Any *disadvantage* to running signal through TBC?

[DaveS]

Just wondering what the downside might be to leaving the TBC in the configuration even if capturing a tape that *might not* need it....

This is for mostly (NTSC) VHS source, some SVHS and some 8mm / Hi8. TBC is TBC-1000.

I've got some decent cables to / from the TBC, and with the 4:2:2 processing w/ the above sources, I would think that the resolution of the processing is greater than my source so I would be ok although I haven't done the math (yet?).

Since I'm going analog -> digital -> analog on the TBC, I suppose there would be the chance of changing slightly how the picture looks, in addition to any slight signal loss.

I'm not sure if there's a downside to using it to replace the sync signal if the cap. is looking ok (and the JVC & sony VCRs each have a 'light' TBC in them which I suppose I can turn off). Signal level coming out of the TBC should be nice & strong.

There are no macrovision, etc. issues I'm trying to deal w/ as these are all homemade videos I'm capping.

After the TBC, signal goes through Sima SCC and on to the ADVC-100 (of which the merits are fully debated already in other posts : - ) ).

Any thoughts would be appreciated...TIA

[vhelp]

hi DaveS,

I have the same devices as you, except i have the TBC-100 card.

I thought I would share a little something that I found in my LaserDisc endeavors :P

I'm currently testing out my ATI-TV Wonder card (ATW) and as some of you
may already know, it's noisy. Even when I used my TBC. BUT..

w/ when I connected it to m LD player, (ie, -> LD Plr -> TBC -> ATW) I could
barely see any noise (I usually refer to line-noise) it's very minimal. Much
better than before. And, I'm still using S-Video connections. And, this is all
very strange to me, because for years, I've ben plauged by this line-noise
and could not get rid of it (unless I used my ADVC-100)

So, I'm stumped as to my no noise, when I use my LD plyr. But capture
with my satalette or vhs or dvd, and I have line-noise. Very strange indeed.

I'm theorizing that it's due to the older electronics in my LD (and quite posibly
the 2D-Comb filter of the LD plyr as well)
I don't know but it's all very interesting, and offers me some more
options to more color accuracy in my LD analog captures vs. my ADVC-100
capture and LD's :P

Anyways.. I just thought I'd add that regarding the above TBC-100 and LD
players, it would seem to cut down on the noise level a lot.. FWIW

Thanks,
-vhelp

[lordsmurf]

Sometimes the "junk" in a signal is so embedded in the images, that if a TBC removes the "junk", the image is ruined.

This is only something I see on really old tapes that have been copied many many times.

[DaveS]

vhelp -

can you run one of your other signals (vhs, etc.) through your LD player & capture ... if so, does the noise still go away (e.g. is the the player electronics or in the signal)...

any thoughts on using the TBC all the time? do you (or anyone else) notice any reason not to?

[dwiesel]

Ah, how fortunate to find this forum, and timely, since I just bought the TBC-1000 several days ago. Let me share my findings.

I spent the last few days testing sample video footage from both laserdisc and a high quality SP mode VHS, and have done back to back comparisons with and without using the TBC-1000. (FYI, I currently use Pinnacle AV/DV Studio 9 to capture, using the PCI card that came with Pinnacle. I capture to YUV2 AVI and use TMPGenc to render). This is what I found

FROM LASERDISC: when using the TBC-1000, the image looked worse than without the TBC-1000. I define worse as "slightly blurrier" or "less sharp"…and in testing the in/out combinations of composite and s-video, the best image is (as you might guess) when in/out are both s-video. Even with this do I see a slightly blurrier image.

Someone mentioned that it reduced "laser noise"…I checked for this too, and found no change (and my LD is an older one that has significant noise). Regardless of the TBC-1000, I do find that the capture process eliminates MUCH of the inter-signal noise as a result of laser rot. And to make life more complicated, I have two LD players, and both yield different audio and video quality (one reveals significantly less noise than the other on certain discs).

Lastly, in checking the color and brightness/contrast changes when using the TBC-1000, they looked no different then without using the TBC-1000. In summary, using the TBC-1000 had no beneficial effects when capturing from laserdisc, and in fact created a blurrier image.

FROM VHS: my source was a commercial SP tape that plays perfectly on my VCR (no jumping or instability). When using the TBC-1000, I saw no tangible difference in sharpness, or stability; the image didn't appear better in any way…I DID notice a change in color and brightness/contrast. Using the TBC-1000 yielded a brighter image with more contrast, and less color, which more closely matched the originally video when watching it on TV from the VCR. Without the TBC-1000, the resulting DVD image is slightly darker with slightly less contrast, and the color is slightly over-saturated.

I find it very hard to assess video quality in terms of color/brightness/contrast (and in fact it drives me crazy) because:

a) These three qualities are very subjective
b) TV settings for these all vary, and can be adjusted.

