[MPlayer-users] Convert NTSC to PAL for DVD

[Giacomo Comes]

On Sun, Sep 17, 2006 at 06:58:21PM +0200, Hans du Plooy wrote:
> On Sat, 2006-09-09 at 22:33 -0700, RC wrote:
> > Other than that, it's a standard PAL DVD encode, as described in the
> > HTML docs.
> 
> OK, I'm baffled.  I took the example from the HTML docs, copy audio
> instead of re-encode, add the interlaced goodies as you suggested:
> 
> mencoder -oac copy -ovc lavc -of mpeg -mpegopts format=dvd -vf
> scale=720:576,harddup -srate 48000 -af lavcresample=48000 -lavcopts
> vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=5000:keyint=15:aspect=16/9:ildct:ilme:mbd=2 -ofps 25 -o VTS_01_0.mpg VTS_01_0.VOB
> 
> What baffles me is that the resulting file is bigger than the original.
> If I play either file in mplayer, both report a bitrate of 9800kbit/s.
> 
> Can anyone enlighten me as to why?

It is possible to make DVDs that have the same bitrate
but with quite different final file size. It depends
which lavc options you use for that.
In your case the main reason for the difference in the file
size is that you didn't add b-frames. If you add 2 b-frames
the file size will be about 20% smaller.
All the commercial DVD I have seen use 2 b-frames and some
DVD player will not perform proper fast forward if the mpeg
does not have b-frames.

Giacomo