In Exterior View System (EVS) 1.1, the logical camera device that consists of multiple physical camera devices is supported. To use this virtual device, device implementations must support the Synchronization Framework.
Enumerate, open, and close logical camera device
The app can use the same IEvsEnumerator
methods to use the
available logical camera devices. The returned EvsCamera
object, which
represents a logical camera device, must contain the following items in the metadata:
ANDROID_REQUEST_AVAILABLE_CAPABILITIES_LOGICAL_MULTI_CAMERA
If a returned EvsCamera object represents a logical camera, its camera metadata must contain this capability key in itsANDROID_REQUEST_AVAILABLE_CAPABILITIES
field.ANDROID_LOGICAL_MULTI_CAMERA_PHYSICAL_IDS
field lists physical camera device identifiers.ANDROID_LOGICAL_MULTI_CAMERA_SENSOR_SYNC_TYPE
field can have either of below enum values:ANDROID_LOGICAL_MULTI_CAMERA_SENSOR_SYNC_TYPE_APPROXIMATE
is for sensors in master-master mode, no hardware shutter/exposure sync.ANDROID_LOGICAL_MULTI_CAMERA_SENSOR_SYNC_TYPE_CALIBRATED
is for sensors in master-slave mode, hardware shutter/exposure sync. Synchronized GMSL2 cameras must have this value.
The app can retrieve a descriptor of physical camera devices through
IEvsCamera
in the new getPhysicalCameraInfo(stringcameraId)
method.
/** * Returns the description of the physical camera device that backs this * logical camera. * * If a requested device does not either exist or back this logical device, * this method returns a null camera descriptor. And, if this is called on * a physical camera device, this method is the same as getCameraInfo_1_1() * method if a given device ID is matched. Otherwise, this returns a * null camera descriptor. * * @param deviceId Physical camera device identifier string. * @return info The description of a member physical camera device. * This must be the same value as reported by * EvsEnumerator::getCameraList_1_1(). */ getPhysicalCameraInfo(string deviceId) generates (CameraDesc info);
Configure multi-camera support
All logical cameras are required to be defined statically and must be enumerated through a configuration manager implementation. As EVS allows each device in the group to be configured differently, EVS provides a list of member devices and indicates whether or not the image capture is synchronized.
<!-- camera group 0 --> <group id='group0' synchronized='CALIBRATED'> <caps> <!-- list of supported controls supported by all physical devices --> <supported_controls> <control name='BRIGHTNESS' min='0' max='255'/> <control name='CONTRAST' min='0' max='255'/> </supported_controls> <!-- list of stream configuration supported by all physical devices --> <stream id='0' width='640' height='480' format='RGBA_8888' framerate='30'/> </caps> <!-- list of parameters --> <characteristics> <parameter name='REQUEST_AVAILABLE_CAPABILITIES' type='enum' size='1' value='LOGICAL_MULTI_CAMERA' /> <parameter name='LOGICAL_MULTI_CAMERA_PHYSICAL_IDS' type='byte[]' size='2' value='/dev/video3,/dev/video4' /> </characteristics> </group>