Help fix these VHS flaws please...

[nharikrishna]

Hello, thank you all for having a go at the Sample clip.

pirej: The picture looks a lot better except for the purple tone. Please give details on the settings done in those filters.

Basically, from restoration point of view, there are 4 parts to this video: One is the audience portion that is reasonably lit (Sample1-Uploaded). The other is moderately lit stage portion (Sample2 - Yet to be uploaded), 3rd is again a stage portion that is below average in terms of lighting (Sample3 - yet to be uploaded) and finally badly lit stage (Sample4 - Uploaded in this post). Yes, that's my uncle at a young age in Sample4.

I'm still wondering if this is some guy in a "video restoring shop" trying to put everyone here to work for free.

No. I don't have a business in video restoration. I started to have video editing, DVD authoring, and now restoration as a hobby and helping neighbors & relatives with converting & restoring their stuff.. I am a software engineer working for one of the largest software services provider.

[pirej]

I was using Neatvideo with the picture of your post #9, and did "auto profile" to get the noise profile.. and then used it in the video sample, then added MsuSmartSharpen "overal and borders", "MSUColorEnhancement"..

[2Bdecided]

That video doesn't have much above IRE 100 (Y=235, RGB=255) except noise:


[Attachment 4498 - Click to enlarge]

So there's little over-bright detail to recover.

You're right, but I don't think nharikrishna has prepared these samples properly.

There's nothing in an analogue camcorder that will clip so neatly at 235
There's nothing in the JVC deck that will clip so neatly at 235
There's nothing in the ADVC110 that will clip so neatly at 235

However, if nharikrishna took the captured DV files, and then made clips in VirtualDub with "full processing" enabled, it would do a YV12>RGB>YV12 conversion, and clip the highlights exactly as seen above. The tiny bits above 235 are due to DV re-compression.

nharikrishna, when editing DV files for upload as samples, you need to use "Direct Stream Copy" in VirtualDub. Then we'll get the full range.


When processing, you need to avoid converting to RGB at all, or at least avoid it before you've fixed the levels.

It's not just the luma level; those blown out flat areas of bright saturated colour in your screen caps (not in the clips you've provided) are indicative of luma+chroma values that give colours outside the allowed RGB range. Such things are common in VHS camcorder footage because video works in YUV colour space, not RGB, and they'd actually look fine on a normal TV - nice and bright, and not flat or clipped. If you manage to write them to DVD without clipping them, they'll still look like fine on a normal TV because DVD uses YUV too. They'll always clip on a PC though, unless you reduce the chroma saturation a bit on those parts. Tricky!


Sample4 has a fixed noise pattern on it - i.e. one which doesn't move as the camera moves. This is either from the original camera or from DNR in the VCR. I suspect it means that typical motion-compensated noise reduction (e.g. mvdegrain in AVIsynth) would be useless on this - it might even make it look worse.


One thing you can do is put the chroma back where it should be, because it's moved down and across due to VHS tape generations. You can also use a warpsharp to make the chroma sharper.

avisource("sample1.avi")

# Make progressive
Bob(0.0,1.0) # better bobbers are available ;)

# Fix (S-)VHS chroma shift
Vshift=2 # determine experimentally
Hshift=-2 # 2 lines per bobbed-field per tape generation (PAL); original=2; copy=4 etc
mergechroma(last.crop(0,Vshift,Hshift,0).addborders(-Hshift,0,0,Vshift))

#I'd normally denoise here

# warp horrible fuzzy chroma to match nice sharp luma
c=aWarpSharp(depth=20.0, thresh=0.75, blurlevel=2, cm=1)

# completely replace chroma with nice version
mergechroma(c)

return last # remove this line to re-interlace at end

#re-interlace
assumetff()
separatefields()
selectevery(4,0,3)
weave()

EDIT: This is what the chroma shift (scripted above) looks like:
original: http://www.mediafire.com/imageview.php?quickkey=vx29bfys36kpmet
fixed chroma position: http://www.mediafire.com/imageview.php?quickkey=p3kozpwd1cmtd4u

It's subtle, but then it's only a 2 pixel shift in both directions. It certainly looks better with it than without it.

Of course you need to do your denoising, cropping, colour hue correction and maybe sharpening too.

But I think you should fix your levels and put the chroma in the right place first.

Cheers,
David.

