Edge noise when TBC is active

[elbenno]

Dears, I recently bought a JVC HR-S8500E for digitizing my old VHS tapes. I love how the TBC is improving the image stability, it does however introduce some edge noise around red areas (like the pants, the Lego logo and especially the letters in the attached video).

Has anyone any experience with this or how to filter it out? Help is much appreciated!

https://dl.dropboxusercontent.com/u/48820378/TBC-ON-OFF.mp4

[LMotlow]

Well, a few problems......

The original video has been deinterlaced, resized, and re-encoded. So we don't know which problems to point to: your re-processing of the original, or the original itself. What can be seen from the sample is that without the tbc you have bad line timing errors and jitter (look at the side borders in your right-hand video). It could also be seen right away that the video is blurry and was captured at the wrong IRE (black levels and gamma too high, brights blown out). The junk to the right of the letters is ghosting, for all we know is on he original tape.

Would be better to submit two clips, one labeled "ON" and one labeled "OFF", from your original captures, unprocessed. We don't know what format you captured to, either, so not much more can be said.

[elbenno]

Hi LMotlow. Thanks for your reply. My current script is:

loadplugin("mvtools2.dll")
import("QTGMC-3.32.avsi")
LoadPlugin("nnedi3.dll")
LoadPlugin("D:\avisynth-JHM\RemoveGrain-1.0\RemoveGrainSSE2.dll")

a=AVISource("band6-tbc.avi", audio=true).converttoYV12().QTGMC(Preset="medium") .SelectEven().BicubicResize(720,576,0,0.5).subtitl e("JVC HR-S8500 TBC ON",size=28,align=2)
b=AVISource("band6-notbc.avi", audio=true).converttoYV12().QTGMC(Preset="medium") .SelectEven().BicubicResize(720,576,0,0.5).subtitl e("JVC HR-S8500 TBC OFF",size=28,align=2)
StackHorizontal(a,b)

The noise is already visibile in the interlaced material. I captured in huffyuv avi via virtualdub. I use a VHS to PC cable from Envivo (Envivo vhs to dvd maker cd-rom P1170) and then applied the script. Original videos I will upload now and send as soon as they are online.

[LMotlow]

Good work. Better to work with the originals than try to guess what's going on. Thanks.

[elbenno]

Here they are:

https://www.dropbox.com/s/hyf3ulozno0fy5e/band6-tbc.avi?dl=0
https://www.dropbox.com/s/bvnbf4cab595u1p/band6-notbc.avi?dl=0

[jagabo]

Those are dot crawl artifacts. The easiest way to get rid of them is to resize to half width then resize back up to full width:

AviSource("band6-tbc.avi") 
LanczosResize(width/2, height)
LanczosResize(width*2,height)

With VHS that's not as destructive as it sounds because the picture doesn't have much horizontal resolution anyway. If you want to be more conservative, or with sharper sources, you can filter only chroma edges by using a mask based on the chroma:

AviSource("band6-tbc.avi") 
ConvertToYV12(interlaced=true) # mt_edge requires YV12

# make a filtered version
lowpass=LanczosResize(width/2, height).LanczosResize(width,height)

# build a mask of chroma edges
SeparateFields()
Uedges = UtoY().mt_edge(thY2=4)
Vedges = VtoY().mt_edge(thY2=4)
edges = Overlay(Uedges, Vedges, mode="add").BilinearResize(width,height).Weave()
Weave()

# overlay the original video with the filtered video only where there were chroma edges
Overlay(last, lowpass, mask=edges)

#further filtering as desired

Adjust thY2 to catch sharper or fuzzier edges.

[LMotlow]

Top image: No TBC. (2X blowup)
Bottom image: TBC ON. (2X blowup)

The top image has less noise than the TBC version. Both have two-sided red chroma bleed, elongated dark edge ghosts, and chroma noise/rainbows. The soft image is no surprise with JVC, but noise increase with TBC ON is fishy. In the top image the dark background noise is fine-grained and random. In the bottom image the background noise looks sharper and approaches a kind of fine herringbone pattern.

No TBC:

TBC ON:

[elbenno]

Thanks again LMotlow. So strange that the TBC is creating so much noise. I played a bit with the options you gave me and the simple horizontal resizing is good enough for me. I would still like to keep the TBC on of course for the more stable image.

