Camera2: Add timestampCalibration tag

Also update the video/optical stabilization docs.

Change-Id: I444cc8d46c0a460bc4311e58bf6166b5c6dbfd14

5 files changed, 92 insertions, 11 deletions

diff --git a/api/current.txt b/api/current.txt
index 25c6ce8..370b098 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -12171,6 +12171,7 @@ package android.hardware.camera2 {
     field public static final android.hardware.camera2.CameraCharacteristics.Key SENSOR_INFO_PHYSICAL_SIZE;
     field public static final android.hardware.camera2.CameraCharacteristics.Key SENSOR_INFO_PIXEL_ARRAY_SIZE;
     field public static final android.hardware.camera2.CameraCharacteristics.Key SENSOR_INFO_SENSITIVITY_RANGE;
+    field public static final android.hardware.camera2.CameraCharacteristics.Key SENSOR_INFO_TIMESTAMP_CALIBRATION;
     field public static final android.hardware.camera2.CameraCharacteristics.Key SENSOR_INFO_WHITE_LEVEL;
     field public static final android.hardware.camera2.CameraCharacteristics.Key SENSOR_MAX_ANALOG_SENSITIVITY;
     field public static final android.hardware.camera2.CameraCharacteristics.Key SENSOR_ORIENTATION;
@@ -12379,6 +12380,8 @@ package android.hardware.camera2 {
     field public static final int SENSOR_INFO_COLOR_FILTER_ARRANGEMENT_GRBG = 1; // 0x1
     field public static final int SENSOR_INFO_COLOR_FILTER_ARRANGEMENT_RGB = 4; // 0x4
     field public static final int SENSOR_INFO_COLOR_FILTER_ARRANGEMENT_RGGB = 0; // 0x0
+    field public static final int SENSOR_INFO_TIMESTAMP_CALIBRATION_CALIBRATED = 1; // 0x1
+    field public static final int SENSOR_INFO_TIMESTAMP_CALIBRATION_UNCALIBRATED = 0; // 0x0
     field public static final int SENSOR_REFERENCE_ILLUMINANT1_CLOUDY_WEATHER = 10; // 0xa
     field public static final int SENSOR_REFERENCE_ILLUMINANT1_COOL_WHITE_FLUORESCENT = 14; // 0xe
     field public static final int SENSOR_REFERENCE_ILLUMINANT1_D50 = 23; // 0x17
diff --git a/core/java/android/hardware/camera2/CameraCharacteristics.java b/core/java/android/hardware/camera2/CameraCharacteristics.java
index 9eea545..4a87680 100644
--- a/core/java/android/hardware/camera2/CameraCharacteristics.java
+++ b/core/java/android/hardware/camera2/CameraCharacteristics.java
@@ -1423,6 +1423,18 @@ public final class CameraCharacteristics extends CameraMetadata<CameraCharacteri
             new Key<Integer>("android.sensor.info.whiteLevel", int.class);
 
     /**
+     * <p>The sensor timestamp calibration quality.</p>
+     * <p>The sensor timestamp calibration quality determines the reliability of
+     * {@link CaptureResult#SENSOR_TIMESTAMP android.sensor.timestamp} provided by the camera device.</p>
+     *
+     * @see CaptureResult#SENSOR_TIMESTAMP
+     * @see #SENSOR_INFO_TIMESTAMP_CALIBRATION_UNCALIBRATED
+     * @see #SENSOR_INFO_TIMESTAMP_CALIBRATION_CALIBRATED
+     */
+    public static final Key<Integer> SENSOR_INFO_TIMESTAMP_CALIBRATION =
+            new Key<Integer>("android.sensor.info.timestampCalibration", int.class);
+
+    /**
      * <p>The standard reference illuminant used as the scene light source when
      * calculating the {@link CameraCharacteristics#SENSOR_COLOR_TRANSFORM1 android.sensor.colorTransform1},
      * {@link CameraCharacteristics#SENSOR_CALIBRATION_TRANSFORM1 android.sensor.calibrationTransform1}, and
diff --git a/core/java/android/hardware/camera2/CameraMetadata.java b/core/java/android/hardware/camera2/CameraMetadata.java
index 33e1915..5a02435 100644
--- a/core/java/android/hardware/camera2/CameraMetadata.java
+++ b/core/java/android/hardware/camera2/CameraMetadata.java
@@ -419,6 +419,33 @@ public abstract class CameraMetadata<TKey> {
     public static final int SENSOR_INFO_COLOR_FILTER_ARRANGEMENT_RGB = 4;
 
