CBaseControlVideo class

[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

The CBaseControlVideo class implements the IBasicVideo interface and controls the video properties of a generic video window. Generally, a CBaseControlVideo object is a video renderer that draws video into a window on the display.

Many CBaseControlVideo member functions require only that the video renderer be connected to a filter graph. If it is not connected, member functions will return VFW_E_NOT_CONNECTED. Properties set on a video renderer persist between successive connections and disconnections. All applications should ensure that they reset the renderer properties before starting a presentation.

When working with video, the application can select a portion of the video to use. This portion is the source rectangle that the CBaseControlVideo object controls. CBaseControlVideo enables your application to set and retrieve the source rectangle. All the rectangles that CBaseControlVideo uses employ width and height values rather than right and bottom values. When no source rectangle has been set, the properties of the source rectangle return the full, native video size.

Protected Data Members	Description
m_pFilter	Pointer to an owning media filter.
m_pInterfaceLock	Externally defined critical section.
m_pPin	Control of the media types for connection.
Member Functions	Description
CBaseControlVideo	Constructs a CBaseControlVideo object.
CopyImage	Creates a memory copy of a video image.
GetImageSize	Retrieves video image size information.
SetControlVideoPin	Sets the pin with which this object should synchronize.
Overridable Member Functions	Description
CheckSourceRect	Determines if a source rectangle is valid.
CheckTargetRect	Determines if a target rectangle is valid.
GetSourceRect	Retrieves the current source video rectangle (pure virtual).
GetStaticImage	Returns the current image in a memory buffer (pure virtual).
GetTargetRect	Retrieves the current target video rectangle (pure virtual).
GetVideoFormat	Retrieves the VIDEOINFOHEADER structure containing the video format.
IsDefaultSourceRect	Determines if the renderer is using the default source rectangle (pure virtual).
IsDefaultTargetRect	Determines if the renderer is using the default target rectangle (pure virtual).
OnUpdateRectangles	Called when the source or target rectangle changes.
OnVideoSizeChange	Passes EC_VIDEO_SIZE_CHANGED to the application.
SetDefaultSourceRect	Sets the default source video rectangle (pure virtual).
SetDefaultTargetRect	Sets the default target video rectangle (pure virtual).
SetSourceRect	Sets the current source video rectangle (pure virtual).
SetTargetRect	Sets the current target rectangle (pure virtual).
IBasicVideo Methods	Description
get_AvgTimePerFrame	Retrieves an approximate average time per frame.
get_BitErrorRate	Retrieves an approximate bit error rate.
get_BitRate	Retrieves an approximate bit rate for the video.
GetCurrentImage	Retrieves a memory rendering of the current image.
get_DestinationHeight	Retrieves the current destination rectangle's height.
get_DestinationLeft	Retrieves the current destination rectangle's left coordinate.
GetDestinationPosition	Retrieves the current destination position.
get_DestinationTop	Retrieves the current destination rectangle's top coordinate.
get_DestinationWidth	Retrieves the current destination rectangle's width.
get_SourceHeight	Retrieves the current source rectangle's height.
get_SourceLeft	Retrieves the current source rectangle's left coordinate.
GetSourcePosition	Retrieves the current source position.
get_SourceTop	Retrieves the current source rectangle's top coordinate.
get_SourceWidth	Retrieves the current source rectangle's width.
get_VideoHeight	Retrieves the native video height.
GetVideoPaletteEntries	Retrieves a range of palette entries for the video.
GetVideoSize	Retrieves the width and height of the native video.
get_VideoWidth	Retrieves the native video width.
IsUsingDefaultDestination	Determines if the renderer is using the default destination window.
IsUsingDefaultSource	Determines if the renderer is using the default source window.
put_DestinationHeight	Sets the destination rectangle's height.
put_DestinationLeft	Sets the destination rectangle's left coordinate.
put_DestinationTop	Sets the destination rectangle's top coordinate.
put_DestinationWidth	Sets the destination rectangle's width.
put_SourceHeight	Sets the source rectangle's height.
put_SourceLeft	Sets the source rectangle's left coordinate.
put_SourceTop	Sets the source rectangle's top coordinate.
put_SourceWidth	Sets the source rectangle's width.
SetDefaultDestinationPosition	Sets the default destination position again.
SetDefaultSourcePosition	Sets the default source position again.
SetDestinationPosition	Sets the destination rectangle position.
SetSourcePosition	Sets the source rectangle position.

 

See also

DirectShow Base Classes