PC as ZonePlayer

[MFoley]

I've purchases a couple of Sonos starter kits and would like my PC to
be part of the system as a zone. I started some software in this
direction. The Sonos ZonePlayers seem to respond to standard UPnP
MediaRenderer commands. Using basic UPnP code, I'm able to have one app
control the Sonos ZonePlayers and PC-based MediaRenderer. However, I
haven't yet determined what Sonos is doing during the "Zone setup->add"
process. I.e. how a ZonePlayer is entered into the Sonos world in
either the PC Desktop Controller or the Sonos Controller. It appears
that this is the major hurdle that I need to overcome to get the PC as
a zone in the Sonos system. Before I dig into figuring out how this is
done, I thought I'd ask if anyone has already determined this or found
doucmentation and would like to share. (I've also asked Sonos to
publish this information which would be the best solutions.)

[Steve Eisner]

Sonos unfortunately is not inclined to release that info as that may impact their sales of ZonePlayers, or their option to create a PC zone themselves.

 

I think you *could* make your app appear to be a zoneplayer by simply exposing the exact same UPNP actions & responses as a zoneplayer does.  In other words, an apparent zone clone.  But my guess is that if you make one misstep -- don't respond as expected -- you will be kicked out of the group (there even seems to be an exposed API to do this?)

 

There are two things that are going to be very tricky for you to write:

#1, the zone mesh network code, which is basicallly what the zone add sets up.  This is what allows zones to negotiate which one should be the master, etc.  Zones are constantly analyzing network status etc. between themselves and other zones and you must participate in this to be a zone.  I'm not sure there is any way for you to get in on this traffic; it may not even use UPNP.

#2, the synchronization code which keeps zoneplayers in perfect sync - this may be a proprietary extension on top of the standard UPNP AV or perhaps is done with the "play speed" parameter, I don't know.

 

If you don't mind ignoring #2, here is something you could write without too much trouble:  instead of trying to include the PC as a first-class zone, make it a "mirror" of one of the zones.  In other words, it just sits there watching a single zone and playing whatever that zone is playing (since one of the things a zone can be playing is another zone, you may need to walk the chain until you find the original source.)  Because of the lag in event notification, there will also be a noticeable delay unless you figure out some sync code...

 

Good luck!  Let us know how it goes...

 

Steve
 

[MFoley]

There are good points there that may or may not be worth the effort to
overcome. I'm traveling starting tomorrow so won't be able to spend too
much time on code until Thanksgiving week. I'll review the code and
documentation in the mean time so perhaps I can be productive when I
get back.

I see the point you raise about Sonos not wanting to publish this
information. However, I think it is short sighted on their part. They
are currently in a position where they can lead this ecosystem and
define/own the platform. Getting developers onto their platform only
strengthens their position which will result in more of their hardware
being sold. Trying to own this entire market as a single, small company
is an uphill battle that I doubt they can win.

[crum...@gmail.com]

Wow, this is great to see someone is working on this. I know if you get
any progress on this app you will make a lot of forum goers happy :)

[MFoley]

I'll spend some more time on it over Thanksgiving. (I'm traveling in
Europe now...) I was hoping to get some technical information to review
from Sonos, but so far no joy there.

[crum...@gmail.com]

MFoley, Sonos seems pretty tight about giving out software details (it
took quite some time for them to even tell us about the UPnP controls).
Good luck, but I wouldn't hold my breath.

[MFoley]

That is what I'm finding as well. Do you have solid documentation on
the controls? I've been taking a more experimental approach.

[crum...@gmail.com]

I assume you've seen Intel's UPnP tools?
http://www.intel.com/cd/ids/developer/asmo-na/eng/downloads/upnp/overview/index.htm#tools

If not, they should help out a bit. You can use Device Spy to control a
ZonePlayer, and then view the exact XML code that was sent (for
implementation in your own programs). I think Microsoft has their own
UPNP DLL which you may prefer.

And of course there's the source code in previous threads in this
forum. Sorry I can't be of more help - to tell the truth I'm more of a
user than a programmer :)

[crum...@gmail.com]

Here's the thread where it was announced:
http://forums.sonos.com/showthread.php?t=189&highlight=upnp

There may be more info in old DE threads too.

[MFoley]

I had missed that thread. Thanks.

I have been using the Intel UPnP tools and still have a great many
contacts there as well as at MSFT from my days working there.

[Steve Eisner]

Take a look at previous threads - I uploaded source a .NET library that wraps UPNP so you don't need to worry about the implementation details so much and can just execute commands against ZonePlayers. 

 

I'll be releasing new code pretty soon as the latest version of Sonos software has changed the format of some APIs.