Symbian
Symbian OS Library

SYMBIAN OS V9.3

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SIP SDP Codec Overview


Purpose

When initiating multimedia teleconferences, voice-over-IP calls, streaming video, or other real-time sessions, there is a need to convey media details, transport addresses, and other session description metadata to the participants.

SDP, or (S)ession (D)escription (P)rotocol, provides the standard representation for such information. This representation is independent of the way that information is transported.

Transport protocols that can deal with SDP include SAP, SIP, RTSP, electronic mail using the MIME extensions, and HTTP.

The SDP Codec subsystem offers its clients an API for encoding SDP descriptions into their internal form, for decoding the descriptions from their internal form, and for setting and getting SDP field values.

You may find the following references useful:

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Architectural Relationships

Calls to the SDP Codec API are synchronous.

The API requires no capabilities.

The API cannot be extended.

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Description of the interface class structure

The client uses some or all of the SDP Codec API classes during the handling of a SDP description.

Interface classes all derive from CBase.

The client has a 'use' relationship with the SDP Codec API library.

The following diagram shows the SDP Codec API class structure.

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Memory overhead

The amount of overhead memory used by every header object of the SDP Codec API is at least the same as the memory used by the header as text.