Fix EventMessage timestamp issue

Stop encoding/decoding presentation time as part of the message.
What's actually in emsg boxes is a presentation time delta,
which is why it's only 32 bits, and hence why it doesn't handle
large absolute timestamps. We were using this field to hold
absolute timestamps only for the purpose of passing presentation
times from DashManifestParser.parseEvent back to the calling
method. After this change, we return Pair<Long, EventMessage>
instead.

Issue: #5490
PiperOrigin-RevId: 233561731

library/core/src/main/java/com/google/android/exoplayer2/extractor/mp4/FragmentedMp4Extractor.java

@@ -591,6 +591,14 @@ private void onEmsgLeafAtomRead(ParsableByteArray atom) {
     long presentationTimeDeltaUs =
         Util.scaleLargeTimestamp(atom.readUnsignedInt(), C.MICROS_PER_SECOND, timescale);
 
+    // The presentation_time_delta is accounted for by adjusting the sample timestamp, so we zero it
+    // in the sample data before writing it to the track outputs.
+    int position = atom.getPosition();
+    atom.data[position - 4] = 0;
+    atom.data[position - 3] = 0;
+    atom.data[position - 2] = 0;
+    atom.data[position - 1] = 0;
+
     // Output the sample data.
     for (TrackOutput emsgTrackOutput : emsgTrackOutputs) {
       atom.setPosition(Atom.FULL_HEADER_SIZE);

library/core/src/main/java/com/google/android/exoplayer2/metadata/emsg/EventMessage.java

@@ -44,13 +44,6 @@ public final class EventMessage implements Metadata.Entry {
    */
   public final long durationMs;
 
-  /**
-   * The presentation time value of this event message in microseconds.
-   * <p>
-   * Except in special cases, application code should <em>not</em> use this field.
-   */
-  public final long presentationTimeUs;
-
   /**
    * The instance identifier.
    */
@@ -70,22 +63,19 @@ public final class EventMessage implements Metadata.Entry {
    * @param durationMs The duration of the event in milliseconds.
    * @param id The instance identifier.
    * @param messageData The body of the message.
-   * @param presentationTimeUs The presentation time value of this event message in microseconds.
    */
-  public EventMessage(String schemeIdUri, String value, long durationMs, long id,
-      byte[] messageData, long presentationTimeUs) {
+  public EventMessage(
+      String schemeIdUri, String value, long durationMs, long id, byte[] messageData) {
     this.schemeIdUri = schemeIdUri;
     this.value = value;
     this.durationMs = durationMs;
     this.id = id;
     this.messageData = messageData;
-    this.presentationTimeUs = presentationTimeUs;
   }
 
   /* package */ EventMessage(Parcel in) {
     schemeIdUri = castNonNull(in.readString());
     value = castNonNull(in.readString());
-    presentationTimeUs = in.readLong();
     durationMs = in.readLong();
     id = in.readLong();
     messageData = castNonNull(in.createByteArray());
@@ -97,7 +87,6 @@ public int hashCode() {
       int result = 17;
       result = 31 * result + (schemeIdUri != null ? schemeIdUri.hashCode() : 0);
       result = 31 * result + (value != null ? value.hashCode() : 0);
-      result = 31 * result + (int) (presentationTimeUs ^ (presentationTimeUs >>> 32));
       result = 31 * result + (int) (durationMs ^ (durationMs >>> 32));
       result = 31 * result + (int) (id ^ (id >>> 32));
       result = 31 * result + Arrays.hashCode(messageData);
@@ -115,9 +104,11 @@ public boolean equals(@Nullable Object obj) {
       return false;
     }
     EventMessage other = (EventMessage) obj;
-    return presentationTimeUs == other.presentationTimeUs && durationMs == other.durationMs
-        && id == other.id && Util.areEqual(schemeIdUri, other.schemeIdUri)
-        && Util.areEqual(value, other.value) && Arrays.equals(messageData, other.messageData);
+    return durationMs == other.durationMs
+        && id == other.id
+        && Util.areEqual(schemeIdUri, other.schemeIdUri)
+        && Util.areEqual(value, other.value)
+        && Arrays.equals(messageData, other.messageData);
   }
 
