Calibrating luminance levels/color for capture from VHS

[sanlyn]

It can work either way. Without the original unaltered video I couldn't say, but AviSynth should work just as well.

[Cherbette]

It can work either way. Without the original unaltered video I couldn't say, but AviSynth should work just as well.

I uploaded two unaltered clips from the Still Cher special...or did you mean the entire show?

[jagabo]

According to Cherbette's script and notes posted earlier, he cropped and used MCTD in AviSynth, then adjusted color etc. with the VDub Levels, HSV, and RGB filters.

That is exactly what I did

So you used:

AviSource("StillCher2.avi")
ConvertToYV12()
MCTemporalDenoise(settings="medium", edgeclean=true, ecrad=3, stabilize=true, maxr=2, interlaced=true)
Crop(22,40,-4,-24)
AddBorders(16, 32, 10, 32)

The followed up with the VirtualDub filters I listed in this post:

https://forum.videohelp.com/threads/338999-Calibrating-luminance-levels-color-for-captu...=1#post2109686

Is that right?

But I remembered jagabo had stated I would probably get better results working with AviSynth rather than RGB in VirtualDub...so I'd like to try that way too.

Well, it depends. Some things are better fixed in YUV and some in RGB. I find YUV to be much less intuitive than RGB for most things. And the fact that you can't just move a slider and see how it changes the picture makes it a lot harder to work in AviSynth.

[Cherbette]

Yezzir that is correct. So you'd actually recommend using RGB in VirtualDub or...? I kind of thought that the color adjustments I did in RGB with VirtualDub looked a little less natural to my eye when used over the entire special. I assumed that adjusting in AviSynth using ColorYUV might be more precise...

[jagabo]

Here's the rough equivalents of those VirtualDub filters in AviSynth:

https://forum.videohelp.com/attachment.php?attachmentid=8878&d=1317211466

ColorYUV(gain_y=40, off_y=-20)

https://forum.videohelp.com/attachment.php?attachmentid=8879&d=1317211480

ColorYUV(cont_u=-26, cont_v=-26)

I don't know how to do the equivalent of the RGB adjustment in YUV but here it is using RGBAdjust():
https://forum.videohelp.com/attachment.php?attachmentid=8880&d=1317211492

ConvertToRGB()
RGBAdjust(g=0.98, b=1.2)

So the full script is:

AviSource("StillCher2.avi")
AssumeTFF()
Crop(24,40,-4,-24)
ColorYUV(gain_y=40, off_y=-20)
ColorYUV(cont_u=-26, cont_v=-26)
McTemporalDenoise(settings="low", interlaced=true) #while still in YV12
AddBorders(16, 32, 12, 32)
ConvertToRGB(interlaced=true)
RGBAdjust(g=0.98, b=1.2)

The color portion of StillCher2.avi looks close to the VirtualDub version. I don't know if this is really the right correction to make to that segment though. The B/W portion is way off because of the RGBAdjust().

If you want to include a gamma change like I did in post #145 change

ColorYUV(gain_y=40, off_y=-20)

to

ColorYUV(gain_y=40, off_y=-28, gamma_y=60)

[sanlyn]

I uploaded two unaltered clips from the Still Cher special...

With VHS, every scene can be different (and probably will be) -- color, contrast, noise, everything. With documentaries, especially, production techs patch in anything, unfiltered, uncorrected, from any source. Even the Dr. John clip shows how scenes vary wildly (look at the first and last frames). Thought you did some good work on the noise and colors, but the levels seem off. With VHS and analog in general, you can't set up a single set of filter settings and apply them to every scene. There are 3 different scenes in the Dr. John clip; I think you can see that the same filters had different effects on each scene.

[Cherbette]

Here's the rough equivalents of those VirtualDub filters in AviSynth:

https://forum.videohelp.com/attachment.php?attachmentid=8878&d=1317211466

ColorYUV(gain_y=40, off_y=-20)

https://forum.videohelp.com/attachment.php?attachmentid=8879&d=1317211480

ColorYUV(cont_u=-26, cont_v=-26)

I don't know how to do the equivalent of the RGB adjustment in YUV but here it is using RGBAdjust():
https://forum.videohelp.com/attachment.php?attachmentid=8880&d=1317211492

ConvertToRGB()
RGBAdjust(g=0.98, b=1.2)

So the full script is:

AviSource("StillCher2.avi")
AssumeTFF()
Crop(24,40,-4,-24)
ColorYUV(gain_y=40, off_y=-20)
ColorYUV(cont_u=-26, cont_v=-26)
McTemporalDenoise(settings="low", interlaced=true) #while still in YV12
AddBorders(16, 32, 12, 32)
ConvertToRGB(interlaced=true)
RGBAdjust(g=0.98, b=1.2)

The color portion of StillCher2.avi looks close to the VirtualDub version. I don't know if this is really the right correction to make to that segment though. The B/W portion is way off because of the RGBAdjust().

