Added in API level 31

Summary: Nested Classes | Methods | Inherited Methods

CameraExtensionSession

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Kotlin |Java

public abstract class CameraExtensionSession
extends Object implements AutoCloseable

java.lang.Object
↳	android.hardware.camera2.CameraExtensionSession

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A camera capture session that enables access to device-specific camera extensions, which often use multi-frame bursts and sophisticated post-process algorithms for image capture.

The capture session will be returned after a successful call to CameraDevice#createExtensionSession as part of the argument in the registered state callback StateCallback#onConfigured method.

Note that CameraExtensionSession is currently limited to a maximum of two output surfaces for continuous repeating and multi-frame processing respectively. Some features such as capture settings will not be supported as the device-specific Extension is allowed to override all capture parameters.

Information about support for specific device-specific extensions can be queried from CameraExtensionCharacteristics.

Summary

Nested classes
class	CameraExtensionSession.ExtensionCaptureCallback A callback object for tracking the progress of a CaptureRequest submitted to the camera device.
class	CameraExtensionSession.StateCallback A callback object for receiving updates about the state of a camera extension session.
class	CameraExtensionSession.StillCaptureLatency Realtime calculated still CameraExtensionSession.capture(CaptureRequest, Executor, ExtensionCaptureCallback) latency.

Public methods
int	capture(CaptureRequest request, Executor executor, CameraExtensionSession.ExtensionCaptureCallback listener) Submit a request for device-specific processing using input from the camera device, to produce a single high-quality output result.
void	close() Close this capture session asynchronously.
CameraDevice	getDevice() Get the camera device that this session is created for.
CameraExtensionSession.StillCaptureLatency	getRealtimeStillCaptureLatency() Return the realtime still capture(CaptureRequest, Executor, ExtensionCaptureCallback) latency.
int	setRepeatingRequest(CaptureRequest request, Executor executor, CameraExtensionSession.ExtensionCaptureCallback listener) Request endlessly repeating device-specific extension processing of camera images.
void	stopRepeating() Cancel any ongoing repeating capture set by setRepeatingRequest.

Inherited methods
From class java.lang.Object Object clone() Creates and returns a copy of this object. boolean equals(Object obj) Indicates whether some other object is "equal to" this one. void finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. final Class<?> getClass() Returns the runtime class of this Object. int hashCode() Returns a hash code value for the object. final void notify() Wakes up a single thread that is waiting on this object's monitor. final void notifyAll() Wakes up all threads that are waiting on this object's monitor. String toString() Returns a string representation of the object. final void wait(long timeoutMillis, int nanos) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. final void wait(long timeoutMillis) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. final void wait() Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
From interface java.lang.AutoCloseable abstract void close() Closes this resource, relinquishing any underlying resources.

Public methods

capture

Added in API level 31

public int capture (CaptureRequest request, 
                Executor executor, 
                CameraExtensionSession.ExtensionCaptureCallback listener)

Submit a request for device-specific processing using input from the camera device, to produce a single high-quality output result.

Note that single capture requests currently do not support client parameters except for controls advertised in CameraExtensionCharacteristics#getAvailableCaptureRequestKeys. The rest of the settings included in the request will be entirely overridden by the device-specific extension.

If CameraExtensionCharacteristics#isPostviewAvailable returns false, the CaptureRequest.Builder#addTarget will support only one ImageFormat.YUV_420_888 or ImageFormat.JPEG target surface. CaptureRequest arguments that include further targets will cause IllegalArgumentException to be thrown. If postview is available, CaptureRequest.Builder#addTarget will support up to two ImageFormat.YUV_420_888 or ImageFormat.JPEG target surfaces for the still capture and postview. IllegalArgumentException will be thrown if a postview target is added without a still capture target, if more than two target surfaces are added, or if the surface formats for postview and capture are not equivalent.

Starting with Android Build.VERSION_CODES.TIRAMISU single capture requests will also support the preview ImageFormat.PRIVATE target surface. These can typically be used for enabling AF/AE triggers. Do note, that single capture requests referencing both output surfaces remain unsupported.

Each request will produce one new frame for one target Surface, set with the CaptureRequest builder's CaptureRequest.Builder#addTarget method.

Multiple requests can be in progress at once. Requests are processed in first-in, first-out order.

Requests submitted through this method have higher priority than those submitted through setRepeatingRequest(CaptureRequest, Executor, ExtensionCaptureCallback), and will be processed as soon as the current repeat processing completes.

Parameters
request	CaptureRequest: the settings for this capture This value cannot be null.
executor	Executor: the executor which will be used for invoking the listener. This value cannot be null.
listener	CameraExtensionSession.ExtensionCaptureCallback: The callback object to notify once this request has been processed. This value cannot be null.

