/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.hardware.camera2;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.hardware.camera2.params.OutputConfiguration;
import android.os.Handler;
import android.view.Surface;
import java.util.List;
/**
* A configured capture session for a {@link CameraDevice}, used for capturing images from the
* camera or reprocessing images captured from the camera in the same session previously.
*
* <p>A CameraCaptureSession is created by providing a set of target output surfaces to
* {@link CameraDevice#createCaptureSession createCaptureSession}, or by providing an
* {@link android.hardware.camera2.params.InputConfiguration} and a set of target output surfaces to
* {@link CameraDevice#createReprocessableCaptureSession createReprocessableCaptureSession} for a
* reprocessable capture session. Once created, the session is active until a new session is
* created by the camera device, or the camera device is closed.</p>
*
* <p>All capture sessions can be used for capturing images from the camera but only reprocessable
* capture sessions can reprocess images captured from the camera in the same session previously.
* </p>
*
* <p>Creating a session is an expensive operation and can take several hundred milliseconds, since
* it requires configuring the camera device's internal pipelines and allocating memory buffers for
* sending images to the desired targets. Therefore the setup is done asynchronously, and
* {@link CameraDevice#createCaptureSession createCaptureSession} and
* {@link CameraDevice#createReprocessableCaptureSession createReprocessableCaptureSession} will
* send the ready-to-use CameraCaptureSession to the provided listener's
* {@link CameraCaptureSession.StateCallback#onConfigured onConfigured} callback. If configuration
* cannot be completed, then the
* {@link CameraCaptureSession.StateCallback#onConfigureFailed onConfigureFailed} is called, and the
* session will not become active.</p>
*<!--
* <p>Any capture requests (repeating or non-repeating) submitted before the session is ready will
* be queued up and will begin capture once the session becomes ready. In case the session cannot be
* configured and {@link StateCallback#onConfigureFailed onConfigureFailed} is called, all queued
* capture requests are discarded.</p>
*-->
* <p>If a new session is created by the camera device, then the previous session is closed, and its
* associated {@link StateCallback#onClosed onClosed} callback will be invoked. All
* of the session methods will throw an IllegalStateException if called once the session is
* closed.</p>
*
* <p>A closed session clears any repeating requests (as if {@link #stopRepeating} had been called),
* but will still complete all of its in-progress capture requests as normal, before a newly
* created session takes over and reconfigures the camera device.</p>
*/
public abstract class CameraCaptureSession implements AutoCloseable {
/**
* Used to identify invalid session ID.
* @hide
*/
public static final int SESSION_ID_NONE = -1;
/**
* Get the camera device that this session is created for.
*/
@NonNull
public abstract CameraDevice getDevice();
/**
* <p>Pre-allocate all buffers for an output Surface.</p>
*
* <p>Normally, the image buffers for a given output Surface are allocated on-demand,
* to minimize startup latency and memory overhead.</p>
*
* <p>However, in some cases, it may be desirable for the buffers to be allocated before
* any requests targeting the Surface are actually submitted to the device. Large buffers
* may take some time to allocate, which can result in delays in submitting requests until
* sufficient buffers are allocated to reach steady-state behavior. Such delays can cause
* bursts to take longer than desired, or cause skips or stutters in preview output.</p>
*
* <p>The prepare() method can be used to perform this preallocation. It may only be called for
* a given output Surface before that Surface is used as a target for a request. The number of
* buffers allocated is the sum of the count needed by the consumer providing the output
* Surface, and the maximum number needed by the camera device to fill its pipeline. Since this
* may be a larger number than what is actually required for steady-state operation, using
* prepare may result in higher memory consumption than the normal on-demand behavior results
* in. Prepare() will also delay the time to first output to a given Surface, in exchange for
* smoother frame rate once the allocation is complete.</p>
*
* <p>For example, an application that creates an
* {@link android.media.ImageReader#newInstance ImageReader} with a maxImages argument of 10,
* but only uses 3 simultaneous Images at once would normally only cause those 3 images to be
* allocated (plus what is needed by the camera device for smooth operation). But using
* prepare() on the ImageReader Surface will result in all 10 Images being allocated. So
* applications using this method should take care to request only the number of buffers
* actually necessary for their application.</p>
*
* <p>If the same output Surface is used in consecutive sessions (without closing the first
* session explicitly), then its already-allocated buffers are carried over, and if it was
* used as a target of a capture request in the first session, prepare cannot be called on it
* in the second session.</p>
*
* <p>Once allocation is complete, {@link StateCallback#onSurfacePrepared} will be invoked with
* the Surface provided to this method. Between the prepare call and the onSurfacePrepared call,
* the Surface provided to prepare must not be used as a target of a CaptureRequest submitted
* to this session.</p>
*
* <p>{@link android.hardware.camera2.CameraCharacteristics#INFO_SUPPORTED_HARDWARE_LEVEL_LEGACY LEGACY}
* devices cannot pre-allocate output buffers; for those devices,
* {@link StateCallback#onSurfacePrepared} will be immediately called, and no preallocation is
* done.</p>
*
* @param surface the output Surface for which buffers should be pre-allocated. Must be one of
* the output Surfaces used to create this session.
