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 3bce2d8902..aaaad2cf26 100644
--- a/library/src/main/java/com/google/android/exoplayer/MediaFormat.java
+++ b/library/src/main/java/com/google/android/exoplayer/MediaFormat.java
@@ -107,7 +107,7 @@ public class MediaFormat {
   }
 
   public static MediaFormat createTx3GFormat() {
-    return createFormatForMimeType(MimeTypes.TEXT_TX3G);
+    return createFormatForMimeType(MimeTypes.APPLICATION_TX3G);
   }
 
   public static MediaFormat createFormatForMimeType(String mimeType) {
diff --git a/library/src/main/java/com/google/android/exoplayer/text/tx3g/SubtitleData.java b/library/src/main/java/com/google/android/exoplayer/text/tx3g/SubtitleData.java
index 1bba2de8bd..5bc846c400 100644
--- a/library/src/main/java/com/google/android/exoplayer/text/tx3g/SubtitleData.java
+++ b/library/src/main/java/com/google/android/exoplayer/text/tx3g/SubtitleData.java
@@ -20,61 +20,29 @@ import java.util.Comparator;
 
 class SubtitleData implements Comparable <SubtitleData>, Comparator<SubtitleData> {
 
-  private long mStartTimePosUs;
-  private long mEndTimePosUs;
-  private String strSubtitle;
+  public final long startTimePosUs;
+  public final String strSubtitle;
 
-  SubtitleData()
+  SubtitleData(long startTimePosUs, String strSubtitle)
   {
-    mStartTimePosUs = 0l;
-    mEndTimePosUs = 0l;
-    strSubtitle = "";
-  }
-
-  protected void setStartTimePos(long time)
-  {
-    mStartTimePosUs = time;
-  }
-
-  protected void setEndTimePos(long time)
-  {
-    mEndTimePosUs = time;
-  }
-
-  protected void setSubtitleText(String text)
-  {
-    strSubtitle = text;
-  }
-
-  protected long getStartTimePos()
-  {
-    return mStartTimePosUs;
-  }
-
-  protected long getEndTimePos()
-  {
-    return mEndTimePosUs;
-  }
-
-  protected String getsubtitleText()
-  {
-    return strSubtitle;
+    this.startTimePosUs = startTimePosUs;
+    this.strSubtitle = strSubtitle;
   }
 
   @Override
   public int compare(SubtitleData o1 , SubtitleData o2) {
-    if (o1.getStartTimePos() < o2.getStartTimePos())
+    if (o1.startTimePosUs < o2.startTimePosUs)
       return -1;
-    if (o1.getStartTimePos() > o2.getStartTimePos())
+    if (o1.startTimePosUs > o2.startTimePosUs)
       return 1;
     return 0;
   }
 
   @Override
   public int compareTo(SubtitleData another) {
-    if (getStartTimePos() < another.getStartTimePos())
+    if (startTimePosUs < another.startTimePosUs)
       return -1;
-    if (getStartTimePos() > another.getStartTimePos())
+    if (startTimePosUs > another.startTimePosUs)
       return 1;
     return 0;
   }
diff --git a/library/src/main/java/com/google/android/exoplayer/text/tx3g/TextParser.java b/library/src/main/java/com/google/android/exoplayer/text/tx3g/TextParser.java
index a802761d6b..008d7af078 100644
--- a/library/src/main/java/com/google/android/exoplayer/text/tx3g/TextParser.java
+++ b/library/src/main/java/com/google/android/exoplayer/text/tx3g/TextParser.java
@@ -30,38 +30,20 @@ import java.util.LinkedList;
 import java.util.List;
 
 /**
- * A simple Text parser that supports Tx3g presentation profile.
- * <p>
- * Supported features in this parser are:
- * <ul>
- *   <li>content
- *   <li>core
- *   <li>presentation
- *   <li>profile
- *   <li>structure
- *   <li>time-offset
- *   <li>timing
- *   <li>tickRate
- *   <li>time-clock-with-frames
- *   <li>time-clock
- *   <li>time-offset-with-frames
- *   <li>time-offset-with-ticks
- * </ul>
- * </p>
- * @see <a href="http://www.w3.org/TR/ttaf1-dfxp/">TTML specification</a>
+ * A simple Text parser that supports tx3g atom.
+ *
+ * Only support to parse a single text track at this version ,
+ * since ExtractorSampleSource does not handle multiple audio/video tracks.
+ *
  */
 public class TextParser implements SubtitleParser {
   private static final String TAG = "TextParser";
 
+  private final List<SubtitleData> subtitleList;
 
-  private final List<SubtitleData> mSubtitleList;
-
-  /**
-   * Equivalent to {@code TtmlParser(true)}.
-   */
   public TextParser() {
     Log.i(TAG,"TextParser ");
-    mSubtitleList = new LinkedList<SubtitleData>();
+    subtitleList = new LinkedList<SubtitleData>();
   }
 
