WMT_VIDEOIMAGE_SAMPLE2 structure (wmsdkidl.h)

项目
4/26/2023

[The feature associated with this page, Windows Media Format 11 SDK, is a legacy feature. It has been superseded by Source Reader and Sink Writer. Source Reader and Sink Writer have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use Source Reader and Sink Writer instead of Windows Media Format 11 SDK, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

The WMT_VIDEOIMAGE_SAMPLE2 structure describes a sample for a Video Image stream. This structure must be used, either alone or with an accompanying image, in each sample passed to the writer for a Video Image stream. For more information, see Writing Video Image Samples.

Syntax

typedef struct __WMT_VIDEOIMAGE_SAMPLE2 {
  DWORD dwMagic;
  DWORD dwStructSize;
  DWORD dwControlFlags;
  DWORD dwViewportWidth;
  DWORD dwViewportHeight;
  DWORD dwCurrImageWidth;
  DWORD dwCurrImageHeight;
  FLOAT fCurrRegionX0;
  FLOAT fCurrRegionY0;
  FLOAT fCurrRegionWidth;
  FLOAT fCurrRegionHeight;
  FLOAT fCurrBlendCoef;
  DWORD dwPrevImageWidth;
  DWORD dwPrevImageHeight;
  FLOAT fPrevRegionX0;
  FLOAT fPrevRegionY0;
  FLOAT fPrevRegionWidth;
  FLOAT fPrevRegionHeight;
  FLOAT fPrevBlendCoef;
  DWORD dwEffectType;
  DWORD dwNumEffectParas;
  FLOAT fEffectPara0;
  FLOAT fEffectPara1;
  FLOAT fEffectPara2;
  FLOAT fEffectPara3;
  FLOAT fEffectPara4;
  BOOL  bKeepPrevImage;
} WMT_VIDEOIMAGE_SAMPLE2;

Members

dwMagic

Reserved. You must set this member to WMT_VIDEOIMAGE_MAGIC_NUMBER_2.

dwStructSize

Size of the structure. Set to sizeof(WMT_VIDEOIMAGE_SAMPLE2).

dwControlFlags

Specifies the type of sample. Use one or more of the flags in the following table, combined with the bitwise OR operator (|):

Flag	Description
WMT_VIDEOIMAGE_SAMPLE_INPUT_FRAME	Indicates that the sample contains an input image. The image data must be included in the sample immediately following the structure. The format of the image must conform to the values set in the input properties for the stream.
WMT_VIDEOIMAGE_SAMPLE_OUTPUT_FRAME	Indicates that the sample should result in a unique output frame in the stream. If this flag is not set, the remainder of the members of the structure are ignored and the frame in the stream will be a duplicate of the previous frame.
WMT_VIDEOIMAGE_SAMPLE_USES_CURRENT_INPUT_FRAME	Indicates that the sample is based, either solely or in part, on the current image. If this flag is set, the first set of value members will be used (those with names containing the string "Curr"). This flag is not valid unless used in combination with WMT_VIDEOIMAGE_SAMPLE_OUTPUT_FRAME.
WMT_VIDEOIMAGE_SAMPLE_USES_PREVIOUS_INPUT_FRAME	Indicates that the sample is based, either solely or in part, on the previous image. If this flag is set, the second set of value members will be used (those with names containing the string "Prev"). This flag is not valid unless used in combination with WMT_VIDEOIMAGE_SAMPLE_OUTPUT_FRAME.

dwViewportWidth

Width of the output frame.

dwViewportHeight

Height of the output frame.

dwCurrImageWidth

Width of the current image.

dwCurrImageHeight

Height of the current image.

fCurrRegionX0

X component of the origin point of the region of interest in the current image.

fCurrRegionY0

Y component of the origin point of the region of interest in the current image.

fCurrRegionWidth

Width of the region of interest in the current image. The specified region of interest will be sized to match the size of the output frame.

fCurrRegionHeight

Height of the region of interest in the current image. The specified region of interest will be sized to match the size of the output frame.

fCurrBlendCoef

Blending coefficient for the current image. This value specifies the transparency of the current image relative to the previous image. The blending coefficients of the two images must total 1.0.

dwPrevImageWidth

Width of the previous image.

dwPrevImageHeight

Height of the previous image.

fPrevRegionX0

X component of the origin point of the region of interest in the previous image.

fPrevRegionY0

Y component of the origin point of the region of interest in the previous image.

fPrevRegionWidth

Width of the region of interest in the previous image. The specified region of interest will be sized to match the size of the output frame.

fPrevRegionHeight

Height of the region of interest in the previous image. The specified region of interest will be sized to match the size of the output frame.

fPrevBlendCoef

Blending coefficient for the previous image. This value specifies the transparency of the previous image relative to the current image. The blending coefficients of the two images must total 1.0.

dwEffectType

The effect identifier of the transition between the previous image and the current image. For more information, see Video Image Transitions.

dwNumEffectParas

The number of effect parameters relevant to the current effect. The final five members of this structure contain the values of effect parameters. This member specifies how many of those parameters contain valid information.

fEffectPara0