Pannasonic AG-1980P TBC cleans up color?

[Gary34]

I have heard the 1980p ag's TBC can be turned on separately from its chroma noise reduction. When you switch it to NOR that turns on it's noise reduction. switching it to edit bypasses all filters and the slider. The JVCs noise reduction works only when it's TBC is turned on.

I well test some of this stuff and I see it on my CRT before it goes through my proc amp because of the monitor output on my TBC 300, from the output of my pinnacle 710 on an LCD and in the Vdub preview at the same time. I don't capture like that though because it splits the signal.

To me it looks like the TBC cleans up my whites. I turned it on and off a few times and I it appears to help with color noise and that makes no sense to me. In my sample I start out with the TBC off then when it's turned on at like 3 seconds in it takes the blue out of the guy's white clothes.

[lordsmurf]

- I read this yesterday, already forgot what you wrote.
- Downloaded sample. Not sure what I'm looking at here. I see a blip, so were you changing a switch (TBC, others)?
- Now re-reading...

^ This matters here, no bias to viewed sample.

EDIT / NOR has nothing to do with NR. --- Where to read or hear that? I want to know.

Read this: https://www.digitalfaq.com/forum/vid...it-switch.html

Looking back at your sample, I see nothing having changed after the blip. Before/after is identical.

If a TBC "cleans up" any color, it's often a caps related issue. But this phenomenon is tape dependent. Correcting a time base can lead to correct colors (generally to legal values, not to illegal). For a color to appear "richer" or the inverse "less saturated" has nothing to do with the VCR analyzing color. It's entirely about the timing, maybe AGC, and there is interplay between video signal aspects.

You stated blue hues disappearing from the white shirt, but that's not how I see it. The full image looks to have an exposure change right at that same moment, so it's coincidence here. It's very slight, due to camera WB, or clouds moving, or both. You must be careful with making conclusions from samples of "live" videos (not test patterns).

[Gary34]

Quote:

EDIT / NOR has nothing to do with NR. --- Where to read or hear that? I want to know.

I am not sure where I got that one at but at least I know it's not accurate now. I'm reasonably certain it wasn't this site. Thanks for the correction.

Quote:

If a TBC "cleans up" any color, it's often a caps related issue.

https://www.digitalfaq.com/forum/vid...filtering.html

That thread confused me some because I thought you were saying the TBC cleans the chroma but maybe you were talking about the chipset and not the TBC.

Also that test is kind of me messing around. Thats probably a big part of why the results are like that. I'll look at them in stacks using pmod later but a test where I'm going against decades of professionals testing with calibrated gear seems like a waste of time. I'd personally would rather just take your word for it.

[lordsmurf]

Chroma noise tends to be corrected as a byproduct of line TBC. Some % of chroma noise is removed purely by the filtering mechanism of line TBC. And that makes sense, given how these TBCs function, and the chips used.

That extends beyond just JVC and Panasonic S-VHS VCRs, or any VCR. Or any passthrough DVD recorder.
- The JVC has extra NR, and that TBC+NR are married.
- The Panasonic S-VHS may have something faint; the Panasonic DVD recorders are married like JVC.

My data/definitions/etc of TBCs have gotten more honed over the years. So always feel free to bump a post when confused, unsure, etc. Or make a new post.

Feel free to ask if an analysis/method/etc is still current. Not because of something "new" existing, but rather if a review of the data has brought about newer/different conclusions. Because that's how science works.

My attention to small details in tests is also been very refined in the past 10 years. I see a lot of bogus and weird tests on Youtube these days, and details often betray them.

This is largely because of how many tapes I've seen. And I also have "WTF is that?" moments when I encounter odd or unexpected outcomes. I'll sometimes still get befuddled by a VHS recording, and have to research and test how/why and how to fix.

It's easy for some Youtuber, Redditor, or newbie to make a sweeping simplistic proclamation after having seen a "large" sample of 5 or even 50 tapes. But look at 5,000, 50,000, 500,000 tapes, and try to do that again. It's why my advice is so nuanced at times, because broad strokes are not always possible. There are several unavoidable basic truths, such as workflows requiring some form of TBC, or with how certain gear function. But other aspects get grungy, such as detecting when/how/why of chroma noise and chroma NR.

In the past, I've help others recreate tests. Because that's also science. Though some people do it just to be argumentative, and "prove" something contrarian. However, I have to give attentions elsewhere in recent years (family, health), so I've had to back away from that generosity of my time. I'm amused at some of the entitled demands I've gotten in these recent years, insisting I help them run experiments.

So I must say, it's refreshing to essentially read "okay, cool, you did this experiment already, shared your results, thanks!" rather than "nuh-uh, I don't believe you, I need to see with my own eyes!" (even though he/she knows nothing about anything, including how to interpret the results).

[aramkolt]

I read somewhere that EDIT per the manual is really only to be used when connecting two tape recorders together and I think it adds some extra stuff to the signal, in my case, using "EDIT" mode was adding an "every other frame" pink/cyan hue to the extreme right edge of the image. this isn't particularly obvious on playback since those colors kind of cancel out if they are blinking at 59.94x per second.

On your capture there, I think I see what you mean on the white shirt having less chroma noise with the TBC. If the TBC had bad caps, I'd expect the chroma noise to likely get worse with the TBC enabled, though the main symptom of a bad TBC board is extreme visual abnormalities, up to and including no picture output at all, or sometimes even a black and white image even if the TBC is not enabled.

