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    12 <concept xml:lang="en" id="GUID-70B3881F-9532-5F1D-B210-99A15DB93FC2"><title>Fast Forwarding and Rewinding</title><prolog><metadata><keywords/></metadata></prolog><conbody><p>This tutorial describes how to fast forward and rewind video clips. </p> <section><title>Purpose</title> <p>The purpose of this tutorial is to show you how to fast forward and rewind video clips during playback. </p> <p><b>Required Background</b> </p> <p>The <xref href="GUID-2DC80BA9-7AA2-5CD3-9105-1DE28CE196C1.dita">Video Client Overview</xref> introduces the video client utilities. </p> <p><b>Introduction</b> </p> <p>You can view a video clip in fast forward, rewind and slow-motion playback. This is achieved by setting the playback velocity to a value higher or lower than normal playback speed. The default playback velocity is 100. Values above 100 and below 0 correspond to fast forward and rewind respectively, while values 1 to 99 represent slow-motioned playback. </p> <p> <b>Note:</b> This functionality is dependent on the capabilities of the underlying play-controller implementation and the characteristics of the video clip. </p> </section> <section><title>Using Playback Velocity </title> <p>The following tasks are covered in this tutorial: </p> <ul><li id="GUID-FB5CC1B8-9BE8-5382-81C7-49D9269B7DEB"><p><xref href="GUID-70B3881F-9532-5F1D-B210-99A15DB93FC2.dita#GUID-70B3881F-9532-5F1D-B210-99A15DB93FC2/GUID-744097F7-7679-5309-98BC-C1FB6442B43B">Fast Forward and Rewind a Video Clip</xref>  </p> </li> </ul> <p id="GUID-744097F7-7679-5309-98BC-C1FB6442B43B"><b>Basic Procedure</b> </p> <p>The high level steps to fast forward and rewind a video clip are shown here: </p> <ol id="GUID-41F59ED3-3585-5688-AB8F-360C59508B27"><li id="GUID-9B1EC0AC-441D-5DF1-8E7D-BF6F79DBE8B7"><p>Create a new video player utility object. </p> </li> <li id="GUID-94EBEFAD-7C5E-5214-B7C9-A4E60D97CC73"><p>Open a video clip to play. </p> </li> <li id="GUID-BD33FE51-7723-5D3D-A2B4-79FEBA6CEDE8"><p>Use <xref href="GUID-0F1F8AC6-B99F-3274-A785-9977197AF762.dita#GUID-0F1F8AC6-B99F-3274-A785-9977197AF762/GUID-45F4B0E5-2EF4-3391-A925-DD31C9E997F6"><apiname>CVideoPlayerUtility::GetPlayRateCapabilitiesL()</apiname></xref> to check the current forward and rewind capabilities. </p> </li> <li id="GUID-56D7CAB6-207C-56D0-B846-F0F0BBEDAF23"><p>Call the <xref href="GUID-0F1F8AC6-B99F-3274-A785-9977197AF762.dita#GUID-0F1F8AC6-B99F-3274-A785-9977197AF762/GUID-B4FB00AA-A85B-3A3F-91BE-C5347462BA95"><apiname>CVideoPlayerUtility::Prepare()</apiname></xref> method. </p> </li> <li id="GUID-B2D54F6F-7BB9-5207-BB02-AAB67941B1BD"><p>Call <xref href="GUID-0F1F8AC6-B99F-3274-A785-9977197AF762.dita#GUID-0F1F8AC6-B99F-3274-A785-9977197AF762/GUID-A9DCC4EB-B4B3-3AF4-B78C-DC3531A32DCC"><apiname>CVideoPlayerUtility::Play()</apiname></xref> to start playback. </p> </li> <li id="GUID-7DB0514F-3C2F-5308-8206-E0A7EFF81EDE"><p>The default playback velocity is 100. To fast forward use <xref href="GUID-0F1F8AC6-B99F-3274-A785-9977197AF762.dita#GUID-0F1F8AC6-B99F-3274-A785-9977197AF762/GUID-7C05E56D-325D-38F0-831D-54F36DB0DDD7"><apiname>CVideoPlayerUtility::SetPlayVelocityL()</apiname></xref> and set <xref href="GUID-5D9F4230-0A5A-3C31-90EB-D404B020F37D.dita"><apiname>aVelocity</apiname></xref> to a value greater than 100. Velocity set in this call takes effect immediately. </p> </li> <li id="GUID-9E493165-5695-50C7-B559-55478092E079"><p>To rewind use <xref href="GUID-0F1F8AC6-B99F-3274-A785-9977197AF762.dita#GUID-0F1F8AC6-B99F-3274-A785-9977197AF762/GUID-7C05E56D-325D-38F0-831D-54F36DB0DDD7"><apiname>CVideoPlayerUtility::SetPlayVelocityL()</apiname></xref> and set <xref href="GUID-5D9F4230-0A5A-3C31-90EB-D404B020F37D.dita"><apiname>aVelocity</apiname></xref> to a value less than 0. Velocity set in this call takes effect immediately. </p> </li> <li id="GUID-069D1596-B643-52D8-9A37-ADB1A59E3CEA"><p>Call <xref href="GUID-0F1F8AC6-B99F-3274-A785-9977197AF762.dita#GUID-0F1F8AC6-B99F-3274-A785-9977197AF762/GUID-C103A911-AF93-3350-B731-C186A279F1DC"><apiname>CVideoPlayerUtility::Stop()</apiname></xref> to halt video playback. </p> </li> </ol> <p><b>Example</b> </p> <codeblock id="GUID-0666098F-F44F-5BF4-805F-251F79D2268C" xml:space="preserve">// Create new video player utility object (iVideoPlayer)

