[MPlayer-users] Bug: Poor quality decoding of ac3 audio

[Rashkae]

On 11-03-02 02:07 PM, Vladimir Mosgalin wrote:
>
> I didn't check this sample, but some ac3 streams which have too loud
> sounds can get cracking and other artifacts when downmixing due to some
> overflows, the solution is to use
> -channels 6 -af volume=-10,pan=.. (downmixing string)
> or -channels 6 -af volume=-10,hrtf if you are downmixing for headphones.
>
>    
Downmixing with pan does indeed allow mplayer to play/decode the audio 
without glitches.  I don't even have to reduce the volume, using the 
'basic' formula of pan=2:1:0:0:1:1:0:0:1:0.5:0.5:1:1 in the documentation.

However, I still think there is a flaw in mplayer somewhere, somehow.  
It is my understanding that mplayer with default options should be using 
liba52 to downmix the  ac3 stream, exactly the same as a52dec does.. but 
I'm getting very different results between the two programs.  As for 
whether the liba52 on my system (0.7.4) is newer or older code than what 
Mplayer svn is using..I don't understand the Mplayer internals nearly 
well enough to tell.