From f0f24aa0d4617905c44f2947e47b26355b84abc3 Mon Sep 17 00:00:00 2001
From: jbibik <jbibik@google.com>
Date: Wed, 19 Jul 2023 14:31:22 +0100
Subject: [PATCH] `WebvttParser` implementation - moved from `WebvttDecoder`

`WebvttDecoder` which used to be `SimpleSubtitleDecoder` will now be called `WebvttParser` and implement `SubtitleParser` interface.

For backwards compatibility, we will have the same functionality provided by `DelegatingSubtitleDecoder` backed-up by a new `WebvttParser` instance. `WebvttSubtitle` will still be used behind the scenes to handle overlapping `Cues`.

PiperOrigin-RevId: 549298733
---
 .../text/DelegatingSubtitleDecoder.java       |  20 +-
 .../text/SubtitleDecoderFactory.java          |   5 -
 ...gSubtitleDecoderWithWebvttParserTest.java} | 136 ++---
 .../text/DefaultSubtitleParserFactory.java    |   7 +-
 .../{WebvttDecoder.java => WebvttParser.java} |  27 +-
 .../extractor/text/SubtitleExtractorTest.java |  37 +-
 .../text/webvtt/WebvttParserTest.java         | 563 ++++++++++++++++++
 7 files changed, 660 insertions(+), 135 deletions(-)
 rename libraries/{extractor/src/test/java/androidx/media3/extractor/text/webvtt/WebvttDecoderTest.java => exoplayer/src/test/java/androidx/media3/exoplayer/text/DelegatingSubtitleDecoderWithWebvttParserTest.java} (92%)
 rename libraries/extractor/src/main/java/androidx/media3/extractor/text/webvtt/{WebvttDecoder.java => WebvttParser.java} (84%)
 create mode 100644 libraries/extractor/src/test/java/androidx/media3/extractor/text/webvtt/WebvttParserTest.java

diff --git a/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/text/DelegatingSubtitleDecoder.java b/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/text/DelegatingSubtitleDecoder.java
index ebbb156af7..d812bd11e5 100644
--- a/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/text/DelegatingSubtitleDecoder.java
+++ b/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/text/DelegatingSubtitleDecoder.java
@@ -15,7 +15,10 @@
  */
 package androidx.media3.exoplayer.text;
 
+import static androidx.annotation.VisibleForTesting.PACKAGE_PRIVATE;
+
 import androidx.annotation.Nullable;
+import androidx.annotation.VisibleForTesting;
 import androidx.media3.extractor.text.CuesWithTiming;
 import androidx.media3.extractor.text.SimpleSubtitleDecoder;
 import androidx.media3.extractor.text.Subtitle;
@@ -43,17 +46,19 @@ import java.util.List;
  *   <li>DelegatingSubtitleDecoder("XXX", new XXXParser(initializationData))
  *   <li>XXXDecoder(initializationData)
  * </ul>
- *
- * <p>TODO(b/289983417): this will only be used in the old decoding flow (Decoder after SampleQueue)
- * while we maintain dual architecture. Once we fully migrate to the pre-SampleQueue flow, it can be
- * deprecated and later deleted.
  */
-/* package */ final class DelegatingSubtitleDecoder extends SimpleSubtitleDecoder {
+// TODO(b/289983417): this will only be used in the old decoding flow (Decoder after SampleQueue)
+// while we maintain dual architecture. Once we fully migrate to the pre-SampleQueue flow, it can be
+// deprecated and later deleted.
+// TODO: remove VisibleForTesting annotation once SubtitleExtractor uses SubtitleParser (rather than
+// SubtitleDecoder) and SubtitleExtractorTest is refactored
+@VisibleForTesting(otherwise = PACKAGE_PRIVATE)
+public final class DelegatingSubtitleDecoder extends SimpleSubtitleDecoder {
 
   private static final Subtitle EMPTY_SUBTITLE = new CuesWithTimingSubtitle(ImmutableList.of());
   private final SubtitleParser subtitleParser;
 
