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-   -   TBC-1000 causing spots on bright white scenes? (http://www.digitalfaq.com/forum/video-workflows/11959-tbc-1000-causing.html)

willow5 06-19-2021 07:05 AM

TBC-1000 causing spots on bright white scenes?
 
Please help, I have a TBC1000 in conjunction with an FS200 (UK) and have noticed that on recordings with bright white scenes, it creates spots on these scenes.

How do I know it is the TBC? Well I simply unplugged the TBC from my workflow and the dots don't appear. Can anyone help me troubleshoot please?

Link here: https://we.tl/t-F0tvAuV9Hu

lordsmurf 06-20-2021 11:43 PM

Attach samples clips to forum posts. Then I can answer. :)

latreche34 06-21-2021 01:24 AM

What white flashes, I though those are lighting effects on the scene, By the way your chroma is way oversaturated and the MPEG compression is horrible.

willow5 06-21-2021 01:26 PM

1 Attachment(s)
Here is a sample @lordsmurf

@latreche34, what do you mean that the MPEG compression is horrible and the chroma is oversaturated ? I did not change any settings, these are using the ATI capture card software

latreche34 06-21-2021 03:12 PM

You should capture lossless, tone down the chroma, then compress to your final format, Oversaturated chroma make compression algorithms go nuts when capturing and encoding on the fly. What white spots? can you take a still and point to the spots with an arrow?
Is this a SECAM tape?

willow5 06-21-2021 03:21 PM

This is a PAL tape. The spots are only visible when I watch the file on a TV (as opposed to a computer monitor).

I don't want to capture in lossless as I don't have that much hard drive space and also not familiar with how to post process using other tools.

latreche34 06-21-2021 03:46 PM

Well then it's a playback issue not a capture issue or TBC issue. Try another way of playing back the file to see if the TV is still exhibiting the same problem.

willow5 06-21-2021 03:51 PM

Thank you. However, the spots are not visible when I remove the TBC from the workflow

latreche34 06-21-2021 04:56 PM

Well, We can't help if we don't see the problem.

willow5 06-21-2021 05:05 PM

I understand, did you try to play the file on a regular TV so far?

latreche34 06-21-2021 05:51 PM

No, I don't think I will go that far, The file looks fine to me besides the harsh compression artifacts and chroma over saturation. If you said you see artifacts it's your job to present them here not me going looking for them for you.

willow5 06-22-2021 04:39 AM

Thank you for your reply. Unfortunately I haven't found a way of demonstrating where the artefacts are using still frames or any other techniques. I even tried filming the TV but the colour dots are not picked up by the camera. Not sure how else I could demonstrate this effectively...

lordsmurf 06-23-2021 03:16 PM

On frame 96, and some immediately before and after, I see luma flashing brighter per field. But is that the content?

This is a terrible video sample. The only flashes I see are the content itself.

Ugh .. Hanson. --- I can hear the Beavis & Butthead commentary in my head now. :laugh:

Perhaps you need to extract and post some stills. Because I don't quickly see what you refer to.

willow5 06-24-2021 03:35 PM

18 Attachment(s)
Here are some stills from a different video, I can now see the spots in these stills

latreche34 06-24-2021 03:52 PM

What spots , can you circle one or point to it with an arrow using MS Paint app. What each picture of those suppose to represent? I don't see any difference between those pictures, I see chroma blatches from weak chroma RF that can be addressed with LTBC/DNR.

willow5 06-24-2021 03:56 PM

Ah ok so this is chroma blatches instead of spots? To me they look like spots but maybe my terminology is incorrect. How can I cure this problem please? I am using an FS200 which has the LTBC enabled

latreche34 06-24-2021 06:50 PM

Those are in the tape and has nothing to do with TV or TBC-1000 as you claimed to be. Now to address those chroma stains it really depends on the origin of the recording, if it is a second gen tape than those are part of the video signal and cannot be removed, if the recording is first generation tape, a built in LTBC inside the VCR works better since it works out of the RF signal recorded on tape, unlike the LTBC built in a DVD recorder or the FS-200 you have that works out of the already processed Y/C signal, big difference. Even worse a composite signal or a low end VCR. Nothing replaces the line TBC built in a VCR or a camcorder, Period.

willow5 06-24-2021 07:12 PM

Understood thanks. These are first generation tapes but I am already using a built in line TBC inside a Panasonic NV-FS200 as recommended on this forum and these stills were taken with it switched on. Can I do anything further?

