CameraCaptureSession
abstract class CameraCaptureSession : AutoCloseable
kotlin.Any | |
↳ | android.hardware.camera2.CameraCaptureSession |
A configured capture session for a CameraDevice
, used for capturing images from the camera or reprocessing images captured from the camera in the same session previously.
A CameraCaptureSession is created by providing a set of target output surfaces to android.hardware.camera2.CameraDevice#createCaptureSession, or by providing an android.hardware.camera2.params.InputConfiguration
and a set of target output surfaces to 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.
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.
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 android.hardware.camera2.CameraDevice#createCaptureSession and createReprocessableCaptureSession
will send the ready-to-use CameraCaptureSession to the provided listener's onConfigured
callback. If configuration cannot be completed, then the onConfigureFailed
is called, and the session will not become active.
If a new session is created by the camera device, then the previous session is closed, and its associated onClosed
callback will be invoked. All of the session methods will throw an IllegalStateException if called once the session is closed.
A closed session clears any repeating requests (as if 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.
Summary
Nested classes | |
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abstract |
A callback object for tracking the progress of a |
abstract |
A callback object for receiving updates about the state of a camera capture session. |
Public constructors | |
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Public methods | |
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abstract Unit |
Discard all captures currently pending and in-progress as fast as possible. |
abstract Int |
capture(request: CaptureRequest, listener: CameraCaptureSession.CaptureCallback?, handler: Handler?) Submit a request for an image to be captured by the camera device. |
abstract Int |
captureBurst(requests: MutableList<CaptureRequest!>, listener: CameraCaptureSession.CaptureCallback?, handler: Handler?) Submit a list of requests to be captured in sequence as a burst. |
open Int |
captureBurstRequests(requests: MutableList<CaptureRequest!>, executor: Executor, listener: CameraCaptureSession.CaptureCallback) Submit a list of requests to be captured in sequence as a burst. |
open Int |
captureSingleRequest(request: CaptureRequest, executor: Executor, listener: CameraCaptureSession.CaptureCallback) Submit a request for an image to be captured by the camera device. |
abstract Unit |
close() Close this capture session asynchronously. |
abstract Unit |
finalizeOutputConfigurations(outputConfigs: MutableList<OutputConfiguration!>!) Finalize the output configurations that now have their deferred and/or extra Surfaces included. |
abstract CameraDevice |
Get the camera device that this session is created for. |
abstract Surface? |
Get the input Surface associated with a reprocessable capture session. |
abstract Boolean |
Return if the application can submit reprocess capture requests with this camera capture session. |
abstract Unit |
Pre-allocate all buffers for an output Surface. |
abstract Int |
setRepeatingBurst(requests: MutableList<CaptureRequest!>, listener: CameraCaptureSession.CaptureCallback?, handler: Handler?) Request endlessly repeating capture of a sequence of images by this capture session. |
open Int |
setRepeatingBurstRequests(requests: MutableList<CaptureRequest!>, executor: Executor, listener: CameraCaptureSession.CaptureCallback) Request endlessly repeating capture of a sequence of images by this capture session. |
abstract Int |
setRepeatingRequest(request: CaptureRequest, listener: CameraCaptureSession.CaptureCallback?, handler: Handler?) Request endlessly repeating capture of images by this capture session. |
open Int |
setSingleRepeatingRequest(request: CaptureRequest, executor: Executor, listener: CameraCaptureSession.CaptureCallback) Request endlessly repeating capture of images by this capture session. |
abstract Unit |
Cancel any ongoing repeating capture set by either |
open Boolean |
supportsOfflineProcessing(surface: Surface) Query whether a given Surface is able to support offline mode. |
open CameraOfflineSession? |
switchToOffline(offlineSurfaces: MutableCollection<Surface!>, executor: Executor, listener: CameraOfflineSession.CameraOfflineSessionCallback) Switch the current capture session and a given set of registered camera surfaces to offline processing mode. |
open Unit |
updateOutputConfiguration(config: OutputConfiguration!) Update |
Public constructors
CameraCaptureSession
CameraCaptureSession()
Public methods
abortCaptures
abstract fun abortCaptures(): Unit
Discard all captures currently pending and in-progress as fast as possible.