   @Override
@@ -136,7 +127,6 @@ public int describeContents() {
   public void writeToParcel(Parcel dest, int flags) {
     dest.writeString(schemeIdUri);
     dest.writeString(value);
-    dest.writeLong(presentationTimeUs);
     dest.writeLong(durationMs);
     dest.writeLong(id);
     dest.writeByteArray(messageData);

library/core/src/main/java/com/google/android/exoplayer2/metadata/emsg/EventMessageDecoder.java

@@ -15,24 +15,27 @@
  */
 package com.google.android.exoplayer2.metadata.emsg;
 
-import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.metadata.MetadataDecoder;
 import com.google.android.exoplayer2.metadata.MetadataInputBuffer;
 import com.google.android.exoplayer2.util.Assertions;
+import com.google.android.exoplayer2.util.Log;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.Util;
 import java.nio.ByteBuffer;
 import java.util.Arrays;
 
 /**
  * Decodes Event Message (emsg) atoms, as defined in ISO/IEC 23009-1:2014, Section 5.10.3.3.
- * <p>
- * Atom data should be provided to the decoder without the full atom header (i.e. starting from the
- * first byte of the scheme_id_uri field).
+ *
+ * <p>Atom data should be provided to the decoder without the full atom header (i.e. starting from
+ * the first byte of the scheme_id_uri field). It is expected that the presentation_time_delta field
+ * should be 0, having already been accounted for by adjusting the sample timestamp.
  */
 public final class EventMessageDecoder implements MetadataDecoder {
 
+  private static final String TAG = "EventMessageDecoder";
+
   @SuppressWarnings("ByteBufferBackingArray")
   @Override
   public Metadata decode(MetadataInputBuffer inputBuffer) {
@@ -43,13 +46,16 @@ public Metadata decode(MetadataInputBuffer inputBuffer) {
     String schemeIdUri = Assertions.checkNotNull(emsgData.readNullTerminatedString());
     String value = Assertions.checkNotNull(emsgData.readNullTerminatedString());
     long timescale = emsgData.readUnsignedInt();
-    long presentationTimeUs = Util.scaleLargeTimestamp(emsgData.readUnsignedInt(),
-        C.MICROS_PER_SECOND, timescale);
+    long presentationTimeDelta = emsgData.readUnsignedInt();
+    if (presentationTimeDelta != 0) {
+      // We expect the source to have accounted for presentation_time_delta by adjusting the sample
+      // timestamp and zeroing the field in the sample data. Log a warning if the field is non-zero.
+      Log.w(TAG, "Ignoring non-zero presentation_time_delta: " + presentationTimeDelta);
+    }
     long durationMs = Util.scaleLargeTimestamp(emsgData.readUnsignedInt(), 1000, timescale);
     long id = emsgData.readUnsignedInt();
     byte[] messageData = Arrays.copyOfRange(data, emsgData.getPosition(), size);
-    return new Metadata(new EventMessage(schemeIdUri, value, durationMs, id, messageData,
-        presentationTimeUs));
+    return new Metadata(new EventMessage(schemeIdUri, value, durationMs, id, messageData));
   }
 
 }

library/core/src/main/java/com/google/android/exoplayer2/metadata/emsg/EventMessageEncoder.java

@@ -16,9 +16,6 @@
 package com.google.android.exoplayer2.metadata.emsg;
 
 import android.support.annotation.Nullable;
-import com.google.android.exoplayer2.C;
-import com.google.android.exoplayer2.util.Assertions;
-import com.google.android.exoplayer2.util.Util;
 import java.io.ByteArrayOutputStream;
 import java.io.DataOutputStream;
 import java.io.IOException;
@@ -37,27 +34,22 @@ public EventMessageEncoder() {
   }
 