[nharikrishna]

Cool. Thanks. Let me also try it out. What is this filter "Overall and Borders"? Is it available for VDub?

[2Bdecided]

The funny part is it's like pushing down on an innertube and it just bulges out somewhere else, there's no net gain.

Not true at all. It'll always look like home movie VHS, but it can have proper levels, better colour, less noise, and more sharpness. You could go mad and manually touch-up the tape drop-outs too.

Whether anyone watching the video will care is a different question. If they're interested in watching it, they'll watch it whatever. If they're not, it won't matter if you make it look like a DVD. The possible exception is when it's so dark you can't see it properly, and you fix the levels to make the people in it visible(!) - most people who want to watch it will appreciate that.

Cheers,
David.

[Lodovico]

Those diagonal streaks (very noticeable in the "before" picture in Pirej's post above) are characteristic of electrical interference during capture. Unless they are recorded on the tape itself, you may be able to eliminate that problem by using better shielded video cable, moving your VCR away from sources of interference, or (which worked for me) switching off nearby equipment.

[pirej]

...What is this filter "Overall and Borders"? Is it available for VDub?

That is the settings name in the MsuSmartSharpen filter for virtualdub.

[redwudz]

The OP may be aware of these VD filter sources, but for others who may be following this thread, here's a couple of popular sites you might bookmark:

http://www.infognition.com/VirtualDubFilters/

http://neuron2.net/

[jagabo]

Sample4 has a fixed noise pattern on it - i.e. one which doesn't move as the camera moves. This is either from the original camera or from DNR in the VCR.

Most likely in the camera, accentuated by the high gain (in camera). You might be able to clean it up some using a dark field calibration image from the same camera.

http://photo.net/learn/dark_noise/

You can adjust levels and gamma to bring out some dark detail but since the noise is nearly as strong as the signal level in some areas (like the guy's eyes) filtering it out will obliterate the picture.

Original, levels+gamma+saturation, levels+gamma+saturation+neat video 100%

[pirej]

Nice "levels+gamma+saturation" tweaks, what did you use to do it?

[jagabo]

I did all of that processing with VirtualDub. I used the Levels and HSV.

I think Levels was 35-255 --> 0-255, gamma 1.5. Then I boosted the saturation by about 30 percent with HSV.

[poisondeathray]

could you fine tune neat video a bit more ? that 3rd screenshot is a big detail killer

or was it the fixed pattern noise that's giving problems?

[jagabo]

could you fine tune neat video a bit more ?

Yes, of course.

that 3rd screenshot is a big detail killer

I turned the filter up all the way to show that removing all the noise also removes all the detail that's has the same scale as the noise.

or was it the fixed pattern noise that's giving problems?

Yes.

[budwzr]

It's like trying to "fix" a Jackson Pollock painting.

I have an idea though. Maybe fix the faces only, and then reshoot the play and mask/composite in the younger faces.

[pirej]

I have never seen this kind of noise like in sample4, it looks like it was recorded through a dirty window.!?!?
The "noise" doesn't move if the camera doesn't move..
edit: smdegrain, neatvideo, sharpening, levels. the (fixed)noise that remained... i guess its not removable if you want to keep the picture details.

[poisondeathray]

^ yes I am looking at it now. Horrible. Maybe lens was dirty ?

[jagabo]

That problem very common with in very low light situations. The individual sub-pixels have varying sensitivity to light. Some are always a little darker, some always a little brighter. When the in-camera gain is cranked way up to compensate for the low light input the differences become apparent. Say the variation is only +/- 1 percent under normal lighting conditions. That's only a little bit of noise in the final picture. But if the gain has to be cranked up 10x for a very dark shot the variation is 10 percent -- very obvious. And that particular camera as a few pixels stuck at full intensity.

[budwzr]

So in layman's terms "The lense was smudged up".

[nharikrishna]

That is the settings name in the MsuSmartSharpen filter for virtualdub.

Thanks. Got it...

[nharikrishna]

2Bdecided

However, if nharikrishna took the captured DV files, and then made clips in VirtualDub with "full processing" enabled, it would do a YV12>RGB>YV12 conversion, and clip the highlights exactly as seen above. The tiny bits above 235 are due to DV re-compression.

nharikrishna, when editing DV files for upload as samples, you need to use "Direct Stream Copy" in VirtualDub. Then we'll get the full range.

