callData (17)

The callData message is used to transport the actual media stream for an active call. Each message contains a small chunk of encrypted audio or video data.

This message is a specialized version of the generic appData message, sent repeatedly during an active call.

Core Data Types

• IxiBytes: See IxiBytes Encoding.

Payload Structure

The payload follows the structure of an AppDataMessage.

Field	Data Type	Min	Max	Description
sessionId	IxiBytes	*	*	The unique identifier of the active call session to which this media chunk belongs.
data	IxiBytes	1	*	The raw, typically compressed, chunk of audio or video data.

Behavioral Notes

• Continuous Stream: Once a call is established (via acceptCall), both clients continuously send and receive a stream of callData messages.
• Implementation: Media chunks are placed in the data field of an AppDataMessage payload and sent using a SpixiMessage of type appData.
• Unreliable Transport: The StreamMessage envelope for callData MUST have its requireRcvConfirmation flag set to false. Real-time media protocols are designed to handle packet loss, and waiting for acknowledgments would introduce unacceptable latency. Lost packets are simply skipped.