-  /* package */ DelegatingSubtitleDecoder(String name, SubtitleParser subtitleParser) {
+  public DelegatingSubtitleDecoder(String name, SubtitleParser subtitleParser) {
     super(name);
     this.subtitleParser = subtitleParser;
   }
@@ -63,7 +68,8 @@ import java.util.List;
     if (reset) {
       subtitleParser.reset();
     }
-    @Nullable List<CuesWithTiming> cuesWithTiming = subtitleParser.parse(data);
+    @Nullable
+    List<CuesWithTiming> cuesWithTiming = subtitleParser.parse(data, /* offset= */ 0, length);
     if (cuesWithTiming == null) {
       return EMPTY_SUBTITLE;
     }
diff --git a/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/text/SubtitleDecoderFactory.java b/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/text/SubtitleDecoderFactory.java
index 815e525eb7..de4450643e 100644
--- a/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/text/SubtitleDecoderFactory.java
+++ b/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/text/SubtitleDecoderFactory.java
@@ -25,7 +25,6 @@ import androidx.media3.extractor.text.SubtitleParser;
 import androidx.media3.extractor.text.cea.Cea608Decoder;
 import androidx.media3.extractor.text.cea.Cea708Decoder;
 import androidx.media3.extractor.text.ttml.TtmlDecoder;
-import androidx.media3.extractor.text.webvtt.WebvttDecoder;
 import java.util.Objects;
 
 /** A factory for {@link SubtitleDecoder} instances. */
@@ -56,7 +55,6 @@ public interface SubtitleDecoderFactory {
    * <p>Supports formats supported by {@link DefaultSubtitleParserFactory} as well as the following:
    *
    * <ul>
-   *   <li>WebVTT ({@link WebvttDecoder})
    *   <li>TTML ({@link TtmlDecoder})
    *   <li>Cea608 ({@link Cea608Decoder})
    *   <li>Cea708 ({@link Cea708Decoder})
@@ -72,7 +70,6 @@ public interface SubtitleDecoderFactory {
         public boolean supportsFormat(Format format) {
           @Nullable String mimeType = format.sampleMimeType;
           return delegate.supportsFormat(format)
-              || Objects.equals(mimeType, MimeTypes.TEXT_VTT)
               || Objects.equals(mimeType, MimeTypes.APPLICATION_TTML)
               || Objects.equals(mimeType, MimeTypes.APPLICATION_CEA608)
               || Objects.equals(mimeType, MimeTypes.APPLICATION_MP4CEA608)
@@ -90,8 +87,6 @@ public interface SubtitleDecoderFactory {
           @Nullable String mimeType = format.sampleMimeType;
           if (mimeType != null) {
             switch (mimeType) {
-              case MimeTypes.TEXT_VTT:
-                return new WebvttDecoder();
               case MimeTypes.APPLICATION_TTML:
                 return new TtmlDecoder();
               case MimeTypes.APPLICATION_CEA608:
diff --git a/libraries/extractor/src/test/java/androidx/media3/extractor/text/webvtt/WebvttDecoderTest.java b/libraries/exoplayer/src/test/java/androidx/media3/exoplayer/text/DelegatingSubtitleDecoderWithWebvttParserTest.java
similarity index 92%
rename from libraries/extractor/src/test/java/androidx/media3/extractor/text/webvtt/WebvttDecoderTest.java
rename to libraries/exoplayer/src/test/java/androidx/media3/exoplayer/text/DelegatingSubtitleDecoderWithWebvttParserTest.java
index e2788b4814..d0127044fa 100644
--- a/libraries/extractor/src/test/java/androidx/media3/extractor/text/webvtt/WebvttDecoderTest.java
+++ b/libraries/exoplayer/src/test/java/androidx/media3/exoplayer/text/DelegatingSubtitleDecoderWithWebvttParserTest.java
@@ -1,11 +1,11 @@
 /*
- * Copyright (C) 2016 The Android Open Source Project
+ * Copyright 2023 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
- *      http://www.apache.org/licenses/LICENSE-2.0
+ *      https://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
@@ -13,11 +13,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package androidx.media3.extractor.text.webvtt;
+package androidx.media3.exoplayer.text;
 
 import static androidx.media3.test.utils.truth.SpannedSubject.assertThat;
 import static com.google.common.truth.Truth.assertThat;
-import static org.junit.Assert.fail;
+import static org.junit.Assert.assertThrows;
 
