Camera: Add ZERO_SHUTTER_LAG modes to noise reduction and edge enhancement

This mode splits processing quality based on stream resolution, to
enable ZSL operation where low-resolution (preview/recording) streams
require more processing since they are immediately user-visible, while
the high-resolution intermediate ZSL stream should have minimal/no
processing since it will be reprocessed into final quality when
necessary

Bug: 22266686

Change-Id: Ib41102b66b07d61a099f021f8c6251f28c62686f

3 files changed, 97 insertions, 4 deletions

diff --git a/core/java/android/hardware/camera2/CameraMetadata.java b/core/java/android/hardware/camera2/CameraMetadata.java
index e8dbc5b..f7c6274 100644
--- a/core/java/android/hardware/camera2/CameraMetadata.java
+++ b/core/java/android/hardware/camera2/CameraMetadata.java
@@ -488,9 +488,13 @@ public abstract class CameraMetadata<TKey> {
      * <li>{@link CaptureRequest#EDGE_MODE android.edge.mode}</li>
      * </ul>
      * </li>
+     * <li>{@link CameraCharacteristics#NOISE_REDUCTION_AVAILABLE_NOISE_REDUCTION_MODES android.noiseReduction.availableNoiseReductionModes} and
+     *   {@link CameraCharacteristics#EDGE_AVAILABLE_EDGE_MODES android.edge.availableEdgeModes} will both list ZERO_SHUTTER_LAG as a supported mode.</li>
      * </ul>
      *
+     * @see CameraCharacteristics#EDGE_AVAILABLE_EDGE_MODES
      * @see CaptureRequest#EDGE_MODE
+     * @see CameraCharacteristics#NOISE_REDUCTION_AVAILABLE_NOISE_REDUCTION_MODES
      * @see CaptureRequest#NOISE_REDUCTION_MODE
      * @see CameraCharacteristics#REPROCESS_MAX_CAPTURE_STALL
      * @see CameraCharacteristics#REQUEST_MAX_NUM_INPUT_STREAMS
@@ -593,9 +597,13 @@ public abstract class CameraMetadata<TKey> {
      * <li>{@link CaptureRequest#REPROCESS_EFFECTIVE_EXPOSURE_FACTOR android.reprocess.effectiveExposureFactor}</li>
      * </ul>
      * </li>
+     * <li>{@link CameraCharacteristics#NOISE_REDUCTION_AVAILABLE_NOISE_REDUCTION_MODES android.noiseReduction.availableNoiseReductionModes} and
+     *   {@link CameraCharacteristics#EDGE_AVAILABLE_EDGE_MODES android.edge.availableEdgeModes} will both list ZERO_SHUTTER_LAG as a supported mode.</li>
      * </ul>
      *
+     * @see CameraCharacteristics#EDGE_AVAILABLE_EDGE_MODES
      * @see CaptureRequest#EDGE_MODE
+     * @see CameraCharacteristics#NOISE_REDUCTION_AVAILABLE_NOISE_REDUCTION_MODES
      * @see CaptureRequest#NOISE_REDUCTION_MODE
      * @see CaptureRequest#REPROCESS_EFFECTIVE_EXPOSURE_FACTOR
      * @see CameraCharacteristics#REPROCESS_MAX_CAPTURE_STALL
@@ -1999,6 +2007,30 @@ public abstract class CameraMetadata<TKey> {
      */
     public static final int EDGE_MODE_HIGH_QUALITY = 2;
 
+    /**
+     * <p>Edge enhancement is applied at different levels for different output streams,
+     * based on resolution. Streams at maximum recording resolution (see {@link android.hardware.camera2.CameraDevice#createCaptureSession }) or below have
+     * edge enhancement applied, while higher-resolution streams have no edge enhancement
+     * applied. The level of edge enhancement for low-resolution streams is tuned so that
+     * frame rate is not impacted, and the quality is equal to or better than FAST (since it
+     * is only applied to lower-resolution outputs, quality may improve from FAST).</p>
+     * <p>This mode is intended to be used by applications operating in a zero-shutter-lag mode
+     * with YUV or PRIVATE reprocessing, where the application continuously captures
+     * high-resolution intermediate buffers into a circular buffer, from which a final image is
+     * produced via reprocessing when a user takes a picture.  For such a use case, the
+     * high-resolution buffers must not have edge enhancement applied to maximize efficiency of
+     * preview and to avoid double-applying enhancement when reprocessed, while low-resolution
+     * buffers (used for recording or preview, generally) need edge enhancement applied for
+     * reasonable preview quality.</p>
+     * <p>This mode is guaranteed to be supported by devices that support either the
+     * YUV_REPROCESSING or PRIVATE_REPROCESSING capabilities
+     * ({@link CameraCharacteristics#REQUEST_AVAILABLE_CAPABILITIES android.request.availableCapabilities} lists either of those capabilities).</p>
+     *
+     * @see CameraCharacteristics#REQUEST_AVAILABLE_CAPABILITIES
+     * @see CaptureRequest#EDGE_MODE
+     */
+    public static final int EDGE_MODE_ZERO_SHUTTER_LAG = 3;
+
     //
     // Enumeration values for CaptureRequest#FLASH_MODE
     //
@@ -2104,6 +2136,31 @@ public abstract class CameraMetadata<TKey> {
      */
     public static final int NOISE_REDUCTION_MODE_MINIMAL = 3;
 