If you want to include a gamma change like I did in post #145 change

ColorYUV(gain_y=40, off_y=-20)

to

ColorYUV(gain_y=40, off_y=-28, gamma_y=60)

Couldn't the black and white portion be corrected by splitting the b/w parts as sanlyn did and reducing them to greyscale?

[jagabo]

Couldn't the black and white portion be corrected by splitting the b/w parts as sanlyn did and reducing them to greyscale?

Yes.

Here's a script that applies approximately the same corrections to the color portion without screwing up the B/W portion:

AviSource("StillCher2.avi")
AssumeTFF()
Crop(24,40,-4,-24)
ColorYUV(gain_y=40, off_y=-20)
ColorYUV(cont_u=-90, cont_v=-40)
McTemporalDenoise(settings="low", interlaced=true)
AddBorders(16, 32, 12, 32)

You can combine both ColorYUV() lines to make it run a little faster.

This script doesn't look too bad with StillCher3.avi.

[sanlyn]

Easy to do either way, as long as the two shots are joined by a simple single-frame cut. It's when you have a dissolve between the two that the trouble starts. But AviSynth has ways around that, too.

[Cherbette]

So it would look something like this?

AviSource("StillCher2.avi")
AssumeTFF()
ConvertToYV12
Crop(24,40,-4,-24)
ColorYUV(gain_y=40, off_y=-20, cont_u=-90, cont_v=-40)
McTemporalDenoise(settings="medium", interlaced=true)
AddBorders(16, 32, 12, 32)

by the way I used medium for McTemporalDenoise....

My next question would be what other alterations would you fellas make to improve the clip or would you need to see more samples? Perhaps sharpening and whether or not I should de-interlace?

[jmac698]

Someone mentioned they were working to gather all the prerequisites of MCTD (MC Temporal Denoise script for Avisynth). I just wanted to mention that there's now an automated installer for this. It certainly helps! What a pain to track down all those files.
Click the link for installer.

It says it's beta, but there's reports on another forum that it does work!
Note that it installs some extra files as well but they are commonly used anyway. You can open up the exe in a zip program and see everything that's there. It also doesn't always read the correct installation directory but you can choose your own. It'll probably be corrected sometime (by the time you read this

http://avisynth.org/mediawiki/MCTemporalDenoise#Required_Filters

Good luck with your Cher project, I agree with all the suggestions so far - except I would add that it *is* possible to preview color adjustments with sliders if you use an Avisynth editor called AvsPmod - if you got to tools, insert user slider, you get a little panel to adjust the filters in realtime - pretty handy!

[Cherbette]

Thank you for that tip...I'm downloading AvsPmod now to play around with it...

[Cherbette]

Here is a clip using the script I posted above except this time I used "low" with McTemporalDenoise:
http://www.mediafire.com/?wt90x90vht4l1m6

[sanlyn]

My next question would be what other alterations would you fellas make to improve the clip or would you need to see more samples? Perhaps sharpening and whether or not I should de-interlace?

These videos don't seem to need sharpening.

Don't deinterlace.

[jmac698]

Just a quick note,
I thought I'd test what I said about avspmod, only to my surprise it has a new feature I wasn't aware of - all sliders are now automatic!
I put in this small script:
ColorBars(width=640, height=480, pixel_type="YV12")
tweak(hue=0,sat=1,bright=0,cont=1)

and if you click the arrows to the bottom right, it shows the control panel I mentioned (if it's not already there). There was a + sign next to Tweak, and all my adjustments were there - brightness, hue, saturation, contrast - and I could adjust them realtime.
There's still an Edit->Insert User Slider, and it inserts text like this:
ColorBars(width=640, height=480, pixel_type="YV12")
tweak(bright=[<"Brightness", -255, 255, 0>])
And this overrides the default tweak sliders, and now they are labelled. So I guess it still has a use to help you fiind only the relevant sliders you want to use instead of seeing all of them.

[sanlyn]

Wait a minute. Learning AviSYnth is tough enough, you have this unintuitive thingie that takes up more of your time? Hm. That's a convenience? I go to look for version 2.2, I see they have a bugfix patch already (why not just release version 2.3?), you have to read 2 tonbs of documentation for this big zipfile patch, etc., etc. Every time someone mentions avspmod, I look into it, waste 2 hours, and end up going back to what I did before. Later. But thanks for the tip. I'll keep looking at this thing.