   /**
-   * Encodes an {@link EventMessage} to a byte array that can be decoded by
-   * {@link EventMessageDecoder}.
+   * Encodes an {@link EventMessage} to a byte array that can be decoded by {@link
+   * EventMessageDecoder}.
    *
    * @param eventMessage The event message to be encoded.
-   * @param timescale Timescale of the event message, in units per second.
    * @return The serialized byte array.
    */
   @Nullable
-  public byte[] encode(EventMessage eventMessage, long timescale) {
-    Assertions.checkArgument(timescale >= 0);
+  public byte[] encode(EventMessage eventMessage) {
     byteArrayOutputStream.reset();
     try {
       writeNullTerminatedString(dataOutputStream, eventMessage.schemeIdUri);
       String nonNullValue = eventMessage.value != null ? eventMessage.value : "";
       writeNullTerminatedString(dataOutputStream, nonNullValue);
-      writeUnsignedInt(dataOutputStream, timescale);
-      long presentationTime = Util.scaleLargeTimestamp(eventMessage.presentationTimeUs,
-          timescale, C.MICROS_PER_SECOND);
-      writeUnsignedInt(dataOutputStream, presentationTime);
-      long duration = Util.scaleLargeTimestamp(eventMessage.durationMs, timescale, 1000);
-      writeUnsignedInt(dataOutputStream, duration);
+      writeUnsignedInt(dataOutputStream, 1000); // timescale
+      writeUnsignedInt(dataOutputStream, 0); // presentation_time_delta
+      writeUnsignedInt(dataOutputStream, eventMessage.durationMs);
       writeUnsignedInt(dataOutputStream, eventMessage.id);
       dataOutputStream.write(eventMessage.messageData);
       dataOutputStream.flush();

library/core/src/test/java/com/google/android/exoplayer2/metadata/emsg/EventMessageDecoderTest.java

@@ -51,7 +51,6 @@ public void testDecodeEventMessage() {
     assertThat(eventMessage.durationMs).isEqualTo(3000);
     assertThat(eventMessage.id).isEqualTo(1000403);
     assertThat(eventMessage.messageData).isEqualTo(new byte[]{0, 1, 2, 3, 4});
-    assertThat(eventMessage.presentationTimeUs).isEqualTo(1000000);
   }
 
 }

library/core/src/test/java/com/google/android/exoplayer2/metadata/emsg/EventMessageEncoderTest.java

@@ -33,25 +33,27 @@ public final class EventMessageEncoderTest {
 
   @Test
   public void testEncodeEventStream() throws IOException {
-    EventMessage eventMessage = new EventMessage("urn:test", "123", 3000, 1000403,
-        new byte[] {0, 1, 2, 3, 4}, 1000000);
-    byte[] expectedEmsgBody = new byte[] {
-        117, 114, 110, 58, 116, 101, 115, 116, 0, // scheme_id_uri = "urn:test"
-        49, 50, 51, 0, // value = "123"
-        0, 0, -69, -128, // timescale = 48000
-        0, 0, -69, -128, // presentation_time_delta = 48000
-        0, 2, 50, -128, // event_duration = 144000
-        0, 15, 67, -45, // id = 1000403
-        0, 1, 2, 3, 4}; // message_data = {0, 1, 2, 3, 4}
-    byte[] encodedByteArray = new EventMessageEncoder().encode(eventMessage, 48000);
+    EventMessage eventMessage =
+        new EventMessage("urn:test", "123", 3000, 1000403, new byte[] {0, 1, 2, 3, 4});
+    byte[] expectedEmsgBody =
+        new byte[] {
+          117, 114, 110, 58, 116, 101, 115, 116, 0, // scheme_id_uri = "urn:test"
+          49, 50, 51, 0, // value = "123"
+          0, 0, 3, -24, // timescale = 1000
+          0, 0, 0, 0, // presentation_time_delta = 0
+          0, 0, 11, -72, // event_duration = 3000
+          0, 15, 67, -45, // id = 1000403
+          0, 1, 2, 3, 4
+        }; // message_data = {0, 1, 2, 3, 4}
+    byte[] encodedByteArray = new EventMessageEncoder().encode(eventMessage);
     assertThat(encodedByteArray).isEqualTo(expectedEmsgBody);
   }
 
   @Test
   public void testEncodeDecodeEventStream() throws IOException {
-    EventMessage expectedEmsg = new EventMessage("urn:test", "123", 3000, 1000403,
-        new byte[] {0, 1, 2, 3, 4}, 1000000);
-    byte[] encodedByteArray = new EventMessageEncoder().encode(expectedEmsg, 48000);
+    EventMessage expectedEmsg =
+        new EventMessage("urn:test", "123", 3000, 1000403, new byte[] {0, 1, 2, 3, 4});
+    byte[] encodedByteArray = new EventMessageEncoder().encode(expectedEmsg);
     MetadataInputBuffer buffer = new MetadataInputBuffer();
     buffer.data = ByteBuffer.allocate(encodedByteArray.length).put(encodedByteArray);
 
@@ -63,30 +65,34 @@ public void testEncodeDecodeEventStream() throws IOException {
 
