[MPlayer-users] Re: Problem with mencoder

[Alban Bedel]

Hi D Richard Felker III,

on Sat, 16 Aug 2003 04:05:51 -0400 you wrote:

> [Automatic answer: RTFM (read DOCS, FAQ), also read
> DOCS/bugreports.html] On Sat, Aug 16, 2003 at 12:18:42AM +0200, Oliver
> Fromme wrote:
> > [Automatic answer: RTFM (read DOCS, FAQ), also read
> > DOCS/bugreports.html]
> > 
> > D Richard Felker III wrote:
> >  > On Fri, Aug 15, 2003 at 07:46:30PM +0200, Oliver Fromme wrote:
> >  > > Please don't remove 3pss encoding.  Without it, it is difficult
> >  > > (though not impossible) to estimate the bitrate when using VBR
> >  > > mp3 audio, which I always do.
> >  > 
> >  > No it's not. VBR always comes out the same average (withing a +- 10
> >  > kbit margin) for movie-length encodings.
> > 
> > That's already too much.  For a 100 minutes movie, 10 kbps
> > difference means about 7 Mbyte in file size.  But I want to
> > calculate the file size as precisely as possible, so it
> > will fit on an CD-R and use all the space.
> > 
> >  > So just make a table of what
> >  > bitrates you get with each VBR setting, and then use those to
> >  > estimate video bitrate.
> > 
> > Those differ a lot.  The average seems to be around 145 kbps
> > with my settings, but for some DVDs it goes up to 160 and
> > beyond, in particular when the movie contains much music
> > (but not always).  On the other hand, I've also had DVDs
> > for which the VBR mp3 encoding ended up at 120 kbps.  With
> > the same mp3lame settings.
> 
> Hmm, it's never seemed to vary that much for me. One other option is
> to use abr instead of vbr (it's usually accurate within +- 2
> kbit/sec), but IIRC the lame docs say the quality might not be as good
> as true vbr at the same average.
I think you use ABR wich try to maintain a given average bitrate and
he use VBR wich try to maintain quality. ABR is good if you want
predicatble size with a more inteligent coding than CBR but that won't
give you as good results as VRB.
	Albeu
-- 

Everything is controlled by a small evil group
to which, unfortunately, no one we know belongs.