<?xml version="1.0" encoding="utf-8"?>

<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->

<!-- This component and the accompanying materials are made available under the terms of the License 

"Eclipse Public License v1.0" which accompanies this distribution, 

and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->

<!-- Initial Contributors:

    Nokia Corporation - initial contribution.

Contributors: 

-->

<!DOCTYPE concept

  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

<concept id="GUID-D5DDC05E-B8C6-5BF0-AEBA-EED1D88BB5BB" xml:lang="en"><title>CAF

Streaming Support Overview</title><abstract><p><xref href="GUID-7EE46FD9-DC9E-5C1F-9AC5-48F5212AF0CA.dita">CAF</xref> Streaming

Support component comprises a framework that provides interfaces for managing <xref href="http://en.wikipedia.org/wiki/Digital_rights_management" scope="external">Digital

Rights Management (DRM)</xref> protected streamed data. </p></abstract><prolog><metadata><keywords/></metadata></prolog><conbody>

<section><title>Purpose</title> <p>CAF streaming framework provides interfaces

for applications to access DRM protected data stream using streaming agents.

A CAF streaming agent is an ECom plug-in that provides streaming <xref href="http://en.wikipedia.org/wiki/Digital_rights_management" scope="external">DRM</xref> data support in CAF. </p> <p>Device creators can

use the interfaces provided by the framework to support streaming DRM content. </p> </section>

<section><title>Key concepts</title> <dl>

<dlentry>

<dt>CAF streaming agent</dt>

<dd><p>A CAF streaming agent is an ECom plug-in that provides streaming <xref href="http://en.wikipedia.org/wiki/Digital_rights_management" scope="external">DRM</xref> data

support. </p> </dd>

</dlentry>

<dlentry>

<dt>Key stream</dt>

<dd><p>A stream of data and meta-data required for decrypting encrypted media

streams. </p> </dd>

</dlentry>

<dlentry>

<dt>Key stream decoder</dt>

<dd><p>A key stream decoder decrypts the key stream. </p> </dd>

</dlentry>

<dlentry>

<dt>Data stream</dt>

<dd><p>A sequence of digitally encrypted packets of data (media data). </p> </dd>

</dlentry>

<dlentry>

<dt>Short-term key</dt>

<dd><p>A key that decrypts data packets. </p> </dd>

</dlentry>

<dlentry>

<dt>Long-term key</dt>

<dd><p>A key that encrypts short-term keys. </p> </dd>

</dlentry>

<dlentry>

<dt>Cryptographic context</dt>

<dd><p>The key data along with its corresponding meta-data, such as algorithms

and usage parameters. </p> </dd>

</dlentry>

<dlentry>

<dt>Rights Object</dt>

<dd><p>A file that includes long-term keys, usage rights such as the validity

and expiry dates for which the subscription is purchased and post-acquisition

rights. </p> </dd>

</dlentry>

<dlentry>

<dt>Session Description Protocol (SDP) </dt>

<dd><p>The SDP protocol specifies the properties of a streaming media session.

The protocol includes information such as audio and video encoding type, addresses

for delivering the respective streams, protection of the streamed data and

so on. </p> </dd>

</dlentry>

</dl> </section>

<section><title>Architecture</title> <p> <i>CAF for Streaming Support</i> handles

DRM protected key stream. The framework handles specific standards including <xref href="http://en.wikipedia.org/wiki/DVB-H" scope="external">DVB-H</xref> and <xref href="http://en.wikipedia.org/wiki/OMA_BCAST" scope="external">OMA DRM BCAST</xref> (DRM

and SmartCard profiles) using CAF streaming agent. The CAF streaming agent

manages the key stream, but does not process the data stream. </p> <p>The

agent receives a key stream containing short-term key. It checks if the received

key stream is supported and if so, associates it with an appropriate key stream

decoder for decryption and pushes the decrypted (cryptographic) context to

data processing stack such as <i>CommsServer</i> for processing the data stream. </p> <p>The

agent and entities in the data processing stack have to be assured and maintained

for setting the cryptographic context (short-term key and relevant algorithms).