*
* @throws CameraAccessException if the camera device is no longer connected or has
* encountered a fatal error
* @throws 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.
* @throws IllegalArgumentException if the Surface is invalid, not part of this Session, or has
* already been used as a target of a CaptureRequest in this
* session or immediately prior sessions.
*
* @see StateCallback#onSurfacePrepared
*/
public abstract void prepare(@NonNull Surface surface) throws CameraAccessException;
/**
* <p>Pre-allocate at most maxCount buffers for an output Surface.</p>
*
* <p>Like the {@link #prepare(Surface)} method, this method can be used to allocate output
* buffers for a given Surface. However, while the {@link #prepare(Surface)} method allocates
* the maximum possible buffer count, this method allocates at most maxCount buffers.</p>
*
* <p>If maxCount is greater than the possible maximum count (which is the sum of the buffer
* count requested by the creator of the Surface and the count requested by the camera device),
* only the possible maximum count is allocated, in which case the function acts exactly like
* {@link #prepare(Surface)}.</p>
*
* <p>The restrictions on when this method can be called are the same as for
* {@link #prepare(Surface)}.</p>
*
* <p>Repeated calls to this method are allowed, and a mix of {@link #prepare(Surface)} and
* this method is also allowed. Note that after the first call to {@link #prepare(Surface)},
* subsequent calls to either prepare method are effectively no-ops. In addition, this method
* is not additive in terms of buffer count. This means calling it twice with maxCount = 2
* will only allocate 2 buffers, not 4 (assuming the possible maximum is at least 2); to
* allocate two buffers on the first call and two on the second, the application needs to call
* prepare with prepare(surface, 2) and prepare(surface, 4).</p>
*
* @param maxCount the buffer count to try to allocate. If this is greater than the possible
* maximum for this output, the possible maximum is allocated instead. If
* maxCount buffers are already allocated, then prepare will do nothing.
* @param surface the output Surface for which buffers should be pre-allocated.
*
* @throws CameraAccessException if the camera device is no longer connected or has
* encountered a fatal error.
* @throws 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.
* @throws IllegalArgumentException if the Surface is invalid, not part of this Session,
* or has already been used as a target of a CaptureRequest in
* this session or immediately prior sessions without an
* intervening tearDown call.
*
* @hide
*/
public abstract void prepare(int maxCount, @NonNull Surface surface)
throws CameraAccessException;
/**
* <p>Free all buffers allocated for an output Surface.</p>
*
* <p>Normally, once allocated, the image buffers for a given output Surface remain allocated
* for the lifetime of the capture session, to minimize latency of captures and to reduce
* memory allocation overhead.</p>
*
* <p>However, in some cases, it may be desirable for allocated buffers to be freed to reduce
* the application's memory consumption, if the particular output Surface will not be used by
* the application for some time.</p>
*
* <p>The tearDown() method can be used to perform this operation. After the call finishes, all
* unfilled image buffers will have been freed. Any future use of the target Surface may require
* allocation of additional buffers, as if the session had just been created. Buffers being
* held by the application (either explicitly as Image objects from ImageReader, or implicitly
* as the current texture in a SurfaceTexture or the current contents of a RS Allocation, will
* remain valid and allocated even when tearDown is invoked.</p>
*
* <p>A Surface that has had tearDown() called on it is eligible to have prepare() invoked on it
* again even if it was used as a request target before the tearDown() call, as long as it
* doesn't get used as a target of a request between the tearDown() and prepare() calls.</p>
*
* @param surface the output Surface for which buffers should be freed. Must be one of the
* the output Surfaces used to create this session.
*
* @throws CameraAccessException if the camera device is no longer connected or has
* encountered a fatal error.
* @throws 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.
* @throws IllegalArgumentException if the Surface is invalid, not part of this Session, or has
* already been used as a target of a CaptureRequest in this
* session or immediately prior sessions.
*
* @hide
*/
public abstract void tearDown(@NonNull Surface surface) throws CameraAccessException;
/**
* <p>
* Finish the deferred output configurations where the output Surface was not configured before.
* </p>
* <p>
* For camera use cases where a preview and other output configurations need to be configured,
* it can take some time for the preview Surface to be ready (e.g., if the preview Surface is
* obtained from {@link android.view.SurfaceView}, the SurfaceView is ready after the UI layout
* is done, then it takes some time to get the preview Surface).
* </p>
* <p>
* To speed up camera startup time, the application can configure the
* {@link CameraCaptureSession} with the desired preview size, and defer the preview output
* configuration until the Surface is ready. After the {@link CameraCaptureSession} is created
* successfully with this deferred configuration and other normal configurations, the
* application can submit requests that don't include deferred output Surfaces. Once the
* deferred Surface is ready, the application can set the Surface to the same deferred output
* configuration with the {@link OutputConfiguration#setDeferredSurface} method, and then finish
* the deferred output configuration via this method, before it can submit requests with this
* output target.
* </p>
* <p>
* The output Surfaces included by this list of deferred {@link OutputConfiguration
* OutputConfigurations} can be used as {@link CaptureRequest} targets as soon as this call
* returns;
* </p>
* <p>
* This method is not supported by Legacy devices.