     //
+    // Enumeration values for CameraCharacteristics#SENSOR_INFO_TIMESTAMP_CALIBRATION
+    //
+
+    /**
+     * <p>Timestamps from {@link CaptureResult#SENSOR_TIMESTAMP android.sensor.timestamp} are in nanoseconds and monotonic,
+     * but can not be compared to timestamps from other subsystems
+     * (e.g. accelerometer, gyro etc.), or other instances of the same or different
+     * camera devices in the same system. Timestamps between streams and results for
+     * a single camera instance are comparable, and the timestamps for all buffers
+     * and the result metadata generated by a single capture are identical.</p>
+     *
+     * @see CaptureResult#SENSOR_TIMESTAMP
+     * @see CameraCharacteristics#SENSOR_INFO_TIMESTAMP_CALIBRATION
+     */
+    public static final int SENSOR_INFO_TIMESTAMP_CALIBRATION_UNCALIBRATED = 0;
+
+    /**
+     * <p>Timestamps from {@link CaptureResult#SENSOR_TIMESTAMP android.sensor.timestamp} are in the same timebase as
+     * android.os.SystemClock#elapsedRealtimeNanos(),
+     * and they can be compared to other timestamps using that base.</p>
+     *
+     * @see CaptureResult#SENSOR_TIMESTAMP
+     * @see CameraCharacteristics#SENSOR_INFO_TIMESTAMP_CALIBRATION
+     */
+    public static final int SENSOR_INFO_TIMESTAMP_CALIBRATION_CALIBRATED = 1;
+
+    //
     // Enumeration values for CameraCharacteristics#SENSOR_REFERENCE_ILLUMINANT1
     //
 
