CameraView/docs/_posts/2018-12-20-controls.md

layout	title	subtitle	category	order	date	disqus
page	Controls	Output parameters and capture options	docs	2	2018-12-20 21:08:53	1

CameraView supports a wide range of controls that will control the behavior of the sensor or the quality of the output.

Everything can be controlled through XML parameters or programmatically. For convenience, most options are represented by enum classes extending the Control class. This makes it possible to use CameraView.set(Control) to set the given control, or CameraOptions.supports(Control) to see if it is supported.

XML Attributes

<com.otaliastudios.cameraview.CameraView
    app:cameraFacing="front|back"
    app:cameraFlash="off|on|auto|torch"
    app:cameraWhiteBalance="auto|incandescent|fluorescent|daylight|cloudy"
    app:cameraHdr="off|on"
    app:cameraAudio="on|off"
    app:cameraAudioBitRate="0"
    app:cameraVideoCodec="deviceDefault|h263|h264"
    app:cameraVideoMaxSize="0"
    app:cameraVideoMaxDuration="0"
    app:cameraVideoBitRate="0"/>

APIs

cameraFacing

Which camera to use, either back facing or front facing. Defaults to the first available value (tries BACK first).

cameraView.setFacing(Facing.BACK);
cameraView.setFacing(Facing.FRONT);

cameraFlash

Flash mode, either off, on, auto or torch. Defaults to OFF.

cameraView.setFlash(Flash.OFF);
cameraView.setFlash(Flash.ON);
cameraView.setFlash(Flash.AUTO);
cameraView.setFlash(Flash.TORCH);

cameraVideoCodec

Sets the encoder for video recordings. Defaults to DEVICE_DEFAULT, which should typically be H_264.

cameraView.setVideoCodec(VideoCodec.DEVICE_DEFAULT);
cameraView.setVideoCodec(VideoCodec.H_263);
cameraView.setVideoCodec(VideoCodec.H_264);

cameraWhiteBalance

Sets the desired white balance for the current session. Defaults to AUTO.

cameraView.setWhiteBalance(WhiteBalance.AUTO);
cameraView.setWhiteBalance(WhiteBalance.INCANDESCENT);
cameraView.setWhiteBalance(WhiteBalance.FLUORESCENT);
cameraView.setWhiteBalance(WhiteBalance.DAYLIGHT);
cameraView.setWhiteBalance(WhiteBalance.CLOUDY);

cameraHdr

Turns on or off HDR captures. Defaults to OFF.

cameraView.setHdr(Hdr.OFF);
cameraView.setHdr(Hdr.ON);

cameraAudio

Turns on or off audio stream while recording videos. Defaults to ON.

cameraView.setAudio(Audio.OFF);
cameraView.setAudio(Audio.ON);

cameraAudioBitRate

Controls the audio bit rate in bits per second. Use 0 or a negative value to fallback to the encoder default. Defaults to 0.

cameraView.setAudioBitRate(0);
cameraView.setAudioBitRate(64000);

cameraVideoMaxSize

Defines the maximum size in bytes for recorded video files. Once this size is reached, the recording will automatically stop. Defaults to unlimited size. Use 0 or negatives to disable.

cameraView.setVideoMaxSize(100000);
cameraView.setVideoMaxSize(0); // Disable

cameraVideoMaxDuration

Defines the maximum duration in milliseconds for video recordings. Once this duration is reached, the recording will automatically stop. Defaults to unlimited duration. Use 0 or negatives to disable.

cameraView.setVideoMaxDuration(100000);
cameraView.setVideoMaxDuration(0); // Disable

cameraVideoBitRate

Controls the video bit rate in bits per second. Use 0 or a negative value to fallback to the encoder default. Defaults to 0.

cameraView.setVideoBitRate(0);
cameraView.setVideoBitRate(4000000);

Manual Focus

There are many ways to focus a CameraView engine:

• Continuous autofocus is activated by default, where present
• User can start focus with a Gesture
• The developer can start focus with the startAutoFocus(float, float) API. This action needs the coordinates of a point to focus, with respect to the view width and height.

The last two actions will trigger the focus callbacks:

cameraView.addCameraListener(new CameraListener() {
    
    @Override
    public void onFocusStart(@NonNull PointF point) {
        // Auto focus was started by a gesture or by startAutoFocus(float, float).
        // The camera is currently trying to focus around that area.
        // This can be used to draw things on screen.
    }

    @Override
    public void onFocusEnd(boolean successful, @NonNull PointF point) {
        // Auto focus operation just ended. If successful, the camera will have converged
        // to a new focus point, and possibly changed exposure and white balance as well.
        // The point is the same that was passed to onFocusStart.
    }
});

Auto focus is not guaranteed to be supported: check the CameraOptions to be sure.

Zoom

There are two ways to control the zoom value:

• User can zoom in or out with a Gesture
• The developer can start manual zoom with the setZoom(float) API, passing in a value between 0 and 1.

Both actions will trigger the zoom callback, which can be used, for example, to draw a seek bar:

cameraView.addCameraListener(new CameraListener() {
    
    @Override
    public void onZoomChanged(float newValue, @NonNull float[] bounds, @Nullable PointF[] fingers) {
        // newValue: the new zoom value
        // bounds: this is always [0, 1]
        // fingers: if caused by touch gestures, these is the fingers position
    }
});

Zoom is not guaranteed to be supported: check the CameraOptions to be sure.

Exposure correction

There are two ways to control the exposure correction value:

• User can change the exposure correction with a Gesture
• The developer can change this value with the setExposureCorrection(float) API, passing in the EV value, in camera stops. This value should be contained in the minimum and maximum supported values, as returned by CameraOptions.

Both actions will trigger the exposure correction callback, which can be used, for example, to draw a seek bar:

cameraView.addCameraListener(new CameraListener() {
    
    @UiThread
    public void onExposureCorrectionChanged(float newValue, @NonNull float[] bounds, @Nullable PointF[] fingers) {
        // newValue: the new correction value
        // bounds: min and max bounds for newValue, as returned by {@link CameraOptions}
        // fingers: finger positions that caused the event, null if not caused by touch
    }
});

EV correction is not guaranteed to be supported: check the CameraOptions to be sure.