I restore SR-MV series JVCs as well and when the timebase corrector on those needs to be recapped, you see additional image noise when the TBC is enabled which is typically the opposite of what a working TBC would do. These days, I just completely recap those TBCs no matter what since I've seen that it is possible for them to go bad as well.

I will say It looks like the whites in the sky could be potentially blown out, or if that's a second generation tape, that's probably baked-in anyway. The only setting I'd consider messing with on an AG1980 is the S-Video luma potentiometer. that will kind of set how bright the brightest brights can be. Ideally how you'd do that is play your tape and look at the signal with a waveform monitor and make sure you aren't seeing signals over 100IRE at the brightest points in that specific tape. Using the histogram in your capture program can also show you if that's happening I believe. Luma (Y) is labeled on the main PCB and it's actually on the TBC card itself, but a holes in the main PCB allow you to get at it without disassembling anything other than taking off the top cover. If your capture card has good AGC, it should dampen down the luma on its own if it is outside of the legal range without losing such details, but I think we all prefer not to rely on AGC circuits if it can be avoided.

[Gary34]

Quote:

So I must say, it's refreshing to essentially read "okay, cool, you did this experiment already, shared your results, thanks!" rather than "nuh-uh, I don't believe you, I need to see with my own eyes!" (even though he/she knows nothing about anything, including how to interpret the results).

That “testing” I did was just me having a calibration CD then already having a CRT by my TBC and an LCD by my capture card and thinking. I got cables to hook this up. Well I might as well. Real testing is a huge rabbit hole inside the rabbit hole and I personally would rather enjoy my capacitors while they last and skip that rabbit hole. Especially when I can look back in the forums and see other really trusted members agreeing with what you’re saying. I would rather just say okay I’m wrong and move on. There are other more fruitful rabbit holes inside the rabbit hole like learning how to use the post capture software better. That’s just my personal view on that though.

Quote:

On your capture there, I think I see what you mean on the white shirt having less chroma noise with the TBC. If the TBC had bad caps, I'd expect the chroma noise to likely get worse with the TBC enabled, though the main symptom of a bad TBC board is extreme visual abnormalities, up to and including no picture output at all, or sometimes even a black and white image even if the TBC is not enabled.

I think I am good for now on my Panasonic 1980p ag. This tape is actually the best one I’ve seen of my full size tapes. My other tapes are EP. This one’s SP. From everything I can see my 1980 is fine and that’s just the tape.

[lordsmurf]

Quote:

Originally Posted by Gary34

I personally would rather enjoy my capacitors while they last

I've had two AG decks fail in years past, and all I did with them was test video. It feels like such as costly waste. My AG-1970 is still failed, as I could not justify $500 for a Deter fix on an inferior-to-1980 test deck.

[Gary34]

Quote:

I will say It looks like the whites in the sky could be potentially blown out, or if that's a second generation tape, that's probably baked-in anyway.

All of my tapes are first gen thankfully.

Quote:

Using the histogram in your capture program can also show you if that's happening I believe.

I use the histogram in Virtualdub. I also use a vectroscope in Pmod. I make a folder with the title of the tape then I save my file with s1+2 for Scene 1 and 2 then b+3 for bright 3 presses above unity, c-5 for contrast five presses under unity, then the same for color. I put my audio plus 3 and now I can’t change that. I see what LS means about crossbar and the drivers. Anyways I did another scene and tried to go back to that with my settings I had because it was just a test and I didn’t recheck anything. I think I just pushed a button once too much. I use the proc amp on my TBC 3000 and put my capture card on all 0s

[Gary34]

Quote:

I will say It looks like the whites in the sky could be potentially blown out

When I got home I looked into what you said. I did clip in the test and in my regular capture. The camera brightness switched for a little bit then switched back. I did a recapture.

[Gary34]

That VHS is really making me think about getting a Mackie 5. The audio is really low and I can raise it with my capture card but it dramatically raises the noise floor. The audio doesn’t have to be that bad.

I’m just getting into my big cassettes and one thing that is blatantly obvious when you’re dealing with two sets of tapes that have 20 years difference between them and one set was stored a lot better than the others is that when someone comes up here wanting a video example of what there tapes are going to look like and all they say is it’s a VHS the only honest answer you can give is it depends on factors. I’m just dealing with a few tapes. Both VHS but way different. Once people see there sources on better gear and see more of what the software can do they get it.

[lordsmurf]

My advice for mixers is;
- at least 3 EQ (low, mid, high)
- RCA in + RCA out, for your own sanity (removes potential adapter noise adds)
- level/volume control
- spend $100 range, mostly meaning Berhinger or Mackie (no Yamaha)

Mackie Mix5 is only 2 EQ, so Mix8 is better.

Behringer Xenyx 802S is a bit cheaper, a whole $10 less, but Mackie probably a % better audio quality, better longevity. (If you look at my older posts, from at least 5-10 years ago, you'll see I often recommended Behringer. It's mostly because Mackie had far more expensive mixers at the time, post-Tapco.)

I have Tapco (Mackie) from about 20 years ago. I only use when needed, it's not plugged in at all times. Lots of VHS audio work can be adjusted in software (Sound Forge), but not all. However, feel free to get heavy into detailed audio corrections with mixers. It's a bit too overboard for me, but I can definitely understand and appreciate the quality gains. (I may also be burned out from my studio days, where we had to give excessive attention to audio quality. I was discussing this just yesterday in another thread. Every single video required waveform analysis.)