* </p>
*
* @param deferredOutputConfigs a list of {@link OutputConfiguration OutputConfigurations} that
* have had {@link OutputConfiguration#setDeferredSurface setDeferredSurface} invoked
* with a valid output Surface.
* @throws CameraAccessException if the camera device is no longer connected or has encountered
* a fatal error.
* @throws 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. Or if this output configuration was already finished with the
* included surface before.
* @throws IllegalArgumentException for invalid output configurations, including ones where the
* source of the Surface is no longer valid or the Surface is from a unsupported
* source.
* @hide
*/
public abstract void finishDeferredConfiguration(
List<OutputConfiguration> deferredOutputConfigs) throws CameraAccessException;
/**
* <p>Submit a request for an image to be captured by the camera device.</p>
*
* <p>The request defines all the parameters for capturing the single image,
* including sensor, lens, flash, and post-processing settings.</p>
*
* <p>Each request will produce one {@link CaptureResult} and produce new frames for one or more
* target Surfaces, set with the CaptureRequest builder's
* {@link CaptureRequest.Builder#addTarget} method. The target surfaces (set with
* {@link CaptureRequest.Builder#addTarget}) must be a subset of the surfaces provided when this
* capture session was created.</p>
*
* <p>Multiple regular and reprocess requests can be in progress at once. If there are only
* regular requests or reprocess requests in progress, they are processed in first-in,
* first-out order. If there are both regular and reprocess requests in progress, regular
* requests are processed in first-in, first-out order and reprocess requests are processed in
* first-in, first-out order, respectively. However, the processing order of a regular request
* and a reprocess request in progress is not specified. In other words, a regular request
* will always be processed before regular requets that are submitted later. A reprocess request
* will always be processed before reprocess requests that are submitted later. However, a
* regular request may not be processed before reprocess requests that are submitted later.<p>
*
* <p>Requests submitted through this method have higher priority than
* those submitted through {@link #setRepeatingRequest} or
* {@link #setRepeatingBurst}, and will be processed as soon as the current
* repeat/repeatBurst processing completes.</p>
*
* <p>All capture sessions can be used for capturing images from the camera but only capture
* sessions created by
* {@link CameraDevice#createReprocessableCaptureSession createReprocessableCaptureSession}
* can submit reprocess capture requests. Submitting a reprocess request to a regular capture
* session will result in an {@link IllegalArgumentException}.</p>
*
* @param request the settings for this capture
* @param listener The callback object to notify once this request has been
* processed. If null, no metadata will be produced for this capture,
* although image data will still be produced.
* @param handler the handler on which the listener should be invoked, or
* {@code null} to use the current thread's {@link android.os.Looper
* looper}.
*
* @return int A unique capture sequence ID used by
* {@link CaptureCallback#onCaptureSequenceCompleted}.
*
* @throws CameraAccessException if the camera device is no longer connected or has
* encountered a fatal error
* @throws 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.
* @throws 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 in a reprocessable capture session; or a
* reprocess capture request is submitted in a
* non-reprocessable capture session; or the reprocess capture
* request was created with a {@link TotalCaptureResult} from
* a different session; or the capture targets a Surface in
* the middle of being {@link #prepare prepared}; or the
* handler is null, the listener is not null, and the calling
* thread has no looper.
*
* @see #captureBurst
* @see #setRepeatingRequest
* @see #setRepeatingBurst
* @see #abortCaptures
* @see CameraDevice#createReprocessableCaptureSession
*/
public abstract int capture(@NonNull CaptureRequest request,
@Nullable CaptureCallback listener, @Nullable Handler handler)
throws CameraAccessException;
/**
* Submit a list of requests to be captured in sequence as a burst. The
* burst will be captured in the minimum amount of time possible, and will
* not be interleaved with requests submitted by other capture or repeat
* calls.
*
* <p>Regular and reprocess requests can be mixed together in a single burst. Regular requests
* will be captured in order and reprocess requests will be processed in order, respectively.
* However, the processing order between a regular request and a reprocess request is not
* specified. Each capture produces one {@link CaptureResult} and image buffers for one or more
* target {@link android.view.Surface surfaces}. The target surfaces (set with
* {@link CaptureRequest.Builder#addTarget}) must be a subset of the surfaces provided when
* this capture session was created.</p>
*
* <p>The main difference between this method and simply calling
* {@link #capture} repeatedly is that this method guarantees that no
* other requests will be interspersed with the burst.</p>
*
* <p>All capture sessions can be used for capturing images from the camera but only capture
* sessions created by
* {@link CameraDevice#createReprocessableCaptureSession createReprocessableCaptureSession}
* can submit reprocess capture requests. Submitting a reprocess request to a regular
* capture session will result in an {@link IllegalArgumentException}.</p>
*
* @param requests the list of settings for this burst capture
* @param listener The callback object to notify each time one of the
* requests in the burst has been processed. If null, no metadata will be
* produced for any requests in this burst, although image data will still
* be produced.
* @param handler the handler on which the listener should be invoked, or
* {@code null} to use the current thread's {@link android.os.Looper
* looper}.
