Re: [Openexr-devel] PIZ-Compression / Multithreading

[Florian Kainz]

Brendan Bolles wrote:
> Hey David, I think you'll find that to optimize for Nuke, you'll also 
> want to switch to Zip compression.  The main reason is that Nuke's 
> scanline renderer can go through and read just the lines it needs.  Piz 
> and Zip16 lump 16 lines together (right?), so Nuke has to read the whole 
> chunk.

I don't know how Nuke works, but if it reads scan lines top-to-bottom or
bottom-to-top (as opposed to accessing the scan lines in random order),
then reading chunks of 16 lines might actually be faster than reading
individual lines.  Also, with 16-line chunks you tend to get slightly
better compression.