+    /**
+     * <p>Noise reduction is applied at different levels for different output streams,
+     * based on resolution. Streams at maximum recording resolution (see {@link android.hardware.camera2.CameraDevice#createCaptureSession }) or below have noise
+     * reduction applied, while higher-resolution streams have MINIMAL (if supported) or no
+     * noise reduction applied (if MINIMAL is not supported.) The degree of noise reduction
+     * for low-resolution streams is tuned so that frame rate is not impacted, and the quality
+     * is equal to or better than FAST (since it is only applied to lower-resolution outputs,
+     * quality may improve from FAST).</p>
+     * <p>This mode is intended to be used by applications operating in a zero-shutter-lag mode
+     * with YUV or PRIVATE reprocessing, where the application continuously captures
+     * high-resolution intermediate buffers into a circular buffer, from which a final image is
+     * produced via reprocessing when a user takes a picture.  For such a use case, the
+     * high-resolution buffers must not have noise reduction applied to maximize efficiency of
+     * preview and to avoid over-applying noise filtering when reprocessing, while
+     * low-resolution buffers (used for recording or preview, generally) need noise reduction
+     * applied for reasonable preview quality.</p>
+     * <p>This mode is guaranteed to be supported by devices that support either the
+     * YUV_REPROCESSING or PRIVATE_REPROCESSING capabilities
+     * ({@link CameraCharacteristics#REQUEST_AVAILABLE_CAPABILITIES android.request.availableCapabilities} lists either of those capabilities).</p>
+     *
+     * @see CameraCharacteristics#REQUEST_AVAILABLE_CAPABILITIES
+     * @see CaptureRequest#NOISE_REDUCTION_MODE
+     */
+    public static final int NOISE_REDUCTION_MODE_ZERO_SHUTTER_LAG = 4;
+
     //
     // Enumeration values for CaptureRequest#SENSOR_TEST_PATTERN_MODE
     //
diff --git a/core/java/android/hardware/camera2/CaptureRequest.java b/core/java/android/hardware/camera2/CaptureRequest.java
index 33cc962..f201fe9 100644
--- a/core/java/android/hardware/camera2/CaptureRequest.java
+++ b/core/java/android/hardware/camera2/CaptureRequest.java
@@ -1569,7 +1569,14 @@ public final class CaptureRequest extends CameraMetadata<CaptureRequest.Key<?>>
      * will be applied. HIGH_QUALITY mode indicates that the
      * camera device will use the highest-quality enhancement algorithms,
      * even if it slows down capture rate. FAST means the camera device will
-     * not slow down capture rate when applying edge enhancement.</p>
+     * not slow down capture rate when applying edge enhancement. Every output stream will
+     * have a similar amount of enhancement applied.</p>
+     * <p>ZERO_SHUTTER_LAG is meant to be used by applications that maintain a continuous circular
+     * buffer of high-resolution images during preview and reprocess image(s) from that buffer
+     * into a final capture when triggered by the user. In this mode, the camera device applies
+     * edge enhancement to low-resolution streams (below maximum recording resolution) to
+     * maximize preview quality, but does not apply edge enhancement to high-resolution streams,
+     * since those will be reprocessed later if necessary.</p>
      * <p>For YUV_REPROCESSING, these FAST/HIGH_QUALITY modes both mean that the camera
      * device will apply FAST/HIGH_QUALITY YUV-domain edge enhancement, respectively.
      * The camera device may adjust its internal noise reduction parameters for best
@@ -1579,6 +1586,7 @@ public final class CaptureRequest extends CameraMetadata<CaptureRequest.Key<?>>
      *   <li>{@link #EDGE_MODE_OFF OFF}</li>
      *   <li>{@link #EDGE_MODE_FAST FAST}</li>
      *   <li>{@link #EDGE_MODE_HIGH_QUALITY HIGH_QUALITY}</li>
