On Wed, Dec 17, 2008 at 8:55 PM, Dan Dennedy <d...@dennedy.org> wrote: > On Wed, Dec 17, 2008 at 2:24 PM, Dan Dennedy <d...@dennedy.org> wrote: >> On Wed, Dec 17, 2008 at 11:12 AM, Jean-Michel Pouré <j...@poure.com> wrote: >>> On Wed, 2008-12-17 at 10:43 -0800, Dan Dennedy wrote: >>>> configure with --enable-pthreads and run ffplay with the -threads >>>> option followed by the number of worker threads to use. It will still >>>> keep a decoder control thread and separate reader/output threads, all >>>> of which are fairly light, so it is a good idea to use (#cores - 1) >>>> for the worker threads. >>> >>> Ah ... this skiploop is not documented. >> >> documented in the source :-). Actually, I knew of it because of 'ffplay -h' >> >>> ffplay -skiploop 48 -threads 2 avchd-test-1.mts works very well. >>> >>> By the way, FFmpeg developers suggested that we do not decode B frames >>> during viewing. I don't know is this can apply to Kdenlive. >> >> Yeah, I'm not sure, but I will experiment with it. I might be okay to >> skip B frames in preview (user might see repeated frames) and then >> process them during render. With ffplay you can use "-skipframe 16" to >> skip B frames. > > I learned that on my dual Athlon, these two options make it about > twice as fast! I also learned that despite this, it does not support > parallelized decoding even though (if I am not mistaken), it appears > most files I tested have 2 slices per frame (determined using "-debug > 1"). Nevertheless, this are some cheap, simple options.
Hmm, I have a H.264 1080p trailer downloaded from Apple's trailers site where multithreaded decoding does work with skiploop=48. I see it has 8 slices per frame. Ah... now I see (using -debug 1) that the AVCHD clip has 4 "packets," or whatever you want to call them (debug lines), per frame, but the slice always =1 whereas in the trailer slice = 1 to 8. -- +-DRD-+ ------------------------------------------------------------------------------ SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. The future of the web can't happen without you. Join us at MIX09 to help pave the way to the Next Web now. Learn more and register at http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ _______________________________________________ Kdenlive-devel mailing list Kdenlive-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kdenlive-devel
