MultiSourceMediaFrameReference Class

Definition

Namespace:

Windows.Media.Capture.Frames

A wrapper class that provides access to time-correlated frames obtained from one or more MediaFrameSource objects. Call TryGetFrameReferenceBySourceId to get the MediaFrameReference representing a frame from a particular media frame source.

public ref class MultiSourceMediaFrameReference sealed : IClosable

/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 262144)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
/// [Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
class MultiSourceMediaFrameReference final : IClosable

[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 262144)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
[Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
public sealed class MultiSourceMediaFrameReference : System.IDisposable

Public NotInheritable Class MultiSourceMediaFrameReference
Implements IDisposable

Inheritance

Object Platform::Object IInspectable MultiSourceMediaFrameReference

Attributes

ContractVersionAttribute MarshalingBehaviorAttribute ThreadingAttribute

Implements

IClosable IDisposable

Windows requirements

Device family	Windows 10 Creators Update (introduced in 10.0.15063.0)
API contract	Windows.Foundation.UniversalApiContract (introduced in v4.0)

Remarks

To get an instance of MultiSourceMediaFrameReference from a media frame source, create a MultiSourceMediaFrameReader by calling CreateMultiSourceFrameReaderAsync on a MediaCapture object, passing in the MediaFrameSource objects from which you want to read. After starting by calling StartAsync, call TryAcquireLatestFrame to get a MultiSourceMediaFrameReference which contains the latest correlated frames from the media frame sources.

Get the time-correlated media frame from a particular media frame source by calling MultiSourceMediaFrameReference.TryGetFrameReferenceBySourceId and passing in the value of the MediaFrameSourceInfo.Id property for the desired media frame source.

Each MultiSourceMediaFrameReader maintains a circular buffer of MediaFrameReference objects obtained from MultiSourceMediaFrameReference.TryGetFrameReferenceBySourceId. After all of the MediaFrameReference objects in the buffer have been used, subsequent calls to TryAcquireLatestFrame will cause the system to call Close (or Dispose in C#) on the oldest buffer object in order to reuse it. Once the object has been disposed, you can no longer use it to access the frame data. For this reason, you should not store the MediaFrameReference object longer than you actually need to process the frame. If your app scenario requires you to keep a reference to the data for longer, you should use one of the APIs provided to get the underlying data. These methods include:

• BufferMediaFrame.Buffer
• VideoMediaFrame.SoftwareBitmap
• VideoMediaFrame.GetVideoFrame
• VideoMediaFrame.CameraIntrinsics

It is the responsibility of the app to call Close (or Dispose) on the objects returned by these APIs when they are no longer being used.

Important

If you access the SoftwareBitmap or Direct3DSurface objects provided by the VideoMediaFrame property of a MediaFrameReference, the system creates a strong reference to these objects, which means that they will not be disposed when you call Dispose on the containing MediaFrameReference. You must explicitly call the Dispose method of the SoftwareBitmap or Direct3DSurface directly for the objects to be immediately disposed. Otherwise, the garbage collector will eventually free the memory for these objects, but you can't know when this will occur, and if the number of allocated bitmaps or surfaces exceeds the maximum amount allowed by the system, the flow of new frames will stop.

For how-to guidance on using MediaFrameSource to capture frames, see Process media frames with MediaFrameReader.

Methods

Close()	Disposes of the object and associated resources.
Dispose()	Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
TryGetFrameReferenceBySourceId(String)	Attempts to get a time-correlated MediaFrameReference for the specified media frame source.

See also

• IClosable
• Object
• Process media frames with MediaFrameReader