Multiple small fixes for subtitles/mp4.

1. [Cleanup] Remove unused Track types, including TYPE_TIME_CODE.
2. Add subtitle track type, which is different to the existing text type.
3. Set duration on the media formats for text and subtitle tracks. This
   was causing the player to report unknown media duration for mp4 files
   containing such tracks.
4. Make TextTrackRenderer do the right thing when not started.

Issue: #635

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);
   }
 

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);
     }

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;
       }
 

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;
 

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));
     }