[pulseaudio-discuss] ANN: automatic multichannel profile selection for PulseAudio

Manuel Amador (Rudd-O) rudd-o at rudd-o.com
Tue Jan 11 11:10:31 UTC 2022

I have just released pautosurround — a companion for PulseAudio to be 
used in HTPC and home theater scenarios.

The code is here: https://github.com/Rudd-O/pautosurround

Many people have been, through fortune or hard work, blessed with the 
opportunity to have a home cinema.

Quite a few of those people run an HTPC with Linux (and PulseAudio) on 
it.  This HTPC tends to be connected — through either HDMI or a 
multichannel sound card — to an advanced receiver or home theater 
system, with support for multichannel audio (5.1, 7.1 or more).

If you are fortunate enough to find yourself in this scenario, 
PulseAudio is fantastic for you.  Through the PulseAudio volume control, 
it lets you select whether you want your audio to be stereo, or 5.1, or 
7.1.  When listening to tunes, you select stereo, and enjoy your home 
theater's intelligent upmixing of sound.  When watching movies, you 
select 5.1 or 7.1, and the receiver gets the full multichannel signal 
from your favorite media player.

As long as you remember to switch to the appropriate profile, you should 
be good.  But, if you don't, well, things don't sound very well:

  * If you play stereo music in multichannel mode, the receiver thinks
    it's getting multichannel sound, and so it can't intelligently upmix
    or do Dolby Pro Logic.
  * If you play movies in stereo mode, the receiver doesn't get all the
    channels — you might miss the center channel, the surround sounds
    will be faked, and you'll get no subwoofer / LFE signal either.

Come to think of it, that's a bit of a bother.  Shouldn't the profile be 
automatic?  After all, the media player already knows it's either 
playing stereo sound or multichannel sound.  You already know the 
computer is connected to a multichannel receiver.  Why can't the 
computer know to select the appropriate output mode?

Well, now it can.   With pautosurround, the computer autoselects 5.1 
when multichannel content is played, and reverts back to its 
previously-selected profile once it's done.  This is something that not 
even Windows has.


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/pulseaudio-discuss/attachments/20220111/de92c2b5/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: OpenPGP_signature
Type: application/pgp-signature
Size: 833 bytes
Desc: OpenPGP digital signature
URL: <https://lists.freedesktop.org/archives/pulseaudio-discuss/attachments/20220111/de92c2b5/attachment.sig>

More information about the pulseaudio-discuss mailing list