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Basic-Video-Capturer-Java

README.md

Basic Video Capturer Camera

Sample app shows how to use device camera as the video source with the custom video capturer using the Camera package.

Camera class was deprecated in API level 21. Please check Basic Video Capturer Camera 2 project for more up to date implementation.

Note: Check Custom Video Driver project to see how to use custom video capturer and custom video renderer together.

A custom video capturer will be helpful when:

  • modifying the camera stream content - image composition (adding watermark logo) or image processing (mirroring the video, removing the background or putting a virtual hat on the user).
  • streaming any content other than the one coming from the device camera, e.g. streaming content of a particular view's game or content (check Screen-Sharing project).

Using a custom video capturer

The MirrorVideoCapturer is a custom class that extends the BaseVideoCapturer class, defined in the OpenTok Android SDK. During construction of a Publisher object, the code sets a custom video capturer by calling the capturer method of the Publisher:

MirrorVideoCapturer mirrorVideoCapturer = new MirrorVideoCapturer(
                    MainActivity.this,
                    Publisher.CameraCaptureResolution.HIGH,
                    Publisher.CameraCaptureFrameRate.FPS_30);

publisher = new Publisher.Builder(MainActivity.this)
        .capturer(mirrorVideoCapturer)
        .build();

The CustomVideoCapturer class extends the BaseVideoCapturer class, defined in the OpenTok Android SDK. The getCaptureSettings method returns the settings of the video capturer, including the frame rate, width, height, video delay, and video format for the capturer:

@Override
public CaptureSettings getCaptureSettings() {

    CaptureSettings captureSettings = new CaptureSettings();

    VideoUtils.Size resolution = new VideoUtils.Size();
    resolution = getPreferredResolution();

    int frameRate = getPreferredFrameRate();

    if (camera != null) {
        settings = new CaptureSettings();
        configureCaptureSize(resolution.width, resolution.height);
        captureSettings.fps = frameRate;
        captureSettings.width = captureWidth;
        captureSettings.height = captureHeight;
        captureSettings.format = NV21;
        captureSettings.expectedDelay = 0;
    } else {
        captureSettings.fps = frameRate;
        captureSettings.width = resolution.width;
        captureSettings.height = resolution.height;
        captureSettings.format = ARGB;
    }

    return settings;
}

The app calls startCapture() to start capturing video from the custom video capturer.

The class also implements the PreviewCallback interface. The onPreviewFrame method of this interface is called as preview frames of the camera become available. In this method, the app calls the provideByteArrayFrame method of the MirrorVideoCapturer class (inherited from the BaseVideoCapturer class). This method provides a video frame, defined as a byte array, to the video capturer:

provideByteArrayFrame(data, NV21, captureWidth, captureHeight, currentRotation, isFrontCamera());

The publisher adds this video frame to the published stream.

Further Reading