Also, why is it when I remove the TBC-1000 from the workflow, the blatches are minimised and barely visible? This is what originally led me to believe it could be a fault with the TBC-1000.

Please accept my apologies for claiming this is a TV or TBC 1000 issue. I am still learning here

latreche34 06-25-2021 02:20 AM

Could be the Panasonic VCR electronic compoenet aged and needs recapping, but to assess that we need short clips of line TBC ON and OFF, If the frame TBC is causing this it could be that it needs recapping and/or removal of the distribution amp, We also need shrot clips of TBC-1000 ON and OFF to confirm that. So far you are asking questions but you havn't provided enough information for someone to help.

willow5 06-25-2021 02:39 AM

I understand sorry for the lack of information.

In order to make this more scientific, I will provide stills from 3 further scenarios:

1) LTBC off, TBC1000 off
2) LTBC on, TBC1000 off
3) LTBC off, TBC 1000 on

The 4th case of LTBC on, TBC1000 on is already included.

I will aim to do this later today. Thank you for your help

willow5 06-25-2021 01:55 PM

23 Attachment(s)
OK here is the first of the different scenarios I have captured to make this more scientific.

These stills are with the LTBC ON, TBC1000 OFF (scenario 2 above)

willow5 06-25-2021 02:06 PM

13 Attachment(s)
Ltbc off, tbc1000 off

willow5 06-25-2021 02:10 PM

15 Attachment(s)
Ltbc off, tbc1000 on

latreche34 06-25-2021 05:01 PM

That's the quality of the recording on the tape, there is nothing you can do about it, all scenarios has the same chroma noise.

willow5 06-26-2021 04:53 AM

Thank you. Did you say earlier that a LTBC can minimise this noise? If so do you see any noticeable difference with the LTBC ON?

latreche34 06-26-2021 10:13 AM

To observe line TBC in action you have to post short clips, See my recent thread about a line TBC in action video.

hodgey 06-26-2021 11:29 AM

There is a fair bit of color noise in both cases, but it looks like the TBC-1000 is increasing the saturation making it more noticeable. It's possible the differences between the TV and PC monitor make it more noticeable on the TV.

The FS200 does not have digital noise reduction like in the TBC/DNR function in the newer JVC SVHS decks (one of those is demonstrated in latreche34 other thread). The line-TBC won't reduce color noise on it's own (On bad tapes it may make it easier for the video decoder in the next device in the chain to decode the color correctly, that doesn't look like an issue here though.) The FS200 has analog chroma noise reduction but it's usually way less effective than the 3D digital one in later SVHS VCRs as it's only looking for changes between a line or two, rather than being able to look at differences between whole fields like the 3D DNR is. (The downside of the 3D DNR in the JVC SVHS decks is that it can cause some ghosting between fields/frames.) That said, vcr issues or aging electronics can make it worse.

There is post-processing you can do to reduce the noise, tools like avisynth have a plethora of noise reduction filters, though I've found that even the simple HQDN3D denoiser that comes with ffmpeg and by extension tons of open source video tools can be surprisingly effective on it. If you are doing any post-processing it's useful to capture in a lossless format and compress to something else after any post-processing.

willow5 06-26-2021 12:52 PM

Thank you

@Hodgey, when you say the TBC-1000 is increasing the saturation, could it point to a fault with the TBC1000?

lordsmurf 06-27-2021 09:52 AM

A faulty input board or connection of a TBC can increase noise, mess with luma, which has a side effect of increaseing saturation and chroma noise. But that should be somewhat obvious if the TBC is at fault, by viewing both with and without TBC, at least directly to TV and to capture card.

willow5 06-27-2021 10:21 AM

Thank you @lordsmurf. Is there an obvious fault with the TBC1000 from the stills I posted ?

lordsmurf 06-29-2021 03:49 PM

Can you make me some side-by-side images? I can't take time to click around hunting.

