VHS Purple Vertical Lines

[danchan]

Hi!

I'm trying to digitize a couple of home recordings using my old JVC HR-S6722 Video Recoder and S-VHS cable and the picture has horizontal lines across entire video. Could you tell if it's an issue with the tape itself of could it be connected to hardware related problem?


[Attachment 55763 - Click to enlarge]


[Attachment 55764 - Click to enlarge]


[Attachment 55765 - Click to enlarge]

RAW Video Sample: https://www76.zippyshare.com/v/4AoW3pi9/file.html

[jagabo]

Those are Hanover bars. You can blur them away. Some capture devices do that while capturing, others don't.

[KarMa]

On a side note, those deep artifacts, like the one above the number 1988 are usually from actual linear damage to the tape. Often times from crap getting on the guide posts and scratching a length of tape. Nothing can really be done about that.

[flashandpan007]

"VHS Purple Vertical Lines"

... but that is horizontal, not vertical

[jagabo]

A close look reveals those might not be Hanover bars. There's something in the luma channel as well. That might be an issue with the way you made sample images though. A raw video sample would be more helpful.

[danchan]

jagabo: Thanks for the reply. The footage indeed looks better after running the ChromaDestripe function. I've edited the post with the exported RAW sample.

KarMa: It's definitely that. The tape has been played by almost everyone in the family and there's no chance that it was even stored properly.

flashandpan007: All I was thinking about were the horizontal lines... I don't know why gave the title about "the vertical ones"

[jagabo]

Here's what I got from the source you provided (with AviSynth):


[Attachment 55771 - Click to enlarge]

I blurred away the Hanover bars and some residual horizontal lines in the luma, then made a quick levels and white balance adjustment (not perfect).

But there are some issues you should check. The sample provided was RGB. Video capture should be YUV 4:2:2 or 4:2:0 (the latter only for PAL). After blurring away the Hanover bars there are some horizontal lines (aside from the normal interlace combing) left in the luma. They do seem to be related to the Hanover bars so it may have something to do with the conversion to RGB.

Does the video look all bluish like the cap when you watch the tape on TV?

[danchan]

That just looks a whole lot better.

Oh, I forgot about changing the output mode to direct copy in VirtualDub. The source is indeed Lagarith compressed 4:2:2 YUV Video.

The footage is an amateur one so that's why probably the colors look like that. Below I attached two fragments of the original footage (with the proper "direct copy" setting). The color in the second one is better although both samples are from the same VHS tape.

https://www38.zippyshare.com/v/iZj9n2A2/file.html
https://www38.zippyshare.com/v/1cgPVCtm/file.html

[jagabo]

Here's the same frame from yuv 4:2:2 video with only ConvertToYV12(interlaced=true) in AviSynth to blur the Hanover bars away:


[Attachment 55780 - Click to enlarge]

Most of the horizontal lines that are left are in the luma channel. Some of it is because the brightness of the two fields differs a bit. Note that the YV12 conversion is similar to what a TV would do to eliminate the Hanover bars.

[danchan]

So the best way to get rid of those is to use another video capture/grabber device?

[johnmeyer]

So the best way to get rid of those is to use another video capture/grabber device?

If you do not see any hint of the artifact when you play the tape and watch it on the TV, and it only shows up in the capture, then yes, that is what you have to do.

[danchan]

Thank you for clarifying these matters! I will try to capture this VHS once again using another capture device.