diff --git a/library/src/androidTest/assets/ttml/multiple_regions.xml b/library/src/androidTest/assets/ttml/multiple_regions.xml
index edc704d8b1..3bde2c99b5 100644
--- a/library/src/androidTest/assets/ttml/multiple_regions.xml
+++ b/library/src/androidTest/assets/ttml/multiple_regions.xml
@@ -8,7 +8,7 @@
         <layout>
             <region xml:id="region1" ttm:origin="10% 10%" extent="20% 20%"/>
             <region xml:id="region2" ttm:origin="40% 40%" extent="20% 20%"/>
-            <region xml:id="region3" ttm:origin="10% 80%" extent="10% 10%"/>
+            <region xml:id="region3" ttm:origin="10% 80%"/>
             <region xml:id="region4" ttm:origin="60% 10%" extent="20% 20%"/>
             <region xml:id="ultimate" ttm:origin="45% 45%" extent="35% 35%"/>
         </layout>
diff --git a/library/src/androidTest/java/com/google/android/exoplayer/text/ttml/TtmlParserTest.java b/library/src/androidTest/java/com/google/android/exoplayer/text/ttml/TtmlParserTest.java
index ce2282ab86..04686b959c 100644
--- a/library/src/androidTest/java/com/google/android/exoplayer/text/ttml/TtmlParserTest.java
+++ b/library/src/androidTest/java/com/google/android/exoplayer/text/ttml/TtmlParserTest.java
@@ -156,10 +156,13 @@ public final class TtmlParserTest extends InstrumentationTestCase {
     assertEquals("lorem", ttmlCue.text.toString());
     assertEquals(10.f / 100.f, ttmlCue.position);
     assertEquals(10.f / 100.f, ttmlCue.line);
+    assertEquals(20.f / 100.f, ttmlCue.size);
+
     ttmlCue = output.get(1);
     assertEquals("amet", ttmlCue.text.toString());
     assertEquals(60.f / 100.f, ttmlCue.position);
     assertEquals(10.f / 100.f, ttmlCue.line);
+    assertEquals(20.f / 100.f, ttmlCue.size);
 
     output = subtitle.getCues(5000000);
     assertEquals(1, output.size());
@@ -167,6 +170,7 @@ public final class TtmlParserTest extends InstrumentationTestCase {
     assertEquals("ipsum", ttmlCue.text.toString());
     assertEquals(40.f / 100.f, ttmlCue.position);
     assertEquals(40.f / 100.f, ttmlCue.line);
+    assertEquals(20.f / 100.f, ttmlCue.size);
 
     output = subtitle.getCues(9000000);
     assertEquals(1, output.size());
@@ -174,6 +178,7 @@ public final class TtmlParserTest extends InstrumentationTestCase {
     assertEquals("dolor", ttmlCue.text.toString());
     assertEquals(10.f / 100.f, ttmlCue.position);
     assertEquals(80.f / 100.f, ttmlCue.line);
+    assertEquals(Cue.DIMEN_UNSET, ttmlCue.size);
 
