diff --git a/library/src/main/java/com/google/android/exoplayer/MediaFormat.java b/library/src/main/java/com/google/android/exoplayer/MediaFormat.java
index 898223969f..34407f4042 100644
--- a/library/src/main/java/com/google/android/exoplayer/MediaFormat.java
+++ b/library/src/main/java/com/google/android/exoplayer/MediaFormat.java
@@ -94,11 +94,19 @@ public class MediaFormat {
   }
 
   public static MediaFormat createTextFormat(String mimeType) {
-    return createFormatForMimeType(mimeType);
+    return createTextFormat(mimeType, C.UNKNOWN_TIME_US);
+  }
+
+  public static MediaFormat createTextFormat(String mimeType, long durationUs) {
+    return createFormatForMimeType(mimeType, durationUs);
   }
 
   public static MediaFormat createFormatForMimeType(String mimeType) {
-    return new MediaFormat(mimeType, NO_VALUE, C.UNKNOWN_TIME_US, NO_VALUE, NO_VALUE, NO_VALUE,
+    return createFormatForMimeType(mimeType, C.UNKNOWN_TIME_US);
+  }
+
+  public static MediaFormat createFormatForMimeType(String mimeType, long durationUs) {
+    return new MediaFormat(mimeType, NO_VALUE, durationUs, NO_VALUE, NO_VALUE, NO_VALUE,
         NO_VALUE, NO_VALUE, null);
   }
 
diff --git a/library/src/main/java/com/google/android/exoplayer/extractor/mp4/AtomParsers.java b/library/src/main/java/com/google/android/exoplayer/extractor/mp4/AtomParsers.java
index 10b94e5007..06395188ac 100644
--- a/library/src/main/java/com/google/android/exoplayer/extractor/mp4/AtomParsers.java
+++ b/library/src/main/java/com/google/android/exoplayer/extractor/mp4/AtomParsers.java
@@ -45,7 +45,7 @@ import java.util.List;
     Atom.ContainerAtom mdia = trak.getContainerAtomOfType(Atom.TYPE_mdia);
     int trackType = parseHdlr(mdia.getLeafAtomOfType(Atom.TYPE_hdlr).data);
     if (trackType != Track.TYPE_AUDIO && trackType != Track.TYPE_VIDEO
-        && trackType != Track.TYPE_TEXT && trackType != Track.TYPE_TIME_CODE) {
+        && trackType != Track.TYPE_TEXT && trackType != Track.TYPE_SUBTITLE) {
       return null;
     }
 
@@ -344,9 +344,9 @@ import java.util.List;
         parseAudioSampleEntry(stsd, childAtomType, childStartPosition, childAtomSize, durationUs,
             holder, i);
       } else if (childAtomType == Atom.TYPE_TTML) {
-        holder.mediaFormat = MediaFormat.createTextFormat(MimeTypes.APPLICATION_TTML);
+        holder.mediaFormat = MediaFormat.createTextFormat(MimeTypes.APPLICATION_TTML, durationUs);
       } else if (childAtomType == Atom.TYPE_tx3g) {
-        holder.mediaFormat = MediaFormat.createTextFormat(MimeTypes.APPLICATION_TX3G);
+        holder.mediaFormat = MediaFormat.createTextFormat(MimeTypes.APPLICATION_TX3G, durationUs);
       }
       stsd.setPosition(childStartPosition + childAtomSize);
     }
diff --git a/library/src/main/java/com/google/android/exoplayer/extractor/mp4/Mp4Extractor.java b/library/src/main/java/com/google/android/exoplayer/extractor/mp4/Mp4Extractor.java
index 368b09561d..4c7f18df63 100644
--- a/library/src/main/java/com/google/android/exoplayer/extractor/mp4/Mp4Extractor.java
+++ b/library/src/main/java/com/google/android/exoplayer/extractor/mp4/Mp4Extractor.java
@@ -230,8 +230,7 @@ public final class Mp4Extractor implements Extractor, SeekMap {
       }
 
