Android APIs
public final class

StreamConfigurationMap

extends Object
java.lang.Object
   ↳ android.hardware.camera2.params.StreamConfigurationMap

Class Overview

Immutable class to store the available stream configurations to set up Surfaces for creating a capture session with createCaptureSession(List, CameraCaptureSession.StateListener, Handler).

This is the authoritative list for all output formats (and sizes respectively for that format) that are supported by a camera device.

This also contains the minimum frame durations and stall durations for each format/size combination that can be used to calculate effective frame rate when submitting multiple captures.

An instance of this object is available from CameraCharacteristics using the SCALER_STREAM_CONFIGURATION_MAP key and the get(CameraCharacteristics.Key) method.

CameraCharacteristics characteristics = cameraManager.getCameraCharacteristics(cameraId);
 StreamConfigurationMap configs = characteristics.get(
         CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);

See Also

Summary

Public Methods
boolean equals(Object obj)
Check if this StreamConfigurationMap is equal to another StreamConfigurationMap.
final int[] getOutputFormats()
Get the image format output formats in this stream configuration.
<T> long getOutputMinFrameDuration(Class<T> klass, Size size)
Get the minimum frame duration for the class/size combination (in nanoseconds).
long getOutputMinFrameDuration(int format, Size size)
Get the minimum frame duration for the format/size combination (in nanoseconds).
<T> Size[] getOutputSizes(Class<T> klass)
Get a list of sizes compatible with klass to use as an output.
Size[] getOutputSizes(int format)
Get a list of sizes compatible with the requested image format.
long getOutputStallDuration(int format, Size size)
Get the stall duration for the format/size combination (in nanoseconds).
<T> long getOutputStallDuration(Class<T> klass, Size size)
Get the stall duration for the class/size combination (in nanoseconds).
int hashCode()
Returns an integer hash code for this object.
boolean isOutputSupportedFor(int format)
Determine whether or not output surfaces with a particular user-defined format can be passed createCaptureSession.
boolean isOutputSupportedFor(Surface surface)
Determine whether or not the surface in its current state is suitable to be included in a capture session as an output.
static <T> boolean isOutputSupportedFor(Class<T> klass)
Determine whether or not output streams can be configured with a particular class as a consumer.
[Expand]
Inherited Methods
From class java.lang.Object

Public Methods

public boolean equals (Object obj)

Check if this StreamConfigurationMap is equal to another StreamConfigurationMap.

Two vectors are only equal if and only if each of the respective elements is equal.

Parameters
obj the object to compare this instance with.
Returns
  • true if the objects were equal, false otherwise

public final int[] getOutputFormats ()

Get the image format output formats in this stream configuration.

All image formats returned by this function will be defined in either ImageFormat or in PixelFormat (and there is no possibility of collision).

Formats listed in this array are guaranteed to return true if queried with {@link #isOutputSupportedFor(int).

Returns
  • an array of integer format
See Also

public long getOutputMinFrameDuration (Class<T> klass, Size size)

Get the minimum frame duration for the class/size combination (in nanoseconds).

This assumes a the klass is set up to use an implementation-defined format. For user-defined formats, use getOutputMinFrameDuration(int, Size).

klass should be one of the ones which is supported by isOutputSupportedFor(Class).

size should be one of the ones returned by getOutputSizes(int).

This should correspond to the frame duration when only that stream is active, with all processing (typically in android.*.mode) set to either OFF or FAST.

When multiple streams are used in a request, the minimum frame duration will be max(individual stream min durations).

Parameters
klass a class which is supported by isOutputSupportedFor(Class) and has a non-empty array returned by getOutputSizes(Class)
size an output-compatible size
Returns
  • a minimum frame duration >= 0 in nanoseconds
Throws
IllegalArgumentException if klass or size was not supported
NullPointerException if size or klass was null
See Also

public long getOutputMinFrameDuration (int format, Size size)

Get the minimum frame duration for the format/size combination (in nanoseconds).

format should be one of the ones returned by getOutputFormats().

size should be one of the ones returned by getOutputSizes(int).

This should correspond to the frame duration when only that stream is active, with all processing (typically in android.*.mode) set to either OFF or FAST.

When multiple streams are used in a request, the minimum frame duration will be max(individual stream min durations).

Parameters
format an image format from ImageFormat or PixelFormat
size an output-compatible size
Returns
  • a minimum frame duration >= 0 in nanoseconds
Throws
IllegalArgumentException if format or size was not supported
NullPointerException if size was null
See Also

public Size[] getOutputSizes (Class<T> klass)

Get a list of sizes compatible with klass to use as an output.

Since some of the supported classes may support additional formats beyond an opaque/implementation-defined (under-the-hood) format; this function only returns sizes for the implementation-defined format.

Some classes such as ImageReader may only support user-defined formats; in particular isOutputSupportedFor(Class) will return true for that class and this method will return an empty array (but not null).

If a well-defined format such as NV21 is required, use getOutputSizes(int) instead.

The klass should be a supported output, that querying #isOutputSupportedFor(Class) should return true.

Parameters
klass a non-null Class object reference
Returns
  • an array of supported sizes for implementation-defined formats, or null iff the klass is not a supported output
Throws
NullPointerException if klass was null
See Also

public Size[] getOutputSizes (int format)

Get a list of sizes compatible with the requested image format.

The format should be a supported format (one of the formats returned by getOutputFormats()).

