filter (virtual dub) to stabilize old VHS recording?

[Guest]

Archived from groups: rec.video.desktop (More info?)

Hello

I have captured an old video from VHS tape.
It appears that a few frames of the video sometimes starts to 'jump'
for 0.5 - 1 second. I hope you understand what I mean, a picture suddenly
is placed ~100 pixels above, the rest of the picture on the top
is placed at the bottom... after 10-30 frames everything is ok again. (it's a
defect on the VHS tape, not from capturing)

Is there any filter (for virtual dub maybe) which can stabilize these frames again?
I believe this isn't a really hard to program filter (it only has to find out how many pixels
the frame jumped and copy it to the bottom again) - but I haven't found anything like
that.

Any help would be appreciated.

Thanks
Bodo

 

[Guest]

Archived from groups: rec.video.desktop (More info?)

"Bodo Malo" <bodomalo@sms.at> wrote in message
news:36p1h6F52t7a3U1@individual.net...
> Hello
>
> I have captured an old video from VHS tape.
> It appears that a few frames of the video sometimes starts to 'jump'
> for 0.5 - 1 second. I hope you understand what I mean, a picture
> suddenly
> is placed ~100 pixels above, the rest of the picture on the top
> is placed at the bottom... after 10-30 frames everything is ok again.
> (it's a
> defect on the VHS tape, not from capturing)
>
> Is there any filter (for virtual dub maybe) which can stabilize these
> frames again?
> I believe this isn't a really hard to program filter (it only has to
> find out how many pixels
> the frame jumped and copy it to the bottom again) - but I haven't
> found anything like
> that.

You may need to use something in the analog domain before
the video is captured. Typically we use a TimeBase Corrector
(TBC) or a capture device with TBC functionality.

We are about to replace an old RT2500 board (for which they
have lost the discs/drivers) with a $15 firewire board and a
Canopus ADVC-300 which is reputed to include TBC functionality
just for cleaning up old VHS, etc.

 

[Shez]

Archived from groups: rec.video.desktop (More info?)

In the faraway land of rec.video.desktop, Richard Crowley
<rcrowley7@xprt.net> said:
>> Is there any filter (for virtual dub maybe) which can stabilize these
>>frames again?
>> I believe this isn't a really hard to program filter (it only has to
>>find out how many pixels
>> the frame jumped and copy it to the bottom again) - but I haven't
>>found anything like
>> that.
>
>You may need to use something in the analog domain before
>the video is captured. Typically we use a TimeBase Corrector
>(TBC) or a capture device with TBC functionality.

Failing that, there is certainly a VirtualDub filter which can fix this,
it's called Frame Tweaker (tweaker.vdf). You have to manually compile a
list of frames that need adjusting, and say how many pixels to shift the
affected ones. Any blank area resulting from the shifting can optionally
be filled with a chunk of the previous frame. You can also tell it to
copy a frame and paste it as a whole over a later damaged frame, useful
for removing bright flashes for instance.

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