<?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-D1F29744-EB92-5811-A735-B0BC1B352ED5" xml:lang="en"><title>Video+
−
Renderer Overview</title><shortdesc>This topic describes the Video Renderer component and is aimed+
−
at video controller and video adaptation developers who want to take advantage+
−
of rendering to graphics surfaces. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>+
−
<section><title>Purpose</title> <p>The Video Renderer renders video to a graphics+
−
surface. The Video Renderer can be used by video decoders, video post-processors+
−
and video controllers. It can also be used to implement the <xref href="GUID-FC735256-6CB5-5EED-8E7D-42EFA039E6FD.dita">ECam+
−
viewfinder</xref> using a graphics surface. </p> <p>The Video Renderer has+
−
two modes: timed and non-timed. In timed mode, the Video Renderer renders+
−
a frame at a specific time. In non-timed mode, the Video Renderer renders+
−
a frame immediately. </p> <p>On the Symbian platform, <xref href="GUID-D93978BE-11A3-5CE3-B110-1DEAA5AD566C.dita">ScreenPlay</xref> (also+
−
known as the New Graphics Architecture or NGA) enables rendering to a graphics+
−
surface. The Video Renderer can only be used in conjunction with ScreenPlay.+
−
The Video Renderer does not contain any video or graphics processing software.+
−
All operations that are needed to display video content on the screen are+
−
handled by the <xref href="GUID-0DC3E5AA-1706-5255-ACD6-E7AB732E1095.dita">Graphics+
−
Composition Components</xref>. </p> <p>The Video Renderer component is classified+
−
as Optional Replaceable. This means that device creators can either substitute+
−
it with their own implementation or remove it if they do not want to use it. </p> </section>+
−
<section><title>Required background</title> <p>To understand the Video Renderer,+
−
the reader must be familiar with the following: </p> <ul>+
−
<li id="GUID-EAFD5638-403D-5D2F-A787-BD41EEE13CC3"><p><xref href="GUID-ADA8CECB-0E70-5B9C-8F36-0714AAF0CD13.dita">Graphics+
−
Surfaces</xref>  </p> </li>+
−
</ul> </section>+
−
<section><title>Architecture</title> <p>The Video Renderer can be implemented+
−
in two different ways, as shown in the following diagram: </p> <fig id="GUID-33691E6E-8B90-579B-876B-6F14E953BB7C">+
−
<title>              The two Video Renderer architectures            </title>+
−
<image href="GUID-BE11D652-3B39-51D2-ACE9-571E8EB71E94_d0e328424_href.png" placement="inline"/>+
−
</fig> <p> <b>Note</b>: For simplicity, only the Multimedia Framework client/controller+
−
thread boundary has been shown; other thread boundaries may exist. </p> <p>In+
−
both architectures, the <xref href="GUID-0EE3180B-4814-517E-A6DD-748136C17D55.dita">Video+
−
Client API</xref> (<xref href="GUID-42D1182F-46D8-3C78-8D3C-C1BB465FCA1F.dita"><apiname>CVideoPlayerUtility2</apiname></xref>) is responsible+
−
for retrieving graphics surface handles from the video player controller and+
−
registering them with the <xref href="GUID-0C4B86B5-530A-5839-86C1-46E7ABE281E0.dita">Window+
−
Server</xref>. The difference in the two approaches is in the implementation+
−
of the video adaptation and the video player controller: </p> <ul>+
−
<li id="GUID-F47C767B-5040-5E2D-B4A4-E6635B417371"><p> <b>Video adaptation+
−
approach</b>  </p> <p>The video adaptation uses the Video Renderer to create+
−
and manage graphics surfaces and handle video rendering. The video player+
−
controller simply passes surface information between <xref href="GUID-EB58901D-66BD-56BF-B0CD-5FC4F73F06F3.dita">DevVideoPlay</xref> and+
−
the client. An example of this is the Symbian reference AVI player controller+
−
and <xref href="http://developer.symbian.org/wiki/index.php/File:Xvid.zip" scope="external">XVid decoder</xref>. Symbian recommends this approach for+