 import android.text.Layout.Alignment;
 import android.text.Spanned;
@@ -25,7 +25,8 @@ import androidx.media3.common.text.Cue;
 import androidx.media3.common.text.TextAnnotation;
 import androidx.media3.common.util.Assertions;
 import androidx.media3.common.util.ColorParser;
-import androidx.media3.extractor.text.SubtitleDecoderException;
+import androidx.media3.extractor.text.Subtitle;
+import androidx.media3.extractor.text.webvtt.WebvttParser;
 import androidx.media3.test.utils.TestUtil;
 import androidx.test.core.app.ApplicationProvider;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
@@ -37,10 +38,9 @@ import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
-/** Unit test for {@link WebvttDecoder}. */
+/** Unit test for a {@link DelegatingSubtitleDecoder} backed by {@link WebvttParser}. */
 @RunWith(AndroidJUnit4.class)
-public class WebvttDecoderTest {
-
+public final class DelegatingSubtitleDecoderWithWebvttParserTest {
   private static final String TYPICAL_FILE = "media/webvtt/typical";
   private static final String TYPICAL_WITH_BAD_TIMESTAMPS =
       "media/webvtt/typical_with_bad_timestamps";
@@ -61,32 +61,27 @@ public class WebvttDecoderTest {
       "media/webvtt/with_css_text_combine_upright";
   private static final String WITH_BOM = "media/webvtt/with_bom";
   private static final String EMPTY_FILE = "media/webvtt/empty";
-
   @Rule public final Expect expect = Expect.create();
 
   @Test
   public void decodeEmpty() throws IOException {
-    WebvttDecoder decoder = new WebvttDecoder();
+    DelegatingSubtitleDecoder decoder =
+        new DelegatingSubtitleDecoder(
+            "DelegatingSubtitleDecoderWithWebvttParser", new WebvttParser());
     byte[] bytes = TestUtil.getByteArray(ApplicationProvider.getApplicationContext(), EMPTY_FILE);
-    try {
-      decoder.decode(bytes, bytes.length, /* reset= */ false);
-      fail();
-    } catch (SubtitleDecoderException expected) {
-      // Do nothing.
-    }
+    assertThrows(
+        IllegalArgumentException.class,
+        () -> decoder.decode(bytes, bytes.length, /* reset= */ false));
   }
 
   @Test
   public void decodeTypical() throws Exception {
-    WebvttSubtitle subtitle = getSubtitleForTestAsset(TYPICAL_FILE);
-
+    Subtitle subtitle = getSubtitleForTestAsset(TYPICAL_FILE);
     assertThat(subtitle.getEventTimeCount()).isEqualTo(4);
-
     assertThat(subtitle.getEventTime(0)).isEqualTo(0L);
     assertThat(subtitle.getEventTime(1)).isEqualTo(1_234_000L);
     Cue firstCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(0)));
     assertThat(firstCue.text.toString()).isEqualTo("This is the first subtitle.");
-
     assertThat(subtitle.getEventTime(2)).isEqualTo(2_345_000L);
     assertThat(subtitle.getEventTime(3)).isEqualTo(3_456_000L);
     Cue secondCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(2)));
@@ -95,15 +90,12 @@ public class WebvttDecoderTest {
 
   @Test
   public void decodeWithBom() throws Exception {
-    WebvttSubtitle subtitle = getSubtitleForTestAsset(WITH_BOM);
-
+    Subtitle subtitle = getSubtitleForTestAsset(WITH_BOM);
     assertThat(subtitle.getEventTimeCount()).isEqualTo(4);
-
     assertThat(subtitle.getEventTime(0)).isEqualTo(0L);
     assertThat(subtitle.getEventTime(1)).isEqualTo(1_234_000L);
     Cue firstCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(0)));
     assertThat(firstCue.text.toString()).isEqualTo("This is the first subtitle.");
-
     assertThat(subtitle.getEventTime(2)).isEqualTo(2_345_000L);
     assertThat(subtitle.getEventTime(3)).isEqualTo(3_456_000L);
     Cue secondCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(2)));
@@ -112,15 +104,12 @@ public class WebvttDecoderTest {
 
