Re: [Bluez-devel] CVS audio-api.txt : 1st question

Brad Midgley
2007-07-06T23:44:17Z

Hi

> In my opinion the native elements wouldn't do any encoding/decoding
> work: this is clearly GStreamer Job as a media converting framework.
> I think we would have to:
> - extend the already included RTP GStreamer element to accept sbc and
> mp3 encoded streams.
> - wrap libsbc into a GStreamer element to do convert to do PCM to sbc.
> - create an a2dp Gstreamer element

Although this is really cool to deliver mp3 to the headset (less cpu
load, less transcoding noise), it might go too far down the road of an
early optimization for the case of a single audio client.

Mikko L at Nokia basically said they wouldn't consider anything along
these lines since it gets so complicated when a system sound needs to
interrupt mp3 playback. Do you:

- mix two mp3 streams together (technically possible)
- reconfigure the set for sbc and encode the streams to sbc (best
case is a delay, worst case a crash in the set during reconfiguration)
- stop the mp3 player and play the system sound mp3 instead (tricky)

It doesn't help that there's not much notion of a sound "card" that
can natively decode mp3. The audio servers don't account for this
possibility at all.

Brad