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IDirectDrawVideoPort::GetBandwidthInfo

  • Article

This method retrieves the minimum required overlay zoom factors and device limitations of a video port that uses the provided output pixel format.

HRESULT GetBandwidthInfo( 
  LPDDPIXELFORMAT lpddpfFormat, 
  DWORD dwWidth, 
  DWORD dwHeight, 
  DWORD dwFlags, 
  LPDDVIDEOPORTBANDWIDTH lpBandwidth
);

Parameters

  • lpddpfFormat
    Address of a DDPIXELFORMAT structure that describes the output pixel format for which bandwidth information will be retrieved.
  • dwWidth and dwHeight
    Dimensions of an overlay or video data. The interpretation of these parameters depends on the value specified in the dwFlags parameter.
  • dwFlags
    Flags indicating how the method is to interpret the dwWidth and dwHeight parameters. The following table shows the possible flags.
    Flag Description
    DDVPB_OVERLAY The dwWidth and dwHeight parameters indicate the size of the source overlay surface. Use this flag when the video port depends on the overlay source size.
    DDVPB_TYPE The dwWidth and dwHeight parameters are not set. The method will retrieve the device's dependency type in the dwCaps member of the associated DDVIDEOPORTBANDWIDTH structure. Use this flag the first time you call this method.
    DDVPB_VIDEOPORT The dwWidth and dwHeight parameters indicate the prescale size of the video data that the video port writes to the frame buffer. Use this flag when the video port depends on the overlay zoom factor.
  • lpBandwidth
    Address of a DDVIDEOPORTBANDWIDTH structure that will be filled with the retrieved bandwidth and device dependency information.

Return Values

If the method succeeds, the return value is DD_OK.

If the method fails, the return value may be one of the following error values:

DDERR_INVALIDOBJECT
DDERR_INVALIDPARAMS

Remarks

This method will usually be called twice. When you make the first call, specify the DDVPB_TYPE flag in the dwFlags parameter to retrieve information about the device's overlay dependency type. Subsequent calls using the DDVPB_VIDEOPORT or DDVPB_OVERLAY flags must be interpreted considering the device's dependency type.

Requirements

OS Versions: Windows CE 2.12 and later. Version 2.12 requires DXPAK 1.0 or later.
Header: Dvp.h.
Link Library: Ddraw.lib.

 Last updated on Thursday, April 08, 2004

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