Camera2: Document supported target combinations for a session.

Since most camera devices cannot support all combinations of target
sizes given the maximum stream counts, enumerate a set of guaranteed
configurations that can be used to create a session.

Also fix minor docs formatting in StreamConfigurationMap

Bug: 16899526
Change-Id: Ic7c94051dd47964f2be98343163ebd242b19bd24

2 files changed, 123 insertions, 1 deletions

diff --git a/core/java/android/hardware/camera2/CameraDevice.java b/core/java/android/hardware/camera2/CameraDevice.java
index 6a9d565..097b430 100644
--- a/core/java/android/hardware/camera2/CameraDevice.java
+++ b/core/java/android/hardware/camera2/CameraDevice.java
@@ -216,6 +216,128 @@ public abstract class CameraDevice implements AutoCloseable {
      * <p>Configuring a session with an empty or null list will close the current session, if
      * any. This can be used to release the current session's target surfaces for another use.</p>
      *
+     * <p>While any of the sizes from {@link StreamConfigurationMap#getOutputSizes} can be used when
+     * a single output stream is configured, a given camera device may not be able to support all
+     * combination of sizes, formats, and targets when multiple outputs are configured at once.  The
+     * tables below list the maximum guaranteed resolutions for combinations of streams and targets,
+     * given the capabilities of the camera device.</p>
+     *
+     * <p>If an application tries to create a session using a set of targets that exceed the limits
+     * described in the below tables, one of three possibilities may occur. First, the session may
+     * be successfully created and work normally. Second, the session may be successfully created,
+     * but the camera device won't meet the frame rate guarantees as described in
+     * {@link StreamConfigurationMap#getOutputMinFrameDuration}. Or third, if the output set
+     * cannot be used at all, session creation will fail entirely, with
+     * {@link CameraCaptureSession.StateListener#onConfigureFailed} being invoked.</p>
+     *
+     * <p>For the type column, {@code PRIV} refers to any target whose available sizes are found
+     * using {@link StreamConfigurationMap#getOutputSizes(Class)} with no direct application-visible
+     * format, {@code YUV} refers to a target Surface using the
+     * {@link android.graphics.ImageFormat#YUV_420_888} format, {@code JPEG} refers to the
+     * {@link android.graphics.ImageFormat#JPEG} format, and {@code RAW} refers to the
+     * {@link android.graphics.ImageFormat#RAW_SENSOR} format.</p>
+     *
+     * <p>For the maximum size column, {@code PREVIEW} refers to the best size match to the
+     * device's screen resolution, or to 1080p ({@code 1920x1080}), whichever is
+     * smaller. {@code RECORD} refers to the camera device's maximum supported recording resolution,
+     * as determined by {@link android.media.CamcorderProfile}. And {@code MAXIMUM} refers to the
+     * camera device's maximum output resolution for that format or target from
+     * {@link StreamConfigurationMap#getOutputSizes}.</p>
+     *
+     * <p>To use these tables, determine the number and the formats/targets of outputs needed, and
+     * find the row(s) of the table with those targets. The sizes indicate the maximum set of sizes
+     * that can be used; it is guaranteed that for those targets, the listed sizes and anything
+     * smaller from the list given by {@link StreamConfigurationMap#getOutputSizes} can be
+     * successfully used to create a session.  For example, if a row indicates that a 8 megapixel
+     * (MP) YUV_420_888 output can be used together with a 2 MP {@code PRIV} output, then a session
+     * can be created with targets {@code [8 MP YUV, 2 MP PRIV]} or targets {@code [2 MP YUV, 2 MP
+     * PRIV]}; but a session with targets {@code [8 MP YUV, 4 MP PRIV]}, targets {@code [4 MP YUV, 4
+     * MP PRIV]}, or targets {@code [8 MP PRIV, 2 MP YUV]} would not be guaranteed to work, unless
+     * some other row of the table lists such a combination.</p>
+     *
+     * <style scoped>
+     *  #rb { border-right-width: thick; }
+     * </style>
+     * <p>Legacy devices ({@link CameraCharacteristics#INFO_SUPPORTED_HARDWARE_LEVEL}
+     * {@code == }{@link CameraMetadata#INFO_SUPPORTED_HARDWARE_LEVEL_LEGACY LEGACY}) support at
+     * least the following stream combinations:
+     *
+     * <table>
+     * <tr><th colspan="7">LEGACY-level guaranteed configurations</th></tr>
+     * <tr> <th colspan="2" id="rb">Target 1</th> <th colspan="2" id="rb">Target 2</th>  <th colspan="2" id="rb">Target 3</th> <th rowspan="2">Sample use case(s)</th> </tr>
