[x264-devel] Re: CABAC performance

[Loren Merritt]

On Tue, 29 May 2007, Son Minh Tran wrote:

> Have you ever tested the performance of CABAC in x264. It is strange that 
> with  toggling between using / not using CABAC (without / with --no-cabac 
> option) I didn't see the improvement about 16% of bitrate at the cost of 
> encoder speed fps (complexity) about 25-30%. In fact I had about 4-11% 
> improvement in bitrate for only max 6% increase in the fps speed of encoder. 
> You have a optimized CABAC encoder or I miss some things while turning off 
> the CABAC

Encoding CABAC takes the same amount of time as decoding CABAC. But the 
encoder does lots of other computations, most of which are analysis only 
and not duplicated in the decoder. So CABAC is a large fraction of the 
decode time, and a small fraction of the encode time.

Where did you hear "16% bitrate and 25-30% speed"?

--Loren Merritt

-- 
This is the x264-devel mailing-list
To unsubscribe, go to: http://developers.videolan.org/lists.html