Ok. I guess Full processing was enabled in VDub. I need to check that tonight. Will try and post sample made at "Direct Stream Copy". Before saving the sample clips, I selected "cedocida" codec in VDub under Video --> Compressionso it produces DV Compliant file. Please tell me if I need to be selecting something else.

It's not just the luma level; those blown out flat areas of bright saturated colour in your screen caps (not in the clips you've provided) are indicative of luma+chroma values that give colours outside the allowed RGB range. Such things are common in VHS camcorder footage because video works in YUV colour space, not RGB, and they'd actually look fine on a normal TV - nice and bright, and not flat or clipped. If you manage to write them to DVD without clipping them, they'll still look like fine on a normal TV because DVD uses YUV too. They'll always clip on a PC though, unless you reduce the chroma saturation a bit on those parts. Tricky!

This is an excellent point. To test it out, I recorded the same video onto a MiniDV tape (via firewire) and played on a normal CRT-based TV, and the colours are not as bad as we see in the picture(s) above. That's not to say the colors are vibrant though.

When processing, you need to avoid converting to RGB at all, or at least avoid it before you've fixed the levels.

How do I do it?

[nharikrishna]

Those diagonal streaks (very noticeable in the "before" picture in Pirej's post above) are characteristic of electrical interference during capture. Unless they are recorded on the tape itself, you may be able to eliminate that problem by using better shielded video cable, moving your VCR away from sources of interference, or (which worked for me) switching off nearby equipment.

I will see if changing to better cables works. I didn't have any other equipment near the VCR except my Canopus 110, and the PC. The PC draws power from a UPS. The VCR is connected directly to the wall power, and not from a surge protector.

[nharikrishna]

I have never seen this kind of noise like in sample4, it looks like it was recorded through a dirty window.!?!?
The "noise" doesn't move if the camera doesn't move..
edit: smdegrain, neatvideo, sharpening, levels. the (fixed)noise that remained... i guess its not removable if you want to keep the picture details.

[Attachment 4524 - Click to enlarge]

There is fair bit of improvement visible in your screenshot. Thanks.

[2Bdecided]

Before saving the sample clips, I selected "cedocida" codec in VDub under Video --> Compressionso it produces DV Compliant file. Please tell me if I need to be selecting something else.

Cedocida is your best choice - but with "Direct Stream Copy" selected (on the "video" menu) it doesn't matter - it won't go through the codec anyway - it just copies the raw bytes from the source file to the destination file without doing anything to them.

Cheers,
David.

[lordsmurf]

I don't like the coring from the "levels+gamma+saturation" tweak by jagabo. It creates false dark pixels, a salt and pepper look. The NeatVideo is overdone, obviously.

An auto white balance filter may be worthwhile.

[jagabo]

I don't like the coring from the "levels+gamma+saturation" tweak by jagabo. It creates false dark pixels, a salt and pepper look.

I didn't like it either. There's not a lot that can be done when there's that much noise and so little signal. Remember, it's not random noise, it's variations inherent in the camera's CCD. Certain pixels are always lighter, some are always darker.

[lordsmurf]

CCD with VHS?
I must've missed something important earlier in the thread.

[sanlyn]

Thanks guys, I am trying most of the advises given, especially turning down Neat Video's values, turning down noise reduction in the VCR (my VCR has only ONE button for TBC/NR, so if I want to turn off NR, it will turn off the TBC as well), Gaussian Blur ...etc.

-If you're using NeatVideo, you don 't need Gaussian blur unless you have some serious problem videos.

- The additional DNR on your JVC creates artifacts and block noise. Use the TBC, but turn DNR off.

- You should use the Advanced view settings in NeatVideo. If you look at the "Noise Filter Settings" window, you'll see a right-hand panel of menu items that handle various noise reduction parameters. For a fairly clean VHS, you don't want to do a lot of high-frequency (fine-detail) filtering -- that's usually where the "plastic" look comes from.

In the menu for "Noise Reduction Amounts", try setting "High" to 60%, and "Mid" and "Low" to 75%. You'll also see below these a setting for "Y" (try 60%), and for "Cr" and "Cb" (try 80% on these two).

Below that are 4 check boxes ("Very low freq", "High quality", etc.) Load NeatVideo with a frame that has a lot of noise and fine detail as well as larger soft-edge objects such as heavy clothing or big blobby shadows. Check and uncheck these boxes then observe what happens in the preview window. With the right settings on "Mid" and "Low", you'll avoid block noise in large-area patches.