+     * <tr> <th>Type</th><th id="rb">Max size</th> <th>Type</th><th id="rb">Max size</th> <th>Type</th><th id="rb">Max size</th></tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code MAXIMUM}</td> <td colspan="2" id="rb"></td> <td colspan="2" id="rb"></td> <td>Simple preview, GPU video processing, or no-preview video recording.</td> </tr>
+     * <tr> <td>{@code JPEG}</td><td id="rb">{@code MAXIMUM}</td> <td colspan="2" id="rb"></td> <td colspan="2" id="rb"></td> <td>No-viewfinder still image capture.</td> </tr>
+     * <tr> <td>{@code YUV }</td><td id="rb">{@code MAXIMUM}</td> <td colspan="2" id="rb"></td> <td colspan="2" id="rb"></td> <td>In-application video/image processing.</td> </tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code JPEG}</td><td id="rb">{@code MAXIMUM}</td> <td colspan="2" id="rb"></td> <td>Standard still imaging.</td> </tr>
+     * <tr> <td>{@code YUV }</td><td id="rb">{@code PREVIEW}</td> <td>{@code JPEG}</td><td id="rb">{@code MAXIMUM}</td> <td colspan="2" id="rb"></td> <td>In-app processing plus still capture.</td> </tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td colspan="2" id="rb"></td> <td>Standard recording.</td> </tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code YUV }</td><td id="rb">{@code PREVIEW}</td> <td colspan="2" id="rb"></td> <td>Preview plus in-app processing.</td> </tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code YUV }</td><td id="rb">{@code PREVIEW}</td> <td>{@code JPEG}</td><td id="rb">{@code MAXIMUM}</td> <td>Still capture plus in-app processing.</td> </tr>
+     * </table><br>
+     * </p>
+     *
+     * <p>Limited-capability ({@link CameraCharacteristics#INFO_SUPPORTED_HARDWARE_LEVEL}
+     * {@code == }{@link CameraMetadata#INFO_SUPPORTED_HARDWARE_LEVEL_LIMITED LIMITED}) devices
+     * support at least the following stream combinations in addition to those for
+     * {@link CameraMetadata#INFO_SUPPORTED_HARDWARE_LEVEL_LEGACY LEGACY} devices:
+     *
+     * <table>
+     * <tr><th colspan="7">LIMITED-level additional guaranteed configurations</th></tr>
+     * <tr><th colspan="2" id="rb">Target 1</th><th colspan="2" id="rb">Target 2</th><th colspan="2" id="rb">Target 3</th> <th rowspan="2">Sample use case(s)</th> </tr>
+     * <tr><th>Type</th><th id="rb">Max size</th><th>Type</th><th id="rb">Max size</th><th>Type</th><th id="rb">Max size</th></tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code PRIV}</td><td id="rb">{@code RECORD }</td> <td colspan="2" id="rb"></td> <td>High-resolution video recording with preview.</td> </tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code YUV }</td><td id="rb">{@code RECORD }</td> <td colspan="2" id="rb"></td> <td>High-resolution in-app video processing with preview.</td> </tr>
+     * <tr> <td>{@code YUV }</td><td id="rb">{@code PREVIEW}</td> <td>{@code YUV }</td><td id="rb">{@code RECORD }</td> <td colspan="2" id="rb"></td> <td>Two-input in-app video processing.</td> </tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code PRIV}</td><td id="rb">{@code RECORD }</td> <td>{@code JPEG}</td><td id="rb">{@code RECORD }</td> <td>High-resolution recording with video snapshot.</td> </tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code YUV }</td><td id="rb">{@code RECORD }</td> <td>{@code JPEG}</td><td id="rb">{@code RECORD }</td> <td>High-resolution in-app processing with video snapshot.</td> </tr>
+     * <tr> <td>{@code YUV }</td><td id="rb">{@code PREVIEW}</td> <td>{@code YUV }</td><td id="rb">{@code PREVIEW}</td> <td>{@code JPEG}</td><td id="rb">{@code MAXIMUM}</td> <td>Two-input in-app processing with still capture.</td> </tr>
+     * </table><br>
+     * </p>
+     *
+     * <p>FULL-capability ({@link CameraCharacteristics#INFO_SUPPORTED_HARDWARE_LEVEL}
+     * {@code == }{@link CameraMetadata#INFO_SUPPORTED_HARDWARE_LEVEL_FULL FULL}) devices
+     * support at least the following stream combinations in addition to those for
+     * {@link CameraMetadata#INFO_SUPPORTED_HARDWARE_LEVEL_LIMITED LIMITED} devices:
+     *
+     * <table>
+     * <tr><th colspan="7">FULL-capability additional guaranteed configurations</th></tr>
+     * <tr><th colspan="2" id="rb">Target 1</th><th colspan="2" id="rb">Target 2</th><th colspan="2" id="rb">Target 3</th> <th rowspan="2">Sample use case(s)</th> </tr>
+     * <tr><th>Type</th><th id="rb">Max size</th><th>Type</th><th id="rb">Max size</th><th>Type</th><th id="rb">Max size</th> </tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code PRIV}</td><td id="rb">{@code MAXIMUM}</td> <td colspan="2" id="rb"></td> <td>Maximum-resolution GPU processing with preview.</td> </tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code YUV }</td><td id="rb">{@code MAXIMUM}</td> <td colspan="2" id="rb"></td> <td>Maximum-resolution in-app processing with preview.</td> </tr>
