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Old 13th February 2005, 04:29   #1  |  Link
Paazabel
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A quick resizing question ...

I am cropping 6 lines of VHS butchered crud from the bottom of a frame. To maintain aspect ratio:

crop(4,0,712,474)

I want to resize this to 720x480 again. What's the best way to do this without losing a lot of detail? I have tried various methods, but they all seem to soften the image (even Lanczos, though it is supposed to "sharpen"). Given that I don't have such a great source to work from in the first place (it is VHS, after all), that seems a high price to pay for 8 pixels on the sides and 6 on the bottom ...

Any suggestions?
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Old 13th February 2005, 05:49   #2  |  Link
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Give us a screen grab of a typical *source* frame, so we can experiment with it. But I can tell you, small resizes like that are notoriously difficult.
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Old 13th February 2005, 06:19   #3  |  Link
Paazabel
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*ponders* Hmmmm ... I don't think this person would take well to having their picture about on the Net ...

I've run into this before, but always with higher quality source. In those cases, the minor quality loss has never been an issue. However, this is really grainy stuff, and I've run a variety of filters on it ranging from dust to degrain. I get the best results from degrain (it works wonders on VHS noise), but I lose some of the minute details. The subject is a bit sweaty, and when he thinks, there are lines on his forehead from raising his eyebrows. These subtle details are lost when I do very much of anything to the video. I've had to crank degrain back to very low levels to preserve them.

I ran across another thread where scharfis_brain suggested to capture multiple times and average them together. This sounds like it might be an interesting method, though not sure how to go about it, yet.

I'll see if I can find a similar clip that I can post for demonstration purposes.
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Old 13th February 2005, 06:40   #4  |  Link
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First you talked about resizing. Now it's all about degraining. You gotta keep your focus!
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Old 13th February 2005, 06:53   #5  |  Link
Paazabel
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You think I have A.D.D. or something? I can keep my foc--oooo! Shiny!

It's about resize. I am fairly content with my "graininess" problem, but I seem to be losing more detail than I want to give up for a 712x474 to 720x480 resize ...

That, and I've been staring at this one video clip (and Doom9) for almost 2 days non-stop. I think your first response of these being "notoriously tricky" may have me simply encode the 6 junk lines at the bottom ... not like they will see it on the DVD.
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Old 13th February 2005, 06:57   #6  |  Link
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There's a filter called BorderControl. It will replace the crap with good lines from just above.
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