[MPlayer-users] 2pass encoding... faster first pass?

[D Richard Felker III]

On Sat, Apr 09, 2005 at 01:39:59PM +0930, Mark Williams (MWP) wrote:
> > On Sat, Apr 09, 2005 at 04:06:52AM +0930, Mark Williams (MWP) wrote:
> > > Greetings all,
> > > 
> > > Most of the time i use mencoder options similar to:
> > > 
> > > LAVC="vcodec=mpeg4:vqmin=2:vqmax=16:vmax_b_frames=2:vme=4:mbd=2:v4mv:keyint=250:vlelim=-4:vcelim=7:vstrict=0:mbcmp=3:precmp=0:cmp=0:subcmp=0:predia=1:dia=1:trell:aspect=4/3:vbitrate=$BITRATE"
> > > 
> > > VF="crop=$CROPXY,scale=$SCALEXY,pp=vb/hb/dr,hqdn3d"
> > > 
> > > Which gives VERY slow encoding, but great quality.
> > > 
> > > When doing 2pass video encodings can i use faster settings for the first pass,
> > > then the above for the second pass?
> > > Or do i need to use the same settings for each pass?
> > 
> > You can use faster -lavcopts, but I would advise against changing
> > filters at all. Also, vlelim=-4:vcelim=7 probably lower quality, and
> > same for vmax_b_frames=2 (use at most 1, imo, and maybe 0).
> 
> So what values would you sugest for vlelim & vcelim?

Not using them.

> Also, ive tried setting vrc_buf_size to 1835 as sugested in the man page, but
> when i do i get lots of "rc buffer underflow" messages (about one per encoded frame).
> Do you know what is going on here?

Suggested in the man page??
The buffer sizes and maxrate/minrate values there are for making
compliant DVD/VCD/SVCD streams. They severely lower quality and should
not be used unless you're trying to meet one of these bad standards
(which you're obviously not since you're encoding to mpeg4...)

Rich