[FFmpeg-devel] [PATCH] Issue 543, clarification of -bt in docs

Michael Niedermayer michaelni
Mon Jul 21 13:38:22 CEST 2008


On Mon, Jul 21, 2008 at 04:18:33AM -0700, tripp wrote:
> 
> hi,
> 
> --- On Mon, 7/21/08, Michael Niedermayer <michaelni at gmx.at> wrote:
> 
>  
> > > +For 1 pass BT specifies how hard the RC code should try to achieve CBR.
> > 
> > I do not like the way this is said, because its not true and will misslead
> > users into thinking low bt would achive CBR.
> 
> 
> ??
> i used your exact words.

Yes, but ive not said it well.
CBR is bad in there because CBR hints toward VBV ...

and bt does not try to achive a constant instantaneaos rate

bt tries to match a "previous sum of bits" curve. Which for 1 pass
is a straight increasing line and for 2 pass it is the calculated ideal
curve.

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Let us carefully observe those good qualities wherein our enemies excel us
and endeavor to excel them, by avoiding what is faulty, and imitating what
is excellent in them. -- Plutarch
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