[MPlayer-users] Re: Problem with mencoder

D Richard Felker III dalias at aerifal.cx
Fri Aug 15 22:48:32 CEST 2003

On Fri, Aug 15, 2003 at 07:46:30PM +0200, Oliver Fromme wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> Stefan Seyfried wrote:
>  > rcooley <rcooley at spamcop.net> writes:
>  > > Stefan Seyfried wrote:
>  > > > It's time to remove 3pass encoding and instead provide a
>  > > 
>  > > However, you lose the advantage of not having to re-encode the audio in 
>  > > the second pass.
>  > 
>  > just use "-oac copy" or "-oac pcm" in the first pass (which can go to
>  > /dev/null), so you also only need to encode audio once (in the second
>  > pass).
> 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. So just make a table of what
bitrates you get with each VBR setting, and then use those to estimate
video bitrate.

Or....since you have to encode audio in both passes when you don't
have 3pass mode, you could just look at the resulting audio bitrate
from the first pass, and then change vbitrate parameter slightly in
the second pass to compensate.


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