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debwalsh 07-29-2005 01:06 PM

Built-in TBCs vs. Standalones
I've got a TBC built into my JVC S-VHS deck that I'm using for my VHS conversions. On some of my tapes, I get a roll or jitter that doesn't appear in the same spot if I turn off the TBC - the picture quality overall isn't as clean, either. I'm wondering, would a standalone TBC clean up the image and not introduce the roll or jitter? And are the inputs standard enough that I could use it with my Beta decks? I'm looking at the Datavideo TBC-1000, and before I plunk down a couple hundred dollars, I want to make sure it's going to do better than what I already have in hand.

So, advice, opinions, etc., very welcome, and thanks!

lordsmurf 07-29-2005 07:26 PM

3 Attachment(s)
I have explained this over and over and over again in words, but it never seems to come across as well as I'd like. So this time, let's try some video clips and images. These are MPEG-2 (interlaced) video clips, either watch them in a DVD player software, or author and burn to disc and watch on your tv.

A TBC is not made to clean video, not in the visual sense. The JVC is a line TBC system to partially stabilize, and then it ALSO has a bunch of DNR (digital noise reduction) circuits, the DigiPure technology. That is what cleans the signal, the TBC only stabilizes it just enough to get it to where the DNR will work. DNR cannot work on an unstable signal.

  • This is what a JVC S-VHS VCR is good for - see attached file JVC-TBC-Auto.mpg
  • Compare to a regular VHS VCR - see attached file Regular-VHS.mpg

Notice how all the chroma noise noise and other grain type noise is now totally gone, the JVC left you a clean signal. The VHS signal is unfiltered, dirty quality video.

Now then, a full frame standalone TBC, again, is not to clean. It purifies the signal so that digital equipment can effectively work with it. Digital equipment is much more precise than analog was, it requires a stable signal, although clean video helps the encodes look better too. Too much noise angers and confuses an MPEG encoder (which is why some of the poorer encoders, like Panasonic, tend to fair worse than LSI and Renesas and others).

Check out these images/videos to understand what a full frame TBC accomplishes.

Attachment 441


lordsmurf 07-29-2005 07:33 PM

Oh, and nothing works 100% of the time. You will run across tapes that are just full of errors, often because the tapes has degraded, or because it was recorded on faulty equipment (misaligned heads is most common reason).

For those, you have to just find the lesser of evils, although owning a bunch of different hardware can help (several VCRs, for example), as different equipment acts slightly different, even among the same line or company.

cp32 12-05-2005 06:38 AM

Got a Jvc combo. I noticed a huge difference from the crappy emerson vcr to the JVC . I m able to play tapes I couldnt before. IIIIIIIIIIIIIIIIIIIIIIIIIIIII like it !

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