Microsoft Silverlight, versions 3 and greater
Silverlight managed programming model and Silverlight XAML
This technique relates to:
The objective of this technique is to use the AutoPlay property
    				of MediaElement object, which prevents the MediaElement from
    				playing its media source automatically. 
By default the value of AutoPlay is true, which causes
    				any media that is the Source of the MediaElement to
    				play as soon as either the entire source file is loaded (for nonstreaming
    				media) or an initial buffer is loaded (for streaming media). To prevent
    				the possible accessibility issues, developers can instead specifically set AutoPlay to
    				false, so that the user always controls whether the media plays. This
    				technique would thus be used in combination with providing user interface
    				controls that go along with the MediaElement, and
    				that enable the user to control the media. In particular, the user
    				interface controls enable the media to play, pause or stop, with event
    				wiring for those controls associated with the Play, Pause or Stop methods
    				of the MediaElement object. 
This example has a UI definition in XAML and interaction logic in C#.
The following is the basic UI in XAML. Note the AutoPlay="false" setting.
<UserControl x:Class="MediaElementControlsAutoPlay.MainPage"
   xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
   xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  >
   <Grid x:Name="LayoutRoot">
       <Grid.ColumnDefinitions>
           <ColumnDefinition Width="*" />
           <ColumnDefinition Width="*" />
           <ColumnDefinition Width="*"/>
       </Grid.ColumnDefinitions>
       <Grid.RowDefinitions>
           <RowDefinition Height="*" />
           <RowDefinition Height="Auto" />
       </Grid.RowDefinitions>
       <MediaElement x:Name="media" Source="/xbox.wmv"
          Width="300" Height="300" 
          Grid.Column="0" Grid.Row="0" Grid.ColumnSpan="3"
          AutoPlay="False"
          AutomationProperties.Name="Video of new Fable game for XBox"           
       />
       <Button Click="StopMedia" 
    Grid.Column="0" Grid.Row="1" Content="Stop" />
       <Button Click="PauseMedia" 
    Grid.Column="1" Grid.Row="1" Content="Pause" />
       <Button Click="PlayMedia" 
    Grid.Column="2" Grid.Row="1" Content="Play" />
   </Grid>
</UserControl>
The following is the C# logic.
 private void StopMedia(object sender, RoutedEventArgs e)
 {
     media.Stop();
 }
 private void PauseMedia(object sender, RoutedEventArgs e)
 {
     media.Pause();
 }
 private void PlayMedia(object sender, RoutedEventArgs e)
 {
     media.Play();
 }
 
This example is shown in operation in the working example of Media Element Controls with AutoPlay False.
Resources are for information purposes only, no endorsement implied.
Silverlight
    						Media Framework - a framework and a media player control implementation
    						that incorporates many of the Silverlight techniques related to MediaElement 
 Using a browser that supports Silverlight, open an HTML page that
    					references a Silverlight application through an object tag. The application
    					is expected to use a MediaElement object to play
    					prerecorded media. 
Check that the media does not play automatically as soon as the application loads and displays. Rather, the user is presented with a user interface that can start the media per the user's action.
#2 is true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
Techniques are informative—that means they are not required. The basis for determining conformance to WCAG 2.0 is the success criteria from the WCAG 2.0 standard—not the techniques. For important information about techniques, please see the Understanding Techniques for WCAG Success Criteria section of Understanding WCAG 2.0.