Now given those facts, though I didn't see a tangible difference in quality, I have to say I think the image looked better WITHOUT using the TBC-1000. Though the brightness/contrast/color levels were truer to the original VHS with the TBC, I think coincidentally they were too bright with too much contrast, so they needed to have less contrast. I will probably have to test using a VHS tape where these levels are different, but I think I will only use the TBC-1000 for lower quality VHS tapes. Since my main concern is sharpness, maybe it did play a role in my intangible opinion that the image looked better without the TBC…after all, using the TBC with a laserdisc was blurrier. And if I do want to change the color/brightness/contrast levels, I can always do so in the capture screen.


I hope this helps…please provide feedback as I'm still a newbie…thanks!

[upshot]

dwiesel:

As I understand it... A tbc does not affect the "quality" of color/brightness/contrast It's function is to correct wave/jitter problems that arise from vhs tape as it gets old or physically changes. That being said most tbc's come with some chroma/base/contrast adjustment built in (sliders) but the intent here is only to correct not "enhance".

A source is a source... Without the resources of say industrial light and magic your only filtering some flaws out...

I've never seen the results of a serious TBC ($5000 and up) but as I understand they take the entire video in filter, correct, bell, whistle, etc. etc. then spit it out... Your tbc-1000 is not quite to that level...

[dwiesel]

I hear everything you're saying, and am only reporting my findings...my TBC is the TBC-1000 for $300, which everyone says is a great middle of the road TBC unit.

Like I said, since my VHS was already high quality SP mode tape, the unit could only do so much to make it better.

[donpedro]

Just wondering what the downside might be to leaving the TBC in the configuration even if capturing a tape that *might not* need it....

Maybe it is out of the area that concern you, but I believe that you will loos Close Caption portion of signal.

[henasau]

@Dwiesel
I found your comparison very interesting.
I wonder what are your findings with a lesser quality source.
I am capping VHS-C and Video 8 home movies.
Have you done any capping and comparison in this type of source.

[dwiesel]

Nope, haven't done any more TBC testing at all...probably not for a while, I've got to get the laserdiscs done first...I do know I'll likely not use the TBC unless my VHS captures look poor.

[henasau]

This is bad news for me. After reading your post I decided to wait with my purchase. I am just not sure how beneficial the TBC would be in my case.
I could be wrong but I thing the TBC is more usefull to correct signal with "vertical" problems. My source It has "horizontal" problems, I think.

Being quite new to all this I can't be sure.
Anyway first on my shopping list is a good SVHS VCR.

Anyone else can put some light what the TBC like Datavideo 1000 can fix.
Jittery lines as example ???

[DaveS]

...
Anyone else can put some light what the TBC like Datavideo 1000 can fix.
Jittery lines as example ???

see http://www.digitalfaq.com/capture/vcrtbcsuggestions.htm for some info..

[dwiesel]

henasau...for whatever it's worth, you're talking to someone who only saves as RGB24 or YUV2 AVI's because I can see a quality difference between these uncompressed formats and DV AVI.

Again, your source tapes may need it, but the only one I tested made no difference (I wish it had for the money I spent).

[disturbed1]

On all but the most expensive TBC's there is always a quality loss, no matter how slight it may be.

Anytime you convert a signal type to another, you run the risk of degrading the signal (picture) quality. With that many AD-DA conversions, it would be blurry, or less detailed than the original. To what degree depends on the quality of the internal transistors.

The TBC should only be in the chain when it's needed, and being used.

With the line noise issue(s) sounds like an input/output level problem. Perhaps the one or the other isn't strong enough, or too strong of a signal. Get a line level signal matcher. A simple potentiometer to vary the ohms can be handy to match the signal levels. Some devices may have the output signal at 200 ohms, while others expect (and are tuned for) 100 ohms.

You could also be picking up EMF noise from inside your computer, or any other powersources close by. Some devices are more sensitive than others to this noise.

I have an old Bravado MJPEG capture card that had a bad noise problem from TV captures. Once I moved the TV and cable box further away, all was fine. I never noticed it with Hi8/VHS captures because the cable box and TV were tuned off.

[ironwood321]

After the TBC, signal goes through Sima SCC and on to the ADVC-100 (of which the merits are fully debated already in other posts : - ) ).

Why are feeding the signal through a "Sima SCC" after the TBC? Doesn't the TBC clean up the signal enough to have nothing left which the "Sima SCC" can remove?

[DaveS]

After the TBC, signal goes through Sima SCC and on to the ADVC-100 (of which the merits are fully debated already in other posts : - ) ).

Why are feeding the signal through a "Sima SCC" after the TBC? Doesn't the TBC clean up the signal enough to have nothing left which the "Sima SCC" can remove?

the reason I did that was that the SCC has manual adjustments for tint, color, brightness, contrast, sharpness, and red, blue and green levels...it also does some level of correction, but I can't turn that off...having the manual control on the signal after the TBC seems to work well..I suppose I could alter brightness, etc. after I have the file on my pc, but I like the 'real time' manual adjustment...I have no idea whether this would be the 'best' approach...

reading all the above posts, from a purist approach, taking the tbc out of the chain if it's not needed would probably be best, but practically speaking, I'm not sure I can tell a difference when it's in but not needed

I have avoided putting a s-video switch in the chain b/c unless I were to spend big $ it seems to be a potential weak link..I do have two vcr's and can pull the plugs out & put back in to the other to avoid the switch in the chain