−
new implementations. </p> </li>+
−
<li id="GUID-64AFC8B9-9BED-5B6D-8946-89BBBF9ACBC5"><p> <b>Video player controller+
−
approach</b>  </p> <p>The video player controller uses the Video Renderer+
−
to create and manage graphics surfaces, and handle video rendering and timing.+
−
This approach is suitable for implementations where DevVideoPlay is only used+
−
as a codec interface or where DevVideoPlay is not used. </p> </li>+
−
</ul> <p>In both architectures, the <xref href="GUID-81A0A2E9-4BB9-58BF-B2D3-08098E7E9C7C.dita">Surface+
−
Update</xref> component provides a communication channel between the Video+
−
Renderer and the composition engine. </p> </section>+
−
<section><title>APIs</title> <p>The Video Renderer component contains the+
−
following DLL with its associated APIs: </p> <table id="GUID-78EF57A1-34BE-5D0B-9B9B-4328FEC0C2C9">+
−
<tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/>+
−
<thead>+
−
<row>+
−
<entry>DLL</entry>+
−
<entry>Description</entry>+
−
</row>+
−
</thead>+
−
<tbody>+
−
<row>+
−
<entry><p> <b>videorenderer.dll </b>  </p> </entry>+
−
<entry><p>The functionality of the Video Renderer is provided by the following+
−
key classes: </p> <ul>+
−
<li id="GUID-D40C598C-FCE4-5840-A58D-A1A8BAB2E52E"><p> <xref href="GUID-AFEC8287-41C9-36BB-B0F7-ECC034D34DC6.dita"><apiname>CVideoRenderer</apiname></xref> -+
−
a utility class for rendering video to graphics surfaces on behalf of a client. </p> </li>+
−
<li id="GUID-1C64FB8F-DAAD-5C76-9650-2984B68499E5"><p> <xref href="GUID-6BB74A8C-B243-368C-8114-E9D4C4D511D0.dita"><apiname>MVideoRendererObserver</apiname></xref> -+
−
an observer class that provides notifications about the availability and status+
−
of buffers submitted for rendering. </p> </li>+
−
<li id="GUID-DB5CFCD9-7ED3-54F6-8E88-182481933170"><p> <xref href="GUID-95DB347F-D669-394D-9BD4-3A2BD18554D4.dita"><apiname>TVideoFrameBuffer</apiname></xref> -+
−
represents a buffer for a single decoded video picture. </p> </li>+
−
</ul> <p>The Video Renderer also uses a resource file (<filepath>videorenderer.rss</filepath>)+
−
to store supported pixel formats and timed mode values. For more information,+
−
see <xref href="GUID-6021BE18-3416-55DF-A628-0071024D7586.dita">Video Renderer+
−
Resource File</xref>. </p> </entry>+
−
</row>+
−
</tbody>+
−
</tgroup>+
−
</table> </section>+
−
<section><title>Typical uses</title> <p>The Video Renderer is used for the+
−
following: </p> <ul>+
−
<li id="GUID-89CA724E-B873-5C9E-8923-700C48D6EC7A"><p>Creating a surface for+
−
video rendering </p> </li>+
−
<li id="GUID-0698BBA1-E5EB-561A-AA77-27C80927C1DF"><p>Supplying buffers to+
−
decode video frames into </p> </li>+
−
<li id="GUID-F650FB8E-2222-5BAD-B7A3-3F90DDCCD2F7"><p>Rendering a buffer on+
−
the display (timed or non-timed) </p> </li>+
−
<li id="GUID-78941DFB-FBDF-5583-9FCE-DDD53818D202"><p>Destroying a surface. </p> </li>+
−
</ul> </section>+
−
</conbody><related-links>+
−
<link href="GUID-0EE3180B-4814-517E-A6DD-748136C17D55.dita"><linktext>Video Client</linktext>+
−
</link>+
−
<link href="GUID-DDE1A8A9-1D67-53BF-8A65-340F139AD4AB.dita"><linktext>Multimedia+
−
Framework (MMF)</linktext></link>+
−
<link href="GUID-97F83011-BE3C-512C-9599-028CBB92BD51.dita"><linktext>Multimedia+
−
Plug-ins</linktext></link>+
−
<link href="GUID-842D8124-554F-5D89-9E20-8B48EA539D2F.dita"><linktext>Video HAI</linktext>+
−
</link>+
−
<link href="GUID-63CB6C7E-44EC-5D0B-A37D-FE78F7D76592.dita"><linktext>Graphics+
−
Surface Composition Collection</linktext></link>+
−
<link href="GUID-C7B420DE-CEDA-5D3F-8095-71136E862CDF.dita"><linktext>Surface Manager+
−
Component</linktext></link>+
−
</related-links></concept>+
−