The camera device will discard all of its current work as fast as possible. Some in-flight captures may complete successfully and call CaptureCallback#onCaptureCompleted
, while others will trigger their CaptureCallback#onCaptureFailed
callbacks. If a repeating request or a repeating burst is set, it will be cleared.
This method is the fastest way to switch the camera device to a new session with android.hardware.camera2.CameraDevice#createCaptureSession or 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 StateCallback#onReady
callback will be called, if the session has not been closed. Otherwise, the StateCallback#onClosed
callback will be fired when a new session is created by the camera device.
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.
This means that using 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).
Exceptions | |
---|---|
android.hardware.camera2.CameraAccessException |
if the camera device is no longer connected or has encountered a fatal error |
java.lang.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. |
capture
abstract fun capture(
request: CaptureRequest,
listener: CameraCaptureSession.CaptureCallback?,
handler: Handler?
): Int
Submit a request for an image to be captured by the camera device.
The request defines all the parameters for capturing the single image, including sensor, lens, flash, and post-processing settings.
Each request will produce one CaptureResult
and produce new frames for one or more target Surfaces, set with the CaptureRequest builder's CaptureRequest.Builder#addTarget
method. The target surfaces (set with CaptureRequest.Builder#addTarget
) must be a subset of the surfaces provided when this capture session was created.
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 requests 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.
Requests submitted through this method have higher priority than those submitted through setRepeatingRequest
or setRepeatingBurst
, and will be processed as soon as the current repeat/repeatBurst processing completes.
All capture sessions can be used for capturing images from the camera but only capture sessions created by createReprocessableCaptureSession
can submit reprocess capture requests. Submitting a reprocess request to a regular capture session will result in an IllegalArgumentException
.
Submitting a request that targets Surfaces with an unsupported dynamic range combination will result in an IllegalArgumentException
.
Parameters | |
---|---|
request |
CaptureRequest: the settings for this capture This value cannot be null . |
listener |
CameraCaptureSession.CaptureCallback?: 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. |
handler |
Handler?: the handler on which the listener should be invoked, or null to use the current thread's looper . |
Return | |
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Int |
int A unique capture sequence ID used by CaptureCallback#onCaptureSequenceCompleted . |
Exceptions | |
---|---|
android.hardware.camera2.CameraAccessException |
if the camera device is no longer connected or has encountered a fatal error |
java.lang.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. |
java.lang.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 TotalCaptureResult from a different session; or the capture targets a Surface in the middle of being prepared ; or the handler is null, the listener is not null, and the calling thread has no looper; or the request targets Surfaces with an unsupported dynamic range combination |
captureBurst
abstract fun captureBurst(
requests: MutableList<CaptureRequest!>,
listener: CameraCaptureSession.CaptureCallback?,
handler: Handler?
): Int
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.
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 CaptureResult
and image buffers for one or more target surfaces
. The target surfaces (set with CaptureRequest.Builder#addTarget
) must be a subset of the surfaces provided when this capture session was created.
The main difference between this method and simply calling capture
repeatedly is that this method guarantees that no other requests will be interspersed with the burst.
All capture sessions can be used for capturing images from the camera but only capture sessions created by createReprocessableCaptureSession
can submit reprocess capture requests. Submitting a reprocess request to a regular capture session will result in an IllegalArgumentException
.
Submitting a request that targets Surfaces with an unsupported dynamic range combination will result in an IllegalArgumentException
.
Parameters | |
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requests |
MutableList<CaptureRequest!>: the list of settings for this burst capture This value cannot be null . |
listener |
CameraCaptureSession.CaptureCallback?: 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. |
handler |
Handler?: the handler on which the listener should be invoked, or null to use the current thread's looper . |
Return | |
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Int |
int A unique capture sequence ID used by CaptureCallback#onCaptureSequenceCompleted . |
Exceptions | |
---|---|
android.hardware.camera2.CameraAccessException |
if the camera device is no longer connected or has encountered a fatal error |
java.lang.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. |
java.lang.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 TotalCaptureResult from a different session; or one of the captures targets a Surface in the middle of being prepared ; or if the handler is null, the listener is not null, and the calling thread has no looper; or the request targets Surfaces with an unsupported dynamic range combination. |
captureBurstRequests
open fun captureBurstRequests(
requests: MutableList<CaptureRequest!>,
executor: Executor,
listener: CameraCaptureSession.CaptureCallback
): Int
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.
