| description | ms.assetid | title | ms.topic | ms.date | ms.custom |
|---|---|---|---|---|---|
VMR Support for DirectX Video Acceleration |
4bb5612d-3841-4920-a5ef-39ce357a6d1c |
VMR Support for DirectX Video Acceleration |
article |
4/26/2023 |
UpdateFrequency5 |
[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
DirectX Video Acceleration is an Application Programming Interface (API) and a corresponding Device Driver Interface (DDI) for hardware acceleration of digital video decoding processing, with support of alpha blending for such purposes as DVD subpicture support. DirectX VA is documented in the Windows DDK. The IAMVideoAccelerator interface, which provides user mode access to DirectX VA functionality on a hardware device, is documented in this SDK.
The VMR supports IAMVideoAccelerator, and its implementation is identical to the old Overlay Mixer except for one important difference. The Overlay Mixer guaranteed that the output is rendered into an overlay surface, while the VMR can send the output for further processing, for example a 3D operation, or it might send the output to an offscreen surface which is then blitted to the primary surface.