About Video Rendering in DirectShow

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Microsoft DirectShow 9.0

About Video Rendering in DirectShow

DirectShow provides several filters that render video:

  • Video Renderer filter. This filter is available for all platforms that support DirectX, and has no particular system requirements. The Video Renderer uses DirectDraw whenever possible to render the video; otherwise, it uses GDI. This filter is the default video renderer on platforms earlier than Windows XP.
  • Video Mixing Renderer Filter 7 (VMR-7). The VMR-7 is available on Windows XP, where it is the default video renderer. The VMR-7 always uses DirectDraw 7 for rendering. It provides many powerful features not available in the older Video Renderer filter, including a plug-in model where the application controls the DirectDraw surfaces used for rendering.
  • Video Mixing Renderer Filter 9 (VMR-9). The VMR-9 is a newer version of the Video Mixing Renderer that uses Direct3D 9 for rendering. It is available for all platforms that support DirectX. It is not the default renderer, however, because it has higher system requirements than the Video Renderer filter.
  • The Overlay Mixer filter is designed specifically for DVD playback and broadcast video. It also supports Video Port Extensions (VPEs), enabling it to work with hardware MPEG-2 decoders or analog TV tuners that send video directly to the graphics card.
  • The Enhanced Video Renderer (EVR) filter is available starting in Windows Vista. It offers improved video performance compared with earlier video renderers, especially when Windows Vista desktop composition is enabled.

Generally, the EVR is preferred for applications that target Windows Vista or later, and the VMR-9 is preferred for applications running on earlier versions of Windows. For more information about using the VMR-7 and VMR-9 filters, see Using the Video Mixing Renderer.

Windowed Mode and Windowless Mode

A DirectShow video renderer can operate in either windowed mode or windowless mode.

  • In windowed mode, the renderer creates its own window to display the video. Typically you will make this window the child of an application window. For more information, see Using Windowed Mode.
  • In windowless mode, the renderer draws the video directly onto an application window. It does not create its own window. For more information about this mode, see Using Windowless Mode.

The Video Renderer filter supports windowed mode only. The VMR-7 and VMR-9 filters support both modes. They default to windowed mode for backward compatibility.

See Also