[MEncoder-users] How to keep lavc bitrate within DVD spec?

[Laine Lee]

On 10/3/08 8:58 AM, "Francois Visagie" <francois.visagie at gmail.com> wrote:

> Hi All,
> 
> I'm using the following 2-pass command line with MEncoder
> Sherpya-SVN-r27323-4.2.4 on Windows XP to encode PAL DV AVI material (bottom
> field first) to DVD-compliant MPEG-2:
> 
> mencoder -field-dominance 1 -mc 0 -vf hqdn3d=2:1:2,harddup -oac lavc -ovc
> lavc -lavcopts
> abitrate=128:acodec=ac3:autoaspect:cmp=2:ilme:ildct:keyint=15:last_pred=2:mbcm
> p=2:mbd=2:mv0:precmp=2:predia=2:preme=2:subcmp=6:top=0:trell:vbitrate=6680:vco
> dec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vstrict=0
> -of mpeg -mpegopts format=dvd:tsaf %1 -o %OUTPUT% >%OUTPUT%.%PASS%.txt
> 
> The highish bitrate is affordable for this particular 34min video.
> 
> The encode of that video results in:
> 
> BUFFER UNDEFLOW at stream 0, raising muxrate to 11088 kb/s, delta_scr: 39896
> Pos: 55.6s 1391f (46%) 3.46fps Trem: 7min 101mb A-V:0.000 [6844:128]
> 
> BUFFER UNDEFLOW at stream 0, raising muxrate to 12196 kb/s, delta_scr: 36269
> Pos: 55.7s 1392f (46%) 3.46fps Trem: 7min 101mb A-V:0.000 [6847:128]
> 
> As you can see, vrc_maxrate=9800. However, despite that, above the bitrate
> shoots over the DVD spec and with the resultant MPEG-2 file the muxer I'm
> currently using moans and aborts at the same point.
> 
> I've Googled the mailing list and the most relevant posting I could find at
> http://lists.mplayerhq.hu/pipermail/mencoder-users/2006-September/004041.html
> implicitly
> suggests not using MEncoder.
> 
> Using MEncoder, how can I prevent bitrate exceeding the DVD spec, apart from
> cutting out the footage that causes the bitrate spike? I really hope you
> have a solution for that.
> 
> Thanks kindly,
> 
> Francois

Pardon me if I'm missing the obvious, but I don't see exactly what your
resulting bitrate is. Maybe you could simply try raising the muxrate to
avoid getting the error:

muxrate=36000

-- 
Laine Lee