       Track track = AtomParsers.parseTrak(atom, moov.getLeafAtomOfType(Atom.TYPE_mvhd));
-      if (track == null || (track.type != Track.TYPE_AUDIO && track.type != Track.TYPE_VIDEO
-          && track.type != Track.TYPE_TEXT)) {
+      if (track == null) {
         continue;
       }
 
diff --git a/library/src/main/java/com/google/android/exoplayer/extractor/mp4/Track.java b/library/src/main/java/com/google/android/exoplayer/extractor/mp4/Track.java
index c53a9760b2..6cdcd9568f 100644
--- a/library/src/main/java/com/google/android/exoplayer/extractor/mp4/Track.java
+++ b/library/src/main/java/com/google/android/exoplayer/extractor/mp4/Track.java
@@ -17,6 +17,7 @@ package com.google.android.exoplayer.extractor.mp4;
 
 import com.google.android.exoplayer.C;
 import com.google.android.exoplayer.MediaFormat;
+import com.google.android.exoplayer.util.Util;
 
 /**
  * Encapsulates information describing an MP4 track.
@@ -26,27 +27,19 @@ public final class Track {
   /**
    * Type of a video track.
    */
-  public static final int TYPE_VIDEO = 0x76696465;
+  public static final int TYPE_VIDEO = Util.getIntegerCodeForString("vide");
   /**
    * Type of an audio track.
    */
-  public static final int TYPE_AUDIO = 0x736F756E;
+  public static final int TYPE_AUDIO = Util.getIntegerCodeForString("soun");
   /**
    * Type of a text track.
    */
-  public static final int TYPE_TEXT = 0x74657874;
+  public static final int TYPE_TEXT = Util.getIntegerCodeForString("text");
   /**
-   * Type of a hint track.
+   * Type of a subtitle track.
    */
-  public static final int TYPE_HINT = 0x68696E74;
-  /**
-   * Type of a meta track.
-   */
-  public static final int TYPE_META = 0x6D657461;
-  /**
-   * Type of a time-code track.
-   */
-  public static final int TYPE_TIME_CODE = 0x746D6364;
+  public static final int TYPE_SUBTITLE = Util.getIntegerCodeForString("sbtl");
 
   /**
    * The track identifier.
@@ -54,8 +47,7 @@ public final class Track {
   public final int id;
 
   /**
-   * One of {@link #TYPE_VIDEO}, {@link #TYPE_AUDIO}, {@link #TYPE_HINT}, {@link #TYPE_META} and
-   * {@link #TYPE_TIME_CODE}.
+   * One of {@link #TYPE_VIDEO}, {@link #TYPE_AUDIO}, {@link #TYPE_TEXT} and {@link #TYPE_SUBTITLE}.
    */
   public final int type;
 
diff --git a/library/src/main/java/com/google/android/exoplayer/text/TextTrackRenderer.java b/library/src/main/java/com/google/android/exoplayer/text/TextTrackRenderer.java
index 51fb6e263e..47ef4a41c4 100644
--- a/library/src/main/java/com/google/android/exoplayer/text/TextTrackRenderer.java
+++ b/library/src/main/java/com/google/android/exoplayer/text/TextTrackRenderer.java
@@ -206,6 +206,10 @@ public class TextTrackRenderer extends TrackRenderer implements Callback {
       }
     }
 
+    if (getState() != TrackRenderer.STATE_STARTED) {
+      return;
+    }
+
     boolean textRendererNeedsUpdate = false;
     long subtitleNextEventTimeUs = Long.MAX_VALUE;
     if (subtitle != null) {
@@ -228,7 +232,7 @@ public class TextTrackRenderer extends TrackRenderer implements Callback {
       textRendererNeedsUpdate = true;
     }
 
-    if (textRendererNeedsUpdate && getState() == TrackRenderer.STATE_STARTED) {
+    if (textRendererNeedsUpdate) {
       // textRendererNeedsUpdate is set and we're playing. Update the renderer.
       updateTextRenderer(subtitle.getCues(positionUs));
     }