wp7videoBrush

<MediaElement
x:Name="butterflyMediaElement"
Source="sampleMedia/Butterfly.wmv" IsMuted="True"
Opacity="0.0" IsHitTestVisible="False" />

<TextBlock Canvas.Left="5" Canvas.Top="30"
FontFamily="Verdana" FontSize="120"
FontWeight="Bold" TextWrapping="Wrap"
Text="Video">

<!-- Paint the text with video. -->
<TextBlock.Foreground>
<VideoBrush SourceName="butterflyMediaElement" Stretch="UniformToFill" />
</TextBlock.Foreground>
</TextBlock>