The behavior of this method matches that of captureBurst(java.util.List,android.hardware.camera2.CameraCaptureSession.CaptureCallback,android.os.Handler)
, except that it uses java.util.concurrent.Executor
as an argument instead of android.os.Handler
.
Parameters | |
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requests |
MutableList<CaptureRequest!>: the list of settings for this burst capture This value cannot be null . |
executor |
Executor: the executor which will be used for invoking the listener. This value cannot be null . Callback and listener events are dispatched through this Executor , providing an easy way to control which thread is used. To dispatch events through the main thread of your application, you can use Context.getMainExecutor() . Otherwise, provide an Executor that dispatches to an appropriate thread. |
listener |
CameraCaptureSession.CaptureCallback: The callback object to notify each time one of the requests in the burst has been processed. This value cannot be null . |
Return | |
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Int |
int A unique capture sequence ID used by CaptureCallback#onCaptureSequenceCompleted . |
Exceptions | |
---|---|
android.hardware.camera2.CameraAccessException |
if the camera device is no longer connected or has encountered a fatal error |
java.lang.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. |
java.lang.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 TotalCaptureResult from a different session; or one of the captures targets a Surface in the middle of being prepared ; or if the executor is null; or if the listener is null; or the request targets Surfaces with an unsupported dynamic range combination. |
captureSingleRequest
open fun captureSingleRequest(
request: CaptureRequest,
executor: Executor,
listener: CameraCaptureSession.CaptureCallback
): Int
Submit a request for an image to be captured by the camera device.
The behavior of this method matches that of capture(android.hardware.camera2.CaptureRequest,android.hardware.camera2.CameraCaptureSession.CaptureCallback,android.os.Handler)
, except that it uses java.util.concurrent.Executor
as an argument instead of android.os.Handler
.
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 . Callback and listener events are dispatched through this Executor , providing an easy way to control which thread is used. To dispatch events through the main thread of your application, you can use Context.getMainExecutor() . Otherwise, provide an Executor that dispatches to an appropriate thread. |
listener |
CameraCaptureSession.CaptureCallback: The callback object to notify once this request has been processed. This value cannot be null . |
Return | |
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Int |
int A unique capture sequence ID used by CaptureCallback#onCaptureSequenceCompleted . |
Exceptions | |
---|---|
android.hardware.camera2.CameraAccessException |
if the camera device is no longer connected or has encountered a fatal error |
java.lang.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. |
java.lang.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 TotalCaptureResult from a different session; or the capture targets a Surface in the middle of being prepared ; or the executor is null, or the listener is not null; or the request targets Surfaces with an unsupported dynamic range combination; |
close
abstract fun close(): Unit
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 for common usage scenarios like creating a new session or closing the camera device, it is faster to call respective APIs directly (see below for more details) without calling into this method. This API is only useful when application wants to unconfigure the camera but keep the device open for later use.
Creating a new capture session with android.hardware.camera2.CameraDevice#createCaptureSession will close any existing capture session automatically, and call the older session listener's StateCallback#onClosed
callback. Using android.hardware.camera2.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.
Closing the device with CameraDevice#close
directly without calling this API is also recommended for quickly closing the camera.
Once a session is closed, all methods on it will throw an IllegalStateException, and any repeating requests or bursts are stopped (as if 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, StateCallback#onClosed
will be called.
Closing a session is idempotent; closing more than once has no effect.
Exceptions | |
---|---|
java.lang.Exception |
if this resource cannot be closed |
finalizeOutputConfigurations
abstract fun finalizeOutputConfigurations(outputConfigs: MutableList<OutputConfiguration!>!): Unit
Finalize the output configurations that now have their deferred and/or extra Surfaces included.
