[Tig] DPX 10bit or 12bit for Film OUT

Bob Friesenhahn bfriesen at simple.dallas.tx.us
Thu Dec 23 15:01:20 GMT 2010

On Thu, 23 Dec 2010, Jack James wrote:
> Very rare to use 12-bit dpx. In fact I would imagine some film
> recorders can't read 12-bit files. This is the case for 35mm sourced
> material, so it will apply to RED footage just as much. I very much
> doubt that RED footage can even fill out a 12-bit space, but perhaps
> that's for another topic

While being simple (essentially 16-bit DPX with lower 4 bits 
implicitly ignored), 12 bit DPX is indeed quite rare.  Perhaps the 
only support for it was promoted by support for it in GraphicsMagick. 

There is indeed value to 12 bit DPX since HD-SDI is capable of 
transferring 12-bits and DPX is a good container for it.  At least one 
very-high end HD camera (Genesis camera from Panavision) has developed 
support for 12-bit HD-SDI captured into 12 bit DPX, using 
GraphicsMagick's 12-bit DPX as the reference for the format.  At least 
that is what I am lead to believe based on discussions with John Galt.

Regardless, if you are planning to use more than the standard 10-bit 
DPX, you might as well go all the way to 16-bit for processing since 
it takes the same disk space as 12-bit.  Since the file formats are 
virtually the same, it is trivial to "unmask" 12-bits into 16-bit (or 
scale), providing the "missing" bits necessary to promote to 16-bits.

Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/

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