source. Usually you'd place a line-level TBC in circuit before the frame-level. The reason for this, is that if the frame-level TBC comes first then the next TBC in line won't see anything to correct, and will do nothing.

I've used the AVT-8710 contrast and brightness controls, but only after I became very accustomed to the way such adjustments look in my setup. Adjusting the black levels and white levels by eye is really difficult; you stand a good chance of crushing blacks and blowing out highlights with those controls. Some tapes are just plain washed-out to begin with, but be careful how you adjust those levels. They can always be corrected in software later, where you can use histograms that more clearly let you see what you're doing. Once you destroy blacks and highlights, they're gone forever unless you recapture.

[orsetto]

Avoid using the AG1970 TBC in tandem with the AVT8710 unless absolutely necessary- the AG1970 circuit can goof some signals to an extent that confuses the AVT8710. The built-in AG1970 TBC doesn't do much and adds little that the AVT8710 can't do by itself. Switch the Panasonic TBC off on the front panel unless urgently needed to pre-correct flagging/bending verticals.

[Nelson37]

What did you have to do to get the TBC working?

[sanlyn]

Avoid using the AG1970 TBC in tandem with the AVT8710 unless absolutely necessary- the AG1970 circuit can goof some signals to an extent that confuses the AVT8710. The built-in AG1970 TBC doesn't do much and adds little that the AVT8710 can't do by itself. Switch the Panasonic TBC off on the front panel unless urgently needed to pre-correct flagging/bending verticals.

I've used the 8710 and similar TBC's with that Panasonic and other players with built-in TBC from Panny, JVC, and an ancient Toshiba. In the possibility of any disturbance from combining them, you'll certainly see it on output. The two TBC's are not alike in function, and the AG1970's TBC isn't all that effective to begin with. The 8710 can't correct wiggling verticals or other line-level warping, although the Panny doesn't help all that much. On the other hand, your inlusion of the words "absolutely necessary" certainly applies; just hooking up extra hardware in-circuit if it's not needed is a waste of AC and doesn't accomplish anything.

Buy I'm curious about how a player's onboard TBC would "Confuses" the 8710? How? There's the possibility of a grayish transparent bottom border appearing on some few copy-protected tapes from using TBC's combined, but that seldom happens. For most VHS, I'd go for the line-level function, without the frame-level TBC. If the tape's copy protected, well . . .you know what you need.

I'm also wondering about the OP's remark that he specifically got a frame-level TBC for this project, but gave no reason for its necessity. Frame level TBC's can solve some dire problems, but they're not cure-all's. I've hooked up 8710's to many devices, players, cable boxes, DVR;s, and what have you. Never saw one misbehave.

[sanlyn]

Avoid using the AG1970 TBC in tandem with the AVT8710 unless absolutely necessary- the AG1970 circuit can goof some signals to an extent that confuses the AVT8710. The built-in AG1970 TBC doesn't do much and adds little that the AVT8710 can't do by itself. Switch the Panasonic TBC off on the front panel unless urgently needed to pre-correct flagging/bending verticals.

I've used the 8710 and similar TBC's with that Panasonic and other players with built-in TBC from Panny, JVC, and an ancient Toshiba. In the possibility of any disturbance from combining them, you'll certainly see it on output. The two TBC's are not alike in function; the AG1970's TBC isn't all that effective to begin with, as I recall, though it's been a while since I used one. The 8710 can't correct wiggling verticals or other line-level warping, although the Panny doesn't help all that much. Your use of the term "absolutely necessary" certainly applies; just hooking up extra hardware in-circuit if it's not needed is a waste and doesn't accomplish anything.

But I'm curious about how a player's onboard TBC would "Confuse" the 8710? How? I just might encounter that in the future, and wondering how to avoid it. There's the possibility of a grayish transparent bottom border appearing on some few copy-protected tapes from using TBC's together, but that doesn't always happen. For most VHS, I'd go for the line-level function, without the frame-level TBC. If the tape's copy protected, well . . .you know what you need.

I'm also wondering about the OP's remark that he specifically got a frame-level TBC for this project, but gave no reason for its necessity. Frame level TBC's can solve some dire problems, but they're not cure-all's. I've hooked up 8710's to many devices, players, cable boxes, DVR;s, and what have you. Never saw one misbehave.

[orsetto]

I'm curious about how a player's onboard TBC would "Confuses" the 8710? How?

Its just a shorthand way of saying the two TBCs are not always compatible. As you've pointed out, the built-in VCR "line" TBC is rather different from an external full-frame TBC like the AVT. The built-in has more obvious visible effect in correcting problems like flagging verticals and overall washboard distortions, while the AVT does things like filter copy protection (and the distortions it produces) and maintain lip sync during dropped frames and other VHS glitches. Each TBC adds a little bit of image degradation in exchange for its corrections, in the case of the AG1970 its ancient TBC can output artifacts that cause the AVT to overcompensate trying to "correct" the AG1970 TBC and make the problem worse (blended artifacts). You notice this more with an AG1970 because its TBC is practically useless, encouraging users to try doubling up with the external TBC. Newer VCRs with newer TBCs like AG1980 or JVC SVHS or DVHS or Mitsubishi DVHS are much better at "one button visible cleanup", leaving a user less inclined to add the AVT8710 unless there are additional problems like copy protection or computer card sensitivities. Potential TBC conflict depends on the tapes, the VCRs, and the capture hardware. If capturing to a standalone DVD recorder, odds are very high you will only need the built-in VCR TBC. Computer capture is more sensitive to dropped frames and more likely to need an external TBC. Some combinations will benefit from using both TBCs, others may require compromising on one or the other alone for best results.

[sanlyn]

Thanks, orsetto. I didn't encounter that problem, but my example of things being OK was a one-time event. I get the gist, though, and can use your tips should I encounter those problems.

After by own JVC/TBC player died a while back, my solution was to use a non-TBC player but feed it thru a Panasonic or Toshiba DVD recorder as a TBC "pass-thru", and add the AVT-8710 -- only when needed, though. The onboard TBC's in those recorders usually did a nice enough job. I agree, every little snatch of unnecessary wire or circuitry comes with a price.