[x265] [PATCH] no-rdo: Replace optimized merge routine to decrease bitrate by 1.6%

[Steve Borho]

On Thu, Oct 3, 2013 at 12:58 AM, Deepthi Nandakumar <
deepthi at multicorewareinc.com> wrote:

> This patch essentially reverts a merge optimization that was pushed a few
> weeks ago.
>
> The merge optimization included removing a cost estimate (merge mode with
> residual) from consideration. This caused a bitrate/quality drop in rd 0/1
> - this penalty needs to be investigated more before it becomes either a
> user option or part of rd 0/1.
>

I did a quick test with "x265 \mcw\city_4cif.y4m out.hevc -F2 --rd=0" on my
slow laptop:

current tip:
 encoded 600 frames in 177.32s (3.38 fps), 515.63 kb/s, Global PSNR: 34.654

this patch applied:
 encoded 600 frames in 244.51s (2.45 fps), 506.49 kb/s, Global PSNR: 34.611

Not a very compelling change at first glance; I'm inclined to leave the
current behavior until there is an unambiguous improvement or if you have
better circumstantial evidence than my quick tests.

-- 
Steve Borho
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