   @Test
   public void testEncodeEventStreamMultipleTimesWorkingCorrectly() throws IOException {
-    EventMessage eventMessage = new EventMessage("urn:test", "123", 3000, 1000403,
-        new byte[] {0, 1, 2, 3, 4}, 1000000);
-    byte[] expectedEmsgBody = new byte[] {
-        117, 114, 110, 58, 116, 101, 115, 116, 0, // scheme_id_uri = "urn:test"
-        49, 50, 51, 0, // value = "123"
-        0, 0, -69, -128, // timescale = 48000
-        0, 0, -69, -128, // presentation_time_delta = 48000
-        0, 2, 50, -128, // event_duration = 144000
-        0, 15, 67, -45, // id = 1000403
-        0, 1, 2, 3, 4}; // message_data = {0, 1, 2, 3, 4}
-    EventMessage eventMessage1 = new EventMessage("urn:test", "123", 3000, 1000402,
-        new byte[] {4, 3, 2, 1, 0}, 1000000);
-    byte[] expectedEmsgBody1 = new byte[] {
-        117, 114, 110, 58, 116, 101, 115, 116, 0, // scheme_id_uri = "urn:test"
-        49, 50, 51, 0, // value = "123"
-        0, 0, -69, -128, // timescale = 48000
-        0, 0, -69, -128, // presentation_time_delta = 48000
-        0, 2, 50, -128, // event_duration = 144000
-        0, 15, 67, -46, // id = 1000402
-        4, 3, 2, 1, 0}; // message_data = {4, 3, 2, 1, 0}
+    EventMessage eventMessage =
+        new EventMessage("urn:test", "123", 3000, 1000403, new byte[] {0, 1, 2, 3, 4});
+    byte[] expectedEmsgBody =
+        new byte[] {
+          117, 114, 110, 58, 116, 101, 115, 116, 0, // scheme_id_uri = "urn:test"
+          49, 50, 51, 0, // value = "123"
+          0, 0, 3, -24, // timescale = 1000
+          0, 0, 0, 0, // presentation_time_delta = 0
+          0, 0, 11, -72, // event_duration = 3000
+          0, 15, 67, -45, // id = 1000403
+          0, 1, 2, 3, 4
+        }; // message_data = {0, 1, 2, 3, 4}
+    EventMessage eventMessage1 =
+        new EventMessage("urn:test", "123", 3000, 1000402, new byte[] {4, 3, 2, 1, 0});
+    byte[] expectedEmsgBody1 =
+        new byte[] {
+          117, 114, 110, 58, 116, 101, 115, 116, 0, // scheme_id_uri = "urn:test"
+          49, 50, 51, 0, // value = "123"
+          0, 0, 3, -24, // timescale = 1000
+          0, 0, 0, 0, // presentation_time_delta = 0
+          0, 0, 11, -72, // event_duration = 3000
+          0, 15, 67, -46, // id = 1000402
+          4, 3, 2, 1, 0
+        }; // message_data = {4, 3, 2, 1, 0}
     EventMessageEncoder eventMessageEncoder = new EventMessageEncoder();
-    byte[] encodedByteArray = eventMessageEncoder.encode(eventMessage, 48000);
+    byte[] encodedByteArray = eventMessageEncoder.encode(eventMessage);
     assertThat(encodedByteArray).isEqualTo(expectedEmsgBody);
-    byte[] encodedByteArray1 = eventMessageEncoder.encode(eventMessage1, 48000);
+    byte[] encodedByteArray1 = eventMessageEncoder.encode(eventMessage1);
     assertThat(encodedByteArray1).isEqualTo(expectedEmsgBody1);
   }
 

library/core/src/test/java/com/google/android/exoplayer2/metadata/emsg/EventMessageTest.java

@@ -30,8 +30,8 @@ public final class EventMessageTest {
 
   @Test
   public void testEventMessageParcelable() {
-    EventMessage eventMessage = new EventMessage("urn:test", "123", 3000, 1000403,
-        new byte[] {0, 1, 2, 3, 4}, 1000);
+    EventMessage eventMessage =
+        new EventMessage("urn:test", "123", 3000, 1000403, new byte[] {0, 1, 2, 3, 4});
     // Write to parcel.
     Parcel parcel = Parcel.obtain();
     eventMessage.writeToParcel(parcel, 0);

