[Bluez-devel] how to change volume for a2dp headset?

[Bluez-devel] how to change volume for a2dp headset?

[Galaha Shine]

hi,

I just wonder if it is possible to change a2dp headset volume by D-bus
command?

I notice there is a D-bus API SetSpeakerGain in bluez 3.36. I've try it
with my sco headset and it works. But it doesn't work when I try it with
a a2dp headset. Dbus returns an error that is unconnected. Then I
download bluez 4.13 which is the latest build. I notice that API
SetSpeakerGain becomes deprecated. Meanwhile I find control-api.txt
which seems haven't been implemented yet. 

Could anybody give me a hint how to control a2dp headset from host side
by D-bus command?

regards,
Galaha


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Re: [Bluez-devel] how to change volume for a2dp headset?

[Johan Hedberg]

Hi Galaha,

On Oct 16, 2008, at 19:31, Galaha Shine wrote:
> I just wonder if it is possible to change a2dp headset volume by D-bus
> command?
>
> I notice there is a D-bus API SetSpeakerGain in bluez 3.36. I've try  
> it
> with my sco headset and it works. But it doesn't work when I try it  
> with
> a a2dp headset. Dbus returns an error that is unconnected. Then I
> download bluez 4.13 which is the latest build. I notice that API
> SetSpeakerGain becomes deprecated. Meanwhile I find control-api.txt
> which seems haven't been implemented yet.
>
> Could anybody give me a hint how to control a2dp headset from host  
> side
> by D-bus command?

The simple answer is that you can't do that at the moment. BlueZ has  
never supported controller (CT) side features of the AVRCP profile.  
There has been some talk about adding friendly D-Bus methods for this  
into the org.bluez.Control interface but it seems we forgot to add  
place holders for it into the control-api.txt API doc when the other  
new AVRCP features (that David Stockwell has worked on) were added  
there. I guess we should look into implementing this once David's  
patches get integrated upstream, but until then you'll have to control  
your A2DP volume from the headphone side.

Johan 

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