Parse and expose proj and st3d/stereo_mode

As described in:
https://github.com/google/spatial-media/blob/master/docs/spherical-video-v2-rfc.md.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=130776689

library/src/androidTest/java/com/google/android/exoplayer2/FormatTest.java

@@ -55,10 +55,12 @@ public final class FormatTest extends TestCase {
     DrmInitData.SchemeData DRM_DATA_2 = new DrmInitData.SchemeData(C.UUID_NIL, VIDEO_WEBM,
         TestUtil.buildTestData(128, 1 /* data seed */));
     DrmInitData drmInitData = new DrmInitData(DRM_DATA_1, DRM_DATA_2);
+    byte[] projectionData = new byte[] {1, 2, 3};
 
     Format formatToParcel = new Format("id", MimeTypes.VIDEO_MP4, MimeTypes.VIDEO_H264, null,
-        1024, 2048, 1920, 1080, 24, 90, 2, 6, 44100, C.ENCODING_PCM_24BIT, 1001, 1002, 0, "und",
-        Format.OFFSET_SAMPLE_RELATIVE, INIT_DATA, drmInitData);
+        1024, 2048, 1920, 1080, 24, 90, 2, projectionData, C.STEREO_MODE_TOP_BOTTOM, 6, 44100,
+        C.ENCODING_PCM_24BIT, 1001, 1002, 0, "und", Format.OFFSET_SAMPLE_RELATIVE, INIT_DATA,
+        drmInitData);
 
     Parcel parcel = Parcel.obtain();
     formatToParcel.writeToParcel(parcel, 0);

library/src/main/java/com/google/android/exoplayer2/C.java

@@ -364,6 +364,21 @@ public final class C {
   public static final int MSG_CUSTOM_BASE = 10000;
 
   /**
+   * Indicates Monoscopic stereo layout, used with 360/3D/VR videos.
+   */
+  public static final int STEREO_MODE_MONO = 0;
+
+  /**
+   * Indicates Top-Bottom stereo layout, used with 360/3D/VR videos.
+   */
+  public static final int STEREO_MODE_TOP_BOTTOM = 1;
+
+  /**
+   * Indicates Left-Right stereo layout, used with 360/3D/VR videos.
+   */
+  public static final int STEREO_MODE_LEFT_RIGHT = 2;
+
+  /**
    * Converts a time in microseconds to the corresponding time in milliseconds, preserving
    * {@link #TIME_UNSET} values.
    *

library/src/main/java/com/google/android/exoplayer2/extractor/mp4/Atom.java

@@ -126,6 +126,9 @@ import java.util.List;
   public static final int TYPE_mean = Util.getIntegerCodeForString("mean");
   public static final int TYPE_name = Util.getIntegerCodeForString("name");
   public static final int TYPE_data = Util.getIntegerCodeForString("data");
+  public static final int TYPE_st3d = Util.getIntegerCodeForString("st3d");
+  public static final int TYPE_sv3d = Util.getIntegerCodeForString("sv3d");
+  public static final int TYPE_proj = Util.getIntegerCodeForString("proj");
   public static final int TYPE_vp08 = Util.getIntegerCodeForString("vp08");
   public static final int TYPE_vp09 = Util.getIntegerCodeForString("vp09");
   public static final int TYPE_vpcC = Util.getIntegerCodeForString("vpcC");

library/src/main/java/com/google/android/exoplayer2/extractor/mp4/AtomParsers.java

@@ -29,6 +29,7 @@ import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.Util;
 import com.google.android.exoplayer2.video.AvcConfig;
 import com.google.android.exoplayer2.video.HevcConfig;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
@@ -663,6 +664,8 @@ import java.util.List;
 
     List<byte[]> initializationData = null;
     String mimeType = null;
+    byte[] projectionData = null;
+    int stereoMode = Format.NO_VALUE;
     while (childPosition - position < size) {
       parent.setPosition(childPosition);
       int childStartPosition = parent.getPosition();
@@ -705,6 +708,27 @@ import java.util.List;
       } else if (childAtomType == Atom.TYPE_pasp) {
         pixelWidthHeightRatio = parsePaspFromParent(parent, childStartPosition);
         pixelWidthHeightRatioFromPasp = true;
+      } else if (childAtomType == Atom.TYPE_sv3d) {
+        projectionData = parseProjFromParent(parent, childStartPosition, childAtomSize);
+      } else if (childAtomType == Atom.TYPE_st3d) {
+        int version = parent.readUnsignedByte();
+        parent.skipBytes(3); // Flags.
+        if (version == 0) {
+          int layout = parent.readUnsignedByte();
+          switch (layout) {
+            case 0:
+              stereoMode = C.STEREO_MODE_MONO;
+              break;
+            case 1:
+              stereoMode = C.STEREO_MODE_TOP_BOTTOM;
+              break;
+            case 2:
+              stereoMode = C.STEREO_MODE_LEFT_RIGHT;
+              break;
+            default:
+              break;
+          }
+        }
       }
       childPosition += childAtomSize;
     }
@@ -716,7 +740,7 @@ import java.util.List;
 
     out.format = Format.createVideoSampleFormat(Integer.toString(trackId), mimeType, null,
         Format.NO_VALUE, Format.NO_VALUE, width, height, Format.NO_VALUE, initializationData,
-        rotationDegrees, pixelWidthHeightRatio, drmInitData);
+        rotationDegrees, pixelWidthHeightRatio, projectionData, stereoMode, drmInitData);
   }
 
   /**
@@ -1041,6 +1065,23 @@ import java.util.List;
   }
 
   /**
+   * Parses the proj box from sv3d box, as specified by https://github.com/google/spatial-media
+   */
+  private static byte[] parseProjFromParent(ParsableByteArray parent, int position, int size) {
+    int childPosition = position + Atom.HEADER_SIZE;
+    while (childPosition - position < size) {
+      parent.setPosition(childPosition);
+      int childAtomSize = parent.readInt();
+      int childAtomType = parent.readInt();
+      if (childAtomType == Atom.TYPE_proj) {
+        return Arrays.copyOfRange(parent.data, childPosition, childPosition + childAtomSize);
+      }
+      childPosition += childAtomSize;
+    }
+    return null;
+  }
+
+  /**
    * Parses the size of an expandable class, as specified by ISO 14496-1 subsection 8.3.3.
    */
   private static int parseExpandableClassSize(ParsableByteArray data) {

library/src/main/java/com/google/android/exoplayer2/util/ParsableByteArray.java

@@ -373,6 +373,13 @@ public final class ParsableByteArray {
   }
 
   /**
+   * Reads the next four bytes as a 32-bit floating point value.
+   */
+  public float readFloat() {
+    return Float.intBitsToFloat(readInt());
+  }
+
+  /**
    * Reads the next eight bytes as a 64-bit floating point value.
    */
   public double readDouble() {