*
* @return int A unique capture sequence ID used by
* {@link CaptureCallback#onCaptureSequenceCompleted}.
*
* @throws CameraAccessException if the camera device is no longer connected or has
* encountered a fatal error
* @throws 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.
* @throws IllegalArgumentException If the requests target no Surfaces, or the requests target
* Surfaces not currently configured as outputs; or one of the
* requests targets a set of Surfaces that cannot be submitted
* simultaneously in a reprocessable capture session; or a
* reprocess capture request is submitted in a
* non-reprocessable capture session; or one of the reprocess
* capture requests was created with a
* {@link TotalCaptureResult} from a different session; or one
* of the captures targets a Surface in the middle of being
* {@link #prepare prepared}; or if the handler is null, the
* listener is not null, and the calling thread has no looper.
*
* @see #capture
* @see #setRepeatingRequest
* @see #setRepeatingBurst
* @see #abortCaptures
*/
public abstract int captureBurst(@NonNull List<CaptureRequest> requests,
@Nullable CaptureCallback listener, @Nullable Handler handler)
throws CameraAccessException;
/**
* Request endlessly repeating capture of images by this capture session.
*
* <p>With this method, the camera device will continually capture images
* using the settings in the provided {@link CaptureRequest}, at the maximum
* rate possible.</p>
*
* <p>Repeating requests are a simple way for an application to maintain a
* preview or other continuous stream of frames, without having to
* continually submit identical requests through {@link #capture}.</p>
*
* <p>Repeat requests have lower priority than those submitted
* through {@link #capture} or {@link #captureBurst}, so if
* {@link #capture} is called when a repeating request is active, the
* capture request will be processed before any further repeating
* requests are processed.<p>
*
* <p>To stop the repeating capture, call {@link #stopRepeating}. Calling
* {@link #abortCaptures} will also clear the request.</p>
*
* <p>Calling this method will replace any earlier repeating request or
* burst set up by this method or {@link #setRepeatingBurst}, although any
* in-progress burst will be completed before the new repeat request will be
* used.</p>
*
* <p>This method does not support reprocess capture requests because each reprocess
* {@link CaptureRequest} must be created from the {@link TotalCaptureResult} that matches
* the input image to be reprocessed. This is either the {@link TotalCaptureResult} of capture
* that is sent for reprocessing, or one of the {@link TotalCaptureResult TotalCaptureResults}
* of a set of captures, when data from the whole set is combined by the application into a
* single reprocess input image. The request must be capturing images from the camera. If a
* reprocess capture request is submitted, this method will throw IllegalArgumentException.</p>
*
* @param request the request to repeat indefinitely
* @param listener The callback object to notify every time the
* request finishes processing. If null, no metadata will be
* produced for this stream of requests, although image data will
* still be produced.
* @param handler the handler on which the listener should be invoked, or
* {@code null} to use the current thread's {@link android.os.Looper
* looper}.
*
* @return int A unique capture sequence ID used by
* {@link CaptureCallback#onCaptureSequenceCompleted}.
*
* @throws CameraAccessException if the camera device is no longer connected or has
* encountered a fatal error
* @throws 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.
* @throws IllegalArgumentException If the request references no Surfaces or references Surfaces
* that are not currently configured as outputs; or the request
* is a reprocess capture request; or the capture targets a
* Surface in the middle of being {@link #prepare prepared}; or
* the handler is null, the listener is not null, and the
* calling thread has no looper; or no requests were passed in.
*
* @see #capture
* @see #captureBurst
* @see #setRepeatingBurst
* @see #stopRepeating
* @see #abortCaptures
*/
public abstract int setRepeatingRequest(@NonNull CaptureRequest request,
@Nullable CaptureCallback listener, @Nullable Handler handler)
throws CameraAccessException;
/**
* <p>Request endlessly repeating capture of a sequence of images by this
* capture session.</p>
*
* <p>With this method, the camera device will continually capture images,
* cycling through the settings in the provided list of
* {@link CaptureRequest CaptureRequests}, at the maximum rate possible.</p>
*
* <p>If a request is submitted through {@link #capture} or
* {@link #captureBurst}, the current repetition of the request list will be
* completed before the higher-priority request is handled. This guarantees
* that the application always receives a complete repeat burst captured in
* minimal time, instead of bursts interleaved with higher-priority
* captures, or incomplete captures.</p>
*
* <p>Repeating burst requests are a simple way for an application to
* maintain a preview or other continuous stream of frames where each
* request is different in a predicatable way, without having to continually
* submit requests through {@link #captureBurst}.</p>
*
* <p>To stop the repeating capture, call {@link #stopRepeating}. Any
* ongoing burst will still be completed, however. Calling
* {@link #abortCaptures} will also clear the request.</p>
*
* <p>Calling this method will replace a previously-set repeating request or
* burst set up by this method or {@link #setRepeatingRequest}, although any
* in-progress burst will be completed before the new repeat burst will be
* used.</p>
*
* <p>This method does not support reprocess capture requests because each reprocess
* {@link CaptureRequest} must be created from the {@link TotalCaptureResult} that matches
* the input image to be reprocessed. This is either the {@link TotalCaptureResult} of capture
* that is sent for reprocessing, or one of the {@link TotalCaptureResult TotalCaptureResults}
* of a set of captures, when data from the whole set is combined by the application into a
* single reprocess input image. The request must be capturing images from the camera. If a
* reprocess capture request is submitted, this method will throw IllegalArgumentException.</p>
*
* @param requests the list of requests to cycle through indefinitely
* @param listener The callback object to notify each time one of the
* requests in the repeating bursts has finished processing. If null, no
* metadata will be produced for this stream of requests, although image
* data will still be produced.
