VirtualDub Filter for problem with "Horizontal Sync Issues"?

[lonerzzz]

Hello,

I am new to video processing, but not to image processing. I have a problem with an old family video recorded from camcorder to VHS 20 years ago. The major problem with the video is that it suffers from what I am going to call a "horizontal sync issue" in that some horizontal lines don't start at the correct point and are shifted to the right by up to 20 pixels as highlighted in the attached image. They are dynamic in nature and appear at various points throughout the image while some stay in roughly the same place for some time.

I don't know the technical term for the issue and have had no luck in finding a plugin that can fix this. I tried Flaxen VHS and VHS sync restore, but they didn't fix the issue and didn't appear suited to the task.

Any direction would be much appreciated.

Thanks,

Jason

[jagabo]

That can only be fixed with a time base corrector before capturing.

[lonerzzz]

That's unfortunate. The problem was in the original camcorder signal and was duplicated onto the 20 year old VHS that is my source.

Are they any suggestions on what would be the best alternate to a time base corrector to resolve this sort of issue?

I know through my image processing background that I could largely fix this if I had a means to convert to and from single images, but I have not found any tool that encodes an image sequence into AVI or MPEG.

[guns1inger]

Virtualdub can export and import imgae sequences, and output AVI files or frameserve to an mpeg-2 encoder.

The lastest Photoshop can import and export AVI files, and allows you to clone from frame to frame and use other photoshop tricks on video footage.

I seem to remember a vdub filter for shifting individual scan lines, but I don't hink it was all that friendly. If I can find it I will post back here.

[lonerzzz]

Thanks a bunch for the alternatives. I'll give them a try.

Jason

[2Bdecided]

That's unfortunate. The problem was in the original camcorder signal and was duplicated onto the 20 year old VHS that is my source.

That won't necessarily stop a TBC from working here. A TBC needs the original sync pulses to re-align the lines. The original dub probably copied over the original sync pulses intact, so the TBC can still work its magic.

Once you digitise the result, the original sync pulses are gone, and it's too late to do the job properly. I've heard people talk about automated solutions in VirtualDub and AVIsynth, but they don't really work - the algorithms are too dependent on picture content.

Cheers,
David.

[lordsmurf]

And not just any TBC, one built into a device that is made to correct this kind of error. For this exact issue, I'd try the Panasonic AG-1970, or the Panasonic ES10 passthrough method.

It may be worth paying somebody to correctly capture and restore this tape for you. Much cheaper than buying loads of gear.