   @Test
   public void decodeTypicalWithBadTimestamps() throws Exception {
-    WebvttSubtitle subtitle = getSubtitleForTestAsset(TYPICAL_WITH_BAD_TIMESTAMPS);
-
+    Subtitle subtitle = getSubtitleForTestAsset(TYPICAL_WITH_BAD_TIMESTAMPS);
     assertThat(subtitle.getEventTimeCount()).isEqualTo(4);
-
     assertThat(subtitle.getEventTime(0)).isEqualTo(0L);
     assertThat(subtitle.getEventTime(1)).isEqualTo(1_234_000L);
     Cue firstCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(0)));
     assertThat(firstCue.text.toString()).isEqualTo("This is the first subtitle.");
-
     assertThat(subtitle.getEventTime(2)).isEqualTo(2_345_000L);
     assertThat(subtitle.getEventTime(3)).isEqualTo(3_456_000L);
     Cue secondCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(2)));
@@ -129,15 +118,12 @@ public class WebvttDecoderTest {
 
   @Test
   public void decodeTypicalWithIds() throws Exception {
-    WebvttSubtitle subtitle = getSubtitleForTestAsset(TYPICAL_WITH_IDS_FILE);
-
+    Subtitle subtitle = getSubtitleForTestAsset(TYPICAL_WITH_IDS_FILE);
     assertThat(subtitle.getEventTimeCount()).isEqualTo(4);
-
     assertThat(subtitle.getEventTime(0)).isEqualTo(0L);
     assertThat(subtitle.getEventTime(1)).isEqualTo(1_234_000L);
     Cue firstCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(0)));
     assertThat(firstCue.text.toString()).isEqualTo("This is the first subtitle.");
-
     assertThat(subtitle.getEventTime(2)).isEqualTo(2_345_000L);
     assertThat(subtitle.getEventTime(3)).isEqualTo(3_456_000L);
     Cue secondCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(2)));
@@ -146,15 +132,12 @@ public class WebvttDecoderTest {
 
   @Test
   public void decodeTypicalWithComments() throws Exception {
-    WebvttSubtitle subtitle = getSubtitleForTestAsset(TYPICAL_WITH_COMMENTS_FILE);
-
+    Subtitle subtitle = getSubtitleForTestAsset(TYPICAL_WITH_COMMENTS_FILE);
     assertThat(subtitle.getEventTimeCount()).isEqualTo(4);
-
     assertThat(subtitle.getEventTime(0)).isEqualTo(0L);
     assertThat(subtitle.getEventTime(0 + 1)).isEqualTo(1_234_000L);
     Cue firstCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(0)));
     assertThat(firstCue.text.toString()).isEqualTo("This is the first subtitle.");
-
     assertThat(subtitle.getEventTime(2)).isEqualTo(2_345_000L);
     assertThat(subtitle.getEventTime(2 + 1)).isEqualTo(3_456_000L);
     Cue secondCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(2)));
@@ -163,25 +146,20 @@ public class WebvttDecoderTest {
 
   @Test
   public void decodeWithTags() throws Exception {
-    WebvttSubtitle subtitle = getSubtitleForTestAsset(WITH_TAGS_FILE);
-
+    Subtitle subtitle = getSubtitleForTestAsset(WITH_TAGS_FILE);
     assertThat(subtitle.getEventTimeCount()).isEqualTo(8);
-
     assertThat(subtitle.getEventTime(0)).isEqualTo(0L);
     assertThat(subtitle.getEventTime(1)).isEqualTo(1_234_000L);
     Cue firstCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(0)));
     assertThat(firstCue.text.toString()).isEqualTo("This is the first subtitle.");
-
     assertThat(subtitle.getEventTime(2)).isEqualTo(2_345_000L);
     assertThat(subtitle.getEventTime(3)).isEqualTo(3_456_000L);
     Cue secondCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(2)));
     assertThat(secondCue.text.toString()).isEqualTo("This is the second subtitle.");
-
     assertThat(subtitle.getEventTime(4)).isEqualTo(4_000_000L);
     assertThat(subtitle.getEventTime(5)).isEqualTo(5_000_000L);
     Cue thirdCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(4)));
     assertThat(thirdCue.text.toString()).isEqualTo("This is the third subtitle.");
-
     assertThat(subtitle.getEventTime(6)).isEqualTo(6_000_000L);
     assertThat(subtitle.getEventTime(7)).isEqualTo(7_000_000L);
     Cue fourthCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(6)));
@@ -190,10 +168,8 @@ public class WebvttDecoderTest {
 