[jmac698]

I'm not a particular supporter of this tool. I just paste scripts into it and press F5. I can preview the video and make changes to the script. Honestly, that's all I've ever used of the program. I didn't even read any manual. It just works for me. Please use what you are comfortable with, however for me, being able to edit the script on the same screen as the video is a big plus over, say virtualdub.
I'm not aware of any bugfix patch and I don't use/need it. The link the program is automatically filled in by the forum: https://www.videohelp.com/tools/AvsP

[Cherbette]

I'm sure there is still plenty of things I can do to tweak the Still Cher special but in the meantime I've come across another clip of much lesser quality much like post #51 in this thread. It is a multi-generation short spa ad and aside from all the tweaking that needs to be done to the color, luma, and noise reduction, it starts and stops rather abruptly so I'd like to add some sort of fadein/fadeout too:
http://www.mediafire.com/?lq06kj4sk6zvich

[sanlyn]

AviSynth has a Fade command: http://avisynth.org/mediawiki/Fade . Eventually you'll have to refer to AviSynth on a regular basis. In Windows, look in your AviSynth program folder (the AviSYnth folder that contains "plugins" and other folders). Look for AviSYnth main folder \ Docs \ English \ index.htm , and double-click that index file to open AviSynth docs.

At this point I think the thread has left the capture phase and moved into Restoration. Your previous post StillCher4 has tape damage, not a subject we can do much about in the capture phase.

[sanlyn]

I'm not a particular supporter of this tool. I just paste scripts into it and press F5. I can preview the video and make changes to the script. Honestly, that's all I've ever used of the program. I didn't even read any manual. It just works for me. Please use what you are comfortable with, however for me, being able to edit the script on the same screen as the video is a big plus over, say virtualdub.
I'm not aware of any bugfix patch and I don't use/need it. The link the program is automatically filled in by the forum: https://www.videohelp.com/tools/AvsP

Your suggestion was perfectly OK, kmac698, I shouldn't have posted my silly rant (which I've deleted). Meant no reflection on you or your post, it was just my personal gripe about the general state of what some call "AviSynth chaos". Avspmod is obviously a decent app, as many people use it.

[Cherbette]

Your previous post StillCher4 has tape damage, not a subject we can do much about in the capture phase.

Should I start a new thread in the Restoration category?

[themaster1]

I like this game
I propose this (video with Cher):
http://imageshack.us/f/851/cherj.jpg/

video here (x264):
http://goo.gl/H18wk

[Cherbette]

It says unavailable but I'll check it out. The contrast is definitely better than I started out with but the hue still looks a bit too yellow in that comparison grab. May I ask what you did to this clip?

[jagabo]

Really, Cherbette. After 170+ posts in this thread you should have gained enough knowledge to start thinking for yourself.

[Cherbette]

Really, Cherbette. After 170+ posts in this thread you should have gained enough knowledge to start thinking for yourself.

This is all completely brand-new to me still and Avisynth and its scripts are still very foreign to me (I'm trying). I'm hoping to gain enough knowledge here for various types of video problems to go out on my own but if I've worn out my welcome then I'll understand...

[jmac698]

Apology accepted, Sanlyn! By Avisynth chaos, I guess you mean that it's a steep learning curve for beginners, or that some aspects are not well-documented?

Cherbette, hmm, I'm starting to notice you're a fan of Cher I had an idea to fix that graphic part by freeze-framing a good frame to cover the whole part, in other words writing over the tape glitch. But I agree we should take this to restoration out of respect for the board's policies - threads are organized for the benefit of others searching in the future.

[Cherbette]

I agree...I'll make a new thread in the proper forum and point back to this thread...

[jagabo]

Really, Cherbette. After 170+ posts in this thread you should have gained enough knowledge to start thinking for yourself.

This is all completely brand-new to me still and Avisynth and its scripts are still very foreign to me (I'm trying). I'm hoping to gain enough knowledge here for various types of video problems to go out on my own but if I've worn out my welcome then I'll understand...

Seeing yet another script or VirtualDub filter chain for yet another video with the same basic problems isn't going to help you. You need to start using the tools that have been given to you and experimenting with your own adjustments. You'll never get a feel for how they work otherwise.

Some basic color science:

R = red
G = green
B = blue

red + green = yellow
red + blue = magenta
green + blue = cyan
red + green + blue = white

For example, if your video is too yellow add blue. Or subtract red and green. Or a little of both.

Y = luma (gray scale)
U = blue - Y
V = red - Y

AviSynth ColorYUV arguments:
gain_x: multiply x by the indicated value
off_x: add the indicated value to x
cont_x: (x - 128) * value + 128 (x<128 gets smaller, x>128 gets bigger)
gamma_x: gamma curve adjustment to x (http://en.wikipedia.org/wiki/Gamma_correction)

A gray scale image has U and V set to 128 (or is it 127, I forget)

[Cherbette]

That is true...what I can start doing instead is posting my idea of what the script should be along with video or photo examples and whomever cam chime-in on alterations...

Btw the information you posted there although very basic is gonna be useful for me. It was something I hadn't understood thus far. The last part with YUV is still a bit confusing. Can you maybe post a couple examples of what the script might look like if the clip is too yellow or too green?

[jagabo]

The last part with YUV is still a bit confusing.

Yeah, for me too. I just experiment with different values until I get what I want!

Can you maybe post a couple examples of what the script might look like if the clip is too yellow or too green?

I'll see if I can work something out...