+     * <tr> <td>{@code YUV }</td><td id="rb">{@code PREVIEW}</td> <td>{@code YUV }</td><td id="rb">{@code MAXIMUM}</td> <td colspan="2" id="rb"></td> <td>Maximum-resolution two-input in-app processsing.</td> </tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code JPEG}</td><td id="rb">{@code MAXIMUM}</td> <td>Video recording with maximum-size video snapshot</td> </tr>
+     * <tr> <td>{@code YUV }</td><td id="rb">{@code 640x480}</td> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code YUV }</td><td id="rb">{@code MAXIMUM}</td> <td>Standard video recording plus maximum-resolution in-app processing.</td> </tr>
+     * <tr> <td>{@code YUV }</td><td id="rb">{@code 640x480}</td> <td>{@code YUV }</td><td id="rb">{@code PREVIEW}</td> <td>{@code YUV }</td><td id="rb">{@code MAXIMUM}</td> <td>Preview plus two-input maximum-resolution in-app processing.</td> </tr>
+     * </table><br>
+     * </p>
+     *
+     * <p>RAW-capability ({@link CameraCharacteristics#REQUEST_AVAILABLE_CAPABILITIES} includes
+     * {@link CameraMetadata#REQUEST_AVAILABLE_CAPABILITIES_RAW RAW}) devices additionally support
+     * at least the following stream combinations on both
+     * {@link CameraMetadata#INFO_SUPPORTED_HARDWARE_LEVEL_FULL FULL} and
+     * {@link CameraMetadata#INFO_SUPPORTED_HARDWARE_LEVEL_LIMITED LIMITED} devices:
+     *
+     * <table>
+     * <tr><th colspan="7">RAW-capability additional guaranteed configurations</th></tr>
+     * <tr><th colspan="2" id="rb">Target 1</th><th colspan="2" id="rb">Target 2</th><th colspan="2" id="rb">Target 3</th> <th rowspan="2">Sample use case(s)</th> </tr>
+     * <tr><th>Type</th><th id="rb">Max size</th><th>Type</th><th id="rb">Max size</th><th>Type</th><th id="rb">Max size</th> </tr>
+     * <tr> <td>{@code RAW }</td><td id="rb">{@code MAXIMUM}</td> <td colspan="2" id="rb"></td> <td colspan="2" id="rb"></td> <td>No-preview DNG capture.</td> </tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code RAW }</td><td id="rb">{@code MAXIMUM}</td> <td colspan="2" id="rb"></td> <td>Standard DNG capture.</td> </tr>
+     * <tr> <td>{@code YUV }</td><td id="rb">{@code PREVIEW}</td> <td>{@code RAW }</td><td id="rb">{@code MAXIMUM}</td> <td colspan="2" id="rb"></td> <td>In-app processing plus DNG capture.</td> </tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code RAW }</td><td id="rb">{@code MAXIMUM}</td> <td>Video recording with DNG capture.</td> </tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code YUV }</td><td id="rb">{@code PREVIEW}</td> <td>{@code RAW }</td><td id="rb">{@code MAXIMUM}</td> <td>Preview with in-app processing and DNG capture.</td> </tr>
+     * <tr> <td>{@code YUV }</td><td id="rb">{@code PREVIEW}</td> <td>{@code YUV }</td><td id="rb">{@code PREVIEW}</td> <td>{@code RAW }</td><td id="rb">{@code MAXIMUM}</td> <td>Two-input in-app processing plus DNG capture.</td> </tr>
+     * <tr> <td>{@code PRIV}</td><td id="rb">{@code PREVIEW}</td> <td>{@code JPEG}</td><td id="rb">{@code MAXIMUM}</td> <td>{@code RAW }</td><td id="rb">{@code MAXIMUM}</td> <td>Still capture with simultaneous JPEG and DNG.</td> </tr>
+     * <tr> <td>{@code YUV }</td><td id="rb">{@code PREVIEW}</td> <td>{@code JPEG}</td><td id="rb">{@code MAXIMUM}</td> <td>{@code RAW }</td><td id="rb">{@code MAXIMUM}</td> <td>In-app processing with simultaneous JPEG and DNG.</td> </tr>
+     * </table><br>
+     * </p>
+     *
+     * <p>Since the capabilities of camera devices vary greatly, a given camera device may support
+     * target combinations with sizes outside of these guarantees, but this can only be tested for
+     * by attempting to create a session with such targets.</p>
+     *
      * @param outputs The new set of Surfaces that should be made available as
      *                targets for captured image data.
      * @param listener The listener to notify about the status of the new capture session.
diff --git a/core/java/android/hardware/camera2/params/StreamConfigurationMap.java b/core/java/android/hardware/camera2/params/StreamConfigurationMap.java
index c0b7967..5d226e3 100644
--- a/core/java/android/hardware/camera2/params/StreamConfigurationMap.java
+++ b/core/java/android/hardware/camera2/params/StreamConfigurationMap.java
@@ -142,7 +142,7 @@ public final class StreamConfigurationMap {
      * or in {@link PixelFormat} (and there is no possibility of collision).</p>
      *
      * <p>Formats listed in this array are guaranteed to return true if queried with
-     * {@link #isOutputSupportedFor(int).</p>
+     * {@link #isOutputSupportedFor(int)}.</p>
      *
      * @return an array of integer format
      *