   @Test
   public void decodeWithPositioning() throws Exception {
-    WebvttSubtitle subtitle = getSubtitleForTestAsset(WITH_POSITIONING_FILE);
-
+    Subtitle subtitle = getSubtitleForTestAsset(WITH_POSITIONING_FILE);
     assertThat(subtitle.getEventTimeCount()).isEqualTo(16);
-
     assertThat(subtitle.getEventTime(0)).isEqualTo(0L);
     assertThat(subtitle.getEventTime(1)).isEqualTo(1_234_000L);
     Cue firstCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(0)));
@@ -202,12 +178,10 @@ public class WebvttDecoderTest {
     assertThat(firstCue.positionAnchor).isEqualTo(Cue.ANCHOR_TYPE_END);
     assertThat(firstCue.textAlignment).isEqualTo(Alignment.ALIGN_NORMAL);
     assertThat(firstCue.size).isEqualTo(0.35f);
-
     // Unspecified values should use WebVTT defaults
     assertThat(firstCue.line).isEqualTo(-1f);
     assertThat(firstCue.lineType).isEqualTo(Cue.LINE_TYPE_NUMBER);
     assertThat(firstCue.verticalType).isEqualTo(Cue.TYPE_UNSET);
-
     assertThat(subtitle.getEventTime(2)).isEqualTo(2_345_000L);
     assertThat(subtitle.getEventTime(3)).isEqualTo(3_456_000L);
     Cue secondCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(2)));
@@ -215,7 +189,6 @@ public class WebvttDecoderTest {
     // Position is invalid so defaults to 0.5
     assertThat(secondCue.position).isEqualTo(0.5f);
     assertThat(secondCue.textAlignment).isEqualTo(Alignment.ALIGN_OPPOSITE);
-
     assertThat(subtitle.getEventTime(4)).isEqualTo(4_000_000L);
     assertThat(subtitle.getEventTime(5)).isEqualTo(5_000_000L);
     Cue thirdCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(4)));
@@ -226,7 +199,6 @@ public class WebvttDecoderTest {
     assertThat(thirdCue.textAlignment).isEqualTo(Alignment.ALIGN_CENTER);
     // Derived from `align:middle`:
     assertThat(thirdCue.positionAnchor).isEqualTo(Cue.ANCHOR_TYPE_MIDDLE);
-
     assertThat(subtitle.getEventTime(6)).isEqualTo(6_000_000L);
     assertThat(subtitle.getEventTime(7)).isEqualTo(7_000_000L);
     Cue fourthCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(6)));
@@ -237,7 +209,6 @@ public class WebvttDecoderTest {
     // Derived from `align:middle`:
     assertThat(fourthCue.position).isEqualTo(0.5f);
     assertThat(fourthCue.positionAnchor).isEqualTo(Cue.ANCHOR_TYPE_MIDDLE);
-
     assertThat(subtitle.getEventTime(8)).isEqualTo(8_000_000L);
     assertThat(subtitle.getEventTime(9)).isEqualTo(9_000_000L);
     Cue fifthCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(8)));
@@ -246,7 +217,6 @@ public class WebvttDecoderTest {
     // Derived from `align:right`:
     assertThat(fifthCue.position).isEqualTo(1.0f);
     assertThat(fifthCue.positionAnchor).isEqualTo(Cue.ANCHOR_TYPE_END);
-
     assertThat(subtitle.getEventTime(10)).isEqualTo(10_000_000L);
     assertThat(subtitle.getEventTime(11)).isEqualTo(11_000_000L);
     Cue sixthCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(10)));
@@ -255,13 +225,11 @@ public class WebvttDecoderTest {
     // Derived from `align:center`:
     assertThat(sixthCue.position).isEqualTo(0.5f);
     assertThat(sixthCue.positionAnchor).isEqualTo(Cue.ANCHOR_TYPE_MIDDLE);
-
     assertThat(subtitle.getEventTime(12)).isEqualTo(12_000_000L);
     assertThat(subtitle.getEventTime(13)).isEqualTo(13_000_000L);
     Cue seventhCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(12)));
     assertThat(seventhCue.text.toString()).isEqualTo("This is the seventh subtitle.");
     assertThat(seventhCue.positionAnchor).isEqualTo(Cue.ANCHOR_TYPE_START);
-
     assertThat(subtitle.getEventTime(14)).isEqualTo(14_000_000L);
     assertThat(subtitle.getEventTime(15)).isEqualTo(15_000_000L);
     Cue eighthCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(14)));
@@ -271,15 +239,12 @@ public class WebvttDecoderTest {
 
