Per-Pixel Alpha Blending

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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.]

Four media subtypes have been defined for per-pixel alpha blending. These subtypes are only supported when the VMR is in mixing mode. The VMR will reject the connection if it is not in mixing mode when an upstream filter attempts to connect using one of these subtypes. These subtypes are defined in uuids.h:

  • MEDIASUBTYPE_ARGB1555
  • MEDIASUBTYPE_ARGB4444
  • MEDIASUBTYPE_ARGB32
  • MEDIASUBTYPE_AYUV

For more information, see Uncompressed RGB Video Subtypes and YUV Video Subtypes.