     output = subtitle.getCues(21000000);
     assertEquals(1, output.size());
@@ -181,6 +186,7 @@ public final class TtmlParserTest extends InstrumentationTestCase {
     assertEquals("She first said this", ttmlCue.text.toString());
     assertEquals(45.f / 100.f, ttmlCue.position);
     assertEquals(45.f / 100.f, ttmlCue.line);
+    assertEquals(35.f / 100.f, ttmlCue.size);
     output = subtitle.getCues(25000000);
     ttmlCue = output.get(0);
     assertEquals("She first said this\nThen this", ttmlCue.text.toString());
diff --git a/library/src/main/java/com/google/android/exoplayer/text/ttml/TtmlNode.java b/library/src/main/java/com/google/android/exoplayer/text/ttml/TtmlNode.java
index 4dd33407c1..abf9a4643c 100644
--- a/library/src/main/java/com/google/android/exoplayer/text/ttml/TtmlNode.java
+++ b/library/src/main/java/com/google/android/exoplayer/text/ttml/TtmlNode.java
@@ -53,6 +53,7 @@ import java.util.TreeSet;
   public static final String ANONYMOUS_REGION_ID = "";
   public static final String ATTR_ID = "id";
   public static final String ATTR_TTS_BACKGROUND_COLOR = "backgroundColor";
+  public static final String ATTR_TTS_EXTENT = "extent";
   public static final String ATTR_TTS_FONT_STYLE = "fontStyle";
   public static final String ATTR_TTS_FONT_SIZE = "fontSize";
   public static final String ATTR_TTS_FONT_FAMILY = "fontFamily";
@@ -180,7 +181,7 @@ import java.util.TreeSet;
     for (Entry<String, SpannableStringBuilder> entry : regionOutputs.entrySet()) {
       TtmlRegion region = regionMap.get(entry.getKey());
       cues.add(new Cue(cleanUpText(entry.getValue()), null, region.line, Cue.TYPE_UNSET,
-          Cue.TYPE_UNSET, region.position, Cue.TYPE_UNSET, Cue.DIMEN_UNSET));
+          Cue.TYPE_UNSET, region.position, Cue.TYPE_UNSET, region.width));
     }
     return cues;
   }
diff --git a/library/src/main/java/com/google/android/exoplayer/text/ttml/TtmlParser.java b/library/src/main/java/com/google/android/exoplayer/text/ttml/TtmlParser.java
index 984bc6d160..e0907d0364 100644
--- a/library/src/main/java/com/google/android/exoplayer/text/ttml/TtmlParser.java
+++ b/library/src/main/java/com/google/android/exoplayer/text/ttml/TtmlParser.java
@@ -17,6 +17,7 @@ package com.google.android.exoplayer.text.ttml;
 
 import com.google.android.exoplayer.C;
 import com.google.android.exoplayer.ParserException;
+import com.google.android.exoplayer.text.Cue;
 import com.google.android.exoplayer.text.SimpleSubtitleParser;
 import com.google.android.exoplayer.util.ColorParser;
 import com.google.android.exoplayer.util.ParserUtil;
@@ -74,9 +75,8 @@ public final class TtmlParser extends SimpleSubtitleParser {
           + "(?:(\\.[0-9]+)|:([0-9][0-9])(?:\\.([0-9]+))?)?$");
   private static final Pattern OFFSET_TIME =
       Pattern.compile("^([0-9]+(?:\\.[0-9]+)?)(h|m|s|ms|f|t)$");
-  private static final Pattern FONT_SIZE =
-      Pattern.compile("^(([0-9]*.)?[0-9]+)(px|em|%)$");
-  private static final Pattern ORIGIN_COORDINATES =
+  private static final Pattern FONT_SIZE = Pattern.compile("^(([0-9]*.)?[0-9]+)(px|em|%)$");
+  private static final Pattern PERCENTAGE_COORDINATES =
       Pattern.compile("^(\\d+\\.?\\d*?)% (\\d+\\.?\\d*?)%$");
 
   // TODO: read and apply the following attributes if specified.
@@ -183,23 +183,42 @@ public final class TtmlParser extends SimpleSubtitleParser {
     return globalStyles;
   }
 