   @Test
   public void decodeWithOverlappingTimestamps() throws Exception {
-    WebvttSubtitle subtitle = getSubtitleForTestAsset(WITH_OVERLAPPING_TIMESTAMPS_FILE);
-
+    Subtitle subtitle = getSubtitleForTestAsset(WITH_OVERLAPPING_TIMESTAMPS_FILE);
     assertThat(subtitle.getEventTimeCount()).isEqualTo(8);
-
     Cue firstCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(0)));
     assertThat(firstCue.text.toString()).isEqualTo("Displayed at the bottom for 3 seconds.");
     assertThat(firstCue.line).isEqualTo(-1f);
     assertThat(firstCue.lineType).isEqualTo(Cue.LINE_TYPE_NUMBER);
-
     List<Cue> firstAndSecondCue = subtitle.getCues(subtitle.getEventTime(1));
     assertThat(firstAndSecondCue).hasSize(2);
     assertThat(firstAndSecondCue.get(0).text.toString())
@@ -290,12 +255,10 @@ public class WebvttDecoderTest {
         .isEqualTo("Appears directly above for 1 second.");
     assertThat(firstAndSecondCue.get(1).line).isEqualTo(-2f);
     assertThat(firstAndSecondCue.get(1).lineType).isEqualTo(Cue.LINE_TYPE_NUMBER);
-
     Cue thirdCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(4)));
     assertThat(thirdCue.text.toString()).isEqualTo("Displayed at the bottom for 2 seconds.");
     assertThat(thirdCue.line).isEqualTo(-1f);
     assertThat(thirdCue.lineType).isEqualTo(Cue.LINE_TYPE_NUMBER);
-
     List<Cue> thirdAndFourthCue = subtitle.getCues(subtitle.getEventTime(5));
     assertThat(thirdAndFourthCue).hasSize(2);
     assertThat(thirdAndFourthCue.get(0).text.toString())
@@ -306,7 +269,6 @@ public class WebvttDecoderTest {
         .isEqualTo("Appears directly above the previous cue, then replaces it after 1 second.");
     assertThat(thirdAndFourthCue.get(1).line).isEqualTo(-2f);
     assertThat(thirdAndFourthCue.get(1).lineType).isEqualTo(Cue.LINE_TYPE_NUMBER);
-
     Cue fourthCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(6)));
     assertThat(fourthCue.text.toString())
         .isEqualTo("Appears directly above the previous cue, then replaces it after 1 second.");
@@ -316,22 +278,18 @@ public class WebvttDecoderTest {
 
   @Test
   public void decodeWithVertical() throws Exception {
-    WebvttSubtitle subtitle = getSubtitleForTestAsset(WITH_VERTICAL_FILE);
-
+    Subtitle subtitle = getSubtitleForTestAsset(WITH_VERTICAL_FILE);
     assertThat(subtitle.getEventTimeCount()).isEqualTo(6);
-
     assertThat(subtitle.getEventTime(0)).isEqualTo(0L);
     assertThat(subtitle.getEventTime(1)).isEqualTo(1_234_000L);
     Cue firstCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(0)));
     assertThat(firstCue.text.toString()).isEqualTo("Vertical right-to-left (e.g. Japanese)");
     assertThat(firstCue.verticalType).isEqualTo(Cue.VERTICAL_TYPE_RL);
-
     assertThat(subtitle.getEventTime(2)).isEqualTo(2_345_000L);
     assertThat(subtitle.getEventTime(3)).isEqualTo(3_456_000L);
     Cue secondCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(2)));
     assertThat(secondCue.text.toString()).isEqualTo("Vertical left-to-right (e.g. Mongolian)");
     assertThat(secondCue.verticalType).isEqualTo(Cue.VERTICAL_TYPE_LR);
-
     assertThat(subtitle.getEventTime(4)).isEqualTo(4_000_000L);
     assertThat(subtitle.getEventTime(5)).isEqualTo(5_000_000L);
     Cue thirdCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(4)));
@@ -341,17 +299,14 @@ public class WebvttDecoderTest {
 