+     *   <li>{@link #EDGE_MODE_ZERO_SHUTTER_LAG ZERO_SHUTTER_LAG}</li>
      * </ul></p>
      * <p><b>Available values for this device:</b><br>
      * {@link CameraCharacteristics#EDGE_AVAILABLE_EDGE_MODES android.edge.availableEdgeModes}</p>
@@ -1593,6 +1601,7 @@ public final class CaptureRequest extends CameraMetadata<CaptureRequest.Key<?>>
      * @see #EDGE_MODE_OFF
      * @see #EDGE_MODE_FAST
      * @see #EDGE_MODE_HIGH_QUALITY
+     * @see #EDGE_MODE_ZERO_SHUTTER_LAG
      */
     @PublicKey
     public static final Key<Integer> EDGE_MODE =
@@ -1979,7 +1988,14 @@ public final class CaptureRequest extends CameraMetadata<CaptureRequest.Key<?>>
      * will be applied. HIGH_QUALITY mode indicates that the camera device
      * will use the highest-quality noise filtering algorithms,
      * even if it slows down capture rate. FAST means the camera device will not
-     * slow down capture rate when applying noise filtering.</p>
+     * slow down capture rate when applying noise filtering. Every output stream will
+     * have a similar amount of enhancement applied.</p>
+     * <p>ZERO_SHUTTER_LAG is meant to be used by applications that maintain a continuous circular
+     * buffer of high-resolution images during preview and reprocess image(s) from that buffer
+     * into a final capture when triggered by the user. In this mode, the camera device applies
+     * noise reduction to low-resolution streams (below maximum recording resolution) to maximize
+     * preview quality, but does not apply noise reduction to high-resolution streams, since
+     * those will be reprocessed later if necessary.</p>
      * <p>For YUV_REPROCESSING, these FAST/HIGH_QUALITY modes both mean that the camera device
      * will apply FAST/HIGH_QUALITY YUV domain noise reduction, respectively. The camera device
      * may adjust the noise reduction parameters for best image quality based on the
@@ -1990,6 +2006,7 @@ public final class CaptureRequest extends CameraMetadata<CaptureRequest.Key<?>>
      *   <li>{@link #NOISE_REDUCTION_MODE_FAST FAST}</li>
      *   <li>{@link #NOISE_REDUCTION_MODE_HIGH_QUALITY HIGH_QUALITY}</li>
      *   <li>{@link #NOISE_REDUCTION_MODE_MINIMAL MINIMAL}</li>
+     *   <li>{@link #NOISE_REDUCTION_MODE_ZERO_SHUTTER_LAG ZERO_SHUTTER_LAG}</li>
      * </ul></p>
      * <p><b>Available values for this device:</b><br>
      * {@link CameraCharacteristics#NOISE_REDUCTION_AVAILABLE_NOISE_REDUCTION_MODES android.noiseReduction.availableNoiseReductionModes}</p>
@@ -2005,6 +2022,7 @@ public final class CaptureRequest extends CameraMetadata<CaptureRequest.Key<?>>
      * @see #NOISE_REDUCTION_MODE_FAST
      * @see #NOISE_REDUCTION_MODE_HIGH_QUALITY
      * @see #NOISE_REDUCTION_MODE_MINIMAL
+     * @see #NOISE_REDUCTION_MODE_ZERO_SHUTTER_LAG
      */
     @PublicKey
     public static final Key<Integer> NOISE_REDUCTION_MODE =
diff --git a/core/java/android/hardware/camera2/CaptureResult.java b/core/java/android/hardware/camera2/CaptureResult.java
index 9dee045..0f80051 100644
--- a/core/java/android/hardware/camera2/CaptureResult.java
+++ b/core/java/android/hardware/camera2/CaptureResult.java
@@ -2081,7 +2081,14 @@ public class CaptureResult extends CameraMetadata<CaptureResult.Key<?>> {
      * will be applied. HIGH_QUALITY mode indicates that the
      * camera device will use the highest-quality enhancement algorithms,
      * even if it slows down capture rate. FAST means the camera device will
-     * not slow down capture rate when applying edge enhancement.</p>
+     * not slow down capture rate when applying edge enhancement. Every output stream will
+     * have a similar amount of enhancement applied.</p>
+     * <p>ZERO_SHUTTER_LAG is meant to be used by applications that maintain a continuous circular
