Re: Speeding up thumbnail generation (like multi threaded). Thoughts please.

[Philip Van Hoof <spam pvanhoof be>]

On Fri, 2009-08-28 at 22:11 +0200, Mark wrote:

> 
> Now for the results:
> 
> Glib
> ----------------------
> 1927 images thumbnailed in 2.29 minutes. That is roughly 0.07 seconds
> per thumbnail
> 
> GraphicsMagick
> ----------------------
> 1927 images thumbnailed in 3.08 minutes. That is roughly 0.09 seconds
> per thumbnail
> 
> FreeImage
> ----------------------
> 1927 images thumbnailed in 5.45 minutes. That is roughly 0.17 seconds
> per thumbnail

You want to override GdkPixbuf's support for Jpeg and thumbnail all JPEG
images using EPeg. It'll beat GdkPixbuf by 5 times or something.

That's because afaik does EPeg use libjpeg in a way that it skips rows
and columns, and that way performs better on both I/O (having to read
less of the original), memory (same reason) and CPU (having to
decompress less, having to scale less or nothing).

We are already using EPeg for this on the Maemo Fremantle platform, by
the way. Scaling truly large JPEG images goes magically fast with it.


-- 
Philip Van Hoof, freelance software developer
home: me at pvanhoof dot be 
gnome: pvanhoof at gnome dot org 
http://pvanhoof.be/blog
http://codeminded.be