* @param handler the handler on which the listener should be invoked, or
* {@code null} to use the current thread's {@link android.os.Looper
* looper}.
*
* @return int A unique capture sequence ID used by
* {@link CaptureCallback#onCaptureSequenceCompleted}.
*
* @throws CameraAccessException if the camera device is no longer connected or has
* encountered a fatal error
* @throws 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.
* @throws IllegalArgumentException If the requests reference no Surfaces or reference Surfaces
* not currently configured as outputs; or one of the requests
* is a reprocess capture request; or one of the captures
* targets a Surface in the middle of being
* {@link #prepare prepared}; or the handler is null, the
* listener is not null, and the calling thread has no looper;
* or no requests were passed in.
*
* @see #capture
* @see #captureBurst
* @see #setRepeatingRequest
* @see #stopRepeating
* @see #abortCaptures
*/
public abstract int setRepeatingBurst(@NonNull List<CaptureRequest> requests,
@Nullable CaptureCallback listener, @Nullable Handler handler)
throws CameraAccessException;
/**
* <p>Cancel any ongoing repeating capture set by either
* {@link #setRepeatingRequest setRepeatingRequest} or
* {@link #setRepeatingBurst}. Has no effect on requests submitted through
* {@link #capture capture} or {@link #captureBurst captureBurst}.</p>
*
* <p>Any currently in-flight captures will still complete, as will any burst that is
* mid-capture. To ensure that the device has finished processing all of its capture requests
* and is in ready state, wait for the {@link StateCallback#onReady} callback after
* calling this method.</p>
*
* @throws CameraAccessException if the camera device is no longer connected or has
* encountered a fatal error
* @throws 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 #setRepeatingRequest
* @see #setRepeatingBurst
* @see StateCallback#onIdle
*/
public abstract void stopRepeating() throws CameraAccessException;
/**
* Discard all captures currently pending and in-progress as fast as possible.
*
* <p>The camera device will discard all of its current work as fast as possible. Some in-flight
* captures may complete successfully and call {@link CaptureCallback#onCaptureCompleted}, while
* others will trigger their {@link CaptureCallback#onCaptureFailed} callbacks. If a repeating
* request or a repeating burst is set, it will be cleared.</p>
*
* <p>This method is the fastest way to switch the camera device to a new session with
* {@link CameraDevice#createCaptureSession} or
* {@link CameraDevice#createReprocessableCaptureSession}, at the cost of discarding in-progress
* work. It must be called before the new session is created. Once all pending requests are
* either completed or thrown away, the {@link StateCallback#onReady} callback will be called,
* if the session has not been closed. Otherwise, the {@link StateCallback#onClosed}
* callback will be fired when a new session is created by the camera device.</p>
*
* <p>Cancelling will introduce at least a brief pause in the stream of data from the camera
* device, since once the camera device is emptied, the first new request has to make it through
* the entire camera pipeline before new output buffers are produced.</p>
*
* <p>This means that using {@code abortCaptures()} to simply remove pending requests is not
* recommended; it's best used for quickly switching output configurations, or for cancelling
* long in-progress requests (such as a multi-second capture).</p>
*
* @throws CameraAccessException if the camera device is no longer connected or has
* encountered a fatal error
* @throws 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 #setRepeatingRequest
* @see #setRepeatingBurst
* @see CameraDevice#createCaptureSession
* @see CameraDevice#createReprocessableCaptureSession
*/
public abstract void abortCaptures() throws CameraAccessException;
/**
* Return if the application can submit reprocess capture requests with this camera capture
* session.
*
* @return {@code true} if the application can submit reprocess capture requests with this
* camera capture session. {@code false} otherwise.
*
* @see CameraDevice#createReprocessableCaptureSession
*/
public abstract boolean isReprocessable();
/**
* Get the input Surface associated with a reprocessable capture session.
*
* <p>Each reprocessable capture session has an input {@link Surface} where the reprocess
* capture requests get the input images from, rather than the camera device. The application
* can create a {@link android.media.ImageWriter ImageWriter} with this input {@link Surface}
* and use it to provide input images for reprocess capture requests. When the reprocessable
* capture session is closed, the input {@link Surface} is abandoned and becomes invalid.</p>
*
* @return The {@link Surface} where reprocessing capture requests get the input images from. If
* this is not a reprocess capture session, {@code null} will be returned.
*
* @see CameraDevice#createReprocessableCaptureSession
* @see android.media.ImageWriter
* @see android.media.ImageReader
*/
@Nullable
public abstract Surface getInputSurface();
/**
* Close this capture session asynchronously.
