com.twilio.video

Interface VideoCapturer

All Superinterfaces:

VideoCapturer

public interface VideoCapturer
extends VideoCapturer

Generic video capturing interface that extends VideoCapturer.

This interface provides an extension of the WebRTC video capturing interface. Implementations of this interface or VideoCapturer can be used when creating local video tracks. As a result, callers can leverage capturers provided by the SDK, capturers provided by WebRTC, or custom capturers.

The LocalVideoTrack API directly relates to the video capturer programming model. When a caller creates a local video track, the following methods are called in the order listed.

1. VideoCapturer.isScreencast() - The return value is used to create a VideoSource.
2. VideoCapturer.initialize(SurfaceTextureHelper, Context, CapturerObserver) - This method is called so the video capturer can setup to capture frames. The video capturer should retain a reference to the capturer observer and prepare to forward frames. If the video capturer wants to deliver texture frames, it should do this by rendering on the SurfaceTexture provided by surfaceTextureHelper, register itself as a listener, and forward the frames to the capturer observer. This method will be called exactly once before VideoCapturer.startCapture(int, int, int). The local video track retains ownership of the surfaceTextureHelper.
3. VideoCapturer.startCapture(int, int, int) - The video capturer should start capturing in a format as close as possible to width x height at framerate. The video capturer should capture and deliver frames to the capturer observer provided in initialize on a dedicated thread.

When a caller releases a local video track, the following methods are called in the order listed.

1. VideoCapturer.stopCapture() - The video capturer should stop capturing frames. The SDK expects this method to block until frames have stopped being captured.
2. VideoCapturer.dispose() - Perform final cleanup.

Threading Recommendations

Each of these methods are called on the same thread that creates and releases a local video track which for most cases will be the main thread. As a result, video capturers should minimize the amount of work done in each callback and delegate operations on a dedicated thread. A recommended approach would be to create a capturing thread when VideoCapturer.initialize(SurfaceTextureHelper, Context, CapturerObserver) is called and then begin capturing and delivering frames to the capturer observer on the capturing thread when VideoCapturer.startCapture(int, int, int) is called.

Capturers should then stop capturing and join the capturer thread when VideoCapturer.stopCapture()} is called.

See Also:

LocalVideoTrack

Method Summary

Modifier and Type	Method and Description
default void	changeCaptureFormat(int width, int height, int framerate)
default void	dispose() This method provides an optional step to perform a final cleanup.
default VideoFormat	getCaptureFormat()

Methods inherited from interface tvi.webrtc.VideoCapturer

initialize, isScreencast, startCapture, stopCapture

Method Detail

getCaptureFormat

default VideoFormat getCaptureFormat()

changeCaptureFormat

default void changeCaptureFormat(int width,
                                 int height,
                                 int framerate)

Specified by:

changeCaptureFormat in interface VideoCapturer

dispose

default void dispose()

This method provides an optional step to perform a final cleanup.

Specified by:

dispose in interface VideoCapturer