1.3.1 Initialization Sequence

The initialization sequence has the following goals:

  1. To establish the client and server protocol versions and capabilities.

  2. To establish a list of audio formats supported by both the client and the server.

  3. To begin recording audio data.

Initially, the server sends a Version PDU to the client within the already established dynamic virtual channel. The client will respond with its own Version PDU. Next, the server will send a Sound Formats PDU, which contains a list of the audio formats the server supports. The client sends its own Sound Formats PDU to the server, establishing the common list of audio formats. All audio data will be encoded using one of the formats in this list.

Once the audio formats have been exchanged, the server will indicate that it has requested to begin recording, by sending an Open PDU. The client will attempt to start recording from an attached audio capture device and return the result to the server in an Open Reply PDU. At this point, the client will begin sending audio data.

Initialization sequence

Figure 1: Initialization sequence