Class EncodingCamera

A desktop webcam encoded with the pure C# Vp8Encoder: a subclass captures I420 pictures on a thread of its own and gives them to Deliver(Func<VideoFrame>), which paces, previews and encodes them. Up to 30 pictures per second normally; at half size and 10 per second when the peer asks for less.

Inheritance
object
EncodingCamera
MediaFoundationCamera
V4l2Camera
Implements
Inherited Members
Namespace: Uniform.Chat.Desktop.Cameras
Assembly: Uniform.Chat.dll
Syntax
public abstract class EncodingCamera : IVideoCamera, IAsyncDisposable

Properties

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CanSwitch

Whether the device has another camera to switch to.

Declaration
public abstract bool CanSwitch { get; }
Property Value
Type Description
bool
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Low

Whether to capture at half size, as the peer asked for less.

Declaration
protected bool Low { get; }
Property Value
Type Description
bool

Methods

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Deliver(Func<VideoFrame>)

Take a captured picture: dropped while paused or ahead of the frame rate; every third one previewed; encoded and given.

Declaration
protected void Deliver(Func<VideoFrame> picture)
Parameters
Type Name Description
Func<VideoFrame> picture
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DisposeAsync()

Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources asynchronously.

Declaration
public abstract ValueTask DisposeAsync()
Returns
Type Description
ValueTask

A task that represents the asynchronous dispose operation.
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LimitBitrate(long)

Follow the peer's limit: a coarser quantizer for lower rates; half size at 10 per second below Uniform.Chat.Desktop.Cameras.EncodingCamera.FallbackBelow, full size from Uniform.Chat.Desktop.Cameras.EncodingCamera.RestoreFrom.

Declaration
public void LimitBitrate(long bitsPerSecond)
Parameters
Type Name Description
long bitsPerSecond
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RequestKeyframe()

Make the next frame a keyframe.

Declaration
public void RequestKeyframe()
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SetPaused(bool)

Stop sending and previewing, or start again; the device keeps capturing, so it resumes at once.

Declaration
public void SetPaused(bool pause)
Parameters
Type Name Description
bool pause
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Start()

Start capturing and encoding.

Declaration
public abstract void Start()
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SwitchCamera()

Switch to the device's next camera, e.g. from the front to the back; nothing with one camera.

Declaration
public abstract void SwitchCamera()

Events

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FrameEncoded

Raised with each encoded VP8 frame, the first a keyframe; on any thread.

Declaration
public event Action<byte[]>? FrameEncoded
Event Type
Type Description
Action<byte[]>
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Previewed

Raised with small pictures of what the camera sees, for a preview, a few per second; on any thread. Cameras without a preview never raise it.

Declaration
public event Action<VideoFrame>? Previewed
Event Type
Type Description
Action<VideoFrame>

Implements