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DECIMATION_USAGE enumeration (strmif.h)

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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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

Describes the strategy that the Overlay Mixer Filter filter uses to scale the video image down to a smaller size.

Syntax

typedef enum _DECIMATION_USAGE {
  DECIMATION_LEGACY = 0,
  DECIMATION_USE_DECODER_ONLY,
  DECIMATION_USE_VIDEOPORT_ONLY,
  DECIMATION_USE_OVERLAY_ONLY,
  DECIMATION_DEFAULT
} DECIMATION_USAGE;

Constants

 
DECIMATION_LEGACY
Value: 0
Decimate the video by taking the following steps, in the order listed, until one of them succeeds.


  1. Try to use the overlay scaler on the VGA chip.

  2. If the Overlay Mixer is connected through a video port, try to use the scaler on the video port.

  3. Crop the video image.
DECIMATION_USE_DECODER_ONLY
Decimate using the scaler on the video decoder. If that fails, crop the video image.
DECIMATION_USE_VIDEOPORT_ONLY
Decimate using the scaler on the video port. If that fails, crop the video image.
DECIMATION_USE_OVERLAY_ONLY
Decimate using the overlay scaler on the VGA chip. If that fails, crop the video image.
DECIMATION_DEFAULT
Decimate the video by taking the following steps, in the order listed, until one of them succeeds.


  1. Try to use the scaler on the video decoder.

  2. Try to use the overlay scaler on the VGA chip.

  3. If the Overlay Mixer is connected through a video port, try to use the scaler on the video port.

  4. Crop the video image.


This mode is the default decimation strategy.

Requirements

Requirement Value
Header strmif.h (include Dshow.h)

See also

DirectShow Enumerated Types

IAMVideoDecimationProperties