collaborating on bluetooth audio
Michael 'Mickey' Lauer
mickey at openmoko.org
Sun Jan 28 16:09:46 CET 2007
FYI: I have forwarded this from the community-list, since it seems to
be right on the spot for the devel-list.
Lars Hallberg wrote:
> Brad Midgley skrev:
>> > After reading the LCA slides on pulse-audio it seems to be the
>> best choice for an
>> > audiorouting app
>> FYI, I mocked up some diagrams including one that incorporates pulse.
>> I am hoping to have some of these ideas validated, so let me know if
>> you have any thoughts on it.
> I like the use of D-bus for finding out whats there and hove to use it.
> But there really should be *one* audio connection manager. Were I can
> find a headset whether it is connected by usb or blutooth or anything
> else. And find out hove to connect to it (preferably in many ways, ie:
> hove to build a gst stream, hove to connect by pulse, hove to get a dsp
> interface, hove to get at it with alsa, hove to get at it by some
> lowlevel interface (eg: by blutooth directly). So an app can choose to
> connect the best way it know.
> For apps that don't care much for latency, it shuld be possible
> streaming the sound by D-bus, encoded with mimetype, or tell the D-bus
> service to play a file with (optionally?) given mimetype. Record to a
> file or D-bus stream into given mimetype. Then those apps only need to
> know hove to talk D-bus to get sound support. Don't need to know
> anything about encoders or conections, just ask the system what is
> That gives a few D-bus services:
> General audio connection mgt, possably xfer agent.
> Blutooth audio device discovery agent.
> USB audio device discovery agent.
> Build audio connection service (possably several different
> 'protocol'/sources/targets). Support for mixer to?
> D-bus audio sink (passably several different for different formats -
> destinations). Support volume?
> D-bus audio source (passably several different for different formats -
> source). Support volume?
> This can be implemented in one demon, in several demons, inside other
> demons (like ones who discover other usb/blutooth devices). D-bus
> activation should let the app just talk to the D-bus interface the
> General audio connection manager point it to. Even pulse could be
> started on demand if we want :-)
> It need not be implemented in one shot ether. It's possably starting out
> supporting, say, only pulse and only main audio and blutooth. But USB
> shuld be a priority too.
> The D-bus audio sink/source may be left to more advanced media player
> apps/libs to implement. The audio connection mgr only need interface to
> register services and offer them.
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Michael 'Mickey' Lauer | OpenMoko Software Team
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