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

[Brendan Bolles]

On Dec 11, 2009, at 3:31 PM, Florian Kainz wrote:

> 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.


If you're zoomed out in Nuke, the scanline renderer is only drawing  
every Nth scanline, so with Zip it will only decode and cache the  
lines it needs.  That's why Zip is a good choice for Nuke.  Virtually  
every other program reads the whole file every time, so Zip16  
performs a little better for them.


Brendan