The processed data is then passed to the appropriate streaming player middleware

(audio or video device drivers) for playback or recording using <b>Multimedia

Framework</b>. </p> <fig id="GUID-CF002BDE-3759-5603-AC5C-546ADC4DAA86">

<title>              CAF Streaming Support Architecture            </title>

</fig> <p>For information about the set-up and tear down of streaming session,

see <xref href="GUID-DD95C4FA-B044-5A0E-A556-C7171AEFED8E.dita">Streaming Session

Sequence</xref>. </p> </section>

<section><title>APIs</title> <p>The streaming CAF interfaces are defined using

the namespace <xref href="GUID-D6AB6275-9EEF-370C-8556-D6354FB46583.dita"><apiname>StreamAccess</apiname></xref>. </p> <table id="GUID-E60A4002-2D6B-5F94-B3D3-661AF3BE8722">

<tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/>

<thead>

<row>

<entry>Class Name</entry>

<entry>Description</entry>

</row>

</thead>

<tbody>

<row>

<entry><p> <xref href="GUID-D6AB6275-9EEF-370C-8556-D6354FB46583.dita#GUID-D6AB6275-9EEF-370C-8556-D6354FB46583/GUID-358B5544-5184-342E-9968-7EDA1D185811"><apiname>StreamAccess::CAgentKeyStreamDecoder</apiname></xref>  </p> </entry>

<entry><p>Represents the base class for a CAF streaming agent </p> </entry>

</row>

<row>

<entry><p> <xref href="GUID-D6AB6275-9EEF-370C-8556-D6354FB46583.dita#GUID-D6AB6275-9EEF-370C-8556-D6354FB46583/GUID-88594631-30C1-3046-B2D4-1DE7128699A2"><apiname>StreamAccess::CKeyStreamDecoder</apiname></xref>  </p> </entry>

<entry><p>Allows clients to instantiate key stream decoders for short-term

key streams in protected broadcasts. </p> </entry>

</row>

<row>

<entry><p> <xref href="GUID-D6AB6275-9EEF-370C-8556-D6354FB46583.dita#GUID-D6AB6275-9EEF-370C-8556-D6354FB46583/GUID-8CBEED82-471C-3198-ACED-C1A2F5C23216"><apiname>StreamAccess::CStreamAgentFactory</apiname></xref>  </p> </entry>

<entry><p>Represents a factory class responsible for creating instances of <xref href="GUID-D6AB6275-9EEF-370C-8556-D6354FB46583.dita#GUID-D6AB6275-9EEF-370C-8556-D6354FB46583/GUID-88594631-30C1-3046-B2D4-1DE7128699A2"><apiname>StreamAccess::CKeyStreamDecoder</apiname></xref>. </p> </entry>

</row>

<row>

<entry><p> <xref href="GUID-D6AB6275-9EEF-370C-8556-D6354FB46583.dita#GUID-D6AB6275-9EEF-370C-8556-D6354FB46583/GUID-F7615BC3-73C7-33B4-96B6-00AF9B10AB3C"><apiname>StreamAccess::CKeyStreamSink</apiname></xref>  </p> </entry>

<entry><p>Defines the abstract class for key stream sink. Key stream sink

is used for applying keys decrypted by the CAF streaming agent to their correct

destination. </p> </entry>

</row>

</tbody>

</tgroup>

</table> <p>A CAF streaming agent plug-in must implement <xref href="GUID-CB467A21-BFBF-3DB8-8163-8E3ED9191B4C.dita"><apiname>CAgentKeyStreamDecoder</apiname></xref>.

A streaming player middleware, for example the Multimedia Framework controller

(MMF controller), must use <xref href="GUID-EE67D14D-1011-3B27-ADEC-C6C192339903.dita"><apiname>CKeyStreamDecoder</apiname></xref>. The figure

below shows the key classes of CAF streaming agent. </p> <fig id="GUID-5A9F3FAB-E8FC-53B4-B71B-1D2A616E89BA">

<title>              Class diagram            </title>

</fig> </section>

<section><title>Typical uses</title> <p>CAF Streaming Support provides interfaces

to create an ECom based streaming agent. A streaming player middleware such

as MMF controller uses streaming agent to view and access the key stream.

For more information, see <xref href="GUID-D5DDC05E-B8C6-5BF0-AEBA-EED1D88BB5BB.dita">CAF

Streaming Support Tutorials</xref> . </p> </section>

</conbody><related-links>

<link href="GUID-92FC3BBB-9C80-5665-8421-5C6A11BE4A5C.dita"><linktext> CAF Streaming

Support Concepts</linktext></link>

<link href="GUID-4AAE6CC7-7F0B-51B7-8F6F-7E538841DF41.dita"><linktext>Writing CAF

Streaming Agents</linktext></link>

</related-links></concept>