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-   -   Remove Banding in sky (https://www.dvinfo.net/forum/cineform-software-showcase/493296-remove-banding-sky.html)

Mike Harrington March 18th, 2011 11:01 PM

Remove Banding in sky
 
i need a bit of help removing some banding in a bright blue sky

I shot some fighter jets on RED, and converted to Cineform and my final output is PhotoJpeg Quicktime (not my choice)

I am thinking the 12 bit to 8 bit drop is leading to the banding...
any clues as to get rid of this crap
I know one way is to implement some type of dithering(not sure how)
Ideally there would be a better way to compress the data to 8 bit....perhaps

thanks

David Newman March 18th, 2011 11:24 PM

Re: Remove Banding in sky
 
Yes, PhotoJPEG not the best choice, but it will do if you let the bit-rate climb. Place the CineForm master into an AE composite, set the comp to 16-bit mode. Add a 16-bit noise filter with 0.4% noise (1-LSB of 8-bit worth of noise) then encode to PhotoJPEG at a high quality setting. If you still see banding, bump the noise. This is the dithering you need.

Mike Harrington March 19th, 2011 02:22 PM

Re: Remove Banding in sky
 
thank you David....
can you explain the logic behind the .4%
specifically decoding what you mean by 1-LSB

Thanks again

David Newman March 19th, 2011 04:28 PM

Re: Remove Banding in sky
 
8-bit is 256 levels. 1-bit or the LSB (Less Significant Bit) 1/256th of the full range. 1/256 = 0.0039 or approximately 0.4% of full range.

Mike Harrington March 19th, 2011 05:31 PM

Re: Remove Banding in sky
 
thanks...appreciated as always..
might delve more into this using google later..


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