+  /**
+   * Parses a region declaration. Supports origin and extent definition but only when defined in
+   * terms of percentage of the viewport. Regions that do not correctly declare origin are ignored.
+   */
   private Pair<String, TtmlRegion> parseRegionAttributes(XmlPullParser xmlParser) {
     String regionId = ParserUtil.getAttributeValue(xmlParser, TtmlNode.ATTR_ID);
     String regionOrigin = ParserUtil.getAttributeValue(xmlParser, TtmlNode.ATTR_TTS_ORIGIN);
+    String regionExtent = ParserUtil.getAttributeValue(xmlParser, TtmlNode.ATTR_TTS_EXTENT);
     if (regionOrigin == null || regionId == null) {
       return null;
     }
-    Matcher originMatcher = ORIGIN_COORDINATES.matcher(regionOrigin);
+    float position = Cue.DIMEN_UNSET;
+    float line = Cue.DIMEN_UNSET;
+    Matcher originMatcher = PERCENTAGE_COORDINATES.matcher(regionOrigin);
     if (originMatcher.matches()) {
       try {
-        float position = Float.parseFloat(originMatcher.group(1)) / 100.f;
-        float line = Float.parseFloat(originMatcher.group(2)) / 100.f;
-        return new Pair<>(regionId, new TtmlRegion(position, line));
+        position = Float.parseFloat(originMatcher.group(1)) / 100.f;
+        line = Float.parseFloat(originMatcher.group(2)) / 100.f;
       } catch (NumberFormatException e) {
-        Log.w(TAG, "Ignoring malformed region declaration: '" + regionOrigin + "'", e);
+        Log.w(TAG, "Ignoring region with malformed origin: '" + regionOrigin + "'", e);
+        position = Cue.DIMEN_UNSET;
       }
     }
-    return null;
+    float width = Cue.DIMEN_UNSET;
+    if (regionExtent != null) {
+      Matcher extentMatcher = PERCENTAGE_COORDINATES.matcher(regionExtent);
+      if (extentMatcher.matches()) {
+        try {
+          width = Float.parseFloat(extentMatcher.group(1)) / 100.f;
+        } catch (NumberFormatException e) {
+          Log.w(TAG, "Ignoring malformed region extent: '" + regionExtent + "'", e);
+        }
+      }
+    }
+    return position != Cue.DIMEN_UNSET ? new Pair<>(regionId, new TtmlRegion(position, line, width))
+        : null;
   }
 
   private String[] parseStyleIds(String parentStyleIds) {
@@ -387,10 +406,11 @@ public final class TtmlParser extends SimpleSubtitleParser {
       matcher = FONT_SIZE.matcher(expression);
     } else if (expressions.length == 2){
       matcher = FONT_SIZE.matcher(expressions[1]);
-      Log.w(TAG, "multiple values in fontSize attribute. Picking the second "
-          + "value for vertical font size and ignoring the first.");
+      Log.w(TAG, "Multiple values in fontSize attribute. Picking the second value for vertical font"
+          + " size and ignoring the first.");
     } else {
-      throw new ParserException();
+      throw new ParserException("Invalid number of entries for fontSize: " + expressions.length
+          + ".");
     }
 
     if (matcher.matches()) {
@@ -406,11 +426,11 @@ public final class TtmlParser extends SimpleSubtitleParser {
           out.setFontSizeUnit(TtmlStyle.FONT_SIZE_UNIT_PERCENT);
           break;
         default:
-          throw new ParserException();
+          throw new ParserException("Invalid unit for fontSize: '" + unit + "'.");
       }
       out.setFontSize(Float.valueOf(matcher.group(1)));
     } else {
-      throw new ParserException();
+      throw new ParserException("Invalid expression for fontSize: '" + expression + "'.");
     }
   }
 
diff --git a/library/src/main/java/com/google/android/exoplayer/text/ttml/TtmlRegion.java b/library/src/main/java/com/google/android/exoplayer/text/ttml/TtmlRegion.java
index 757d134ad7..135018a861 100644
--- a/library/src/main/java/com/google/android/exoplayer/text/ttml/TtmlRegion.java
+++ b/library/src/main/java/com/google/android/exoplayer/text/ttml/TtmlRegion.java
@@ -24,14 +24,16 @@ import com.google.android.exoplayer.text.Cue;
 
   public final float position;
   public final float line;
+  public final float width;
 
   public TtmlRegion() {
-    this(Cue.DIMEN_UNSET, Cue.DIMEN_UNSET);
+    this(Cue.DIMEN_UNSET, Cue.DIMEN_UNSET, Cue.DIMEN_UNSET);
   }
 
-  public TtmlRegion(float position, float line) {
+  public TtmlRegion(float position, float line, float width) {
     this.position = position;
     this.line = line;
+    this.width = width;
   }
 
 }