VideoSink Class
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VideoSink Class

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Exposes the capture graph for video devices. Derive from this class to receive video information and to obtain the capture graph through VideoSink.CaptureSource.


Namespace:  System.Windows.Media
Assembly:  System.Windows (in System.Windows.dll)

public abstract class VideoSink

The VideoSink type exposes the following members.

Public methodVideoSinkInitializes a new instance of the VideoSink class.

Public propertyAllocationModeSpecifies how the camera video buffer is maintained on Windows Phone.
Public propertyCaptureSourceGets or sets a capture source that is associated with this VideoSink.

Public methodEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodFinalizeFrees resources that are used by the VideoSink class. (Overrides Object.Finalize().)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Protected methodOnCaptureStartedWhen overridden in a derived class, is invoked when a video device starts capturing video data.
Protected methodOnCaptureStoppedWhen overridden in a derived class, is invoked when a video device stops capturing video data.
Protected methodOnFormatChangeWhen overridden in a derived class, is invoked when a video device reports a video format change.
Protected methodOnSampleWhen overridden in a derived class, is invoked when a video device captures a complete video sample.
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)

To obtain video information from a video input device in Windows Phone, you derive a custom video sink from VideoSink, which exposes several virtual callbacks:

When you derive from VideoSink, you must provide overrides for the callbacks in order to compile. However, you can have a functional VideoSink that has empty callback overrides and can use only the methods of the CaptureSource from VideoSink.CaptureSource. For more information, see CaptureSource.

Implementing VideoSink Overrides

To work with raw video from a capture graph, you must override OnSample and provide an implementation in your video sink that converts the sampleData to your destination format. You usually use the numbers that are obtained from the VideoFormat properties to convert a bit stream to a supported video format. A typical logic design for sample processing uses a series of nested loops and attempts type matches for appropriate data types for frames and pixels.

If you provide a meaningful override of OnSample, you should also provide a meaningful override of OnFormatChange. The information for VideoFormat that is associated with this sink might change between the time that the device was first connected and the time of capture. Handling OnFormatChange is the only way that you know the true format information at run time.

OnCaptureStarted and OnCaptureStopped are useful as UI change notifications to advise users that audio is currently being captured or that capture has stopped. You can also use the notifications as sentinels to block certain other actions in your application while the capture is ongoing.

Version Notes

Windows Phone

 It is recommended to not use VideoSink (with ARBG format) if you intend to save the video to a file by collecting video data to a buffer and writing your own encoder. Use FileSink instead.

If you want to save video capture to an MP4 file in order to play back at a later time, it is recommended to use FileSink.

Windows Phone OS

Supported in: 8.1, 8.0, 7.1

Windows Phone

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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