Dual-Core processor utilization?

[HTKatzmarek]

I'm wondering if there's been any thought to making the mencoder process make use of multiple cores to speed up the process. This would reduce the time needed to encode, particularly on 3-pass operations.

Thx for any comments

 

[sej7278]

slysoft don't write mencoder, and i think only a subset of the codecs used are multithreaded.

i know x264 is multithreaded - and you can get an almost linear speedup, i.e. each core adds about 94% speed.

xvid isn't multithreaded - well the bleeding-edge build is, but only uses about 1.5 cores, i.e. 2 cores is only about 50% faster and 4 cores makes no further difference.

i don't think its possible to have core1 working on pass1 and core2 on pass2, it simply wouldn't make sense.

 

[Peer]

slysoft don't write mencoder, and i think only a subset of the codecs used are multithreaded.

i know x264 is multithreaded - and you can get an almost linear speedup, i.e. each core adds about 94% speed.

xvid isn't multithreaded - well the bleeding-edge build is, but only uses about 1.5 cores, i.e. 2 cores is only about 50% faster and 4 cores makes no further difference.

i don't think its possible to have core1 working on pass1 and core2 on pass2, it simply wouldn't make sense.

Yes, x264 is the only codec that really gains speed with multithreading in mencoder, but also the results didn't play on the PSP, so this multithreading approach was abandoned.

MPEG4 speedup with multithread is less than 10%, actually most of the time 2 or 3% - most of the time one thread waits for the other thread to release some common resource.

So it's useless for now..

 

[Peer]

I'm wondering if there's been any thought to making the mencoder process make use of multiple cores to speed up the process. This would reduce the time needed to encode, particularly on 3-pass operations.

The best way to speed up a 3pass encoding is to do a 2pass encoding

Seriously: 3-pass is just not worth the effort. If you have a PC doing the job over night, it's fine, why not. But you'll still have trouble telling the difference from 2-pass.

 

[HTKatzmarek]

OK...thx for the input.

 

[Eltaco]

I actually worked on ripping my entire DVD collection. I have a DVDROM and a DVDRW drive and would rip 2 DVD's at a time. I know that doesn't speed up a single encode. Using taskmanager I saw that durring a single encode it would rarely top above 50%, so while running 2 encodes would be slower total time than encoding individuals. Sorry if I am not making sense. It just was easier for me starting from scratch.