i've noticed that when i connect a ear peice vs. some BT headphones that one gets an aditional profile, "media audio" and "phone audio" so i did some research. adroid uses a2dp (advanced audio distribution profile) there are actually more than one profile in this profile.
1) thing to keep in mind "A2DP was initially used in conjunction with an intermediate Bluetooth transceiver that connects to a standard audio output jack, encodes
the incoming audio to a Bluetooth-friendly format, and sends the signal wirelessly to Bluetooth headphones that decode
and play the audio.Bluetooth headphones
, especially the more advanced models, often come with a microphone and support for the Headset (HSP)
, Hands-Free (HFP)
and Audio/Video Remote Control (AVRCP) profiles
A) decoding needs to occur on the device, the more decoding that occurs the more processing that the device needs to have hardware capable of doing so.
B) the above is a definition of a headphone device. their usto be 2 different types of profiles offered for headsets and headphones, this got confusing really confusing when choosing a headset or headphone for said device.
C) because people would never actually need to use 2 channels of audio (stereo) or high quality sound for phone calls it was stupid to process all of that quality people weren't using only to drain the battery so quickly, they came up with a stripped down version of the headphone high quality profile, it's defining principle was that it was mono (1 channel) and low quality, to dramatically save battery and allow smaller size headsets.
2)headset profiles have a bi-directional (2 way) connection at all times and headphones only needed to have a uni-directional (one way) connection. if your headset is playing music through the car, and it is constantly listening to the mic, then it's constantly processing what is playing from your car speakers at the exact same time, and this would cause problems.