CBaseControlVideo Class

  • 项目

This class implements the IBasicVideo dual 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.

The CBaseControlVideo class supports both properties and methods. Properties are more easily accessible from many Automation controllers (such as the Microsoft Visual Basic® programming system). However, some operations require applications to be able to change several properties simultaneously; for this reason, methods are provided that enable a number of related properties to be changed.

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 top, left, width, and height rather than top, left, right, and bottom, which is favored in Win32 programming. When no source rectangle has been set, the properties of the source rectangle return the full, native video size.

Protected Data Members

Member 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

Member function 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.

Overrideable Member Functions

Member function Description
CheckSourceRect Determines if a source rectangle is valid.
CheckTargetRect Determines if a target rectangle is valid.
GetSourceRect Retrieves the current source video rectangle as a pure virtual function.
GetStaticImage Returns the current image in a memory buffer as a pure virtual function.
GetTargetRect Retrieves the current target video rectangle as a pure virtual function.
GetVideoFormat Retrieves the VIDEOINFOHEADER structure containing the video format.
IsDefaultSourceRect Determines if the renderer is using the default source rectangle as a pure virtual function.
IsDefaultTargetRect Determines if the renderer is using the default target rectangle as a pure virtual function.
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 as a pure virtual function.
SetDefaultTargetRect Sets the default target video rectangle as a pure virtual function.
SetSourceRect Sets the current source video rectangle as a pure virtual function.
SetTargetRect Sets the current target rectangle as a pure virtual function.

Implemented IBasicVideo Methods

Method 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.

Requirements

DirectShow applications and DirectShow filters have different include file and link library requirements. See Setting Up the Build Environment for more information.

OS Versions: Windows CE 2.12 and later. Version 2.12 requires DXPAK 1.0 or later.
Header:

Last updated on Wednesday, April 13, 2005

© 2005 Microsoft Corporation. All rights reserved.