 
@@ -74,29 +56,27 @@ public class TextParser implements SubtitleParser {
     text = (text == null) ? "" : text;
     Log.i(TAG,"parse(" + text + "," + startTimeUs + ")" );
 
-    SubtitleData cue = new SubtitleData();
-    cue.setSubtitleText(text);
-    cue.setStartTimePos(startTimeUs);
-    mSubtitleList.add(cue);
+    SubtitleData cue = new SubtitleData(startTimeUs, text);
 
-    Collections.sort(mSubtitleList, new Comparator<SubtitleData>() {
+    subtitleList.add(cue);
+
+    Collections.sort(subtitleList, new Comparator<SubtitleData>() {
       @Override
       public int compare(SubtitleData o1 , SubtitleData o2) {
-        if (o1.getStartTimePos() < o2.getStartTimePos())
+        if (o1.startTimePosUs < o2.startTimePosUs)
           return -1;
-        if (o1.getStartTimePos() > o2.getStartTimePos())
+        if (o1.startTimePosUs > o2.startTimePosUs)
           return 1;
         return 0;
       }
     });
-    TextSubtitle textSubtitle = new TextSubtitle(mSubtitleList);
+    TextSubtitle textSubtitle = new TextSubtitle(subtitleList);
     return textSubtitle;
   }
 
   @Override
   public boolean canParse(String mimeType) {
-    boolean rtn = MimeTypes.TEXT_TX3G.equals(mimeType);
-    Log.i(TAG,"canParse " + mimeType + "," + rtn);
+    boolean rtn = MimeTypes.APPLICATION_TX3G.equals(mimeType);
     return rtn;
   }
 }
diff --git a/library/src/main/java/com/google/android/exoplayer/text/tx3g/TextSubtitle.java b/library/src/main/java/com/google/android/exoplayer/text/tx3g/TextSubtitle.java
index 32f1a76d24..ad74ec9b80 100644
--- a/library/src/main/java/com/google/android/exoplayer/text/tx3g/TextSubtitle.java
+++ b/library/src/main/java/com/google/android/exoplayer/text/tx3g/TextSubtitle.java
@@ -22,7 +22,7 @@ import com.google.android.exoplayer.text.Cue;
 import com.google.android.exoplayer.text.Subtitle;
 
 /**
- * A representation of a TTML subtitle.
+ * A representation of a tx3g subtitle.
  */
 public final class TextSubtitle implements Subtitle {
   static String TAG = "TextSubtitle";
@@ -47,7 +47,6 @@ public final class TextSubtitle implements Subtitle {
 
   @Override
   public int getEventTimeCount() {
-    //LOG.I(TAG,"getEventTimeCount() = " + text.size());
     return text.size();
   }
 
@@ -55,7 +54,6 @@ public final class TextSubtitle implements Subtitle {
   public long getEventTime(int index) {
     if (index > text.size() - 1) return -1;
 
-    //LOG.I(TAG,"getEventTime(" + index + ") = " + text.get(index).getStartTimePos());
     return text.get(index).getStartTimePos();
   }
 
@@ -77,6 +75,7 @@ public final class TextSubtitle implements Subtitle {
   }
 
   private int findTheClosed(long timeUs) {
+    //TODO : Time complexity is O(n),not good solution.
 
     int length = text.size();
     for (int i = 0; i < length ; i++) {
diff --git a/library/src/main/java/com/google/android/exoplayer/util/MimeTypes.java b/library/src/main/java/com/google/android/exoplayer/util/MimeTypes.java
index dea171b6df..d81ea84991 100644
--- a/library/src/main/java/com/google/android/exoplayer/util/MimeTypes.java
+++ b/library/src/main/java/com/google/android/exoplayer/util/MimeTypes.java
@@ -53,12 +53,12 @@ public class MimeTypes {
   public static final String AUDIO_OPUS = BASE_TYPE_AUDIO + "/opus";
 
   public static final String TEXT_VTT = BASE_TYPE_TEXT + "/vtt";
-  public static final String TEXT_TX3G = BASE_TYPE_TEXT + "/tx3g";
 
   public static final String APPLICATION_ID3 = BASE_TYPE_APPLICATION + "/id3";
   public static final String APPLICATION_EIA608 = BASE_TYPE_APPLICATION + "/eia-608";
   public static final String APPLICATION_TTML = BASE_TYPE_APPLICATION + "/ttml+xml";
   public static final String APPLICATION_M3U8 = BASE_TYPE_APPLICATION + "/x-mpegURL";
+  public static final String APPLICATION_TX3G = BASE_TYPE_APPLICATION + "/x-quicktime-tx3g";
 
   private MimeTypes() {}