Below that are the sharpening settings. You should seldom have to go higher than 50%.

In the other big NeatVideo window ("Device Noise Profile"), look at the upper right-hand corner. The "Working color space" should be set for "YCrCb" for color (use NV's own YCbCr, even if your video is RGB).

If these settings still give you a bit too much fine-grain noise or "snow", then instead of making a big increase in high-frequency settings you might first want to try NeatVideo's "Temporal Filter" to "1 frame" at 20%. Keep in mind that this temporal filter setting actually samples 3 frames, not 1. At a setting of 2, NeatVideo's temp filter samples 5 frames. Unless you have a really serious temporal noise problem, you should never have to go higher than 2 or over 40% for this filter.

Everyone has their favorite setup with NeatVideo, and everyone tends to work on different video sources in different ways. NeatVideo has custom settings for a reason. Never use their defaults; they are starter settings, and they're too drastic as-is. Have a little patience with this product. Once you get the hang of it, you'll be surprised at what it can do.

[nharikrishna]

Thanks guys, I am trying most of the advises given, especially turning down Neat Video's values, turning down noise reduction in the VCR (my VCR has only ONE button for TBC/NR, so if I want to turn off NR, it will turn off the TBC as well), Gaussian Blur ...etc.

-If you're using NeatVideo, you don 't need Gaussian blur unless you have some serious problem videos.

- The additional DNR on your JVC creates artifacts and block noise. Use the TBC, but turn DNR off.

- You should use the Advanced view settings in NeatVideo. If you look at the "Noise Filter Settings" window, you'll see a right-hand panel of menu items that handle various noise reduction parameters. For a fairly clean VHS, you don't want to do a lot of high-frequency (fine-detail) filtering -- that's usually where the "plastic" look comes from.

In the menu for "Noise Reduction Amounts", try setting "High" to 60%, and "Mid" and "Low" to 75%. You'll also see below these a setting for "Y" (try 60%), and for "Cr" and "Cb" (try 80% on these two).

Below that are 4 check boxes ("Very low freq", "High quality", etc.) Load NeatVideo with a frame that has a lot of noise and fine detail as well as larger soft-edge objects such as heavy clothing or big blobby shadows. Check and uncheck these boxes then observe what happens in the preview window. With the right settings on "Mid" and "Low", you'll avoid block noise in large-area patches.

Below that are the sharpening settings. You should seldom have to go higher than 50%.

In the other big NeatVideo window ("Device Noise Profile"), look at the upper right-hand corner. The "Working color space" should be set for "YCrCb" for color (use NV's own YCbCr, even if your video is RGB).

If these settings still give you a bit too much fine-grain noise or "snow", then instead of making a big increase in high-frequency settings you might first want to try NeatVideo's "Temporal Filter" to "1 frame" at 20%. Keep in mind that this temporal filter setting actually samples 3 frames, not 1. At a setting of 2, NeatVideo's temp filter samples 5 frames. Unless you have a really serious temporal noise problem, you should never have to go higher than 2 or over 40% for this filter.

Everyone has their favorite setup with NeatVideo, and everyone tends to work on different video sources in different ways. NeatVideo has custom settings for a reason. Never use their defaults; they are starter settings, and they're too drastic as-is. Have a little patience with this product. Once you get the hang of it, you'll be surprised at what it can do.

Thanks a lot for the detailed explanation. Will try it out.

[sanlyn]

Thanks a lot for the detailed explanation. Will try it out.

Don't be afraid to experiment with those NeatVideo filters. It's much more difficult to try to "explain" each one than it is to just try them out and see for yourself. In particular, you can avoid many pitfalls my turning down the "Y" filter strengths and lowering sharpening on the "Y" (luma) channel -- I've turned down "Y" filters to 20%, 10% or even turned them off.

Often with very low settings the NV preview window will look as if very little is happening. Remember, the preview looks at only 1 frame. Try those settings by checking a few seconds running in VirtualDub; you'll see an entirely different set of results that way. If you still have some residual "fine dust" noise after running NeatVideo (it will likely be so fine-grained that you'll have to run the video to see it), try a later run with VirtualDub's temporal smoother set to very low values. Even a retail DVD isn't totally "clean", and we all know how much over-filtering destruction is done by typical cable boxes.