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-   -   What is a TBC? Time Base Correction for Videotapes (https://www.digitalfaq.com/forum/video-restore/2251-tbc-time-base.html)

hodgey 08-20-2019 07:27 PM

Quote:

I'm assuming Fortel Y-688 is useless.
Those things look ancient. They were used with U-Matic VCRs which had these special Dub connectors (big ones with lots of pins if you google) which could transmit the raw color signal from the tape. In addition they did stuff like drop-out correction, with the help of RF outputs on the VCRs. I doubt they would be very usable for VHS tapes but I could be wrong. Looks like they require a VCR with external sync input as well.

heavymod 08-20-2019 07:33 PM

Quote:

Originally Posted by hodgey (Post 63578)
Those things look ancient. They were used with U-Matic VCRs which had these special Dub connectors (big ones with lots of pins if you google) which could transmit the raw color signal from the tape. In addition they did stuff like drop-out correction, with the help of RF outputs on the VCRs. I doubt they would be very usable for VHS tapes but I could be wrong. Looks like they require a VCR with external sync input as well.

Cool I guess I figured as much ... is that referring to the first two as well, or just the last one

hodgey 08-20-2019 07:46 PM

Just the Fortel one. The others seem a bit more modern, don't know much beyond that, maybe others here know more.

lordsmurf 08-20-2019 08:26 PM

Quote:

Originally Posted by heavymod (Post 63577)
So are rackmounts like the JVC SA-T100 no good? I.DEN IVT-7 ?
I'm assuming Fortel Y-688 is useless.

JVC SA-T100 has zero information online. And since I don't recall JVC external TBCs at all in the past 25 years, I'm guessing it's older than dirt, and completely useless.

Fortel Y-688 is useless, ancient tech for U-matic decks. I'm not an U-matic expert, but I'd be surprised if this had any modern usefulness.

The biggest problem with tech this old, and from broadcast facilities, is it's almost always in disrepair and out of maintenance. Expect major problems.

I.Den IVT-7 can be a decent, but you must realize it's not a plug-and-play unit. These need to be calibrated, and it's not an easy task. And if you don't have either an oscilloscope, or another known-good TBC to compare it to, or both, then no way to calibrate. It's large, deep, and has sharp edges. The fan must be re-wired/modified inert (or removed), as the bearings are almost always out by this late date, and it was never quiet to begin with. I had one, and sold it earlier this year. Although my unit was eventually repaired into a good state, it's not something I'll ever mess with again. If that person ever decides to sell my former unit, hoping that it was taken care of, it'd probably be the only IVT-7 unit I'd say is fine.

TBC repair is becoming more rare than VCR repair.

Honestly, this is TBC dumpster diving. :blink:

And this is the exact reason why I started guides on what a TBC is, what it should do, and which models to get. Because it's not as easy as seeing those 3 magic letters on a device.

RS456 03-27-2020 04:12 AM

Are TBC's, Video Processors, and Digital Video Convertors the same thing?

lordsmurf 03-27-2020 05:38 AM

Quote:

Originally Posted by RS456 (Post 67539)
Are TBC's, Video Processors, and Digital Video Convertors the same thing?

No.

TBC is time base corrector, and is a loose term. There are many types of TBCs, including TINOs (TBC in name only). For example, line and framesync TBC do completely different things. And then sources matter, so some work perfectly with consumer sources (VHS, etc) while others are disasters.

"video processor" is a generic term that could mean anything. (Sometimes the item does contain TBC, but usually not.)

"digital video converter" is a generic term that could mean anything. (Sometimes the item does contain TBC, but usually not.)

RS456 03-27-2020 05:59 AM

Reason I am asking is because I saw quite a few Video Processors and Digital Video Convertors that look similar to TBCs. Some look identical to TBCs and some even have the advanced TBC features like color, saturation controls etc.

Anyway do I need a TBC if I have Panasonic AG1980 with TBC -> Panasonic VCR with Line-in NR on -> Diamond VC500 -> VDub

If so what is your suggestion for TBC?

lordsmurf 03-27-2020 07:16 AM

Quote:

Originally Posted by RS456 (Post 67542)
Reason I am asking is because I saw quite a few Video Processors and Digital Video Convertors that look similar to TBCs. Some look identical to TBCs and some even have the advanced TBC features like color, saturation controls etc.

