Horizontal Pattern in VHS Capture

[wbo]

I am attempting to restore some of my old VHS tapes with Avisynth and encode using xvid with a high bitrate. Unfortunatly I am used to working with HDTV sources, so working with analog video is a bit new to me.

I have found that many of my tapes have the chroma shifted to the left, which I have been able to fix by using the ChromaShift filter.

However, many of my captures also have strange horizontal lines throughout the video that shift from frame to frame. So far every tape I have captured seams to have this same noise. I have had some success using Convolution3D to reduce the noise, but I am wondering if there may be a better way to reduce or eliminate it. Here is a frame from one of my captures:

http://164.106.37.42/WilliamsPlayZone/video/Christy1.png

The sample frame above has had the chroma shift corrected and has been slightly cropped to eliminate the VHS tracking noise at the bottom of the image. No other filters have been applied.

Any suggestions will be appreciated. Also if anyone has any other suggestions to improve the overall appearance of the video, feel free to offer them since I don't have much experience with analog video :)

If it will help, I can post a small segment of the original capture.

[Guest]

Possibly a frequency-domain filter in the vertical would help. You might try Fizick's Defreq.

[Osmiridium]

You could also try my wdeflicker idea ( see http://forum.doom9.org/showthread.php?t=106898 ). I've noticed my VHS captures have lines with noticably varying brightness, which is much reduced by wdeflicker. The lines look quite similar to those on your sample image.

If you do use it you'll probably want to lower the TemporalSoften values to something a bit lower ( say TemporalSoften(5,25,25,50) ) to minimise the risk of ghosting.

[Fizick]

Try Degrainmedian(norow=true, interlaced=true)

[wbo]

Try Degrainmedian(norow=true, interlaced=true)
Degrainmedian helps reduce the noise some, but it still leaves quite a bit behind.

Defreq sounds like a good idea, but by looking at the graph shown by isng DeFreq(show=1,info=true) I could not find a good place to put the window.

Here is a sample from the original capture with no processing applied: Sample - 160 MB (http://164.106.37.42/WilliamsPlayZone/Video/sample.avi)

[Osmiridium]

Just checked your clip - different sort of noise than I was thinking of, so my idea wasn't much of a help. That'll teach me to turn the brightness up on my moniter before I make any future suggestions. :D