[MPlayer-users] Encoding HDTV streams

D Richard Felker III dalias at aerifal.cx
Wed Feb 16 06:36:30 CET 2005

On Wed, Feb 16, 2005 at 02:56:10PM +1100, MichaelM wrote:
> Hey all.
> I've been toying around with encoding HDTV, complete with AC3 streams. I 
> grabbed a large chunk (about 3.5 GB), and encoded it to xvid using the 
> following command:
> mencoder stream.ts -vf scale=1280:720,dsize=16/9,pp=h1/v1/dr/al/lb -sws 
> 10 -oac copy -ovc xvid -xvidencopts 
> pass=2:bitrate=4000:me_quality=6:vhq=4:chroma_me:qpel -o stream.avi
> The "-oac copy" works, and I get an xvid file with ac3 audio.
> However, if I just want to make another mpeg file like so :
> mencoder stream.ts -oac copy -ovc copy -of mpeg -o stream_1.mpg
> there is no audio. Any idea why "-oac copy" works for xvid, but not 
> standard mpeg ? I've used "oac copy" for streams with mp2 audio with no 
> problems ...
> I'll appreciate any help.

ac3 streams aren't part of normal mpeg, so they have to be stored in
some sort of special private stream. the mpeg muxer in mencoder
doesn't know how to do this, so it can't produce valid mpeg files with
ac3 audio...
i'm sure others could give you a better explanation, but that's the
basic problem. patches to fix this would be welcome.


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