[LMotlow]

Thanks again LMotlow. So strange that the TBC is creating so much noise. I played a bit with the options you gave me and the simple horizontal resizing is good enough for me.

The filtering options were from jagabo.

Looks like something is amiss with the unit's TBC board. My guess is that it happens on every tape, but if it happens only on this one then it's not unusual for the JVC line to have tracking problems with some tapes but not with others. But that disturbance looks electronic, not mechanical. It's common for video crazies like us to have more than one working VCR, especially different models and brands. Most use legacy Panasonics for 6-hour tapes (which JVC doesn't play that well) or tapes that JVC or JVC rebrands won't handle, or use their JVC for tapes that Panasonics have trouble with. But, in summary, the TBC capture should look cleaner than the non-tbc output, not worse.

Your 8500 should have playback mode options for "SHARP", SOFT", "NORMAL", etc. If you have an "EDIT" option, use that for capture. If EDIT isn't available in the menus, use "NORMAL". One of those modes is designed to do no processing before the image goes through the TBC. I haven't used JVC for a while, but mine had "Stabilizer" and "Digital/DNR" options as well as TBC. DNR and TBC often go together, but other options often interfere with the TBC and cause odd behavior.

[jagabo]

It's dot crawl artifacts from incomplete separation of the chroma sub carrier from the luma with a composite signal. Are these captured via composite or s-video cables?

[elbenno]

I cannot find any menu options or buttons for sharp/normal/soft. I do have the edit modus, when I activate it, the crawling dots are still there, and the image does not seem to change. Stabilizer is alsno not there (I think), I do have a spatializer button though?

The current menu options are:

Main menu:


Mode set page 1:


Mode set page 2:

[LMotlow]

I'm not certain what "B.E.S.T." is doing, but on U.S. JVC's it is an image enhancer. Try turning it off and check the results.

"S-VHS" should have an "OFF" setting instead of "AUTO". The 8500 might think you have SVHS tape loaded. That setting has no effect on your s-video output connection but it can affect playback. SVHS is a tape format, but s-video is a signal transmission type that can transmit VHS, VHS-C, SVHS, or DVD formats with no problem.

Digital-3R is an image enhancer and noise reduction. Sometimes it can affect the TBC. Try turning that off as wll. Digital-3R often smears motion. You might have a little more tape noise with it turned off, but that can always be cleaned later. It's actually an early, relatively primitive digital enhancer.

[elbenno]

That's some good points LMotlow, I will turn them off and check the results.
Thanks!

[johnmeyer]

Make sure you are using the S-Video connection, if your VCR has one, and if your digitizer has an input. I have often seen these dot-crawl problems disappear when using S-Video. And, of course, S-Video refers to the video connector, and should not be confused with S-VHS which refers to the the higher-resolution video format. S-Video connections can be used with either VHS or S-VHS, and should always be used when digitizing tapes.

[jagabo]

I'd go with the s-video cap since it has less sever problems with blown out brights. It does seem to have a tiny bit less detail though -- maybe there's a little extra sharpening from the comb filter on the composite cap.

Here's an example of the macroblock artifacts I saw (8x nearest neighbor enlargement of one field):



That's more blocking than I would expect from DV.

I think you should give the Philips and BT based capture device a try.

[LMotlow]

Here's an example of the macroblock artifacts I saw (8x nearest neighbor enlargement of one field):


[Attachment 28844 - Click to enlarge]

That's more blocking than I would expect from DV.

I think you should give the Philips and BT based capture device a try.

@jagabo, doesn't this belong in another thread? ?

[jagabo]

Here's an example of the macroblock artifacts I saw (8x nearest neighbor enlargement of one field):


[Attachment 28844 - Click to enlarge]

That's more blocking than I would expect from DV.

I think you should give the Philips and BT based capture device a try.

@jagabo, doesn't this belong in another thread? ?

LOL. Yes, you're right. I posted in the wrong thread.

[elbenno]

Haha, oops

Thanks John. I just ordered a video capture unit with s-video connection as mine only has VCA. Should arrive somewhere next week.

[elbenno]

With all options off, as suggested by LMotlow, more noise seems to be introduced (as expected) and the crawling dots are still there. I will wait for my new capture cable to come in and see how well the s-video connection handles the video.

[Brad]

I don't see how this could be a cable issue if the "No TBC" capture was done the same way as the interference-pattern "TBC" capture.