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. For example, if the preview Surface is obtained from android.view.SurfaceView
, the SurfaceView will only be ready after the UI layout is done, potentially delaying camera startup.
To speed up camera startup time, the application can configure the CameraCaptureSession
with the eventual preview size (via android.hardware.camera2.params.OutputConfiguration#OutputConfiguration(Size,java.lang.Class)), and defer the preview output configuration until the Surface is ready. After the CameraCaptureSession
is created successfully with this deferred output and other normal outputs, the application can start submitting requests as long as they do not include deferred output Surfaces. Once a deferred Surface is ready, the application can add the Surface to the deferred output configuration with the OutputConfiguration#addSurface
method, and then update the deferred output configuration via this method, before it can submit capture requests with this output target.
This function can also be called in case where multiple surfaces share the same OutputConfiguration, and one of the surfaces becomes available after the CameraCaptureSession
is created. In that case, the application must first create the OutputConfiguration with the available Surface, then enable further surface sharing via OutputConfiguration#enableSurfaceSharing
, before creating the CameraCaptureSession. After the CameraCaptureSession is created, and once the extra Surface becomes available, the application must then call OutputConfiguration#addSurface
before finalizing the configuration with this method.
If the provided OutputConfigurations are unchanged from session creation, this function call has no effect. This function must only be called once for a particular output configuration.
The output Surfaces included by this list of OutputConfigurations
can be used as CaptureRequest
targets as soon as this call returns.
This method is not supported by LEGACY
-level devices.
Parameters | |
---|---|
outputConfigs |
MutableList<OutputConfiguration!>!: a list of OutputConfigurations that have had addSurface invoked with a valid output Surface after CameraDevice#createCaptureSessionByOutputConfigurations . |
Exceptions | |
---|---|
android.hardware.camera2.CameraAccessException |
if the camera device is no longer connected or has encountered a fatal error. |
java.lang.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. |
java.lang.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. Or if one of the output configuration was already finished with an included surface in a prior call. |
getDevice
abstract fun getDevice(): CameraDevice
Get the camera device that this session is created for.
Return | |
---|---|
CameraDevice |
This value cannot be null . |
getInputSurface
abstract fun getInputSurface(): Surface?
Get the input Surface associated with a reprocessable capture session.
Each reprocessable capture session has an input Surface
where the reprocess capture requests get the input images from, rather than the camera device. The application can create a ImageWriter
with this input Surface
and use it to provide input images for reprocess capture requests. When the reprocessable capture session is closed, the input Surface
is abandoned and becomes invalid.
Return | |
---|---|
Surface? |
The Surface where reprocessing capture requests get the input images from. If this is not a reprocess capture session, null will be returned. |
isReprocessable
abstract fun isReprocessable(): Boolean
Return if the application can submit reprocess capture requests with this camera capture session.
Return | |
---|---|
Boolean |
true if the application can submit reprocess capture requests with this camera capture session. false otherwise. |
prepare
abstract fun prepare(surface: Surface): Unit
Pre-allocate all buffers for an output Surface.
Normally, the image buffers for a given output Surface are allocated on-demand, to minimize startup latency and memory overhead.
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.
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.
For example, an application that creates an android.media.ImageReader#newInstance 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.
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.
Once allocation is complete, 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.
Note that if 2 surfaces share the same stream via android.hardware.camera2.params.OutputConfiguration#enableSurfaceSharing
and OutputConfiguration#addSurface
, prepare() only needs to be called on one surface, and android.hardware.camera2.CameraCaptureSession.StateCallback#onSurfacePrepared
will be triggered for both surfaces.
LEGACY
devices cannot pre-allocate output buffers; for those devices, StateCallback#onSurfacePrepared
will be immediately called, and no preallocation is done.
Parameters | |
---|---|
surface |
Surface: the output Surface for which buffers should be pre-allocated. Must be one of the output Surfaces used to create this session. This value cannot be null . |
Exceptions | |
---|---|
android.hardware.camera2.CameraAccessException |
if the camera device is no longer connected or has encountered a fatal error |
java.lang.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. |
java.lang.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. |
setRepeatingBurst
abstract fun setRepeatingBurst(
requests: MutableList<CaptureRequest!>,
listener: CameraCaptureSession.CaptureCallback?,
handler: Handler?
