[MPlayer-users] Mencoder and AC3 surround sound encoding

John Richard Smith BAGSOFCHOICE at oldtolley.fsnet.co.uk
Tue Dec 30 13:57:17 CET 2003


Can mencoder handle AC3 surround sound properly ?

I'm having some problems ripping some dvd's with AC3 audio tracks.

It seems to muck up the indexing (-idx) no matter which options I choose.

I end up with either,

a) no sound at all,

or,

b) Mplayer has to do a index scan before it can play the mpeg4, .avi file.

c) Note no problem with the picture.

ManyDVD's have AC3 surround sound  audio files.
If I understand this correctly AC3 surround sound uses mp3.
However, the audio tracks are set up differently.

typically, I set the audio encoding up with something like,
 

-oac mp3lame -lameopts br=96:cbr
or,
-oac mp3lame -lameopts vbr=0

However the result is not always a happy one.

Where the source mpeg2 DVD had AC3 surround sound audio, mencoder fails 
to create a satisfactory index file but provided that you then play the 
result in mplayer it will do an index scan of the disc before it plays 
the disc, but other programmes will not, including most of the new bread 
of stand alone   "DivX-DVD players" that are  able to play 
mpeg2/mpeg4-5, jpeg, and, mp3,  discs.

I found this to be the case because another dvd ripper programme tells 
me what is on the source mpeg2 dvd disc, and I am able to read what it 
find on it ,namely AC3-DTS audio files, and so by comparing the results 
, and reading the information it seems to imply surround sound, of 
course this could be wrong, I'm no expert.

Am I doing something wrong or is this a mencoder limitation, in that 
currently mencoder cannot encode AC3 surround sound mpeg2 dvd's.

I have searched the mplayer/mencoder help files, but cannot find 
anything . There is nothing specific to cover this aspect of my problem.

thanks,
 

John




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