Camera2: Update stream num tag specs

Change-Id: I69ae1a34828230408a27bf7c016eb514485097b1

diff --git a/core/java/android/hardware/camera2/CameraCharacteristics.java b/core/java/android/hardware/camera2/CameraCharacteristics.java
index bb8b184..913b273 100644 (file)
--- a/core/java/android/hardware/camera2/CameraCharacteristics.java
+++ b/core/java/android/hardware/camera2/CameraCharacteristics.java
@@ -398,16 +398,44 @@ public final class CameraCharacteristics extends CameraMetadata {
             new Key<Byte>("android.quirks.usePartialResult", byte.class);
 
     /**
-     * <p>How many output streams can be allocated at
-     * the same time for each type of stream</p>
-     * <p>Video snapshot with preview callbacks requires 3
-     * processed streams (preview, record, app callbacks) and
-     * one JPEG stream (snapshot)</p>
+     * <p>The maximum numbers of different types of output streams
+     * that can be configured and used simultaneously by a camera device.</p>
+     * <p>This is a 3 element tuple that contains the max number of output simultaneous
+     * streams for raw sensor, processed (and uncompressed), and JPEG formats respectively.
+     * For example, if max raw sensor format output stream number is 1, max YUV streams
+     * number is 3, and max JPEG stream number is 2, then this tuple should be <code>(1, 3, 2)</code>.</p>
+     * <p>This lists the upper bound of the number of output streams supported by
+     * the camera device. Using more streams simultaneously may require more hardware and
+     * CPU resources that will consume more power. The image format for a output stream can
+     * be any supported format provided by {@link CameraCharacteristics#SCALER_AVAILABLE_FORMATS android.scaler.availableFormats}. The formats
+     * defined in {@link CameraCharacteristics#SCALER_AVAILABLE_FORMATS android.scaler.availableFormats} can be catergorized into the 3 stream types
+     * as below:</p>
+     * <ul>
+     * <li>JPEG-compressed format: BLOB.</li>
+     * <li>Raw formats: RAW_SENSOR and RAW_OPAQUE.</li>
+     * <li>processed, uncompressed formats: YCbCr_420_888, YCrCb_420_SP, YV12.</li>
+     * </ul>
+     *
+     * @see CameraCharacteristics#SCALER_AVAILABLE_FORMATS
      */
     public static final Key<int[]> REQUEST_MAX_NUM_OUTPUT_STREAMS =
             new Key<int[]>("android.request.maxNumOutputStreams", int[].class);
 
     /**
+     * <p>The maximum numbers of any type of input streams
+     * that can be configured and used simultaneously by a camera device.</p>
+     * <p>When set to 0, it means no input stream is supported.</p>
+     * <p>The image format for a input stream can be any supported format provided
+     * by android.scaler.availableInputFormats. When using an input stream, there must be
+     * at least one output stream configured to to receive the reprocessed images.</p>
+     * <p>For example, for Zero Shutter Lag (ZSL) still capture use case, the input
+     * stream image format will be RAW_OPAQUE, the associated output stream image format
+     * should be JPEG.</p>
+     */
+    public static final Key<Integer> REQUEST_MAX_NUM_INPUT_STREAMS =
+            new Key<Integer>("android.request.maxNumInputStreams", int.class);
+
+    /**
      * <p>Specifies the number of maximum pipeline stages a frame
      * has to go through from when it's exposed to when it's available
      * to the framework.</p>