): Int
Request endlessly repeating capture of a sequence of images by this capture session.
With this method, the camera device will continually capture images, cycling through the settings in the provided list of CaptureRequests
, at the maximum rate possible.
If a request is submitted through capture
or 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.
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 predictable way, without having to continually submit requests through captureBurst
.
To stop the repeating capture, call stopRepeating
. Any ongoing burst will still be completed, however. Calling abortCaptures
will also clear the request.
Calling this method will replace a previously-set repeating request or burst set up by this method or setRepeatingRequest
, although any in-progress burst will be completed before the new repeat burst will be used.
This method does not support reprocess capture requests because each reprocess CaptureRequest
must be created from the TotalCaptureResult
that matches the input image to be reprocessed. This is either the TotalCaptureResult
of capture that is sent for reprocessing, or one of the 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.
Submitting a request that targets Surfaces with an unsupported dynamic range combination will result in an IllegalArgumentException
.
Parameters | |
---|---|
requests |
MutableList<CaptureRequest!>: the list of requests to cycle through indefinitely This value cannot be null . |
listener |
CameraCaptureSession.CaptureCallback?: 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. |
handler |
Handler?: the handler on which the listener should be invoked, or null to use the current thread's looper . |
Return | |
---|---|
Int |
int A unique capture sequence ID used by CaptureCallback#onCaptureSequenceCompleted . |
Exceptions | |
---|---|
android.hardware.camera2.CameraAccessException |
if the camera device is no longer connected or has encountered a fatal error |
java.lang.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. |
java.lang.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 prepared ; or the handler is null, the listener is not null, and the calling thread has no looper; or no requests were passed in; or the request targets Surfaces with an unsupported dynamic range combination. |
setRepeatingBurstRequests
open fun setRepeatingBurstRequests(
requests: MutableList<CaptureRequest!>,
executor: Executor,
listener: CameraCaptureSession.CaptureCallback
): Int
Request endlessly repeating capture of a sequence of images by this capture session.
The behavior of this method matches that of setRepeatingBurst(java.util.List,android.hardware.camera2.CameraCaptureSession.CaptureCallback,android.os.Handler)
, except that it uses java.util.concurrent.Executor
as an argument instead of android.os.Handler
.
Parameters | |
---|---|
requests |
MutableList<CaptureRequest!>: the list of requests to cycle through indefinitely This value cannot be null . |
executor |
Executor: the executor which will be used for invoking the listener. This value cannot be null . Callback and listener events are dispatched through this Executor , providing an easy way to control which thread is used. To dispatch events through the main thread of your application, you can use Context.getMainExecutor() . Otherwise, provide an Executor that dispatches to an appropriate thread. |
listener |
CameraCaptureSession.CaptureCallback: The callback object to notify each time one of the requests in the repeating bursts has finished processing. This value cannot be null . |
Return | |
---|---|
Int |
int A unique capture sequence ID used by CaptureCallback#onCaptureSequenceCompleted . |
Exceptions | |
---|---|
android.hardware.camera2.CameraAccessException |
if the camera device is no longer connected or has encountered a fatal error |
java.lang.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. |
java.lang.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 prepared ; or the executor is null; or the listener is null; or the request targets Surfaces with an unsupported dynamic range combination. |
setRepeatingRequest
abstract fun setRepeatingRequest(
request: CaptureRequest,
listener: CameraCaptureSession.CaptureCallback?,
handler: Handler?
): Int
Request endlessly repeating capture of images by this capture session.
With this method, the camera device will continually capture images using the settings in the provided CaptureRequest
, at the maximum rate possible.
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 capture
.
Repeat requests have lower priority than those submitted through capture
or captureBurst
, so if capture
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 abortCaptures
will also clear the request.
Calling this method will replace any earlier repeating request or burst set up by this method or setRepeatingBurst
, although any in-progress burst will be completed before the new repeat request will be used.
