[MPlayer-dev-eng] [patch] Documentation update following lavc internal 2-pass mode commit

D Richard Felker III dalias at aerifal.cx
Mon Apr 22 19:40:20 CEST 2002


On Mon, Apr 22, 2002 at 06:38:31PM +0200, Arpi wrote:
> Hi,
> 
> > > +                 (warning: 1kbit = 1000 bits)
> > > +  vratetol=XXX   approximated bitrate tolerance,
> > > +                 same unit as vbitrate.
> > 
> > This is incorrect. Unfortunately vratetol can only be specified in
> > kbits, which is incredibly broken since the desired tolerance may very
> > well be below 1 kbit but nonzero! Someone should fix this! OK if I do,
> heh? it won't work at all if you set it too low. 1kb is already too low,
> it means very constant bitrate, ie. each coded frame same bits long.
> bigger value allow more vbr-like coding.

For certain applications (perhaps making VCD-compliant mpeg video
streams, or something intended for streamed playback over network),
almost-constant bitrate may be essential. I don't see how this is
nonsense...

> > Maybe document how to use this? I couldn't get it to work... pass 2
> > came out identical to pass 1.
> works for me, i got different file sizes (few kbs smaller at 2nd pass)
> and better (not not staisfieing) quality

OK, I'll try it again. Maybe it was broken at first.


Rich




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