Op maandag 17-08-2009 om 14:43 uur [tijdzone +0200], schreef Ed Vaessen: > Hello, > > I am rendering HD 1920x1088 footage to yuv4mpeg (video only) and use the > following pipe: > > mpeg2enc --verbose 0 --multi-thread 4 --aspect 3 --format 3 --frame-rate 3 > --video-bitrate 28000 --nonvideo-bitrate 384 --interlace-mode 0 > --force-b-b-p --video-buffer 448 --video-norm p --keep-hf --no-constraints > --sequence-header-every-gop --min-gop-size 6 --max-gop-size 6 -o % > > This renders without problems to an m2v file. > Now I have an Intel Core i7 920 processor, which is a quad core and can > accommodate 8 threads. Changing the parameter for multi-thread to 8 does > not make the rendering faster. On the contrary, it becomes even slower. > Now I read in the link below that using the multi-thread option in fact > gains very little with mpeg2enc. Does anyone have experience with this? > > > Ed > > http://www.mail-archive.com/[email protected]/msg06378.html
Yes, I have some experience with this; see also this message from a few years back: http://www.mail-archive.com/[email protected]/msg07080.html "> I'm working on an AMD64 dual-core machine, and -M 2 (actually the > only option I came up with myself) results in an overall speed gain > of up to 40%. Almost all of that comes from '-M 1' which uses an I/O readahead thread. That's why you won't see much (if any) improvement between -M 2 and -M 3 (I have tested this on quad cpu systems and -M 4 actually ran slightly slower than -M 1)." Recent rendering on a dual-core machine suggest that the -M switch doesn't accomplish much any more; htop shows that both cores are almost fully used during rendering, no matter what I specify. However, I have no idea how this works out in an 8-core situation; you might want open a terminal window, showing the 'top' or 'htop' command to see how much CPU resources are actually used during rendering. I guess one of the developers can shed some more light on this matter. Best regards, Richard Rasker _______________________________________________ Cinelerra mailing list [email protected] https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