*
* <p>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.</p>
*
* <p>Note that creating a new capture session with {@link CameraDevice#createCaptureSession}
* will close any existing capture session automatically, and call the older session listener's
* {@link StateCallback#onClosed} callback. Using {@link CameraDevice#createCaptureSession}
* directly without closing is the recommended approach for quickly switching to a new session,
* since unchanged target outputs can be reused more efficiently.</p>
*
* <p>Once a session is closed, all methods on it will throw an IllegalStateException, and any
* repeating requests or bursts are stopped (as if {@link #stopRepeating()} was called).
* However, any in-progress capture requests submitted to the session will be completed as
* normal; once all captures have completed and the session has been torn down,
* {@link StateCallback#onClosed} will be called.</p>
*
* <p>Closing a session is idempotent; closing more than once has no effect.</p>
*/
@Override
public abstract void close();
/**
* A callback object for receiving updates about the state of a camera capture session.
*
*/
public static abstract class StateCallback {
/**
* This method is called when the camera device has finished configuring itself, and the
* session can start processing capture requests.
*
* <p>If there are capture requests already queued with the session, they will start
* processing once this callback is invoked, and the session will call {@link #onActive}
* right after this callback is invoked.</p>
*
* <p>If no capture requests have been submitted, then the session will invoke
* {@link #onReady} right after this callback.</p>
*
* <p>If the camera device configuration fails, then {@link #onConfigureFailed} will
* be invoked instead of this callback.</p>
*
* @param session the session returned by {@link CameraDevice#createCaptureSession}
*/
public abstract void onConfigured(@NonNull CameraCaptureSession session);
/**
* This method is called if the session cannot be configured as requested.
*
* <p>This can happen if the set of requested outputs contains unsupported sizes,
* or too many outputs are requested at once.</p>
*
* <p>The session is considered to be closed, and all methods called on it after this
* callback is invoked will throw an IllegalStateException. Any capture requests submitted
* to the session prior to this callback will be discarded and will not produce any
* callbacks on their listeners.</p>
*
* @param session the session returned by {@link CameraDevice#createCaptureSession}
*/
public abstract void onConfigureFailed(@NonNull CameraCaptureSession session);
/**
* This method is called every time the session has no more capture requests to process.
*
* <p>During the creation of a new session, this callback is invoked right after
* {@link #onConfigured} if no capture requests were submitted to the session prior to it
* completing configuration.</p>
*
* <p>Otherwise, this callback will be invoked any time the session finishes processing
* all of its active capture requests, and no repeating request or burst is set up.</p>
*
* @param session the session returned by {@link CameraDevice#createCaptureSession}
*
*/
public void onReady(@NonNull CameraCaptureSession session) {
// default empty implementation
}
/**
* This method is called when the session starts actively processing capture requests.
*
* <p>If capture requests are submitted prior to {@link #onConfigured} being called,
* then the session will start processing those requests immediately after the callback,
* and this method will be immediately called after {@link #onConfigured}.
*
* <p>If the session runs out of capture requests to process and calls {@link #onReady},
* then this callback will be invoked again once new requests are submitted for capture.</p>
*
* @param session the session returned by {@link CameraDevice#createCaptureSession}
*/
public void onActive(@NonNull CameraCaptureSession session) {
// default empty implementation
}
/**
* This method is called when the session is closed.
*
* <p>A session is closed when a new session is created by the parent camera device,
* or when the parent camera device is closed (either by the user closing the device,
* or due to a camera device disconnection or fatal error).</p>
*
* <p>Once a session is closed, all methods on it will throw an IllegalStateException, and
* any repeating requests or bursts are stopped (as if {@link #stopRepeating()} was called).
* However, any in-progress capture requests submitted to the session will be completed
* as normal.</p>
*
* @param session the session returned by {@link CameraDevice#createCaptureSession}
*/
public void onClosed(@NonNull CameraCaptureSession session) {
// default empty implementation
}
/**
* This method is called when the buffer pre-allocation for an output Surface is complete.
*
* <p>Buffer pre-allocation for an output Surface is started by the {@link #prepare} call.
* While allocation is underway, the Surface must not be used as a capture target.
* Once this callback fires, the output Surface provided can again be used as a target for
* a capture request.</p>
*
* <p>In case of a error during pre-allocation (such as running out of suitable memory),
* this callback is still invoked after the error is encountered, though some buffers may
* not have been successfully pre-allocated.</p>
*
* @param session the session returned by {@link CameraDevice#createCaptureSession}
* @param surface the Surface that was used with the {@link #prepare} call.
*/
public void onSurfacePrepared(@NonNull CameraCaptureSession session,
@NonNull Surface surface) {
// default empty implementation
}
}
/**
* Temporary for migrating to Callback naming
* @hide
*/
public static abstract class StateListener extends StateCallback {
}
/**
* <p>A callback object for tracking the progress of a {@link CaptureRequest} submitted to the
* camera device.</p>
*
* <p>This callback is invoked when a request triggers a capture to start,
* and when the capture is complete. In case on an error capturing an image,
* the error method is triggered instead of the completion method.</p>
*
* @see #capture
* @see #captureBurst
* @see #setRepeatingRequest
* @see #setRepeatingBurst
*/
public static abstract class CaptureCallback {
/**
* This constant is used to indicate that no images were captured for
* the request.