    13 // Open the video clip

    14 // Call Prepare()

    15 // Call Play()

    16 

    17 iVideoPlayer->GetPlayRateCapabilitiesL(iVideoPlayRateCapabilities);

    18 // Return the current playback rate capabilities

    19 

    20 //Check that engine has forward capability.

    21 if( iVideoPlayRateCapabilities.iPlayForward)

    22 {

    23 iVideoPlayer->SetPlayVelocityL(200); // fast forward

    24 }

    25 else

    26 {

    27 // Forward is not supported.

    28 }

    29 

    30 // If user wants to rewind. Check that engine has rewind capability.

    31 if( iVideoPlayRateCapabilities.iPlayBackward)

    32 {

    33 iVideoPlayer->SetPlayVelocityL(-200); // rewind

    34 }

    35 else

    36 {

    37 // Rewind is not supported.

    38 }

    39 

    40 // Call Stop()</codeblock> </section> <section><title>See Also</title> <p><xref href="GUID-172F46C1-6066-57FA-A815-5AC23ACE159D.dita">Creating and Preparing a Video Player</xref>  </p> <p><xref href="GUID-F9896E96-1076-552D-AE54-8F9DABED867F.dita">Configuring the Video Player</xref> </p> <p><xref href="GUID-733B9695-0C7C-5637-9025-6CE3BAA1A23E.dita"> Enabling/Disabling Audio or Video Playback Separately</xref>  </p> <p><xref href="GUID-FE7DE542-3FD4-56D2-B281-C670EF1C4FEB.dita">Scaling Automatically</xref>  </p> <p><xref href="GUID-5F4510C9-5B16-593A-A225-37606800915B.dita">Controlling Video Playback</xref>  </p> <p><xref href="GUID-469377FB-AAE8-5245-A8E1-469C65AFE5C5.dita">Stepping Frames</xref>  </p> <p><xref href="GUID-F13C7D36-E4AB-57F1-87A1-EB83AA2258DF.dita">Controlling the Video Controller Plugin</xref>  </p> </section> </conbody></concept>