On Fri, May 27, 2016 at 04:34:53PM +0200, Nicolas George wrote: > Le nonidi 9 prairial, an CCXXIV, Michael Niedermayer a écrit : > > ATM with 10 filters this is 100 times slower than 1 filter > > with 100 filters its 10000 times slower than 1 filter > > with 1000 fiters its 1000000 times slower than 1 filter > > What you say seem strange. The code looks O(n×p) with n the number of > filters and p the average number of pads per filter; p is usually quite > small.
to pass 1 frame through a simple linear chain each filter might have to request from the previous (that is n times) and each request needs to iterate over the whole graph thus O(n*n) per frame unless i misunderstood the code from IRC: <ubitux> michaelni: "no i dont know if someone uses it with 1000 filters" i remember someone doing thousands of drawbox instance of something (one per frame) ... <ubitux> michaelni: well, it was pure madness but there is a ticket somewhere <ubitux> michaelni: http://trac.ffmpeg.org/ticket/5222 > > > well, if that patch is incovenient for your work ATM we can drop it. > > Thanks. > > > But i do want this fixed at some point > > i am alergic to code thats by a factor of "~n" slower than what can > > reasonable easy be done (unless n is somehow bounded and its just > > init code or otherwise irrelevant) > > I can ease your mind on that, I am allergic to that kind of thing too. > Implementing a priority queue of filters that are ready for processing was > in my TODO queue before this series. ok > > As always, time available to work on the project is the limiting factor. > > Regards, > > -- > Nicolas George > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Concerning the gods, I have no means of knowing whether they exist or not or of what sort they may be, because of the obscurity of the subject, and the brevity of human life -- Protagoras
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