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Parallel video encoding



On 8/30/07, Matthew Gillen <me-5yx05kfkO/aqeI1yJSURBw at public.gmane.org> wrote:
>  Disk I/O will completely eclipse any context-switching penalty, and even

I've got too many gigs of memory...let's say I MMAP the file, eh?
Will that help me out :-)  Do you have experience with using mmap in
mencoder?  I went through the man page, but the mmapping support
doesn't appear to be for the entire video itself, but for parts of the
video when passing it to other apps...

> If you want to tinker with option #1, here's an idea that minimizes context
> switching and doesn't involve makefiles:  spawn all the jobs concurrently (ie
> more jobs than MAX_CORES), but set their priorities (ie via nice) so that
> there is a strict ordering, but even the lowest priority job is more important
> than "normal" priority.  That way you don't get context switching overhead,
> but you still make the OS scheduler do all the job-management for you.

I am going to try that.  it appears that mencoder's x264 codec only
allows up to threads=4 :-(  Too bad for people with greater than four
cores!!!
-- 
Kristian Erik Hermansen

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