Vertical dark lines on captured video

[jsr184]

Hi,

This is my very first post here and I'm not very sure if I placed this post at the right place. I hope I did

I searched through google, other forums and this one too looking for an answer to my question. Basically I use GrabbeX grabber and every video I capture appears to have plenty of dark vertical lines which are more visible within darker areas.

Below I pasted magnified sample of what I get:



As I checked first line starts at 2px and they appear every 8px.

Now the question. Is there any filter ( for VirtualDub, AVIDemux ) or any way using any tool like mencoder or ffmpeg to get rid of those line without touching rest of frame's pixels?

If there's ready answer to my question then I'm sorry for double posting but really I have no idea how to name those "vertical line" so that it makes more difficult to find any solution.
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[jagabo]

How did you prepare that sample? Some media players have bad scalers which produce artifacts like that. I recommend you open one of your caps with VirtualDubMod, save an entire frame as PNG, and post that -- if it still has the problem.

Neat Video for VirtualDub should be able to remove that type of periodic noise.

http://www.neatvideo.com/

[jsr184]

The sample comes from single snapshot taken directly from grabber ( BMP file ), so in fact it's the source is totally RAW and uncompressed data. While capturing I never use any compression or filters. I tried to find any filter which could remove those lines but couldn't do it even with VDub. Thing is I don't want to use any kind of filtering which affects entire frame as it's not needed. Lines are very regular which means I need a filter which takes a line before, a line after and recalculates smoothness for middle vertical line. Sound simple but I didn't find yet good solution. Also I didn't find any trace of people who could have exactly same problem. I forgot to mention that capturing via S-Video and Composite gives same result. Also I tried to use several capturing clients from VDub, through slow VLC, iuLabs, Grabbee and even VideoGlade for Mac. All gave exactly same result which means this is the picture which comes out of my grabber.

Take a look at sample whole frame ( previous sample was a magnifed element of whole ):



Look at the sky, the vertical bars are very visible

[poisondeathray]

What is the original source? Does it have the lines?

What format are you capturing to? (are you capturing uncompressed RGB? or some other format?)

Have you tried viewing the captured video with a different decoder?

So is the problem with the original source, the capturing video process, or the screenshot taking process ?

[jsr184]

This seems to be a problem of original source. I capture videos as uncompressed YUYV2 and save it as AVI container. Screenshots are taken as uncompressed BMP so both screenshots and videos contain original source data. I've been using different decoders even for RAW. Conversion YUY2 to RGB24 didn't give any change. I forgot to mention that this is also visible on preview window. This seems to be coming out of my grabber directly.

[jagabo]

It does look like the problem is in your capture device. As I mentioned earlier, the only filter I know of that might be able to remove it is Neat Video. It's very slow. You can try the demo for free.



You'd be better off getting a new capture device!

[jsr184]

I'll try Net Video. I already ordered Pinnacle for Mac and I hope I'll get rid of this problem this way. Also I started thinking it might be my grabber as I didn't find anything like my problem anywhere on the Internet. Maybe changing grabber will really help.