Quantcast AG1980 and color smear on motion - digitalFAQ Forum
  #1  
04-14-2015, 10:23 PM
premiumcapture premiumcapture is offline
Free Member
 
Join Date: Dec 2013
Location: Boston, MA
Posts: 581
Thanked 68 Times in 62 Posts
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
Reply With Quote
Someday, 12:01 PM
admin's Avatar
Ads / Sponsors
 
Join Date: ∞
Posts: 42
Thanks: ∞
Thanked 42 Times in 42 Posts
  #2  
04-15-2015, 08:19 AM
sanlyn sanlyn is offline
Premium Member
 
Join Date: Aug 2009
Location: N. Carolina and NY, USA
Posts: 3,552
Thanked 1,120 Times in 917 Posts
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.
Reply With Quote
  #3  
04-15-2015, 09:08 AM
premiumcapture premiumcapture is offline
Free Member
 
Join Date: Dec 2013
Location: Boston, MA
Posts: 581
Thanked 68 Times in 62 Posts
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.
Reply With Quote
  #4  
04-15-2015, 04:41 PM
NJRoadfan NJRoadfan is offline
Premium Member
 
Join Date: Sep 2010
Posts: 1,044
Thanked 322 Times in 264 Posts
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.
Reply With Quote
  #5  
04-15-2015, 08:46 PM
premiumcapture premiumcapture is offline
Free Member
 
Join Date: Dec 2013
Location: Boston, MA
Posts: 581
Thanked 68 Times in 62 Posts
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.


Attached Files
File Type: avi sample.avi (60.82 MB, 27 downloads)
Reply With Quote
  #6  
04-15-2015, 09:04 PM
NJRoadfan NJRoadfan is offline
Premium Member
 
Join Date: Sep 2010
Posts: 1,044
Thanked 322 Times in 264 Posts
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).
Reply With Quote
  #7  
04-15-2015, 09:09 PM
premiumcapture premiumcapture is offline
Free Member
 
Join Date: Dec 2013
Location: Boston, MA
Posts: 581
Thanked 68 Times in 62 Posts
Quote:
Originally Posted by NJRoadfan View Post
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?
Reply With Quote
  #8  
04-15-2015, 09:12 PM
NJRoadfan NJRoadfan is offline
Premium Member
 
Join Date: Sep 2010
Posts: 1,044
Thanked 322 Times in 264 Posts
Its very likely the VCR. You can rule it out by playing back with a non-DNR/TBC deck for comparison.
Reply With Quote
  #9  
04-15-2015, 09:14 PM
premiumcapture premiumcapture is offline
Free Member
 
Join Date: Dec 2013
Location: Boston, MA
Posts: 581
Thanked 68 Times in 62 Posts
Quote:
Originally Posted by NJRoadfan View Post
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.
Reply With Quote
  #10  
04-16-2015, 09:22 AM
lordsmurf's Avatar
lordsmurf lordsmurf is online now
Site Staff | Video
 
Join Date: Dec 2002
Posts: 8,887
Thanked 1,483 Times in 1,296 Posts
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.

- Did my advice help you? Then become a Premium Member and support this site.
- Find television shows, cartoons, DVDs and Blu-ray releases at the TVPast forums.
Reply With Quote
  #11  
04-16-2015, 10:07 AM
NJRoadfan NJRoadfan is offline
Premium Member
 
Join Date: Sep 2010
Posts: 1,044
Thanked 322 Times in 264 Posts
Odd, I had no problem viewing the sample in VirtualDub, but I do have Lagarith installed.
Reply With Quote
  #12  
04-16-2015, 05:36 PM
premiumcapture premiumcapture is offline
Free Member
 
Join Date: Dec 2013
Location: Boston, MA
Posts: 581
Thanked 68 Times in 62 Posts
Quote:
Originally Posted by lordsmurf View Post
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:


And the boys face:


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.


Attached Images
File Type: png error example 1.png (485.6 KB, 41 downloads)
File Type: png example 2.png (502.3 KB, 41 downloads)
Reply With Quote
  #13  
04-16-2015, 06:33 PM
lordsmurf's Avatar
lordsmurf lordsmurf is online now
Site Staff | Video
 
Join Date: Dec 2002
Posts: 8,887
Thanked 1,483 Times in 1,296 Posts
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.

- Did my advice help you? Then become a Premium Member and support this site.
- Find television shows, cartoons, DVDs and Blu-ray releases at the TVPast forums.
Reply With Quote
  #14  
04-16-2015, 06:49 PM
premiumcapture premiumcapture is offline
Free Member
 
Join Date: Dec 2013
Location: Boston, MA
Posts: 581
Thanked 68 Times in 62 Posts
Quote:
Originally Posted by lordsmurf View Post
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?
Reply With Quote
  #15  
04-16-2015, 07:49 PM
lordsmurf's Avatar
lordsmurf lordsmurf is online now
Site Staff | Video
 
Join Date: Dec 2002
Posts: 8,887
Thanked 1,483 Times in 1,296 Posts
I don't see any smearing (temporal). I only see offset.

- Did my advice help you? Then become a Premium Member and support this site.
- Find television shows, cartoons, DVDs and Blu-ray releases at the TVPast forums.
Reply With Quote
  #16  
04-16-2015, 08:03 PM
premiumcapture premiumcapture is offline
Free Member
 
Join Date: Dec 2013
Location: Boston, MA
Posts: 581
Thanked 68 Times in 62 Posts
What's a good way to tell the difference? Do you have photos of each? I am kind of confused now.
Reply With Quote
  #17  
04-18-2015, 12:51 PM
premiumcapture premiumcapture is offline
Free Member
 
Join Date: Dec 2013
Location: Boston, MA
Posts: 581
Thanked 68 Times in 62 Posts
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?
Reply With Quote
  #18  
04-19-2015, 03:27 PM
msgohan msgohan is offline
Free Member
 
Join Date: Feb 2011
Location: Vancouver, Canada
Posts: 1,037
Thanked 230 Times in 202 Posts
Quote:
Originally Posted by lordsmurf View Post
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.

Barney-luma-big.jpg

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.


Reply With Quote
  #19  
04-19-2015, 03:38 PM
premiumcapture premiumcapture is offline
Free Member
 
Join Date: Dec 2013
Location: Boston, MA
Posts: 581
Thanked 68 Times in 62 Posts
Quote:
Originally Posted by msgohan View Post
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

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

Last edited by premiumcapture; 04-19-2015 at 03:53 PM.
Reply With Quote
  #20  
04-19-2015, 09:46 PM
msgohan msgohan is offline
Free Member
 
Join Date: Feb 2011
Location: Vancouver, Canada
Posts: 1,037
Thanked 230 Times in 202 Posts
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...
Reply With Quote
Reply




Similar Threads
Thread Thread Starter Forum Replies Last Post
Should I trade, sell, or try to fix my AG1980? jczarn Video Hardware Repair 21 10-04-2013 10:09 AM
Capacitor kit for Panasonic AG1980? jczarn Video Hardware Repair 1 09-30-2013 12:28 PM
Different AG1980 issues on two VCRs rds11 Video Hardware Repair 4 08-05-2013 07:14 AM
Top side of Maxell DVD-R fingerprint "smear" ieee488 Blank Media 5 08-15-2010 08:43 PM
DV color space harmful to analog color quality? Verify? DeXeSs Capture, Record, Transfer 6 06-27-2010 01:48 AM

Thread Tools



 
All times are GMT -5. The time now is 02:46 AM