diff --git a/api/current.txt b/api/current.txt
index 2905e1796302a..c6b2c28b69953 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -13440,6 +13440,7 @@ package android.hardware.camera2 {
field public static final int EDGE_MODE_FAST = 1; // 0x1
field public static final int EDGE_MODE_HIGH_QUALITY = 2; // 0x2
field public static final int EDGE_MODE_OFF = 0; // 0x0
+ field public static final int EDGE_MODE_ZERO_SHUTTER_LAG = 3; // 0x3
field public static final int FLASH_MODE_OFF = 0; // 0x0
field public static final int FLASH_MODE_SINGLE = 1; // 0x1
field public static final int FLASH_MODE_TORCH = 2; // 0x2
@@ -13468,6 +13469,7 @@ package android.hardware.camera2 {
field public static final int NOISE_REDUCTION_MODE_HIGH_QUALITY = 2; // 0x2
field public static final int NOISE_REDUCTION_MODE_MINIMAL = 3; // 0x3
field public static final int NOISE_REDUCTION_MODE_OFF = 0; // 0x0
+ field public static final int NOISE_REDUCTION_MODE_ZERO_SHUTTER_LAG = 4; // 0x4
field public static final int REQUEST_AVAILABLE_CAPABILITIES_BACKWARD_COMPATIBLE = 0; // 0x0
field public static final int REQUEST_AVAILABLE_CAPABILITIES_BURST_CAPTURE = 6; // 0x6
field public static final int REQUEST_AVAILABLE_CAPABILITIES_CONSTRAINED_HIGH_SPEED_VIDEO = 9; // 0x9
diff --git a/api/system-current.txt b/api/system-current.txt
index 150b5691458ab..4e76475b69c7e 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -13780,6 +13780,7 @@ package android.hardware.camera2 {
field public static final int EDGE_MODE_FAST = 1; // 0x1
field public static final int EDGE_MODE_HIGH_QUALITY = 2; // 0x2
field public static final int EDGE_MODE_OFF = 0; // 0x0
+ field public static final int EDGE_MODE_ZERO_SHUTTER_LAG = 3; // 0x3
field public static final int FLASH_MODE_OFF = 0; // 0x0
field public static final int FLASH_MODE_SINGLE = 1; // 0x1
field public static final int FLASH_MODE_TORCH = 2; // 0x2
@@ -13808,6 +13809,7 @@ package android.hardware.camera2 {
field public static final int NOISE_REDUCTION_MODE_HIGH_QUALITY = 2; // 0x2
field public static final int NOISE_REDUCTION_MODE_MINIMAL = 3; // 0x3
field public static final int NOISE_REDUCTION_MODE_OFF = 0; // 0x0
+ field public static final int NOISE_REDUCTION_MODE_ZERO_SHUTTER_LAG = 4; // 0x4
field public static final int REQUEST_AVAILABLE_CAPABILITIES_BACKWARD_COMPATIBLE = 0; // 0x0
field public static final int REQUEST_AVAILABLE_CAPABILITIES_BURST_CAPTURE = 6; // 0x6
field public static final int REQUEST_AVAILABLE_CAPABILITIES_CONSTRAINED_HIGH_SPEED_VIDEO = 9; // 0x9
diff --git a/core/java/android/hardware/camera2/CameraMetadata.java b/core/java/android/hardware/camera2/CameraMetadata.java
index e8dbc5b7e054b..f7c6274759a93 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 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). 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. 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). 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). 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. 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).
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.
*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
Available values for this device:
* {@link CameraCharacteristics#EDGE_AVAILABLE_EDGE_MODES android.edge.availableEdgeModes}
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.
*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
Available values for this device:
* {@link CameraCharacteristics#NOISE_REDUCTION_AVAILABLE_NOISE_REDUCTION_MODES android.noiseReduction.availableNoiseReductionModes}
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.
*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
Available values for this device:
* {@link CameraCharacteristics#EDGE_AVAILABLE_EDGE_MODES android.edge.availableEdgeModes}
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.
*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
Available values for this device:
* {@link CameraCharacteristics#NOISE_REDUCTION_AVAILABLE_NOISE_REDUCTION_MODES android.noiseReduction.availableNoiseReductionModes}