[MPlayer-users] Re: variable bitrate, fixed quality

Jonathan Rogers jonner at teegra.net
Wed Jul 9 20:07:21 CEST 2003

Nikolaus Rath wrote:
>>They're explained in the mplayer man page.
> Yes. But an explanation like
>                  vqcomp=<value>
>                      quantizer compression,  depends  upon  vrc_eq  (pass 1/2)
>                      (default: 0.5)
> isn't really helpful if you aren't an MPEG developer.
> Your explanation below is indeed very good. I think that this type of
> explanation should be in the manpage.

It is explained mathematically in the entry for vrc_eq. The default 
function is "tex^qComp", which means that if vqcomp is 0, the 
ratecontrol function always returns 1, meaning constant bitrate. If 
vqcomp is 1, bitrate varies directly with texture complexity, meaning 
constant quality. Understaning of algebra is necessary, but it is 
probably necessary anyway to understand something inherently 
mathematical like video encoding.

Jonathan Rogers

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