PDA

View Full Version : Capture of video with slight horizontal vibration in the frames


Fer
24th January 2002, 19:14
Hello,
Iīm capturing video PAL from a VCR. When you see the video, although the image quality is high, it can be appreciated in the lateral edges a slight vibration of the frames. When I make the capture (384x288, no interlaced, virtualdub, avi_io or ATI video in) this oscillation in the image shows of the following way: two any consecutive frames are horizontally displaced one or two pixels and the vidio looks horrible since all the static objects vibrate and my eyes produce me sickness.

The problem appear for this particular video. Other PAL video donīt produce such problem. No adjustment in the VCR solves the problem. It seems to me that the only solution is to get another copy of the video. Nevertheless, have had somebody this problem? Any suggestion or alternative solutions? Any filter exists that allows displace horizontally alternative frames one or two pixels relative each other?

Thank you for everything and pardon for my bad english.

Krajensky
25th January 2002, 00:55
There's a shareware filter called Digital Stabilizer (shareware) that says "Digital stabilizer can smooth out shakes and vibrations from your footages elegantly."

The site is http://www.dv99.com/

Hope it helps!

Krajensky

Cart
28th January 2002, 06:51
I don't think the stabilizer is meant for that kind of problem, but that is a good idea for a video filter. I usually get some minor horizontal movement when capturing from VHS.

One thing that might help is capturing in a higher resolution and then shrinking the video. Some noise reductions filters might also help. You could even get a hardware TBC if you were really serious.

-Cart
http://www.geocities.com/lukesvideo/index.html

Fer
29th January 2002, 11:16
Cart, I agre with you that the stabilizer is not the solution. This filter has a cutoff frequency of 10 Hz and the horizontal vibration I have has a 25 Hz frequency (PAL 25 fps). Nevertheless thanks a lot to Krajensky since I have discover a very impressive filter as can be seen in the web. Higher resolution, resizing and noise reduction filters do not solve the problem. I think that the VHS tape is seriously damaged, in fat when I take it from the library was passed through the magnet that is used to the sequrity control for the input-output of the books !!! :scared: :mad: :mad: I donīt had time to avoid it. How many times will have made that? Now I have other copy from a library that donīt have magnets! And finally which is a hardware TBC. Thanks a lot.

Krajensky
29th January 2002, 16:56
If it's indeed 25hz, every other frame flickering...have you thought of using Avisynth to separate every other frame, offset it by a pixel, then interleave them back together?

Krajensky

Fer
29th January 2002, 22:31
Interesting suggestion Krajensky. Let me know the way I can make it since I have only used Avisynth to deinterlace DV video with bob and separatefields. With the Avisynth filters

DirectShowSource("c:\vibratingclip.avi")
SelectEven(clip1)

and

DirectShowSource("c:\vibratingclip.avi")
SelectOdd(clip2)

I can separate every other frame in clip1 and clip2 with this avs files in virtualdub.

But how can aply Interleave(clip1,clip2) to merge then (how I must write the avs file) and mainly how I can offset 1 pixel clip1 or clip2 ?

Thanks a lot

Krajensky
29th January 2002, 23:03
Here's a bit from the documentation...

# Shift a 352x240 image 2 pixels to the right
Crop(0,0,350,240).AddBorders(2,0,0,0)

Adapy this to whatever you want...just make sure the third parameter in Crop is the original width minus the first parameter from AddBorders.


So, to fix a 1-pixel jutter to the right on the odd frames (at 352x240)...

AviSource("file.avi")
One=SelectEven
Two=SelectOdd.Crop(0,0,351,240).AddBorders(1,0,0,0)
Interleave(One,Two)

Does that help?