Video Resizer DSP

Article
04/12/2010

Resizes a video stream.

CLSID

CLSID_CResizerDMO

Interfaces

IMediaObject
IMFRealTimeClient
IMFTransform
IPropertyStore
IWMResizerProps

Formats

The Video Resizer DSP supports the following input/output media subtypes when it is acting as a DirectX Media Object (DMO).

MEDIASUBTYPE_IYUV
MEDIASUBTYPE_YUY2
MEDIASUBTYPE_UYVY
MEDIASUBTYPE_I420
MEDIASUBTYPE_RGB32
MEDIASUBTYPE_RGB24
MEDIASUBTYPE_RGB565
MEDIASUBTYPE_RGB8
MEDIASUBTYPE_RGB555
MEDIASUBTYPE_AYUV
MEDIASUBTYPE_V216
MEDIASUBTYPE_YV12

The Video Resizer DSP supports the following input/output media subtypes when it is acting as a Media Foundation Transform (MFT).

MFVideoFormat_IYUV
MFVideoFormat_YUY2
MFVideoFormat_UYVY
MFVideoFormat_I420
MFVideoFormat_RGB32
MFVideoFormat_RGB24
MFVideoFormat_RGB565
MFVideoFormat_RGB8
MFVideoFormat_RGB555
MFVideoFormat_AYUV
MFVideoFormat_V216
MFVideoFormat_YV12

Properties

Remarks

The Video Resizer DSP is implemented as a COM object that can act as a DMO or an MFT. The object has a single class identifier (CLSID) regardless of whether it acts as a DMO or an MFT. For information about when a DSP acts as a DMO or an MFT, see Digital Signal Processor Implementation.

The globally unique identifiers (GUIDs) for RGB media subtypes differ depending on whether a DSP is acting as a DMO or an MFT. The GUIDs for non-RGB media subtypes are the same, regardless of whether a DSP is acting as a DMO or an MFT. For information about the GUIDs that represent media subtypes, see Media Subtype GUIDs.

This DSP can perform both cropping and scaling on the video image. The format of the output type must match the format of the input type. The DSP does not perform color-space conversions.

Before setting the output type, you can define any of the following regions by using the properties listed in this table.

Region	Properties
Source rectangle	MFPKEY_RESIZE_SRC_LEFT MFPKEY_RESIZE_SRC_TOP MFPKEY_RESIZE_SRC_WIDTH MFPKEY_RESIZE_SRC_HEIGHT
Destination rectangle	MFPKEY_RESIZE_DST_LEFT MFPKEY_RESIZE_DST_TOP MFPKEY_RESIZE_DST_WIDTH MFPKEY_RESIZE_DST_HEIGHT
Geometric aperture	MFPKEY_RESIZE_GEOMAPX MFPKEY_RESIZE_GEOMAPY MFPKEY_RESIZE_GEOMAPWIDTH MFPKEY_RESIZE_GEOMAPHEIGHT
Minimum display aperture	MFPKEY_RESIZE_MINAPX MFPKEY_RESIZE_MINAPY MFPKEY_RESIZE_MINAPWIDTH MFPKEY_RESIZE_MINAPHEIGHT
Pan/scan region	MFPKEY_RESIZE_PANSCANAPX MFPKEY_RESIZE_PANSCANAPY MFPKEY_RESIZE_PANSCANAPWIDTH MFPKEY_RESIZE_PANSCANAPHEIGHT

In each case, you must set all of the associated properties for the setting to take effect.

The DSP copies the portion of the source image defined by source rectangle, and stretches or compresses it onto the destination rectangle on the output buffer. The source and destination rectangles do not need to be the same size. The frame size in the output media type must be large enough to hold the destination rectangle.

The geometric aperture, minimum display aperture, and pan/scan region do not affect how the DSP resizes the video. However, they might affect how the downstream component interprets the video frame. In particular, the enhanced video renderer (EVR) uses these values when it calculates the picture aspect ratio and the display area.

If you are using Media Foundation media types, you can set the geometric aperture, minimum display aperture, and pan/scan regions directly in the output media type. Otherwise, if you are using DMO media types, set them using the properties.

For more information, see the following topics in the Media Foundation SDK:

MF_MT_GEOMETRIC_APERTURE Attribute
MF_MT_MINIMUM_DISPLAY_APERTURE Attribute
MF_MT_PAN_SCAN_APERTURE Attribute

Requirements

Minimum supported client	Windows Vista
Minimum supported server	Windows Server 2008
Header	Wmcodecdsp.h
DLL	Vidreszr.dll

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