[Nils]

Audio downmixing is currently restricted to "downmix to stereo" on Mac OSX.

Since my audio set-up consists of a 5.1 USB audio card and a dumb 5 channel amplifier, I have to choose between downmixing to stereo or getting proper 5 channel surround sound, but losing the LFE channel.

After getting my build environment set up (thanks davilla!), I have played around with porting the channel remapping routines that exist on Linux and Windows.

I have a working version now (and therefore LFE mixed into the front speakers):
http://trac.xbmc.org/ticket/9493

Right now it only affects analog output, because I don't have the hardware to test anything else. Downmix format is selected in the audio settings window, where the switches existing in Windows/Linux have been enabled for Mac.

I am hoping for suggestions.

[davilla]

Audio downmixing is currently restricted to "downmix to stereo" on Mac OSX.

Since my audio set-up consists of a 5.1 USB audio card and a dumb 5 channel amplifier, I have to choose between downmixing to stereo or getting proper 5 channel surround sound, but losing the LFE channel.

After getting my build environment set up (thanks davilla!), I have played around with porting the channel remapping routines that exist on Linux and Windows.

I have a working version now (and therefore LFE mixed into the front speakers):
http://trac.xbmc.org/ticket/9493

Right now it only affects analog output, because I don't have the hardware to test anything else. Downmix format is selected in the audio settings window, where the switches existing in Windows/Linux have been enabled for Mac.

I am hoping for suggestions.

Cool, thx. I'll need to get a dev with digital out to test it.

[Nils]

I left the "downmix to stereo" switch (in guisettings.cpp) in place for now, because it works directly on the audio-codecs. I guess this should work together with the AC3 encoder function. Is this used?
Any audio system with AC3 input probably implements downmixing, so the switch can most likely be removed now... same as on Windows and Linux.

[davilla]

I left the "downmix to stereo" switch (in guisettings.cpp) in place for now, because it works directly on the audio-codecs. I guess this should work together with the AC3 encoder function. Is this used?
Any audio system with AC3 input probably implements downmixing, so the switch can most likely be removed now... same as on Windows and Linux.

Not really, downmix to stereo will multi-channel digital to two channel digital. Very useful for sending digital to HDTV that only understand two channel digital. I'd have to play some more with it so that we don't remove existing ability. Our OSX audio expert is busy with real life right now so we are just filling in now.

[davilla]

http://trac.xbmc.org/changeset/31483

"downmix to stereo" is also removed as well as all refs to audiooutput.downmixmultichannel which seem to be only OSX related.

thx again.