[pulseaudio-discuss] Weak bass in stereo mode – possibility of virtual 2.1 sound profiles
tanuk at iki.fi
Fri Nov 16 06:13:09 UTC 2018
On Thu, 2018-11-15 at 23:50 +0500, Alexander E. Patrakov wrote:
> Alexander E. Patrakov <patrakov at gmail.com>:
> > Tanu Kaskinen <tanuk at iki.fi>:
> > > On Sat, 2018-10-13 at 22:29 +0500, Alexander E. Patrakov wrote:
> > > > Note that I am unhappy with it, because it fixes only a particular
> > > > common problem case, while other related issues stay unfixed. E.g. if
> > > > one tries to play 5.1 audio on 7.1 system, with or without this patch:
> > > >
> > > > - Front, Center and LFE channels are mapped 1:1, which is correct
> > > > - Rear (or what mpv calls "Side") source channels are mapped to Side,
> > > > which is also correct, because it's the Side speakers in the ITU-T 7.1
> > > > layout, not Rear, which have the nearest position to what Dolby
> > > > specifies for Surround AC3 speakers.
> > > > - The true rear channels get a mix between Front and Side, which is
> > > > clearly incorrect. ITU R-REC-BS.775-3-201208 says that both sets of
> > > > surround channels should be fed the same signal.
> > >
> > > Regarding that last point, do I understand correctly that the
> > > recommendation is to duplicate the 5.1 rear(/side) channels to both the
> > > side and rear channels in 7.1? Doesn't that cause imbalance by
> > > amplifying the rear channels? Or is it compensated by attenuating the
> > > signal?
> > You understood correctly. In my big patch, it is compensated by
> > attenuating the signal. Anyway, I am going to resubmit it later today
> > without the half-baked change about the LFE volume.
> Sorry, I have to do it later. I have too much non-PulseAudio work to do :(
No problem, I'll postpone reviewing the patch until you've submitted
the new version. From what I already saw, the general idea behind the
patch seems good.
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