Returns
int	int A unique capture sequence ID used by ExtensionCaptureCallback#onCaptureSequenceCompleted.

Throws
CameraAccessException	if the camera device is no longer connected or has encountered a fatal error
IllegalStateException	if this session is no longer active, either because the session was explicitly closed, a new session has been created or the camera device has been closed.
IllegalArgumentException	if the request targets no Surfaces or Surfaces that are not configured as outputs for this session; or the request targets a set of Surfaces that cannot be submitted simultaneously.

close

Added in API level 31

public void close ()

Close this capture session asynchronously.

Closing a session frees up the target output Surfaces of the session for reuse with either a new session, or to other APIs that can draw to Surfaces.

Note that creating a new capture session with CameraDevice.createCaptureSession(SessionConfiguration) or CameraDevice.createExtensionSession(ExtensionSessionConfiguration) will close any existing capture session automatically, and call the older session listener's StateCallback#onClosed callback. Using CameraDevice.createCaptureSession(SessionConfiguration) or CameraDevice.createExtensionSession(ExtensionSessionConfiguration) directly without closing is the recommended approach for quickly switching to a new session, since unchanged target outputs can be reused more efficiently.

Once a session is closed, all methods on it will throw an IllegalStateException, and any repeating requests are stopped (as if stopRepeating() was called).

Closing a session is idempotent; closing more than once has no effect.

Throws
CameraAccessException

getDevice

Added in API level 31

public CameraDevice getDevice ()

Get the camera device that this session is created for.

Returns
CameraDevice	This value cannot be null.

getRealtimeStillCaptureLatency

Added in API level 34

public CameraExtensionSession.StillCaptureLatency getRealtimeStillCaptureLatency ()

Return the realtime still capture(CaptureRequest, Executor, ExtensionCaptureCallback) latency.

The estimations will take into account the current environment conditions, the camera state and will include the time spent processing the multi-frame capture request along with any additional time for encoding of the processed buffer if necessary.

Returns
CameraExtensionSession.StillCaptureLatency	The realtime still capture latency, or null if the estimation is not supported.

Throws
CameraAccessException

setRepeatingRequest

Added in API level 31

public int setRepeatingRequest (CaptureRequest request, 
                Executor executor, 
                CameraExtensionSession.ExtensionCaptureCallback listener)

Request endlessly repeating device-specific extension processing of camera images.

With this method, the camera device will continually capture images and process them using the device-specific extension at the maximum rate possible.

Note that repeating capture requests currently do not support client parameters except for controls advertised in CameraExtensionCharacteristics#getAvailableCaptureRequestKeys. The rest of the settings included in the request will be entirely overridden by the device-specific extension.

The CaptureRequest.Builder#addTarget supports only one target surface. CaptureRequest arguments that include further targets will cause IllegalArgumentException to be thrown.

Repeating requests are a simple way for an application to maintain a preview or other continuous stream of frames.

Repeat requests have lower priority than those submitted through capture(CaptureRequest, Executor, ExtensionCaptureCallback), so if capture(CaptureRequest, Executor, ExtensionCaptureCallback) is called when a repeating request is active, the capture request will be processed before any further repeating requests are processed.

To stop the repeating capture, call stopRepeating().

Calling this method will replace any earlier repeating request.

Parameters
request	CaptureRequest: the request to repeat indefinitely This value cannot be null.
executor	Executor: the executor which will be used for invoking the listener. This value cannot be null.
listener	CameraExtensionSession.ExtensionCaptureCallback: The callback object to notify every time the request finishes processing. This value cannot be null.

Returns
int	int A unique capture sequence ID used by ExtensionCaptureCallback#onCaptureSequenceCompleted.

Throws
CameraAccessException	if the camera device is no longer connected or has encountered a fatal error
IllegalStateException	if this session is no longer active, either because the session was explicitly closed, a new session has been created or the camera device has been closed.
IllegalArgumentException	If the request references no Surfaces or references Surfaces that are not currently configured as outputs.

See also:

• capture(CaptureRequest, Executor, ExtensionCaptureCallback)

stopRepeating

Added in API level 31

public void stopRepeating ()

Cancel any ongoing repeating capture set by setRepeatingRequest. Has no effect on requests submitted through capture.

Any currently in-flight captures will still complete.

Throws
CameraAccessException	if the camera device is no longer connected or has encountered a fatal error
IllegalStateException	if this session is no longer active, either because the session was explicitly closed, a new session has been created or the camera device has been closed.

See also:

• setRepeatingRequest(CaptureRequest, Executor, ExtensionCaptureCallback)