On Wed, Nov 8, 2017 at 8:44 AM, <mont3z.cla...@gmail.com> wrote: > # HG changeset patch > # User hribeiro > # Date 1510110049 28800 > # Tue Nov 07 19:00:49 2017 -0800 > # Node ID e7e951834b57633ae474f50e7878b24271afabd2 > # Parent b6c692f5f5b145eb8d874cfb44db8c85fc2978cc > Disable QP limitations for lowpass subband dct >
Thanks. Temporarily, I agree that removing the requirement to do support lowpass-dct only with CQP>23 is good. I've slightly adjusted the docs below and pushed this to default branch. We need to figure out if we can do this dynamically based on the content. > > diff -r b6c692f5f5b1 -r e7e951834b57 doc/reST/cli.rst > --- a/doc/reST/cli.rst Tue Nov 07 19:15:31 2017 +0530 > +++ b/doc/reST/cli.rst Tue Nov 07 19:00:49 2017 -0800 > @@ -2165,10 +2165,10 @@ > > .. option:: --lowpass-dct > > - If enabled, x265 will use low-pass truncated dct approximation > instead of the > - standard dct. This approximation is less computational intesive but > it generates > - truncated coefficient matrixes for the transformed block. Empirical > analysis shows > - this approximation gives good PSNR results for QP>=23. > + If enabled, x265 will use low-pass subband dct approximation instead > of the > + standard dct for 16x16 and 32x32 blocks. This approximation is less > computational > + intesive but it generates truncated coefficient matrixes for the > transformed block. > + Empirical analysis shows marginal loss in compression and performance > gains up to 10%. > > This approximation should be considered for platforms with > performance and time > constrains. > diff -r b6c692f5f5b1 -r e7e951834b57 source/common/primitives.cpp > --- a/source/common/primitives.cpp Tue Nov 07 19:15:31 2017 +0530 > +++ b/source/common/primitives.cpp Tue Nov 07 19:00:49 2017 -0800 > @@ -272,7 +272,7 @@ > > setupAliasPrimitives(primitives); > > - if (param->bLowPassDct && param->rc.qp > 20) > + if (param->bLowPassDct) > { > enableLowpassDCTPrimitives(primitives); > } > diff -r b6c692f5f5b1 -r e7e951834b57 source/x265.h > --- a/source/x265.h Tue Nov 07 19:15:31 2017 +0530 > +++ b/source/x265.h Tue Nov 07 19:00:49 2017 -0800 > @@ -1510,9 +1510,8 @@ > /* Disable lookahead */ > int bDisableLookahead; > > - /* Use low-pass truncated dct approximation > - * This DCT approximation is less computational intensive and gives > results close to > - * standard DCT for QP >= 23 */ > + /* Use low-pass subband dct approximation > + * This DCT approximation is less computational intensive and gives > results close to standard DCT */ > int bLowPassDct; > > /* Sets the portion of the decode buffer that must be available after > all the > > _______________________________________________ > x265-devel mailing list > x265-devel@videolan.org > https://mailman.videolan.org/listinfo/x265-devel > >
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