   @Test
   public void decodeWithRubies() throws Exception {
-    WebvttSubtitle subtitle = getSubtitleForTestAsset(WITH_RUBIES_FILE);
-
+    Subtitle subtitle = getSubtitleForTestAsset(WITH_RUBIES_FILE);
     assertThat(subtitle.getEventTimeCount()).isEqualTo(8);
-
     // Check that an explicit `over` position is read from CSS.
     Cue firstCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(0)));
     assertThat(firstCue.text.toString()).isEqualTo("Some text with over-ruby.");
     assertThat((Spanned) firstCue.text)
         .hasRubySpanBetween("Some ".length(), "Some text with over-ruby".length())
         .withTextAndPosition("over", TextAnnotation.POSITION_BEFORE);
-
     // Check that `under` is read from CSS and unspecified defaults to `over`.
     Cue secondCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(2)));
     assertThat(secondCue.text.toString())
@@ -364,7 +319,6 @@ public class WebvttDecoderTest {
             "Some text with under-ruby and ".length(),
             "Some text with under-ruby and over-ruby (default)".length())
         .withTextAndPosition("over", TextAnnotation.POSITION_BEFORE);
-
     // Check many <rt> tags with different positions nested in a single <ruby> span.
     Cue thirdCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(4)));
     assertThat(thirdCue.text.toString()).isEqualTo("base1base2base3.");
@@ -377,7 +331,6 @@ public class WebvttDecoderTest {
     assertThat((Spanned) thirdCue.text)
         .hasRubySpanBetween("base1base2".length(), "base1base2base3".length())
         .withTextAndPosition("under3", TextAnnotation.POSITION_AFTER);
-
     // Check a <ruby> span with no <rt> tags.
     Cue fourthCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(6)));
     assertThat(fourthCue.text.toString()).isEqualTo("Some text with no ruby text.");
@@ -386,15 +339,12 @@ public class WebvttDecoderTest {
 
   @Test
   public void decodeWithBadCueHeader() throws Exception {
-    WebvttSubtitle subtitle = getSubtitleForTestAsset(WITH_BAD_CUE_HEADER_FILE);
-
+    Subtitle subtitle = getSubtitleForTestAsset(WITH_BAD_CUE_HEADER_FILE);
     assertThat(subtitle.getEventTimeCount()).isEqualTo(4);
-
     assertThat(subtitle.getEventTime(0)).isEqualTo(0L);
     assertThat(subtitle.getEventTime(1)).isEqualTo(1_234_000L);
     Cue firstCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(0)));
     assertThat(firstCue.text.toString()).isEqualTo("This is the first subtitle.");
-
     assertThat(subtitle.getEventTime(2)).isEqualTo(4_000_000L);
     assertThat(subtitle.getEventTime(3)).isEqualTo(5_000_000L);
     Cue secondCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(2)));
@@ -403,10 +353,8 @@ public class WebvttDecoderTest {
 
