Page History

...

The characteristic UUID shall be set to: TBD

Audio Data Characteristic Descriptors

Client Characteristic Configuration Descriptor

...

Figure below shows the layout of the start of an ADPCM audio frame. 

Gliffy Diagram
macroId ad21b6d5-0c08-4004-90df-771a3095e7c9 name Audio data pagePin 1

The sequence number shall be incremented for every audio frame encoded, even if the frame was discarded (i.e. in noisy environments). The sequence number shall wrap back to 0x00 after 0xFF. 
Both audio encoders shall use 4 bits per sample, and only one audio channel shall be sampled. The 4-bit samples are packed with the first sample in the four most significant bits and the second sample in the four least significant bits.

Audio Frame Buffering

Audio data is always buffered in 100 octet frames, and the device shall ensure that only complete frames are sent (as 5 x 20 octet GATT notifications). No partial frames shall ever be transferred. This ensures that the STB host can always determine where an audio frame starts and ends.  The RVS Server shall be able to buffer a minimum of 2 audio frames.  If frame buffers are exhausted then the complete frame shall be discarded, however the frame sequence number should still be incremented for the next encoded frame.  All buffered content shall be purged when either a disconnection event occurs, audio streaming is disabled via the Audio Control Characteristic or notifications are disabled for the characteristic.

...