[x264-devel] ”ultrafast“ preset preformance decrases after commit "Unify 8-bit and 10-bit CLI and libraries"

[BugMaster]

On Sat, 2 Feb 2019 04:07:31 +0000, wangguan (D) wrote:
> Hi, all

>  

> After the commit “Unify 8-bit and 10-bit CLI and
> libraries"(http://git.videolan.org/gitweb.cgi?p=x264.git;a=commit;h=71ed44c7312438fac7c5c5301e45522e57127db4),
> the “ultrafast” preset costs more time encoding.

> The commit “Unify 8-bit and 10-bit CLI and libraries" moves the
> function param_apply_preset from common/common.c to common/base.c ,
> and also change the content of param_apply_preset.

> Before the commit, in common/common.c, the old version
> param_apply_preset sets “param->analyse.i_trellis = 0;” if preset is ultrafast

> After the commit, in common/base.c, the new version
> param_apply_preset  misses to set “param->analyse.i_trellis = 0;” if preset is ultrafast.

>  

> I think it’s a bug, i_trellis’s default value is 2, and i_trellis
> is set to 0 in “superfast” and “veryfast”.  So it makes no sense for i_trellis to be 2 in “ultrafast”.

> Fixing this can restore the performance in “ultrafast” preset.

>  

> Thank you.

Hi.

It is already fixed in sandbox repository (after Aleksey Vasenev's bug
report from 7 November 2018). It will be pushed to official x264
repository during next release so no need to ping this topic again.