MFSampleExtension_ROIRectangle attribute

Specifies the bounds of the region of interest which indicates the region of the frame that requires different quality.

Data type

ROI_AREA stored as BLOB


After successfully setting CODECAPI_AVEncVideoROIEnabled to a non-zero value on an encoder MFT, the application can set this attribute on input samples and expect it to be honored.

If CODECAPI_AVEncVideoROIEnabled is not set to a non-zero value, the MFSampleExtension_ROIRectangle attribute is ignored on input samples.

MFSampleExtension_ROIRectangle is set on an input sample and is only applied to the current input sample.

The QPDelta field on the ROI_AREA structure specifies the quantization parameter delta for the specified region from the rest of the frame. If QPDelta is positive, this indicates the application wants the rectangle to have lower quality than the rest of the frame.

H.264/AVC encoders: QPDelta shall be between [-25, +25]. The encoder shall ensure that the final QP is in a valid range for the video standard.

The specified region is not required to be MB aligned. Encoders have flexibility to decide the actual boundary. It is recommended to cover the entire specified region.


Minimum supported client
Windows 8.1 [desktop apps | UWP apps]
Minimum supported server
Windows Server 2012 R2 [desktop apps | UWP apps]

See also

Alphabetical List of Media Foundation Attributes