[MPlayer-dev-eng] AC3-surround patch

[Stephen Davies]

On Tue, 27 Nov 2001, Stephen Davies wrote:

> On Tue, 27 Nov 2001, Felix Buenemann wrote:
> 
> > I get heavy distortions on the Canyon trailer for example. When I do a 
> > -dumpaudio and play with a52dec -o oss6 stream.dump it is fine, so stuff in 
> > libac3 is buggy.
> 
> I can hear some clipping on the audio peaks towards the end of the Canyon
> vob.  This could be my fault - I'll investigate.

I think the audible clipping is because the Left/Right exceeds the 16bit
range.  You don't hear it on a downmix because the code takes 6dB off the
front channels as it mixes in the surround and centre.

I'll have a go at a fix.

> > Either you have both front and rear speaker swapped ot it should be:
> > 
> > I tested speaker order with the ac3test.ac3 extracted from AC3TEST.vob.
> 
> Thought I had the channels the right way round but didn't really have a
> suitable test file.  I got ac3test and will investigate.

My channels are the right way round.  Also tested with a DVD - cars
definitely "vroom" the right way.  Twiddling the balance and my speakers
are the right way round too.  Can you double check?

Steve