A2DP

One of the Bluetooth profiles is called A2DP or Advanced Audio Distribution Profile. It is a mode used to stream audio such as streaming of music phones to headphones. The A2DP is different from the Headset and Handsfree profiles because it supports stereo audio. Instead of two-way streaming, A2DP only features one-way streaming.

The A2DP Bluetooth profile defines the streaming process of stereo and mono quality audios from a device to another powered by a Bluetooth connection. One good example is streaming of music from a mobile phone to a car audio setup or a wireless headset. Another example is streaming of music from a laptop or PC to a wireless headset.

The initial use of the technology was performed in the integration of an intermediate Bluetooth transceiver and the standard audio output jack. The technology was able to encode incoming audio into a format that the Bluetooth technology can understand. Then it sends a wireless signal to Bluetooth-capable headphones that will play the audio file.

Bluetooth headphones usually come with a microphone, especially those that are part of the advanced models of the technology. The headphones can support profiles such as handsfree, headset, video/audio remote control, and AVRCP.

Because the A2DP technology is more of a one-way technology, audio streaming with the use of the technology is intended for the purpose of moving music directly to the headset or car radio devices. The profiles that define this type of streaming are under the AVDTP and GADVP.

Other options supported by the A2DP are files in the MPEG-4, MPEG-2, MPEG-1 and ATRAC formats. There are instances when the A2DP is used as an extensible support to codecs like the apt-X.

The BlueZ in the Linux version 3.15 features the A2DP technology support. Instructions on the setup of the technology are found in the Bluez Wiki which is the official protocol stack of the Linux Bluetooth technology.