*
* @hide
*/
public static final int NO_FRAMES_CAPTURED = -1;
/**
* This method is called when the camera device has started capturing
* the output image for the request, at the beginning of image exposure, or
* when the camera device has started processing an input image for a reprocess
* request.
*
* <p>For a regular capture request, this callback is invoked right as
* the capture of a frame begins, so it is the most appropriate time
* for playing a shutter sound, or triggering UI indicators of capture.</p>
*
* <p>The request that is being used for this capture is provided, along
* with the actual timestamp for the start of exposure. For a reprocess
* request, this timestamp will be the input image's start of exposure
* which matches {@link CaptureResult#SENSOR_TIMESTAMP the result timestamp field}
* of the {@link TotalCaptureResult} that was used to
* {@link CameraDevice#createReprocessCaptureRequest create the reprocess request}.
* This timestamp matches the timestamps that will be
* included in {@link CaptureResult#SENSOR_TIMESTAMP the result timestamp field},
* and in the buffers sent to each output Surface. These buffer
* timestamps are accessible through, for example,
* {@link android.media.Image#getTimestamp() Image.getTimestamp()} or
* {@link android.graphics.SurfaceTexture#getTimestamp()}.
* The frame number included is equal to the frame number that will be included in
* {@link CaptureResult#getFrameNumber}.</p>
*
* <p>For the simplest way to play a shutter sound camera shutter or a
* video recording start/stop sound, see the
* {@link android.media.MediaActionSound} class.</p>
*
* <p>The default implementation of this method does nothing.</p>
*
* @param session the session returned by {@link CameraDevice#createCaptureSession}
* @param request the request for the capture that just begun
* @param timestamp the timestamp at start of capture for a regular request, or
* the timestamp at the input image's start of capture for a
* reprocess request, in nanoseconds.
* @param frameNumber the frame number for this capture
*
* @see android.media.MediaActionSound
*/
public void onCaptureStarted(@NonNull CameraCaptureSession session,
@NonNull CaptureRequest request, long timestamp, long frameNumber) {
// Temporary trampoline for API change transition
onCaptureStarted(session, request, timestamp);
}
/**
* Temporary for API change transition
* @hide
*/
public void onCaptureStarted(CameraCaptureSession session,
CaptureRequest request, long timestamp) {
// default empty implementation
}
/**
* This method is called when some results from an image capture are
* available.
*
* <p>The result provided here will contain some subset of the fields of
* a full result. Multiple onCapturePartial calls may happen per
* capture; a given result field will only be present in one partial
* capture at most. The final onCaptureCompleted call will always
* contain all the fields, whether onCapturePartial was called or
* not.</p>
*
* <p>The default implementation of this method does nothing.</p>
*
* @param session the session returned by {@link CameraDevice#createCaptureSession}
* @param request The request that was given to the CameraDevice
* @param result The partial output metadata from the capture, which
* includes a subset of the CaptureResult fields.
*
* @see #capture
* @see #captureBurst
* @see #setRepeatingRequest
* @see #setRepeatingBurst
*
* @hide
*/
public void onCapturePartial(CameraCaptureSession session,
CaptureRequest request, CaptureResult result) {
// default empty implementation
}
/**
* This method is called when an image capture makes partial forward progress; some
* (but not all) results from an image capture are available.
*
* <p>The result provided here will contain some subset of the fields of
* a full result. Multiple {@link #onCaptureProgressed} calls may happen per
* capture; a given result field will only be present in one partial
* capture at most. The final {@link #onCaptureCompleted} call will always
* contain all the fields (in particular, the union of all the fields of all
* the partial results composing the total result).</p>
*
* <p>For each request, some result data might be available earlier than others. The typical
* delay between each partial result (per request) is a single frame interval.
* For performance-oriented use-cases, applications should query the metadata they need
* to make forward progress from the partial results and avoid waiting for the completed
* result.</p>
*
* <p>For a particular request, {@link #onCaptureProgressed} may happen before or after
* {@link #onCaptureStarted}.</p>
*
* <p>Each request will generate at least {@code 1} partial results, and at most
* {@link CameraCharacteristics#REQUEST_PARTIAL_RESULT_COUNT} partial results.</p>
*
* <p>Depending on the request settings, the number of partial results per request
* will vary, although typically the partial count could be the same as long as the
* camera device subsystems enabled stay the same.</p>
*
* <p>The default implementation of this method does nothing.</p>
*
* @param session the session returned by {@link CameraDevice#createCaptureSession}
* @param request The request that was given to the CameraDevice
* @param partialResult The partial output metadata from the capture, which
* includes a subset of the {@link TotalCaptureResult} fields.
*
* @see #capture
* @see #captureBurst
* @see #setRepeatingRequest
* @see #setRepeatingBurst
*/
public void onCaptureProgressed(@NonNull CameraCaptureSession session,
@NonNull CaptureRequest request, @NonNull CaptureResult partialResult) {
// default empty implementation
}
/**
* This method is called when an image capture has fully completed and all the
* result metadata is available.