And yet, that all means nothing.

Cypress also manufactured cases (to my knowledge), not just the inner boards. Both boards and cases were sold under Cypress brands, and to rebadgers. So you may see a Cypress case with non-Cypress internals, or Cypress boards that do not contain TBC. Making matters worse, documentation for both TBCs and non-TBCs were horrible. I've come across items that make zero mention of TBC, yet have it. And then other items claim TBC, but none exists.

DataVideeo had their own internal generic cases, for use with many products, not all of which were TBCs. It cuts down on production/design/R&D costs this way.

Fun, huh? Buying TBCs has an element of gambling, often costing $100s to play. :screwy:

^ This is why I do what I do. I take the mystery out of finding known-working TBCs. :cool:

Quote:

Anyway do I need a TBC if I have Panasonic AG1980 with TBC -> Panasonic VCR with Line-in NR on -> Diamond VC500 -> VDub
Yes. You lack framesync TBC, which is required for capture. Line TBC alone rarely suffices.

dpalomaki 03-27-2020 07:18 AM

Quote:

...advanced TBC features like color, saturation controls etc.
That is generally a capability of a proc amp (processing amplifier). They typically enable adjustment of black level, gain, saturation, and hue (aka: brightness, contrast, color and tint). Many video processors include proc amp features, as do some video digitizers.

But as lordsmurf pointed out gear comes in all flavors and varieties. Thus some TBS also include proc amp capability.

You will encounter a wide variety of additional names for video gear, such as mixer, effects processor, stabilizer, frame synchronizer, distribution amp, edit controller, video switcher, and so on. One has to read the fine print to determine what its capabilities are supposed to be, and research actual performance to assess whether or not is appropriate to the task at hand.

The AG-1980 contains an internal line TBC. Depending on the tape you will need a frame TBC as well. In my experience a few, but not all, tapes do OK without the frame TBC.

A typical connection would be AG-1980 -> frame TBC -> capture device.

Not all tapes play back the same. Try various combination of TBC on/off and NR on/off to see which gives you the best results with any given tape. If you are attempting to digitally archive a copy protected VHS tape (e.g., Macrovision protected) a TBC will most likely be needed.

If you are considering buying an AG-1980 be aware of the surface mount capacitor failure issues. Look for models that have been re-capped. eBay and other auction side offerings are at best a crap shoot with the odds against you.

There are separate threads that discuss the better TBC options.

RS456 03-27-2020 08:18 AM

Actually I really have no intention of digitizing copyrighted material. I am just using that as a test tape. There will be nothing to worry about if that tape gets ruined. I already have an AG1980 and I already recapped it.

RS456 04-21-2020 02:20 PM

Is Faroudja Picture Plus NR Series Digital Video Processor DCDi a TBC? If so is it a good brand?

msgohan 04-22-2020 01:29 AM

I showed Faroudja DVP3000 here: https://forum.videohelp.com/threads/...on-screenshots

It claims "10-bit Adaptive color decoding with Time Base Correction" in the summary and "Two-Line Time Base Correction" in detail: http://www.curtpalme.com/docs/DVP3000_Brochure.pdf

It's pretty disappointing, IMO. You're better off with a decent DVD recorder as passthrough.

RS456 04-22-2020 03:54 AM

Did you use the same VCR on all the samples and if so which VCR did you use? The Faroudja DVP3000 seems like it did a decent job with one problem. The picture seems like it is too bright making it difficult to tell how good of a job it did. For the Panasonic did you use the line TBC with another VCR playing the tape?


Quote:

Originally Posted by msgohan (Post 68175)
I showed Faroudja DVP3000 here: https://forum.videohelp.com/threads/...on-screenshots

It claims "10-bit Adaptive color decoding with Time Base Correction" in the summary and "Two-Line Time Base Correction" in detail: http://www.curtpalme.com/docs/DVP3000_Brochure.pdf

It's pretty disappointing, IMO. You're better off with a decent DVD recorder as passthrough.


msgohan 04-22-2020 05:29 AM

Quote:

Originally Posted by RS456 (Post 68176)
Did you use the same VCR on all the samples and if so which VCR did you use?

All of those samples were played back on Mitsubishi HS-HD2000U with its DNR&TBC function disabled.

