On Sat, May 07, 2016 at 06:12:43PM +0100, Rostislav Pehlivanov wrote: > The problem is that with particularly complex images and especially at > high bit depths and 5-level transforms the coefficients would overflow, > causing huge artifacts to appear. This was discovered thanks to the fate > tests, which will have to be redone as this fixes a multitude of > problems and increases PSNR. > > There is a slight performance drop associated with this change, making > the encoder slower by 1.15 times, however this is necessary in order to > avoid undefined behavior and overflows. > > It would be worth to template the transforms to keep the performance for > 8 bit images as 32 bit coefficients are unnecessary for that case, but > the primary use of the encoder is to encode video at 10 bits. > > Signed-off-by: Rostislav Pehlivanov <atomnu...@gmail.com> > --- > libavcodec/vc2enc_dwt.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-)
i guess things first should be correct and then be optimized so LGTM [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Rewriting code that is poorly written but fully understood is good. Rewriting code that one doesnt understand is a sign that one is less smart then the original author, trying to rewrite it will not make it better.
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