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IWiaVideo interface

The IWiaVideo interface provides methods that allow an application that uses Windows Image Acquisition (WIA) services to acquire still images from a streaming video device.

Note  WIA does not support video devices in Windows Server 2003, Windows Vista, and later. For those versions of the Windows, use DirectShow to acquire images from video.

Members

The IWiaVideo interface inherits from the IUnknown interface. IWiaVideo also has these types of members:

Methods

The IWiaVideo interface has these methods.

MethodDescription
CreateVideoByDevNum

The IWiaVideo::CreateVideoByDevNum method creates a connection to a streaming video device with the device number obtained from a Directshow enumeration.

CreateVideoByName

The IWiaVideo::CreateVideoByName method creates a connection to a streaming video device with the friendly device name obtained from a Directshow enumeration.

CreateVideoByWiaDevID

The IWiaVideo::CreateVideoByWiaDevID method creates a connection to a streaming video device from its WIA_DIP_DEV_ID property.

DestroyVideo

The IWiaVideo::DestroyVideo method shuts down the streaming video. To restart video playback, the application must call one of the IWiaVideo CreateVideo methods again.

GetCurrentState

The IWiaVideo::GetCurrentState method specifies the state of the video stream as a member of the WIAVIDEO_STATE enumeration.

Pause

The IWiaVideo::Pause method pauses video playback.

Play

Begins playback of streaming video.

ResizeVideo

The IWiaVideo::ResizeVideo method resizes the video playback to the largest supported resolution that fits inside the parent window. Call this method whenever the parent window is moved or resized.

TakePicture

The IWiaVideo::TakePicture method extracts a still image from the video stream, and saves the image as a JPEG file.

 

Properties

The IWiaVideo interface has these properties.

PropertyAccess typeDescription

ImagesDirectory

Read/write

The IWiaVideo::ImagesDirectory property specifies the full path and directory where images are stored when calling the IWiaVideo::TakePicture method.

PreviewVisible

Read/write

The IWiaVideo::PreviewVisible property specifies whether the video playback is visible in its parent window. This does not affect the WIAVIDEO_STATE of the video.

 

Remarks

The IWiaVideo interface, like all Component Object Model (COM) interfaces, inherits the IUnknown interface methods.

IUnknown MethodsDescription
IUnknown::QueryInterface Returns pointers to supported interfaces.
IUnknown::AddRef Increments reference count.
IUnknown::Release Decrements reference count.

 

Requirements

Minimum supported client

Windows XP [desktop apps only]

Minimum supported server

Windows Server 2003 [desktop apps only]

Header

Wiavideo.h

DLL

Wiavideo.dll

 

 

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