[Tig] Why isn't HDR(-like) rendering more widespread?

Dan C. Tatut dtatut
Thu Mar 30 01:00:44 BST 2006

Thanks to oktobor for supporting the TIG
True about DPX (sad but true) and true about OpenEXR..

Things will change as soon as there will be devices to capture and record HDR images... but this will come for sure.

What is more important for now is that people in the industry focus on updating their infrastructure in terms of storage. The future is hungry for storage and too few can go above a couple of terabytes. 

Dan Tatut
CHROME Imaging
105 Rue de Lyon
CH-1203 Geneva

Phone: +41 22 807 23 60
Fax: +41 22 807 23 70
Mobile: +41 78 659 11 04
WWW: http://www.chrome-imaging.com

-----Original Message-----
From: Bob Friesenhahn [mailto:bfriesen at simple.dallas.tx.us]
Sent: jeudi, 30. mars 2006 01:58
To: Dan C. Tatut
Cc: glenn chan; tig at tig.colorist.org
Subject: RE: [Tig] Why isn't HDR(-like) rendering more widespread?

On Thu, 30 Mar 2006, Dan C. Tatut wrote:

> Obviously our system supports 32-bit float not only during 
> processing but also in storage. When people ask us why we do not use 
> DPX to store intermediates frames, well, the answer is simple: not 
> 32-bit float definition in DPX/Cineon (which by the way is a shame).

There is clearly a 32-bit float definition in DPX, and has been since 
1994.  It is based on 32-bit float and 64-bit doubles.  There are some 
(including myself) who would like to add 16-bit 'half'.  What is 
needed in DPX (besides actually using the defined floating format) is 
a bit more definition of how floating point values are to be treated. 
It makes sense to use a similar definition as is used in OpenEXR.

> Our frame management is open and gives DPX and Cineon access but 
> also does more. For the exact purpose discussed here. DPX in its 
> current state of definition is not the future. Either a 32-bit float 
> extension is added to it soon, or it will slowly bur surely be 
> replaced by OpenEXR or something equivalent.

The floating point storage is there in DPX but it seems that there is 
fear of actually using it.

While I think that OpenEXR is really neat, it is not designed to be an 
standard DI interchange format like DPX is.  DI interchange formats 
need to be straightforward, specifiable, and ready to use.  OpenEXR is 
too powerful of a tool for DI interchange.  Since DPX has such a bad 
rap, there are folks working on a new format rather than trying to 
fix DPX.

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

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