4.1 Audio Level Protocol initialization and change
An RDP client that has persisted audio level data for both the render and capture dataflows (as defined in [MSDN-EDataFlow]) creates a new session on an RDP server.
The RDP server begins monitoring the RDP audio device for master volume level changes.
The RDP server sends an SAE_Started message to the client.
The RDP client retrieves persisted render dataflow audio level data and sends an SAE_VolumeChange message to the server.
The RDP server changes the master render audio volume to the level in the SAE_VolumeChange message.
The RDP client retrieves persisted capture dataflow audio level data, and sends an SAE_VolumeChange message to the server.
The RDP server changes the master capture audio volume to the level in the SAE_VolumeChange message.
The user changes the render audio volume level in the RDP session.
The RDP server detects the change, and sends an SAE_VolumeChange message to the RDP client.
The RDP client updates its persisted render volume settings to those in the SAE_VolumeChange message.