This method does not support reprocess capture requests because each reprocess CaptureRequest
must be created from the TotalCaptureResult
that matches the input image to be reprocessed. This is either the TotalCaptureResult
of capture that is sent for reprocessing, or one of the 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.
Submitting a request that targets Surfaces with an unsupported dynamic range combination will result in an IllegalArgumentException
.
Parameters | |
---|---|
request |
CaptureRequest: the request to repeat indefinitely This value cannot be null . |
listener |
CameraCaptureSession.CaptureCallback?: 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. |
handler |
Handler?: the handler on which the listener should be invoked, or null to use the current thread's looper . |
Return | |
---|---|
Int |
int A unique capture sequence ID used by CaptureCallback#onCaptureSequenceCompleted . |
Exceptions | |
---|---|
android.hardware.camera2.CameraAccessException |
if the camera device is no longer connected or has encountered a fatal error |
java.lang.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. |
java.lang.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 prepared ; or the handler is null, the listener is not null, and the calling thread has no looper; or no requests were passed in; or the request targets Surfaces with an unsupported dynamic range combination. |
setSingleRepeatingRequest
open fun setSingleRepeatingRequest(
request: CaptureRequest,
executor: Executor,
listener: CameraCaptureSession.CaptureCallback
): Int
Request endlessly repeating capture of images by this capture session.
The behavior of this method matches that of setRepeatingRequest(android.hardware.camera2.CaptureRequest,android.hardware.camera2.CameraCaptureSession.CaptureCallback,android.os.Handler)
, except that it uses java.util.concurrent.Executor
as an argument instead of android.os.Handler
.
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 . Callback and listener events are dispatched through this Executor , providing an easy way to control which thread is used. To dispatch events through the main thread of your application, you can use Context.getMainExecutor() . Otherwise, provide an Executor that dispatches to an appropriate thread. |
listener |
CameraCaptureSession.CaptureCallback: The callback object to notify every time the request finishes processing. This value cannot be null . |
Return | |
---|---|
Int |
int A unique capture sequence ID used by CaptureCallback#onCaptureSequenceCompleted . |
Exceptions | |
---|---|
android.hardware.camera2.CameraAccessException |
if the camera device is no longer connected or has encountered a fatal error |
java.lang.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. |
java.lang.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 prepared ; or the executor is null; or the listener is null; or the request targets Surfaces with an unsupported dynamic range combination. |
stopRepeating
abstract fun stopRepeating(): Unit
Cancel any ongoing repeating capture set by either setRepeatingRequest
or setRepeatingBurst
. Has no effect on requests submitted through capture
or captureBurst
.
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 StateCallback#onReady
callback after calling this method.
Exceptions | |
---|---|
android.hardware.camera2.CameraAccessException |
if the camera device is no longer connected or has encountered a fatal error |
java.lang.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. |
supportsOfflineProcessing
open fun supportsOfflineProcessing(surface: Surface): Boolean
Query whether a given Surface is able to support offline mode.
Surfaces that support offline mode can be passed as arguments to switchToOffline
.
Parameters | |
---|---|
surface |
Surface: An input/output surface that was used to create this session or the result of getInputSurface . This value cannot be null . |
Return | |
---|---|
Boolean |
true if the surface can support offline mode and can be passed as argument to switchToOffline . false otherwise. |
Exceptions | |
---|---|
java.lang.IllegalArgumentException |
if an attempt was made to pass a Surface that was not registered with this capture session. |
java.lang.UnsupportedOperationException |
if an attempt was made to call this method using unsupported camera capture session like CameraConstrainedHighSpeedCaptureSession or CameraOfflineSession . |
See Also
switchToOffline
open fun switchToOffline(
offlineSurfaces: MutableCollection<Surface!>,
executor: Executor,
listener: CameraOfflineSession.CameraOfflineSessionCallback
): CameraOfflineSession?
Switch the current capture session and a given set of registered camera surfaces to offline processing mode.
Devices support this method will report OFFLINE_PROCESSING
capability in CameraCharacteristics#REQUEST_AVAILABLE_CAPABILITIES
. When this method is supported, applications can use it to improve the latency of closing camera or recreating capture session without losing the in progress capture request outputs.
