[MEncoder-users] re-encoding avi to normalise sounds (and turn into 5.1)

[Jiří Heryán]

Jiří Heryán píše v Po 07. 01. 2008 v 10:46 +0100:
> Rich Felker píše v Po 07. 01. 2008 v 02:02 -0500:
> > On Mon, Jan 07, 2008 at 07:27:42AM +0100, Jiří Heryán wrote:
> > > Alex Samad píše v Ne 06. 01. 2008 v 16:23 +1100:
> > > > > > I do my work
> > > > > >  mencoder a.avi -o b.avi -ovc copy -oac lavc -lavcopts acodec=ac3 -af 
> > > > > > volnorm=1,surround=15,center,sub -channels 6
> > > > > > 
> > > > > > it finished okay, but when I play it, the sound volume has increased, but when 
> > > > > > I try to skip ahead or backwards the sounds starts from the beginning
> > > > > > 
> > > Mencoder is IMHO broken,
> > 
> > This is true.
> > 
> > > probably for better purity of the code (see
> > 
> > This is utter nonsense. Saying "purity of the code" about MEncoder is
> > like a Catholic prostitute saying she doesn't use condoms for the sake
> > of her purity...
> > 
> > > endless discusions about hacks in AVI few years ago). It is stupid,
> > > because libavcodec does not contain audio codec compatible with default
> > > container (Congratulations boys, good work!).
> > 
> > Huh? Encoding AC3 with lavc and storing it in AVI should work just
> > fine. If not it's a bug, and I'm sure everyone would be happy if you
> > would track it down and explain what's happening (e.g. what incorrect
> > values are written to headers or what incorrect framing is used,
> > etc...)
> 
> Here is mplayer's status line from recently encoded avi ( -ovc copy -oac
> lavc -lavcopts acodec=ac3 ) after 9.9 s of playing w/o seeking. Video
> and audio are in perfect sync.
> A:8228.6 V:   9.9 A-V:8218.703 ct:  0.988 248/248 17%  2%  0.8% 2 0
> 
> I think it is AC3 codec's issue.

The only difference in header I can detect is VBR mark in broken files
instead of CBR (correct value). Problem can be solved by avisync, until
somebody will fix it in mencoder.

J.Heryan