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List:       mjpeg-users
Subject:    Re: [Mjpeg-users] Chroma spatial shift?
From:       Dan Scholnik <dan.scholnik () nrl ! navy ! mil>
Date:       2009-06-28 17:59:00
Message-ID: 1246211940.12745.23.camel () hal9000
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y4mshift (use -h for documentation).  You don't need to upsample to 444,
but it will give you finer control over the chroma shifts.  Since the
luma alone can be moved by individual pixels (using -y and -Y) you still
have fine control over the differential shift with subsampled formats. 

Dan

On Sat, 2009-06-27 at 09:30 +0200, Marko Cebokli wrote:
> Hello,
> 
> when transferring stuff from VHS to computer (using a camcorder for 
> analog->DV), I get the colors shifted a bit to the right of the luma. I guess 
> this is caused by the delay in the analog circuits in the VCR.
> 
> On live action stuff it is not that bad, but on cartoons, with their sharp 
> outlines, the chroma lag is quite visible.
> 
> It is not just subsampling (my DV is PAL 420), that would just smear the 
> chroma on both (actually all four) sides the same - it is a definitive shift 
> to the right. And it seems to be bigger than one luma pixel, so it is not 
> just the "interstitial/cosited" stuff, which could only account for half a 
> pixel...
> 
> Is there any tool that I could use to shift the chroma a pixel or two relative 
> to the luma? I guess the first step would be upsampling to 444, but then?
> 
> Marko Cebokli
> 
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