I also took one camera shot of this frame played on a Samsung LCD HDTV; that one used a different VCR. I think I posted that on the German Gleitz forum and didn't include it in this VH thread.

Quote:

The Faroudja DVP3000 seems like it did a decent job with one problem. The picture seems like it is too bright making it difficult to tell how good of a job it did.
Open the Panasonic DMR-ES25 image and the DVP3000 image in different tabs and use the keyboard combination CTRL key and + key (hold CTRL then hit = key) on both until they are at 200%. With DVP3000, both left & right edges of the sign, as well as the tall vertical part of the building in the background, are wavy.

Quote:

For the Panasonic did you use the line TBC with another VCR playing the tape?
No. What you're seeing is the Panasonic's own external line time base correction when presented with the same signal as the others.

RS456 04-22-2020 12:46 PM

Now I see it.

Quote:

Originally Posted by msgohan (Post 68180)
All of those samples were played back on Mitsubishi HS-HD2000U with its DNR&TBC function disabled.

No. What you're seeing is the Panasonic's own external line time base correction when presented with the same signal as the others.

Maybe I should try my Panasonic DVD Recorder VCR Combo which from what I read also has a line TBC with my AG1980 playing the tape. But from what lordsmurf is telling me that kind of setup is still no match for VCR with TBC and an external full scale TBC.

What about Leitch DPS-235 TBC? Is that good TBC?

LAZYWRITER 07-31-2020 11:00 AM

Quote:

Originally Posted by lordsmurf (Post 17020)

Important: Never use a TBC without a UPS. Unlike many devices, including most VCRs, a TBC has no fuse to protect the components from power fluctuations. Flickering power can destroy a unit, and nobody is immune to power problems. Heed this advice! A good Cyperpower unit is suggested.

Just wanted to clarify, when you say UPS, do you really mean one with a battery backup, or merely "high quality surge suppressor?"

I ask because I have several high-end line conditioners that suppress surges and output perfect sine waves, but lack a battery backup.

lordsmurf 07-31-2020 02:50 PM

Quote:

Originally Posted by RS456 (Post 68188)
What about Leitch DPS-235 TBC? Is that good TBC?

No.

Quote:

Originally Posted by jbandes (Post 70433)
Yes I should have started a new thread. Sorry

Moved here: http://www.digitalfaq.com/forum/vide...s-mx1-tbc.html

Quote:

Originally Posted by LAZYWRITER (Post 70490)
Just wanted to clarify, when you say UPS, do you really mean one with a battery backup, or merely "high quality surge suppressor?"
I ask because I have several high-end line conditioners that suppress surges and output perfect sine waves, but lack a battery backup.

Battery backup surge protector (usually known as UPS).
Yes, there are variations to this term. Not too different from how "TBC" has variations (line, frame, framesync, etc).

aokeil 08-04-2020 05:38 PM

I understand that an internal TBC is a line TBC and and external TBC is a frame TBC. Are there any external TBCs that do both?

I see TBC boards for sale on ebay. These boards were pulled out of VCRs that probably failed beyond repair. Can these boards be used in anything other than as spare parts for the exact same model?

lordsmurf 08-04-2020 06:33 PM

Quote:

Originally Posted by aokeil (Post 70578)
I understand that an internal TBC is a line TBC and and external TBC is a frame TBC. Are there any external TBCs that do both?

No.

Exception: I think I've observed this on the rare CDM-1200. But the line timing results in some "vertical jitter" (layman jitter) offset, so it's still not perfect. And I've only seen it with a few specific PAL tapes. This was a recent discovery, and I plan to look at it more when I find PAL time. I need to recreate the scenario. Te 1200 was be used as a constant against another TBC, with PAL domain footage. This was an unintended observation that merits further investigation.

Quote:

Originally Posted by aokeil (Post 70579)
I see TBC boards for sale on ebay. These boards were pulled out of VCRs that probably failed beyond repair. Can these boards be used in anything other than as spare parts for the exact same model?

No.

aokeil 08-04-2020 08:00 PM

I see that some AVRs such as the Onkyo tx-sr603x, tx-sr703x, and tx-sr803x have built in TBCs. Would these be line or frame TBCs? Do they do a good job?

And since these AVRs have analogue inputs and HDMI outputs, I was wondering what the quality of these conversions is compared to other capture hardware recommended in this forum.


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