diff --git a/core/java/android/hardware/camera2/CaptureRequest.java b/core/java/android/hardware/camera2/CaptureRequest.java
index bf7bd37..2cfb611 100644
--- a/core/java/android/hardware/camera2/CaptureRequest.java
+++ b/core/java/android/hardware/camera2/CaptureRequest.java
@@ -1020,9 +1020,17 @@ public final class CaptureRequest extends CameraMetadata<CaptureRequest.Key<?>>
      * <p>Video stabilization automatically translates and scales images from the camera
      * in order to stabilize motion between consecutive frames.</p>
      * <p>If enabled, video stabilization can modify the
-     * {@link CaptureRequest#SCALER_CROP_REGION android.scaler.cropRegion} to keep the video stream
-     * stabilized</p>
+     * {@link CaptureRequest#SCALER_CROP_REGION android.scaler.cropRegion} to keep the video stream stabilized.</p>
+     * <p>Switching between different video stabilization modes may take several frames
+     * to initialize, the camera device will report the current mode in capture result
+     * metadata. For example, When "ON" mode is requested, the video stabilization modes
+     * in the first several capture results may still be "OFF", and it will become "ON"
+     * when the initialization is done.</p>
+     * <p>If a camera device supports both this mode and OIS ({@link CaptureRequest#LENS_OPTICAL_STABILIZATION_MODE android.lens.opticalStabilizationMode}),
+     * turning both modes on may produce undesirable interaction, so it is recommended not to
+     * enable both at the same time.</p>
      *
+     * @see CaptureRequest#LENS_OPTICAL_STABILIZATION_MODE
      * @see CaptureRequest#SCALER_CROP_REGION
      * @see #CONTROL_VIDEO_STABILIZATION_MODE_OFF
      * @see #CONTROL_VIDEO_STABILIZATION_MODE_ON
@@ -1258,6 +1266,14 @@ public final class CaptureRequest extends CameraMetadata<CaptureRequest.Key<?>>
      * makes use of mechanical elements to stabilize the camera
      * sensor, and thus allows for longer exposure times before
      * camera shake becomes apparent.</p>
+     * <p>Switching between different optical stabilization modes may take several
+     * frames to initialize, the camera device will report the current mode in
+     * capture result metadata. For example, When "ON" mode is requested, the
+     * optical stabilization modes in the first several capture results may still
+     * be "OFF", and it will become "ON" when the initialization is done.</p>
+     * <p>If a camera device supports both OIS and EIS ({@link CaptureRequest#CONTROL_VIDEO_STABILIZATION_MODE android.control.videoStabilizationMode}),
+     * turning both modes on may produce undesirable interaction, so it is recommended not
+     * to enable both at the same time.</p>
      * <p>Not all devices will support OIS; see
      * {@link CameraCharacteristics#LENS_INFO_AVAILABLE_OPTICAL_STABILIZATION android.lens.info.availableOpticalStabilization} for
      * available controls.</p>
diff --git a/core/java/android/hardware/camera2/CaptureResult.java b/core/java/android/hardware/camera2/CaptureResult.java
index 3d17ed3..65b6627 100644
--- a/core/java/android/hardware/camera2/CaptureResult.java
+++ b/core/java/android/hardware/camera2/CaptureResult.java
@@ -1591,9 +1591,17 @@ public class CaptureResult extends CameraMetadata<CaptureResult.Key<?>> {
      * <p>Video stabilization automatically translates and scales images from the camera
      * in order to stabilize motion between consecutive frames.</p>
      * <p>If enabled, video stabilization can modify the
-     * {@link CaptureRequest#SCALER_CROP_REGION android.scaler.cropRegion} to keep the video stream
-     * stabilized</p>
-     *
+     * {@link CaptureRequest#SCALER_CROP_REGION android.scaler.cropRegion} to keep the video stream stabilized.</p>
+     * <p>Switching between different video stabilization modes may take several frames
+     * to initialize, the camera device will report the current mode in capture result
+     * metadata. For example, When "ON" mode is requested, the video stabilization modes
+     * in the first several capture results may still be "OFF", and it will become "ON"
+     * when the initialization is done.</p>
+     * <p>If a camera device supports both this mode and OIS ({@link CaptureRequest#LENS_OPTICAL_STABILIZATION_MODE android.lens.opticalStabilizationMode}),
+     * turning both modes on may produce undesirable interaction, so it is recommended not to
+     * enable both at the same time.</p>
+     *
+     * @see CaptureRequest#LENS_OPTICAL_STABILIZATION_MODE
      * @see CaptureRequest#SCALER_CROP_REGION
      * @see #CONTROL_VIDEO_STABILIZATION_MODE_OFF
      * @see #CONTROL_VIDEO_STABILIZATION_MODE_ON
@@ -1846,6 +1854,14 @@ public class CaptureResult extends CameraMetadata<CaptureResult.Key<?>> {
      * makes use of mechanical elements to stabilize the camera
      * sensor, and thus allows for longer exposure times before
      * camera shake becomes apparent.</p>
+     * <p>Switching between different optical stabilization modes may take several
+     * frames to initialize, the camera device will report the current mode in
+     * capture result metadata. For example, When "ON" mode is requested, the
+     * optical stabilization modes in the first several capture results may still
+     * be "OFF", and it will become "ON" when the initialization is done.</p>
+     * <p>If a camera device supports both OIS and EIS ({@link CaptureRequest#CONTROL_VIDEO_STABILIZATION_MODE android.control.videoStabilizationMode}),
+     * turning both modes on may produce undesirable interaction, so it is recommended not
+     * to enable both at the same time.</p>
      * <p>Not all devices will support OIS; see
      * {@link CameraCharacteristics#LENS_INFO_AVAILABLE_OPTICAL_STABILIZATION android.lens.info.availableOpticalStabilization} for
      * available controls.</p>
@@ -2117,12 +2133,19 @@ public class CaptureResult extends CameraMetadata<CaptureResult.Key<?>> {
      * row of the image sensor, in nanoseconds.</p>
      * <p>The timestamps are also included in all image
      * buffers produced for the same capture, and will be identical
-     * on all the outputs. The timestamps measure time since an
-     * unspecified starting point, and are monotonically
-     * increasing.</p>
-     * <p>They can be compared with the timestamps for other captures
-     * from the same camera device, but are not guaranteed to be
-     * comparable to any other time source.</p>
+     * on all the outputs.</p>
+     * <p>When {@link CameraCharacteristics#SENSOR_INFO_TIMESTAMP_CALIBRATION android.sensor.info.timestampCalibration} <code>==</code> UNCALIBRATED,
+     * the timestamps measure time since an unspecified starting point,
+     * and are monotonically increasing. They can be compared with the
+     * timestamps for other captures from the same camera device, but are
+     * not guaranteed to be comparable to any other time source.</p>
+     * <p>When {@link CameraCharacteristics#SENSOR_INFO_TIMESTAMP_CALIBRATION android.sensor.info.timestampCalibration} <code>==</code> CALIBRATED,
+     * the timestamps measure time in the same timebase as
+     * android.os.SystemClock#elapsedRealtimeNanos(), and they can be
+     * compared to other timestamps from other subsystems that are using
+     * that base.</p>
+     *
+     * @see CameraCharacteristics#SENSOR_INFO_TIMESTAMP_CALIBRATION
      */
     public static final Key<Long> SENSOR_TIMESTAMP =
             new Key<Long>("android.sensor.timestamp", long.class);