[MPlayer-users] help wanted: using mencoder to make NTSC DVD from transport stream

[D Richard Felker III]

On Sat, Mar 05, 2005 at 06:11:35PM -0500, Norman Ramsey wrote:
> I have an MPEG-2 transport stream I got through a US HDTV broadcast.
> The content is encoded at 720p (that is, 1280x720) with a 16:9 aspect
> ratio.  I want to use this content to burn a DVD for playback
> on standard NTSC (US) DVD players.  Since the DVD will be played
> back on an ordinary television, I want also to account for overscane
> if possible.
> 
> The step I'm having trouble with is using mencoder to create MPG files
> that I can then pass to dvdauthor.  I am going *crazy* trying to figure
> out the right way to scale, get aspect ratio, etc etc.
> 
> Has anybody out there used mencoder to create DVDs from non-DVD video
> content?  If so, can you help or suggest options?  At present, I'm
> using the following options, but I'm sure they're wrong :-(
> 
>   mencoder $i -vf scale=640:360,expand=-32:-64:16:32 -o $j-dvd.mpg -oac lavc \
>               -vc ffmpeg12,mpeg12, \
>               -of mpeg \
>               -ofps 30 \
>               -ovc lavc -lavcopts vcodec=mpeg2video:acodec=mp3:vbitrate=4000
> 
> Is this the right scaling?  I know a standard NTSC DVD is 720x480, but
> this isn't 16:9.  I want to preserve the original aspect ratio.
> And what about the expand option for overscan?  

The aspect ratio and number of pixels have nothing to do with each
other (hint: pixels need not be square). You need to work out the math
for how to scale it (this could be a pain..maybe I'll write a guide on
it later), but be sure to use -lavcopts aspect=16/9 so the final file
is marked as having 16:9 aspect.

Rich