Class VideoFrameQueue<T>

Small queue of video frames received from a source and pending delivery to a sink. Used as temporary buffer between the WebRTC callback (push model) and the video player rendering (pull model). This also handles dropping frames when the source is faster than the sink, by limiting the maximum queue length.

Inheritance

Object

VideoFrameQueue<T>

Implements

IVideoFrameQueue

Namespace: Microsoft.MixedReality.WebRTC

Assembly: Microsoft.MixedReality.WebRTC.dll

Syntax

public class VideoFrameQueue<T> : object, IVideoFrameQueue where T : class, IVideoFrameStorage, new()

Type Parameters

Name	Description
T	The type of video frame storage

Constructors

VideoFrameQueue(Int32)

Create a new queue with a maximum frame length.

Declaration

public VideoFrameQueue(int maxQueueLength)

Parameters

Type	Name	Description
Int32	maxQueueLength	Maxmimum number of frames to enqueue before starting to drop incoming frames

Properties

DequeuedFramesPerSecond

Get the number of frames enqueued per seconds. This is generally an average statistics representing how fast a video sink consumes some video frames, typically to render them.

Declaration

public float DequeuedFramesPerSecond { get; }

Property Value

Type	Description
Single

DroppedFramesPerSecond

Get the number of frames dropped per seconds. This is generally an average statistics representing how many frames were enqueued by a video source but not dequeued fast enough by a video sink, meaning the video sink renders at a slower framerate than the source can produce.

Declaration

public float DroppedFramesPerSecond { get; }

Property Value

Type	Description
Single

QueuedFramesPerSecond

Get the number of frames enqueued per seconds. This is generally an average statistics representing how fast a video source produces some video frames.

Declaration

public float QueuedFramesPerSecond { get; }

Property Value

Type	Description
Single

Methods

Clear()

Clear the queue and drop all frames currently pending.

Declaration

public void Clear()

Enqueue(Argb32VideoFrame)

Try to enqueue a new video frame encoded in raw ARGB format. If the internal queue reached its maximum capacity, do nothing and drop the frame.

Declaration

public bool Enqueue(Argb32VideoFrame frame)

Parameters

Type	Name	Description
Argb32VideoFrame	frame	The video frame to enqueue

Returns

Type	Description
Boolean	Return true if the frame was enqueued successfully, or false if it was dropped

Remarks

This should only be used if the queue has storage for a compatible video frame encoding.

Enqueue(I420AVideoFrame)

Enqueue a new video frame encoded in I420+Alpha format. If the internal queue reached its maximum capacity, do nothing and drop the frame.

Declaration

public bool Enqueue(I420AVideoFrame frame)

Parameters

Type	Name	Description
I420AVideoFrame	frame	The video frame to enqueue

Returns

Type	Description
Boolean	Return true if the frame was enqueued successfully, or false if it was dropped

Remarks

This should only be used if the queue has storage for a compatible video frame encoding.

RecycleStorage(T)

Recycle a frame storage, putting it back into the internal pool for later reuse. This prevents deallocation and reallocation of a frame, and decreases pressure on the garbage collector.

Declaration

public void RecycleStorage(T frame)

Parameters

Type	Name	Description
T	frame	The unused frame storage to recycle for a later new frame

TrackLateFrame()

Track statistics for a late frame, which short-circuits the queue and is delivered as soon as it is received.

Declaration

public void TrackLateFrame()

TryDequeue(out T)

Try to dequeue a video frame, usually to be consumed by a video sink (video player).

Declaration

public bool TryDequeue(out T frame)

Parameters

Type	Name	Description
T	frame	On success, returns the dequeued frame.

Returns

Type	Description
Boolean	Return true on success or false if the queue is empty.

Implements

IVideoFrameQueue