+     * buffer of high-resolution images during preview and reprocess image(s) from that buffer
+     * into a final capture when triggered by the user. In this mode, the camera device applies
+     * edge enhancement to low-resolution streams (below maximum recording resolution) to
+     * maximize preview quality, but does not apply edge enhancement to high-resolution streams,
+     * since those will be reprocessed later if necessary.</p>
      * <p>For YUV_REPROCESSING, these FAST/HIGH_QUALITY modes both mean that the camera
      * device will apply FAST/HIGH_QUALITY YUV-domain edge enhancement, respectively.
      * The camera device may adjust its internal noise reduction parameters for best
@@ -2091,6 +2098,7 @@ public class CaptureResult extends CameraMetadata<CaptureResult.Key<?>> {
      *   <li>{@link #EDGE_MODE_OFF OFF}</li>
      *   <li>{@link #EDGE_MODE_FAST FAST}</li>
      *   <li>{@link #EDGE_MODE_HIGH_QUALITY HIGH_QUALITY}</li>
+     *   <li>{@link #EDGE_MODE_ZERO_SHUTTER_LAG ZERO_SHUTTER_LAG}</li>
      * </ul></p>
      * <p><b>Available values for this device:</b><br>
      * {@link CameraCharacteristics#EDGE_AVAILABLE_EDGE_MODES android.edge.availableEdgeModes}</p>
@@ -2105,6 +2113,7 @@ public class CaptureResult extends CameraMetadata<CaptureResult.Key<?>> {
      * @see #EDGE_MODE_OFF
      * @see #EDGE_MODE_FAST
      * @see #EDGE_MODE_HIGH_QUALITY
+     * @see #EDGE_MODE_ZERO_SHUTTER_LAG
      */
     @PublicKey
     public static final Key<Integer> EDGE_MODE =
@@ -2763,7 +2772,14 @@ public class CaptureResult extends CameraMetadata<CaptureResult.Key<?>> {
      * will be applied. HIGH_QUALITY mode indicates that the camera device
      * will use the highest-quality noise filtering algorithms,
      * even if it slows down capture rate. FAST means the camera device will not
-     * slow down capture rate when applying noise filtering.</p>
+     * slow down capture rate when applying noise filtering. Every output stream will
+     * have a similar amount of enhancement applied.</p>
+     * <p>ZERO_SHUTTER_LAG is meant to be used by applications that maintain a continuous circular
+     * buffer of high-resolution images during preview and reprocess image(s) from that buffer
+     * into a final capture when triggered by the user. In this mode, the camera device applies
+     * noise reduction to low-resolution streams (below maximum recording resolution) to maximize
+     * preview quality, but does not apply noise reduction to high-resolution streams, since
+     * those will be reprocessed later if necessary.</p>
      * <p>For YUV_REPROCESSING, these FAST/HIGH_QUALITY modes both mean that the camera device
      * will apply FAST/HIGH_QUALITY YUV domain noise reduction, respectively. The camera device
      * may adjust the noise reduction parameters for best image quality based on the
@@ -2774,6 +2790,7 @@ public class CaptureResult extends CameraMetadata<CaptureResult.Key<?>> {
      *   <li>{@link #NOISE_REDUCTION_MODE_FAST FAST}</li>
      *   <li>{@link #NOISE_REDUCTION_MODE_HIGH_QUALITY HIGH_QUALITY}</li>
      *   <li>{@link #NOISE_REDUCTION_MODE_MINIMAL MINIMAL}</li>
+     *   <li>{@link #NOISE_REDUCTION_MODE_ZERO_SHUTTER_LAG ZERO_SHUTTER_LAG}</li>
      * </ul></p>
      * <p><b>Available values for this device:</b><br>
      * {@link CameraCharacteristics#NOISE_REDUCTION_AVAILABLE_NOISE_REDUCTION_MODES android.noiseReduction.availableNoiseReductionModes}</p>
@@ -2789,6 +2806,7 @@ public class CaptureResult extends CameraMetadata<CaptureResult.Key<?>> {
      * @see #NOISE_REDUCTION_MODE_FAST
      * @see #NOISE_REDUCTION_MODE_HIGH_QUALITY
      * @see #NOISE_REDUCTION_MODE_MINIMAL
+     * @see #NOISE_REDUCTION_MODE_ZERO_SHUTTER_LAG
      */
     @PublicKey
     public static final Key<Integer> NOISE_REDUCTION_MODE =