[LINUX/MAC/WINDOWS] Active/Passive Multi Zone Audio Support

XBMC interface for Active/Passive Multi-Zone (multi-rooom) Audio

Concept:

XBMC controls one/more sound cards within the same computer.
- enables that PC to connect to amp(s) that run to speakers in multiple locations.
- acts as a switcher (on/off) and volume control for each zone
- the only control interface needed to control multiple rooms/zones
- acts as multiple "source" switch, thus each zone can play different audio

Please Note: This request is NOT for streaming to other devices, that is active/active as shown below...

OK so I've seen threads talking about iTunes and Airtunes support, and multiroom streaming, but from what I can tell none propose quite what I am about to. Support for sending multiple audio streams to different wireless speakers all controlled from xbmc.

Firstly the reasoning behind this is that whilst Airport express stations and itunes offer a very affordable solution to multiroom audio streaming what it doesn't do unfortunately is allow you to send differently audio streams to different express stations.

Obviously this feature would be disabled by default as most people wont have the hardware. However if they did the process might be something like:

SETTING UP
-------------------------------
1. Go into multiroom settings and enable multiroom support
2. Set up your zones
a) create a new zone
b) add wireless speakers to your zone
c) repeat until set up is complete
- Zones would also need to be editable
- Speakers should be able to attached to more than one zone eg kitchen and downstairs

PLAYING MUSIC
-------------------------------------
1) Browse you music as normal when you click to play a track a dialog asks you in what zone you would like to play it in

PLAYING VIDEO
-------------------------------------
When playing a video in the audio options you should be able to include zones to be used for the current playback

Airtunes and Airport express spring to mind as the priority system as that seems to be the one most in need of this feature however i think that any development should be split into frontend and backend so backends for other wireless speaker systems can be added and possibly used together.

I am very new to both C and python scripting so if this was to happen I would need a large amount of help however I am keen to get involved my self.

The Airport Express as audio sink part would probably be the easy part of that concept (if and) when PulseAudio implements it, see:
http://www.pulseaudio.org/ticket/69

The hard part would the XBMC back-end and front-end. Making XBMC support multiple audio-player cores running at the same time, and a front-end GUI to setup those different zones and the the user interface to control playback to them.

You might get some ideas from LinuxMCE which I believe support that (or at least something similar) via its modified Orbiter GUI Pluto framework, see: http://www.linuxmce.org
http://wiki.linuxmce.org/index.php/History
http://wiki.linuxmce.org/index.php/Developers

You can find XBMC development resources here:
http://wiki.xbmc.org/?title=Appendix_D:_...ment_Notes

am i right in thinking that xbmc uses mplayer
does it use this for audio playback, i dont think it would the end of the world if this was only possible for music

unfortunately from what i can tell all the other projects mention so far offer controlling different stream to different zones

anyhow here is a rough idea of how it might work

http://www.digitalintuition.co.uk/multizone.jpg

msaspence Wrote:am i right in thinking that xbmc uses mplayer

No it is a little more complicated than that under the surface, see:
http://wiki.xbmc.org/?title=Audio_Players
http://wiki.xbmc.org/?title=Video_Players
All audio/video players in XBMC works seamlessly to the end-user

are all running at all times?

or are they launched when they are the player being used?

They are only loaded on-demand, they are compiled as separate dynamic link libraries (DLL) and loaded by XBMC's DLL loader.
http://wiki.xbmc.org/?title=Basic_overvi...ource_code

I do not personally know how it works at a source code level, but at least under Linux, Mac, and Windows it is easy to explain as "PAPlayer" is the only audio player and "DVDPlayer" is the only video player. On the Xbox it depends on which format and codecs are used if "DVDPlayer" or "MPlayer" are used.

I think a great addition to XBMC to make it a fully fledged "Media Center" would be Multi-zone Audio control interface.

Successful multi-zone control includes...

1) GUI interface to control all zones
2) Complete command set available via http
3) Ability to send different audio streams to each zone
4) Ability to use each 'channel' of a sound card as a single/separate zone
... e.g. a 5.1 built-in sound card could run 6 separate zones

I should have elaborated/clarified I'm looking for Multi-Zone Audio, not Distributed (Streaming)...

Multi-Zone Audio vs Distributed (Streaming)

Multi-Zone = Zone Unit distributes audio directly to speakers in multiple locations. Single Unit is controlled from multiple locations but is essentially controlling a single unit/interface.

Distributed (aka Streaming) = Distribution Unit (usually with no local control) sends audio to multiple Receivers which, in turn control each zone separately.

Ideally... my HTPC is the 'zone unit' and only system. I'd like to use the HTPC to run/control all zones via the internal sound card. Then control it via a web interface and XBMC (both on HTPC)

I'd be using my Windows Mobile phone's WiFi to run the web site to control the web interface on the HTPC and set each zone to different music and/or different volume levels.

I noticed PulseAudio now has support for AirPort Express... I'm hoping that a dev takes interest and we can start down the road to multi-zone audio support in XBMC!