How to disable volume control? (Set permanent absolute volume)

[FlashStopFall]

I am using this (wonderful) library to add bluetooth audio to my car's (Jeep WJ) factory radio. Because the volume control is done from the radio, I don't want any volume control from the audio source. I see the A2DPNoVolumeControl class, an the set_enabled function in A2DPVolumeControl.h, but I do not know how to use them; my C coding skills are not that great. Are there any examples that use this functionality?

Thank you,
Ian

[FlashStopFall]

Ah, the next page I clicked after posting this had most of the answer: VolumeControl

This works, but still allows the volume to be set on the source device; it just has no effect unless set to zero. Is there any way to disable volume controls on the source device (iPhone) like real bluetooth head units do?

[FlashStopFall]

Also, is there a way to change the default output volume when using A2DPNoVolumeControl?

[pschatzmann]

I am not sure if I understand you correctly: using the A2DPNoVolumeControl is just making sure that the audio is sent to the output as-is (w/o reducing the volume).

If you want to pin it to a fixed value, just implement your own A2DPVolumeControl subclass that sets the volumeFactor to your desired value.

ps. I have added a constructor to the A2DPNoVolumeControl that accepts the fixed reduced volume...

[FlashStopFall]

Thank you! I cannot get into trying it out at the moment, but that sounds like just what I need.

To be clear about my question, would that allow the volume to be set at a specific level and stay there regardless the volume control on the source device (volume slider on iPhone).

As to the other half of my question (should I make a new issue for this?) head unit A2DP receivers usually do not allow commanded volume to be set at all from the source device (i.e. the iOS volume slider is grayed out). This is really what I would like to implement, while then being able to set the output volume level absolutely (because the default/unchanged output level from my DAC is not the ideal input level for the proprietary Chrysler head unit which I am sending the audio to). So my 2nd question is really; has the feature to disable volume control on the source device been implemented?