[x264-devel] Re: patch: visualization for X11

[Måns Rullgård]

Loren Merritt <lorenm at u.washington.edu> writes:

> On Tue, 17 May 2005, [iso-8859-1] Måns Rullgård wrote:
>> Loren Merritt <lorenm at u.washington.edu> writes:
>>>> Another thing that could be visualized is the QP value. Any ideas?
>>>> I'm not sure if it varies between partitions/MBs yet in x264, but it could.
>>>
>>> It used to vary as part of the CBR ratecontrol. I removed that when I
>>> added ABR, because it was unnecessary at sane buffer sizes. But yes,
>>> there are other forms of adaptive quant that could be useful.
>>
>> I guess I could read the code and find out, but what is this ABR
>> anyway?
>
> Average bitrate. As close as possible to the 2pass quantizer
> distribution as you can get in 1 pass. Gracefully degrades to near
> constant bitrate if you restrict VBV.
> It's the algorithm I was saying was about 4dB better than CBR (when
> unrestricted). At small VBV sizes I see around .5 dB gain.

Is the result still within VBV constraints?

-- 
Måns Rullgård
mru at inprovide.com

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