On Fri, Sep 02, 2016 at 01:13:33PM -0700, Jonathan Campbell wrote: > > On 09/02/2016 01:01 PM, Michael Niedermayer wrote: > >On Fri, Sep 02, 2016 at 10:19:23AM -0700, Jonathan Campbell wrote: > >[...] > >>CRC computation isn't fast enough? What should I use then? A sum of > >>byte values? > >av_lfg_init() calls av_md5_sum() > >av_md5_sum() is too slow to be called per ac3 frame > > > >[...] > > > > > >_______________________________________________ > >ffmpeg-devel mailing list > >ffmpeg-devel@ffmpeg.org > >http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > Then for this to work at better performance, I'm going to have to > either directly modify the AVLFG struct state (probably not a good > idea), or add a function to libavutil/lfg.c that allows "fast > seeding" without the use of MD5 which could probably be something as > simple as copy the 32-bit seed 16 times through c->state[] with or > without modification during the loop. Sound good?
yes, something like this probably spliting the input into 16 parts get 16 CRCs and use them instead of replication is probably better [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB You can kill me, but you cannot change the truth.
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