VHS->DivX color fixing; fix it per channel?

[rKane]

I've recently started working on moving Twin Peaks off of VHS and onto my computer. Comparing the first-season episodes to my DVD rips, the VHS tapes have some very messed up colors.

I've been playing around a lot with Tweak and AdjustRGB, and using various combinations thereof, but I've only had limited success.

I tried splitting them into three components (via RGBAdjust then GreyScale), and the blue definitely seems to be lacking (it's greyscale version was very dark), while green and red seem about equal. I was considering comparing these greyscales to similar ones from the DVD rips and adjusting them to match, then recombining the VHS components into a final video; is this possible or reasonable?

(I didn't really see any easy way to make the greyscale images back into their original component colors, for one thing)

Any suggestions on how to fix the colors would be greatly appreciated.

Thanks.

-rK

[rKane]

*hopeful bump*

[Guest]

All you've told us is the colors are "very messed up". How can we tell you how to fix them?

Please do not bump threads. All posts must have content. Add new information if you want to recall attentiuon to a thread.

[morsa]

Neuron:
He says his video seems to be having low levels of blue.

[Guest]

The blue channel can be boosted with RGBAdjust().

To get proper help, he needs to be precise in his problem description. A frame grab would be ideal.

[sh0dan]

Use the internal ColorYUV (http://www.avisynth.org/index.php?page=ColorYUV) filter - it enables you to very detailed adjustment of colors in YUV colorspace.

If the colors are _very_ bad, try coloryuv(autowhite=true).

Try putting up a short clip.

[rKane]

I was curious whether splitting into separate R,G, and B channels and then recombining them after adjustment was a reasonable/possible way to approach the problem.

Unfortunately my server computer is going to be down for a while due to a failed HD, but I'll try to get example pics up as soon as possible.

[sh0dan]

You can do the same adjustments to YUV as you can do with RGB, the math is just a little different:

Increase V = More Red picture. (using off_v in coloryuv)
Increase U = More Blue picture. (off_u)
Decrease both U & V = More green picture (off_u, off_v)

[rKane]

ColorYUV seems the obvious solution now that I think about it, but I think I was just apprehensive about installing the 2.5 beta.

ColorYUV kicks a lot of ***. I tried using autowhite=true, but some scenes ended up fluctuating in color a lot, so I used the autowhited version along with analyze=true to adjust contrasts and offsets so that my videos match up pretty well with the DVDs now.

On a side note, I was trying to use a clip of my DVD rips (encoded in Divx5.02 pro) and when I opened the DVD rips in AviSynth they came out soaked in blue, despite not applying any other filters; I tried some ConvertToYUV and ConvertToRGB things, but nothing worked until I just did a fast repack into Huffy. I don't recall ever trying such a thing under Avisynth2.07, so I can't say if this is just in 2.5. Any idea why it would do this?

Thanks much for reminding me to use ColorYUV, it did a great job : )

[sh0dan]

For DivX 5.0.2, use SwapUV(). This bug is fixed in 5.0.3.

ColorYUV takes some getting used to, but it is a really great tool.