Hi,

OpenEXR 1.6.1 and 1.7.0 do not differ in that respect. v1.6.1 could store 
channels of different types in the file. How applications treat them is quite 
another matter though ...

Piotr


________________________________
From: [email protected] 
[[email protected]] on behalf of Michael Garrett 
[[email protected]]
Sent: 08 May 2013 11:28
To: [email protected]
Subject: Re: [Nuke-users] Re: EXR file size Mantra vs Nuke re-render

I just had another look in exrheader and indeed, a bunch of these channels are 
32-bit, although the beauty is 16 bit and Nuke sees the file as 16 bit in the 
metadata.

Would this be because Houdini is using OpenEXR 1.7, which is backward 
compatible? As far as I knew, 1.6.1 was only able to store a single data type 
across all channels. I'm interested to know, but at least I'm aware of the 
issue now.

Thanks for bringing this to my attention by the way!



On 8 May 2013 11:22, Michael Garrett 
<[email protected]<mailto:[email protected]>> wrote:
Interesting...I had thought that the ability to have a 32 bit channel or layer 
in an otherwise 16 bit half float file was something you could only do with 
OpenEXR 1.7.

I know it's not best practice to have multichannel exr's right now, I'll look 
into the possibility of getting them broken out as well.

I will double check with the lighter as to what her output settings are, but 
both the metadata tag and exrheader are telling me it's zip1 scanline ((aka exr 
compression = 2).



On 8 May 2013 00:00, marty b 
<[email protected]<mailto:[email protected]>> 
wrote:
Good call John.

Mantra render with 16bit 'C' & 32bit extra planes = 2.5Mb
Mantra render with 16bit 'C' & 16bit extra planes = 1Mb

Re-render in Nuke at 16bit = 760KB

In Mantra just set the Quantize of the Extra Image Planes to 16bit float from 
32bit float.

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