Parameters
format an image format from ImageFormat or PixelFormat
Returns
  • an array of supported sizes, or null if the format is not a supported output
See Also

public long getOutputStallDuration (int format, Size size)

Get the stall duration for the format/size combination (in nanoseconds).

format should be one of the ones returned by getOutputFormats().

size should be one of the ones returned by getOutputSizes(int).

A stall duration is how much extra time would get added to the normal minimum frame duration for a repeating request that has streams with non-zero stall.

For example, consider JPEG captures which have the following characteristics:

  • JPEG streams act like processed YUV streams in requests for which they are not included; in requests in which they are directly referenced, they act as JPEG streams. This is because supporting a JPEG stream requires the underlying YUV data to always be ready for use by a JPEG encoder, but the encoder will only be used (and impact frame duration) on requests that actually reference a JPEG stream.
  • The JPEG processor can run concurrently to the rest of the camera pipeline, but cannot process more than 1 capture at a time.

In other words, using a repeating YUV request would result in a steady frame rate (let's say it's 30 FPS). If a single JPEG request is submitted periodically, the frame rate will stay at 30 FPS (as long as we wait for the previous JPEG to return each time). If we try to submit a repeating YUV + JPEG request, then the frame rate will drop from 30 FPS.

In general, submitting a new request with a non-0 stall time stream will not cause a frame rate drop unless there are still outstanding buffers for that stream from previous requests.

Submitting a repeating request with streams (call this S) is the same as setting the minimum frame duration from the normal minimum frame duration corresponding to S, added with the maximum stall duration for S.

If interleaving requests with and without a stall duration, a request will stall by the maximum of the remaining times for each can-stall stream with outstanding buffers.

This means that a stalling request will not have an exposure start until the stall has completed.

This should correspond to the stall duration when only that stream is active, with all processing (typically in android.*.mode) set to FAST or OFF. Setting any of the processing modes to HIGH_QUALITY effectively results in an indeterminate stall duration for all streams in a request (the regular stall calculation rules are ignored).

The following formats may always have a stall duration:

The following formats will never have a stall duration:

All other formats may or may not have an allowed stall duration on a per-capability basis; refer to android.request.availableCapabilities for more details.

See android.sensor.frameDuration for more information about calculating the max frame rate (absent stalls).

Parameters
format an image format from ImageFormat or PixelFormat
size an output-compatible size
Returns
  • a stall duration >= 0 in nanoseconds
Throws
IllegalArgumentException if format or size was not supported
NullPointerException if size was null
See Also

public long getOutputStallDuration (Class<T> klass, Size size)

Get the stall duration for the class/size combination (in nanoseconds).

This assumes a the klass is set up to use an implementation-defined format. For user-defined formats, use getOutputMinFrameDuration(int, Size).

klass should be one of the ones with a non-empty array returned by getOutputSizes(Class).

size should be one of the ones returned by getOutputSizes(Class).

See getOutputStallDuration(int, Size) for a definition of a stall duration.

Parameters
klass a class which is supported by isOutputSupportedFor(Class) and has a non-empty array returned by getOutputSizes(Class)
size an output-compatible size
Returns
  • a minimum frame duration >= 0 in nanoseconds
Throws
IllegalArgumentException if klass or size was not supported
NullPointerException if size or klass was null
See Also

public int hashCode ()

Returns an integer hash code for this object. By contract, any two objects for which equals(Object) returns true must return the same hash code value. This means that subclasses of Object usually override both methods or neither method.

Note that hash values must not change over time unless information used in equals comparisons also changes.

See Writing a correct hashCode method if you intend implementing your own hashCode method.

Returns
  • this object's hash code.

public boolean isOutputSupportedFor (int format)

Determine whether or not output surfaces with a particular user-defined format can be passed createCaptureSession.

This method determines that the output format is supported by the camera device; each output surface target may or may not itself support that format. Refer to the class which provides the surface for additional documentation.

Formats for which this returns true are guaranteed to exist in the result returned by getOutputSizes(int).

Parameters
format an image format from either ImageFormat or PixelFormat
Returns
Throws
IllegalArgumentException if the image format was not a defined named constant from either ImageFormat or PixelFormat
See Also

public boolean isOutputSupportedFor (Surface surface)

Determine whether or not the surface in its current state is suitable to be included in a capture session as an output.

Not all surfaces are usable with the CameraDevice, and not all configurations of that surface are compatible. Some classes that provide the surface are compatible with the CameraDevice in general (see isOutputSupportedFor(Class), but it is the caller's responsibility to put the surface into a state that will be compatible with the CameraDevice.

Reasons for a surface being specifically incompatible might be:

  • Using a format that's not listed by getOutputFormats()
  • Using a format/size combination that's not listed by getOutputSizes(int)
  • The surface itself is not in a state where it can service a new producer.

This is not an exhaustive list; see the particular class's documentation for further possible reasons of incompatibility.

Parameters
surface a non-null Surface object reference
Returns
  • true if this is supported, false otherwise
Throws
NullPointerException if surface was null
See Also

public static boolean isOutputSupportedFor (Class<T> klass)

Determine whether or not output streams can be configured with a particular class as a consumer.

The following list is generally usable for outputs:

Generally speaking this means that creating a Surface from that class may provide a producer endpoint that is suitable to be used with createCaptureSession(List, CameraCaptureSession.StateListener, Handler).

Since not all of the above classes support output of all format and size combinations, the particular combination should be queried with isOutputSupportedFor(Surface).

Parameters
klass a non-null Class object reference
Returns
  • true if this class is supported as an output, false otherwise
Throws
NullPointerException if klass was null
See Also