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/EventSampleStream.java

@@ -112,8 +112,7 @@ public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer,
       }
     }
     int sampleIndex = currentIndex++;
-    byte[] serializedEvent = eventMessageEncoder.encode(eventStream.events[sampleIndex],
-        eventStream.timescale);
+    byte[] serializedEvent = eventMessageEncoder.encode(eventStream.events[sampleIndex]);
     if (serializedEvent != null) {
       buffer.ensureSpaceForWrite(serializedEvent.length);
       buffer.setFlags(C.BUFFER_FLAG_KEY_FRAME);

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/manifest/DashManifestParser.java

@@ -834,13 +834,13 @@ protected EventStream parseEventStream(XmlPullParser xpp)
     String schemeIdUri = parseString(xpp, "schemeIdUri", "");
     String value = parseString(xpp, "value", "");
     long timescale = parseLong(xpp, "timescale", 1);
-    List<EventMessage> eventMessages = new ArrayList<>();
+    List<Pair<Long, EventMessage>> eventMessages = new ArrayList<>();
     ByteArrayOutputStream scratchOutputStream = new ByteArrayOutputStream(512);
     do {
       xpp.next();
       if (XmlPullParserUtil.isStartTag(xpp, "Event")) {
-        EventMessage event = parseEvent(xpp, schemeIdUri, value, timescale,
-            scratchOutputStream);
+        Pair<Long, EventMessage> event =
+            parseEvent(xpp, schemeIdUri, value, timescale, scratchOutputStream);
         eventMessages.add(event);
       } else {
         maybeSkipTag(xpp);
@@ -850,9 +850,9 @@ protected EventStream parseEventStream(XmlPullParser xpp)
     long[] presentationTimesUs = new long[eventMessages.size()];
     EventMessage[] events = new EventMessage[eventMessages.size()];
     for (int i = 0; i < eventMessages.size(); i++) {
-      EventMessage event = eventMessages.get(i);
-      presentationTimesUs[i] = event.presentationTimeUs;
-      events[i] = event;
+      Pair<Long, EventMessage> event = eventMessages.get(i);
+      presentationTimesUs[i] = event.first;
+      events[i] = event.second;
     }
     return buildEventStream(schemeIdUri, value, timescale, presentationTimesUs, events);
   }
@@ -871,11 +871,12 @@ protected EventStream buildEventStream(String schemeIdUri, String value, long ti
    * @param timescale The timescale of the parent EventStream.
    * @param scratchOutputStream A {@link ByteArrayOutputStream} that is used when parsing event
    *     objects.
-   * @return The {@link EventMessage} parsed from this EventStream node.
+   * @return A pair containing the node's presentation timestamp in microseconds and the parsed
+   *     {@link EventMessage}.
    * @throws XmlPullParserException If there is any error parsing this node.
    * @throws IOException If there is any error reading from the underlying input stream.
    */
-  protected EventMessage parseEvent(
+  protected Pair<Long, EventMessage> parseEvent(
       XmlPullParser xpp,
       String schemeIdUri,
       String value,
@@ -890,13 +891,14 @@ protected EventMessage parseEvent(
         timescale);
     String messageData = parseString(xpp, "messageData", null);
     byte[] eventObject = parseEventObject(xpp, scratchOutputStream);
-    return buildEvent(
-        schemeIdUri,
-        value,
-        id,
-        durationMs,
-        messageData == null ? eventObject : Util.getUtf8Bytes(messageData),
-        presentationTimesUs);
+    return Pair.create(
+        presentationTimesUs,
+        buildEvent(
+            schemeIdUri,
+            value,
+            id,
+            durationMs,
+            messageData == null ? eventObject : Util.getUtf8Bytes(messageData)));
   }
 
   /**
@@ -963,9 +965,9 @@ protected byte[] parseEventObject(XmlPullParser xpp, ByteArrayOutputStream scrat
     return scratchOutputStream.toByteArray();
   }
 
-  protected EventMessage buildEvent(String schemeIdUri, String value, long id,
-      long durationMs, byte[] messageData, long presentationTimeUs) {
-    return new EventMessage(schemeIdUri, value, durationMs, id, messageData, presentationTimeUs);
+  protected EventMessage buildEvent(
+      String schemeIdUri, String value, long id, long durationMs, byte[] messageData) {
+    return new EventMessage(schemeIdUri, value, durationMs, id, messageData);
   }
 
   protected List<SegmentTimelineElement> parseSegmentTimeline(XmlPullParser xpp)