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-   -   AG1980 and color smear on motion (http://www.digitalfaq.com/forum/video-workflows/6492-ag1980-color-smear.html)

premiumcapture 04-14-2015 10:23 PM

AG1980 and color smear on motion
 
I recently acquired another 1980 and I notice that during action scenes, color seems to lag behind the action and bleed out of whatever it is supposed to be filling. This is especially true with bright blues for some reason.

Anyone have any experience with this? I have noticed similar phenomenons in my JVCs but beyond putting the VCR in edit there isnt much that makes a big difference. I am using it for commercial tapes over S-Video.

Thanks

sanlyn 04-15-2015 08:19 AM

Where and how did you get the 1980? Sounds like bad caps or a bad y/c card -- not unusual if not purchased from a pro shop that rebuilds old AG's.

premiumcapture 04-15-2015 09:08 AM

I read something about temporal distortion and it being a product of all vcr tbc's. I might be overdramatizing the issue but if you have more info about this it would be appreciated.

NJRoadfan 04-15-2015 04:41 PM

I haven't encountered it with my unit, but colors fainting in and out has been a reported problem with these. Likely caps on the Y/C board. Some video samples would be helpful here.

premiumcapture 04-15-2015 08:46 PM

1 Attachment(s)
Attached is what I consider a good example of the issue. Video is from an old Barney tape I use as a tester and on motion the issue becomes extremely obvious. Video encoded in lagarith.

NJRoadfan 04-15-2015 09:04 PM

That looks like temporal noise reduction. Its obvious when the boy on the right enters the room. You can also see it when the scene cuts to the girl, there is a faint ghost of the previous scene for a frame or two (particularly the light that was on the right hand side of the frame).

premiumcapture 04-15-2015 09:09 PM

Quote:

Originally Posted by NJRoadfan (Post 37685)
That looks like temporal noise reduction. Its obvious when the boy on the right enters the room. You can also see it when the scene cuts to the girl, there is a faint ghost of the previous scene for a frame or two (particularly the light that was on the right hand side of the frame).

That is a straight feed from the AG1980. Is this just part of the tape or is the VCR doing this?

NJRoadfan 04-15-2015 09:12 PM

Its very likely the VCR. You can rule it out by playing back with a non-DNR/TBC deck for comparison.

premiumcapture 04-15-2015 09:14 PM

Quote:

Originally Posted by NJRoadfan (Post 37687)
Its very likely the VCR. You can rule it out by playing back with a non-DNR/TBC deck for comparison.

So are you saying that the VCR is working as expected? I've been gathering tidbits about this issue but haven't really found a lot of info on it.

lordsmurf 04-16-2015 09:22 AM

I don't really see anything wrong with the footage, in terms of smearing. I see chroma offset, and chroma noise. That doesn't help. The jumping is also distracting. All of that can be fixed, FYI.

Sometimes material is broadcast with a temporal chroma offset. It will be a frame or two off, so if you really look hard, you can see it. I'm not sure how or why this happens, just that it does. I've not seen this type of artifact for many years now, not since everything was SD. It was mostly something I saw on analog cable, with was piped over analog (C-band, etc) satellite.

Because you used Lagarith, and not Huffyuv, I can't open it to go frame by frame.

NJRoadfan 04-16-2015 10:07 AM

Odd, I had no problem viewing the sample in VirtualDub, but I do have Lagarith installed.

premiumcapture 04-16-2015 05:36 PM

2 Attachment(s)
Quote:

Originally Posted by lordsmurf (Post 37691)
I don't really see anything wrong with the footage, in terms of smearing. I see chroma offset, and chroma noise. That doesn't help. The jumping is also distracting. All of that can be fixed, FYI.

Sometimes material is broadcast with a temporal chroma offset. It will be a frame or two off, so if you really look hard, you can see it. I'm not sure how or why this happens, just that it does. I've not seen this type of artifact for many years now, not since everything was SD. It was mostly something I saw on analog cable, with was piped over analog (C-band, etc) satellite.

Because you used Lagarith, and not Huffyuv, I can't open it to go frame by frame.

Is chroma offset typical of most videos or is it a sign of a VCR issue?

The jitter and noise is a result of some funky hardware stuff in addition to being a worn tape. I am not looking to capture this particular one but it shows this smearing issue well from what I can see.

In the photo below, look to the left of the girl here or watching the video:
http://www.digitalfaq.com/forum/atta...1&d=1429223521

And the boys face:
http://www.digitalfaq.com/forum/atta...1&d=1429223521

I have tested this particular tape and it has shown itself on my JVC decks as well. I read somewhere on VideoHelp in a post from years ago by someone named Orsetto that this error is the result of VCR TBCs and it shows itself in all VCRs. Not sure if anyone can verify.

lordsmurf 04-16-2015 06:33 PM

Chroma offset is caused by the recording VCR.

You remember 4:2:2, correct? That means the resolution of the chroma is half that of luma. That alone creates image clarity issues, but it's compounded by the color-under recording method used by VHS. It's worse when the recording deck is of subpar quality, as well as when the tape is of subpar quality. Note that dollar amount of the VCR/tape does NOT determine quality.

