[x264-devel] Thresholds about slicetype_decide

[Jason Garrett-Glaser]

On Wed, May 19, 2010 at 7:31 PM, kenter <kenter83 at gmail.com> wrote:
> This result is disappointing, however, I still thanks for your kindly
> help on this issue!
>
> 2010/5/20, Jason Garrett-Glaser <darkshikari at gmail.com>:
>> 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.


You should submit the patch either way even if we don't intend to use
it; it would be nice to see it and have it around for future use.

Dark Shikari