[MEncoder-users] ac3 reencode-channels confusion

[The Wanderer]

On 08/10/2009 05:18 PM, Bernd Butscheidt wrote:

> Hello,
> 
> 
> I have to reencode ac3 audio because I want to do a reencode together
> with the scaletempo option, so "-oac copy" does not work.
> 
> As long as I use the default ("-channels 2"), it seems to work. But
> because the original audio track is a 6-channel-ac3, I switched to
> use "-channels 6".
> 
> No I hear everything which should be in the middle (e.g. every
> speaking actor of the movie) on the right speaker regardless which
> player I use (my standalone, xine or smplayer). Adding the option
> "-af channels=6" didn't help.
> 
> Everything I can see in the output of mencoder which could be related
> to the problem (either with the default or the channel option) is:
> 
> "[ac3 @ 0x30608a0]No channel layout specified. The encoder will guess
> the layout, but it might be incorrect".
> 
> Has anyone an idea what could be done?

At a brief guess, read up on the '-af channels' filter. '-channels' by 
itself doesn't seem to provide a way to specify the channel layout.

-- 
       The Wanderer

Warning: Simply because I argue an issue does not mean I agree with any
side of it.

Secrecy is the beginning of tyranny.