Side story:

In the mid/late 90s, Fuji Pro was a popular VHS tapes that had terrible grain. Yet many cable "pros" loved them -- and I have no idea why. I used to have a second (and third!) job in those days*, and I worked with a cable guy (who also worked this job for a second job). We used to argue all the time about analog video. This was years before digital was in use at most places, and HD wasn't even a concept yet. We didn't even have DVDs yet.

* Back then, you had a 2nd job for extra cash -- not make ends meet! Those were different times. I sometimes miss the 90s.
** In defense of "cable guys", one of my friends was one back in the 70s and 80s (now retired). And he's no dummy.

Anyway, the point is that bad tapes were bad tapes, regardless of the "pro" marketing, or brand name, etc.

If you want to figure this out, you need two main ingredients:
- the VHS tape brand/manufacturer, date of tape, and grade of the tape
- the recording VCR model/brand

Sometimes good tapes reacted badly to bad decks, and bad tapes reacted okay to good decks. It's really no different that DVD/optical media. For example, it's why CMC is mostly crap, but is okay on some burners. Or why Verbatim/MKM/MCC has issues.

Understand?

This is probably NOT something you'll be able to understand without having lots of experience. This is one of those areas where my 20+ years is valuable.

premiumcapture 04-16-2015 06:49 PM

Quote:

Originally Posted by lordsmurf (Post 37698)
Chroma offset is caused by the recording VCR.

You remember 4:2:2, correct? That means the resolution of the chroma is half that of luma. That alone creates image clarity issues, but it's compounded by the color-under recording method used by VHS. It's worse when the recording deck is of subpar quality, as well as when the tape is of subpar quality. Note that dollar amount of the VCR/tape does NOT determine quality.

So the issue in the photos above is chroma offset? I thought chroma offset was when chroma and luma were misaligned. Did I get that wrong?

lordsmurf 04-16-2015 07:49 PM

I don't see any smearing (temporal). I only see offset.

premiumcapture 04-16-2015 08:03 PM

What's a good way to tell the difference? Do you have photos of each? I am kind of confused now. :huh1:

premiumcapture 04-18-2015 12:51 PM

One new development - I realized that most of the tapes I was testing on were commercial/macrovision infested. I played back a recorded tape and it played fine. Does this deck experience issues with macrovision and is there perhaps a better macrovision playback deck?

msgohan 04-19-2015 03:27 PM

1 Attachment(s)
Quote:

Originally Posted by lordsmurf (Post 37701)
I don't see any smearing (temporal). I only see offset.

It's there, as NJRoadfan noted. At the scene cut, elements of the previous scene take about 5 frames to fully disappear even when viewing the luma channel only (I'm looking at the light stand's ghost, particularly).

The video is also infested by dots, by the way. Marked by horizontal arrows.

Attachment 4554

Smearing is a fact of life for temporal DNR (which is just a method of averaging the frames), and the TBC is tied together with the DNR for the AG-1980, HS-HD2000U, etc. That's why Orsetto said TBC VCRs suffer from the artifact. You (premiumcapture) may be particularly sensitive to this effect, as Orsetto and I are. It sucks.

premiumcapture 04-19-2015 03:38 PM

Quote:

Originally Posted by msgohan (Post 37726)
It's there, as NJRoadfan noted. At the scene cut, elements of the previous scene take about 5 frames to fully disappear even when viewing the luma channel only (I'm looking at the light stand's ghost, particularly).

The video is also infested by dots, by the way. Marked by horizontal arrows.

Attachment 4554

Smearing is a fact of life for temporal DNR (which is just a method of averaging the frames), and the TBC is tied together with the DNR for the AG-1980, HS-HD2000U, etc. That's why Orsetto said TBC VCRs suffer from the artifact. You (premiumcapture) may be particularly sensitive to this effect, as Orsetto and I are. It sucks.

I had my BVP on max resolution, I wanted to see what affect it would have on it, those dots are my fault.

Your post makes me happy as I was beggining to belive I was losing my mind and seeing things that weren't there :D

I will end up playing with noise reduction in software no matter what for the tapes I am doing, so I would honestly prefer to leave the noise in and deal with it in software. Is there a VCR with a TBC and no noise reduction? I can certainly turn it off on the JVC but I believe the way my 9800 handles video, it is never truly off. I think part of my sensitivity is the fact that most of my new shooting takes place in 60p and I have gotten used to not seeing blur.

What has your solution been? Just tolerate it or is there a better way? A $30 Sony N700 that I picked up on Craigslist that smells like cigarette smoke has been handling video better in this way than the AG1980.

Thanks

msgohan 04-19-2015 09:46 PM

Grain and noise don't bother me, so I do have an advantage there.

My solution was a non-TBC VCR run into a Panasonic DMR, until I discovered that bright parts of my videos were getting blown out by it. I've been spending money left and right trying to find something else I'm happy with, but everything I've tried so far inevitably has some new flaw. Eventually I may have to accept that my perfectionist standards are too high for any mass-market product to meet, and settle on the least-bad option. If the Intensity Pro 4K's "TBC" had line correction at least as good as my AVR or DVD recorders from various manufacturers, that would've been a good solution, but it doesn't...


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