Offline processing mode and the corresponding CameraOfflineSession
differ from a regular online camera capture session in several ways. Successful offline switches will close the currently active camera capture session. Camera clients are also allowed to call CameraDevice#close
while offline processing of selected capture requests is still in progress. Such side effects free device close is only possible when the offline session moves to the ready state. Once this happens, closing the camera device will not affect the pending offline requests and they must complete as normal.
Offline processing mode switches may need several hundred milliseconds to complete as the underlying camera implementation must abort all currently active repeating requests as well as all other pending requests not specified by the client. Additionally the switch will be blocked until all requests that continue processing within the offline session acquire their initial input frame from camera sensor. The call to switchToOffline
itself is not blocking and will only trigger the offline switch sequence. Clients will be notified via CameraOfflineSessionCallback#onReady
once the entire sequence is complete.
Please note that after a successful call to this method the currently active capture session will no longer be valid and clients will begin receiving capture callbacks with a corresponding CameraOfflineSession
passed as a session argument.
Parameters | |
---|---|
offlineSurfaces |
MutableCollection<Surface!>: Client-specified collection of input/output camera registered surfaces that need to be switched to offline mode along with their pending capture requests. Do note that not all camera registered surfaces can be switched to offline mode. Offline processing support for individual surfaces can be queried using supportsOfflineProcessing . Additionally offline mode switches are not available for shared surfaces OutputConfiguration#enableSurfaceSharing and surfaces as part of a surface group. This value cannot be null . |
executor |
Executor: The executor which will be used for invoking the offline callback listener. This value cannot be null . Callback and listener events are dispatched through this Executor , providing an easy way to control which thread is used. To dispatch events through the main thread of your application, you can use Context.getMainExecutor() . Otherwise, provide an Executor that dispatches to an appropriate thread. |
listener |
CameraOfflineSession.CameraOfflineSessionCallback: The callback object to notify for offline session events. This value cannot be null . |
Return | |
---|---|
CameraOfflineSession? |
camera offline session which in case of successful offline switch will move in ready state after clients receive CameraOfflineSessionCallback#onReady . In case the offline switch was not successful clients will receive respective CameraOfflineSessionCallback#onSwitchFailed notification. This value may be null . |
Exceptions | |
---|---|
java.lang.IllegalArgumentException |
if an attempt was made to pass a Surface that was not registered with this capture session or a shared surface OutputConfiguration#enableSurfaceSharing or surface as part of a surface group. The current capture session will remain valid and active in case of this exception. |
android.hardware.camera2.CameraAccessException |
if the camera device is no longer connected or has encountered a fatal error. |
updateOutputConfiguration
open fun updateOutputConfiguration(config: OutputConfiguration!): Unit
Update OutputConfiguration
after configuration finalization see finalizeOutputConfigurations
.
Any OutputConfiguration
that has been modified via calls to OutputConfiguration#addSurface
or OutputConfiguration#removeSurface
must be updated. After the update call returns without throwing exceptions any newly added surfaces can be referenced in subsequent capture requests.
Surfaces that get removed must not be part of any active repeating or single/burst request or have any pending results. Consider updating any repeating requests first via setRepeatingRequest
or setRepeatingBurst
and then wait for the last frame number when the sequence completes CaptureCallback#onCaptureSequenceCompleted
before calling updateOutputConfiguration to remove a previously active Surface.
Surfaces that get added must not be part of any other registered OutputConfiguration
.
Parameters | |
---|---|
config |
OutputConfiguration!: Modified output configuration. |
Exceptions | |
---|---|
android.hardware.camera2.CameraAccessException |
if the camera device is no longer connected or has encountered a fatal error. |
java.lang.IllegalArgumentException |
if an attempt was made to add a Surface already in use by another buffer-producing API, such as MediaCodec or a different camera device or OutputConfiguration ; or new surfaces are not compatible (see OutputConfiguration#enableSurfaceSharing ); or a Surface that was removed from the modified OutputConfiguration still has pending requests. |
java.lang.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. |