*
* <p>This callback will always fire after the last {@link #onCaptureProgressed};
* in other words, no more partial results will be delivered once the completed result
* is available.</p>
*
* <p>For performance-intensive use-cases where latency is a factor, consider
* using {@link #onCaptureProgressed} instead.</p>
*
* <p>The default implementation of this method does nothing.</p>
*
* @param session the session returned by {@link CameraDevice#createCaptureSession}
* @param request The request that was given to the CameraDevice
* @param result The total output metadata from the capture, including the
* final capture parameters and the state of the camera system during
* capture.
*
* @see #capture
* @see #captureBurst
* @see #setRepeatingRequest
* @see #setRepeatingBurst
*/
public void onCaptureCompleted(@NonNull CameraCaptureSession session,
@NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {
// default empty implementation
}
/**
* This method is called instead of {@link #onCaptureCompleted} when the
* camera device failed to produce a {@link CaptureResult} for the
* request.
*
* <p>Other requests are unaffected, and some or all image buffers from
* the capture may have been pushed to their respective output
* streams.</p>
*
* <p>The default implementation of this method does nothing.</p>
*
* @param session
* The session returned by {@link CameraDevice#createCaptureSession}
* @param request
* The request that was given to the CameraDevice
* @param failure
* The output failure from the capture, including the failure reason
* and the frame number.
*
* @see #capture
* @see #captureBurst
* @see #setRepeatingRequest
* @see #setRepeatingBurst
*/
public void onCaptureFailed(@NonNull CameraCaptureSession session,
@NonNull CaptureRequest request, @NonNull CaptureFailure failure) {
// default empty implementation
}
/**
* This method is called independently of the others in CaptureCallback,
* when a capture sequence finishes and all {@link CaptureResult}
* or {@link CaptureFailure} for it have been returned via this listener.
*
* <p>In total, there will be at least one result/failure returned by this listener
* before this callback is invoked. If the capture sequence is aborted before any
* requests have been processed, {@link #onCaptureSequenceAborted} is invoked instead.</p>
*
* <p>The default implementation does nothing.</p>
*
* @param session
* The session returned by {@link CameraDevice#createCaptureSession}
* @param sequenceId
* A sequence ID returned by the {@link #capture} family of functions.
* @param frameNumber
* The last frame number (returned by {@link CaptureResult#getFrameNumber}
* or {@link CaptureFailure#getFrameNumber}) in the capture sequence.
*
* @see CaptureResult#getFrameNumber()
* @see CaptureFailure#getFrameNumber()
* @see CaptureResult#getSequenceId()
* @see CaptureFailure#getSequenceId()
* @see #onCaptureSequenceAborted
*/
public void onCaptureSequenceCompleted(@NonNull CameraCaptureSession session,
int sequenceId, long frameNumber) {
// default empty implementation
}
/**
* This method is called independently of the others in CaptureCallback,
* when a capture sequence aborts before any {@link CaptureResult}
* or {@link CaptureFailure} for it have been returned via this listener.
*
* <p>Due to the asynchronous nature of the camera device, not all submitted captures
* are immediately processed. It is possible to clear out the pending requests
* by a variety of operations such as {@link CameraCaptureSession#stopRepeating} or
* {@link CameraCaptureSession#abortCaptures}. When such an event happens,
* {@link #onCaptureSequenceCompleted} will not be called.</p>
*
* <p>The default implementation does nothing.</p>
*
* @param session
* The session returned by {@link CameraDevice#createCaptureSession}
* @param sequenceId
* A sequence ID returned by the {@link #capture} family of functions.
*
* @see CaptureResult#getFrameNumber()
* @see CaptureFailure#getFrameNumber()
* @see CaptureResult#getSequenceId()
* @see CaptureFailure#getSequenceId()
* @see #onCaptureSequenceCompleted
*/
public void onCaptureSequenceAborted(@NonNull CameraCaptureSession session,
int sequenceId) {
// default empty implementation
}
/**
* <p>This method is called if a single buffer for a capture could not be sent to its
* destination surface.</p>
*
* <p>If the whole capture failed, then {@link #onCaptureFailed} will be called instead. If
* some but not all buffers were captured but the result metadata will not be available,
* then onCaptureFailed will be invoked with {@link CaptureFailure#wasImageCaptured}
* returning true, along with one or more calls to {@link #onCaptureBufferLost} for the
* failed outputs.</p>
*
* @param session
* The session returned by {@link CameraDevice#createCaptureSession}
* @param request
* The request that was given to the CameraDevice
* @param target
* The target Surface that the buffer will not be produced for
* @param frameNumber
* The frame number for the request
*/
public void onCaptureBufferLost(@NonNull CameraCaptureSession session,
@NonNull CaptureRequest request, @NonNull Surface target, long frameNumber) {
// default empty implementation
}
}
/**
* Temporary for migrating to Callback naming
* @hide
*/
public static abstract class CaptureListener extends CaptureCallback {
}
}