I've split this image into it's Y-U-V channels,

There appears to be no noise in the chroma channels only the Luma  
channel.

This could be due to:

* the chroma channels being half resolution, not enough resolution to  
represent the noise pattern. (below the nyquist value)
* the interference frequency is not high enough to cause colour shifts.

Or due to JPEG compression.

* notice that the noise falls cleanly within Macroblock boundaries.
* the noise may be falling below the quantizable threshold in those  
areas.  Thus not being encoded into the Macroblock.

If you get to capture the image again, maybe do it at a very high  
bitrate, so we don't see compression artifacts.

I have seen this type of noise before, even recorded onto a digibeta  
provided by Universal, but never looked into methods of removing it.

Have you tried a bit of trial and error, to see if the noise goes away?

* Turn off all electrical appliances.

* Try the capture source closer to the computer.

Mark

--
Check out my latest YUV tools at http://silicontrip.net/~mark/lavtools/

On 08/03/2008, at 8:34 AM, Andrea Giuliano wrote:

> Okay, you and Burkhard suspect radio interference. But you have not  
> seen
> the full pictures I sent to Bernhard Praschinger. In those picture you
> could see that the pattern is not spread all over the frame: the  
> trunks
> of the trees, and the rocks too, are only affected very little, if  
> even
> not at all. Could an interference affect some colors and not other?  
> I'm
> not expert of interference, nor of colors, indeed?
>
> So here is a link to one of those frames:
>
> http://www.webalice.it/sarkiaponius/00000669.jpg
>
> It's just 54K big. If you zoom around the trunks or the rocks you will
> surely understand what I'm trying to say (sorry, my native language is
> neapolitan, not english...)


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