Just label like this:
LTNC ON, TBC1000 removed -- LTBC OFF with TBC1000 -- etc
image -- image -- image
image -- image -- image

Just do 3-4 images stacked like that. Put in a zip file. Attach to forum post.

What I'm seeing here is mottled chroma noise. The "white" is probably the only part of the image that's true to the content. But the tape, or the VCR, is making non-white have chroma noise casting.

The TBC input could be at fault. Open it, gently jiggle it while on and connected, so if it is changes quality. Odds are it does.

hodgey 06-29-2021 04:44 PM

Quote:

Originally Posted by willow5 (Post 78323)
Thank you

@Hodgey, when you say the TBC-1000 is increasing the saturation, could it point to a fault with the TBC1000?

Not necessarily no, it seems these tbc units often do increase saturation a little by default. If it's just increasing saturation a little it's possible to lower it either with the capture card's level settings or with post-processing as long as it has not been boosted enough to be clipping.

Is the vcr noise filter setting set to edit, off(the default) or on? Aging electronics in the VCR can result in worse chroma noise, though it may just the tape in this case too. VHS color is very susceptible to noise due to how the format works, so VCRs would have circuitry to reduce it to various degrees, especially on higher end ones.

willow5 06-30-2021 03:00 PM

1 Attachment(s)
Right ok, following Lordsmurf's request for the same frame in a single image, I have done this for 1 frame. The sequence is as follows in a clockwise direction starting TOP LEFT:

LTBC OFF, TBC OFF
LTBC OFF, TBC ON
LTBC ON, TBC ON
LTBC ON, TBC OFF

I can do more frames if needed. Thanks for your assessment and feedback

Jiggling the wires inside the TBC while it is on makes no noticable difference

lordsmurf 06-30-2021 05:37 PM

The forum software makes the image too small.
Either stack vertical, attach again.
Or put the larger original in zip file, attach that.

willow5 06-30-2021 05:51 PM

4 Attachment(s)
Does this work better ?

1.14 = LTBC ON, TBC1000 ON
13 = LTBC OFF, TBC1000 OFF
1.18 = LTBC OFF, TBC1000 ON
18 = LTBC ON, TBC1000 OFF

lordsmurf 06-30-2021 06:25 PM

No.
I need to see all 4 together, same time, full size.

willow5 06-30-2021 06:38 PM

1 Attachment(s)
My apologies, is this better ?

1) LTBC OFF, TBC1000 OFF
2) LTBC OFF, TBC1000 ON
3) LTBC ON, TBC1000 OFF
4) LTBC ON, TBC1000 ON

lordsmurf 06-30-2021 11:47 PM

What does "TBC1000 OFF" mean? Did you remove it from the workflow?

No TBCs at all = blown out whites/highlights.

The other 3 images are similar, full of yellow splotch chroma noise, and it's the content (or the VCR).

I don't think the TBC has anything to do with it.

latreche34 07-01-2021 12:36 AM

Your VCR has more chroma noise when LTBC/DNR is on and no chroma noise when it's off, something wrong with your VCR.

willow5 07-01-2021 07:52 AM

@Lordsmurf, TBC1000 OFF means removed from the workflow and directly into the ATI capture card. Apologies for not making this clear

@latreche34, thank you for the information. What I don't understand, however, is when the LTBC is OFF and the TBC1000 is connected, why the same amount of noise appears. Is this a fault with the VCR as well as the TBC1000 ?


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