Hi, On Wed, May 10, 2017 at 5:02 PM, Michael Niedermayer <mich...@niedermayer.cc > wrote:
> On Wed, May 10, 2017 at 10:28:22PM +0200, Nicolas George wrote: > > Le primidi 21 floréal, an CCXXV, Michael Niedermayer a écrit : > > > fixed, and now your patchset seems to cause a 1% slowdown of the > > > example above > > > > Thanks. The slowdown is to be expected, since this filter used > > non-aligned frames which are now realigned. I guess you can get back the > > previous speed by setting "avctx->alignment = 0" in snow_encoder.init(). > > > > > The default in this patchset is 5 to fix all the alignment problems, at > > the cost of some slowdown in corner cases such as this one. I am not > > qualified to decide the best way of setting an optimal value to get > > speed without crashes. My opinion would be: > > > > - have avctx->alignment default to 0; > > > > - have all codecs with explicit assembly set avctx->alignment to the > > required value; > > > > - have all codecs that use generic DSP code init it through a function > > that sets the alignment accordingly. > > hmm > run fate with intentionally misaligned frames, and make a list of > all codecs that dont crash and work fine. That's generally arch-specific. Codecs using AVX2 need 32byte, SSE2/Neon only need 16, MMX need none (although 8 would probably be slightly faster). Ronald _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
