tvi.webrtc

Class ScreenCapturerAndroid

java.lang.Object

tvi.webrtc.ScreenCapturerAndroid

All Implemented Interfaces:

VideoCapturer, VideoSink

public class ScreenCapturerAndroid
extends java.lang.Object
implements VideoCapturer, VideoSink

An implementation of VideoCapturer to capture the screen content as a video stream. Capturing is done by MediaProjection on a SurfaceTexture. We interact with this SurfaceTexture using a SurfaceTextureHelper. The SurfaceTextureHelper is created by the native code and passed to this capturer in VideoCapturer.initialize(). On receiving a new frame, this capturer passes it as a texture to the native code via CapturerObserver.onFrameCaptured(). This takes place on the HandlerThread of the given SurfaceTextureHelper. When done with each frame, the native code returns the buffer to the SurfaceTextureHelper to be used for new frames. At any time, at most one frame is being processed. Note: This class is only supported on Android Lollipop and above.

Constructor Summary

Constructors

Constructor and Description
ScreenCapturerAndroid(android.content.Intent mediaProjectionPermissionResultData, android.media.projection.MediaProjection.Callback mediaProjectionCallback) Constructs a new Screen Capturer.

Method Summary

Modifier and Type	Method and Description
void	changeCaptureFormat(int width, int height, int ignoredFramerate) Changes output video format.
void	dispose() Perform any final cleanup here.
long	getNumCapturedFrames()
void	initialize(SurfaceTextureHelper surfaceTextureHelper, android.content.Context applicationContext, CapturerObserver capturerObserver) This function is used to initialize the camera thread, the android application context, and the capture observer.
boolean	isScreencast()
void	onFrame(VideoFrame frame) Implementations should call frame.retain() if they need to hold a reference to the frame after this function returns.
void	startCapture(int width, int height, int ignoredFramerate) Start capturing frames in a format that is as close as possible to width x height and framerate.
void	stopCapture() Stop capturing.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ScreenCapturerAndroid

public ScreenCapturerAndroid(android.content.Intent mediaProjectionPermissionResultData,
                             android.media.projection.MediaProjection.Callback mediaProjectionCallback)

Constructs a new Screen Capturer.

Parameters:

mediaProjectionPermissionResultData - the result data of MediaProjection permission activity; the calling app must validate that result code is Activity.RESULT_OK before calling this method.

mediaProjectionCallback - MediaProjection callback to implement application specific logic in events such as when the user revokes a previously granted capture permission.

Method Detail

initialize

public void initialize(SurfaceTextureHelper surfaceTextureHelper,
                       android.content.Context applicationContext,
                       CapturerObserver capturerObserver)

Description copied from interface: VideoCapturer

This function is used to initialize the camera thread, the android application context, and the capture observer. It will be called only once and before any startCapture() request. The camera thread is guaranteed to be valid until dispose() is called. If the VideoCapturer wants to deliver texture frames, it should do this by rendering on the SurfaceTexture in surfaceTextureHelper, register itself as a listener, and forward the frames to CapturerObserver.onFrameCaptured(). The caller still has ownership of surfaceTextureHelper and is responsible for making sure surfaceTextureHelper.dispose() is called. This also means that the caller can reuse the SurfaceTextureHelper to initialize a new VideoCapturer once the previous VideoCapturer has been disposed.

Specified by:

initialize in interface VideoCapturer

startCapture

public void startCapture(int width,
                         int height,
                         int ignoredFramerate)

Description copied from interface: VideoCapturer

Start capturing frames in a format that is as close as possible to width x height and framerate.

Specified by:

startCapture in interface VideoCapturer

stopCapture

public void stopCapture()

Description copied from interface: VideoCapturer

Stop capturing. This function should block until capture is actually stopped.

Specified by:

stopCapture in interface VideoCapturer

dispose

public void dispose()

Description copied from interface: VideoCapturer

Perform any final cleanup here. No more capturing will be done after this call.

Specified by:

dispose in interface VideoCapturer

changeCaptureFormat

public void changeCaptureFormat(int width,
                                int height,
                                int ignoredFramerate)

Changes output video format. This method can be used to scale the output video, or to change orientation when the captured screen is rotated for example.

Specified by:

changeCaptureFormat in interface VideoCapturer

Parameters:

width - new output video width

height - new output video height

ignoredFramerate - ignored

onFrame

public void onFrame(VideoFrame frame)

Description copied from interface: VideoSink

Implementations should call frame.retain() if they need to hold a reference to the frame after this function returns. Each call to retain() should be followed by a call to frame.release() when the reference is no longer needed.

Specified by:

onFrame in interface VideoSink

isScreencast

public boolean isScreencast()

Specified by:

isScreencast in interface VideoCapturer

Returns:

true if-and-only-if this is a screen capturer.

getNumCapturedFrames

public long getNumCapturedFrames()