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DDVIDEOPORTBANDWIDTH structure (dvp.h)

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The DDVIDEOPORTBANDWIDTH structure describes the bandwidth characteristics of an overlay when used with a particular video port extensions (VPE) object/pixel format configuration.

Syntax

typedef struct _DDVIDEOPORTBANDWIDTH {
  DWORD     dwSize;
  DWORD     dwCaps;
  DWORD     dwOverlay;
  DWORD     dwColorkey;
  DWORD     dwYInterpolate;
  DWORD     dwYInterpAndColorkey;
  ULONG_PTR dwReserved1;
  ULONG_PTR dwReserved2;
} *LPDDVIDEOPORTBANDWIDTH, DDVIDEOPORTBANDWIDTH;

Members

dwSize

Specifies the size in bytes of this DDVIDEOPORTBANDWIDTH structure.

dwCaps

Specifies the dependencies of the bandwidth. The driver's DdVideoPortGetBandwidth function sets this member to one of the following values:

Flag Meaning
DDVPBCAPS_DESTINATION The device's capabilities are described in terms of the destination overlay's minimum stretch factor. The bandwidth information set by the driver in the dwOverlay, dwColorkey, dwYInterpolate, and dwYInterpAndColorkey members refers to the destination overlay size.
DDVPBCAPS_SOURCE The device's capabilities are described in terms of the required source overlay's rectangle size (in pixels). The bandwidth information set by the driver in the dwOverlay, dwColorkey, dwYInterpolate, and dwYInterpAndColorkey members refers to the source overlay size.

dwOverlay

Specifies the stretch factor or overlay source size at which the device can support an overlay, multiplied by 1000. The driver sets this value based on its device's type and capabilities, and on the dimensions specified in the dwWidth and dwHeight members of the DD_GETVPORTBANDWIDTHDATA structure passed to DdVideoPortGetBandwidth. For example, a stretch factor of 2 is specified as 2000, and an overlay source size of 750 indicates that the specified source overlay be shrunk to 75 percent of its original size. The driver must return a valid number in this member.

dwColorkey

Specifies the stretch factor or overlay source size at which an overlay with color keying is supported, multiplied by 1000. The driver sets this value based on its device's type and capabilities, and on the dimensions specified in the dwWidth and dwHeight members of the DD_GETVPORTBANDWIDTHDATA structure passed to DdVideoPortGetBandwidth. For example, a stretch factor of 2 is specified as 2000.

dwYInterpolate

Specifies the stretch factor or overlay source size at which an overlay with y-axis interpolation is supported, multiplied by 1000. The driver sets this value based on its device's type and capabilities, and on the dimensions specified in the dwWidth and dwHeight members of the DD_GETVPORTBANDWIDTHDATA structure passed to DdVideoPortGetBandwidth. For example, a stretch factor of 2 is specified as 2000.

dwYInterpAndColorkey

Specifies the stretch factor or overlay source size at which an overlay with y-axis interpolation and color keying is supported, multiplied by 1000. The driver sets this value based on its device's type and capabilities, and on the dimensions specified in the dwWidth and dwHeight members of the DD_GETVPORTBANDWIDTHDATA structure passed to DdVideoPortGetBandwidth. For example, a stretch factor of 2 is specified as 2000.

dwReserved1

Reserved for system use and should be ignored by the driver.

dwReserved2

Reserved for system use and should be ignored by the driver.

Requirements

Requirement Value
Header dvp.h (include Dvp.h)

See also

DD_GETVPORTBANDWIDTHDATA

DdVideoPortGetBandwidth