[x264-devel] Thresholds about slicetype_decide

[Jason Garrett-Glaser]

On Wed, May 19, 2010 at 1:52 AM, kenter <kenter83 at gmail.com> wrote:
> I find there is a bug in my hack, after bug fixing, the PSNR is
> 34.877dB(vs 34.855dB of 8x8 ME version)
>
> However, I still have some questions:
> 1. There is only 0.022dB PSNR gain for slicetype_decide by 16x16 vs
> 8x8 lowres one, Is it reasonable?

Yes, this sounds reasonable.

> 2. The return value of x264_slicetype_mb_cost must be divided by 4
> (i_bcost/4), otherwise, there is a 0.5dB PSNR drop, I think it doesn't
> make sense only if there are some parameters/thresholds related to
> 8x8, can you help me to find out these parameters/thresholds?

Don't know off the top of my head, but dividing by 4 is fine; you
don't lose much precision.

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