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

[Francois Visagie]

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:mbcmp=2:mbd=2:mv0:precmp=2:predia=2:preme=2:subcmp=6:top=0:trell:vbitrate=6680:vcodec=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