   @Test
   public void decodeWithCssFontSizeStyle() throws Exception {
-    WebvttSubtitle subtitle = getSubtitleForTestAsset(WITH_FONT_SIZE);
-
+    Subtitle subtitle = getSubtitleForTestAsset(WITH_FONT_SIZE);
     assertThat(subtitle.getEventTimeCount()).isEqualTo(12);
-
     assertThat(subtitle.getEventTime(0)).isEqualTo(0L);
     assertThat(subtitle.getEventTime(1)).isEqualTo(2_000_000L);
     Cue firstCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(0)));
@@ -414,13 +362,11 @@ public class WebvttDecoderTest {
     assertThat((Spanned) firstCue.text)
         .hasRelativeSizeSpanBetween(0, "Sentence with font-size set to 4.4em.".length())
         .withSizeChange(4.4f);
-
     assertThat(subtitle.getEventTime(2)).isEqualTo(2_100_000L);
     assertThat(subtitle.getEventTime(3)).isEqualTo(2_400_000L);
     Cue secondCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(2)));
     assertThat(secondCue.text.toString()).isEqualTo("Sentence with bad font-size unit.");
     assertThat((Spanned) secondCue.text).hasNoSpans();
-
     assertThat(subtitle.getEventTime(4)).isEqualTo(2_500_000L);
     assertThat(subtitle.getEventTime(5)).isEqualTo(4_000_000L);
     Cue thirdCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(4)));
@@ -428,7 +374,6 @@ public class WebvttDecoderTest {
     assertThat((Spanned) thirdCue.text)
         .hasAbsoluteSizeSpanBetween(0, "Absolute font-size expressed in px unit!".length())
         .withAbsoluteSize(2);
-
     assertThat(subtitle.getEventTime(6)).isEqualTo(4_500_000L);
     assertThat(subtitle.getEventTime(7)).isEqualTo(6_000_000L);
     Cue fourthCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(6)));
@@ -436,13 +381,11 @@ public class WebvttDecoderTest {
     assertThat((Spanned) fourthCue.text)
         .hasRelativeSizeSpanBetween(0, "Relative font-size expressed in % unit!".length())
         .withSizeChange(0.035f);
-
     assertThat(subtitle.getEventTime(8)).isEqualTo(6_100_000L);
     assertThat(subtitle.getEventTime(9)).isEqualTo(6_400_000L);
     Cue fifthCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(8)));
     assertThat(fifthCue.text.toString()).isEqualTo("Sentence with bad font-size value.");
     assertThat((Spanned) secondCue.text).hasNoSpans();
-
     assertThat(subtitle.getEventTime(10)).isEqualTo(6_500_000L);
     assertThat(subtitle.getEventTime(11)).isEqualTo(8_000_000L);
     Cue sixthCue = Iterables.getOnlyElement(subtitle.getCues(subtitle.getEventTime(10)));
@@ -455,8 +398,7 @@ public class WebvttDecoderTest {
 
   @Test
   public void webvttWithCssStyle() throws Exception {
-    WebvttSubtitle subtitle = getSubtitleForTestAsset(WITH_CSS_STYLES);
-
+    Subtitle subtitle = getSubtitleForTestAsset(WITH_CSS_STYLES);
     Spanned firstCueText = getUniqueSpanTextAt(subtitle, 0);
     assertThat(firstCueText.toString()).isEqualTo("This is the first subtitle.");
     assertThat(firstCueText)
@@ -465,17 +407,14 @@ public class WebvttDecoderTest {
     assertThat(firstCueText)
         .hasBackgroundColorSpanBetween(0, firstCueText.length())
         .withColor(ColorParser.parseCssColor("green"));
-
     Spanned secondCueText = getUniqueSpanTextAt(subtitle, 2_345_000);
     assertThat(secondCueText.toString()).isEqualTo("This is the second subtitle.");
     assertThat(secondCueText)
         .hasForegroundColorSpanBetween(0, secondCueText.length())
         .withColor(ColorParser.parseCssColor("peachpuff"));
-
     Spanned thirdCueText = getUniqueSpanTextAt(subtitle, 20_000_000);
     assertThat(thirdCueText.toString()).isEqualTo("This is a reference by element");
     assertThat(thirdCueText).hasUnderlineSpanBetween("This is a ".length(), thirdCueText.length());
-
     Spanned fourthCueText = getUniqueSpanTextAt(subtitle, 25_000_000);
     assertThat(fourthCueText.toString()).isEqualTo("You are an idiot\nYou don't have the guts");
     assertThat(fourthCueText)
@@ -487,7 +426,7 @@ public class WebvttDecoderTest {
 
   @Test
   public void withComplexCssSelectors() throws Exception {
-    WebvttSubtitle subtitle = getSubtitleForTestAsset(WITH_CSS_COMPLEX_SELECTORS);
+    Subtitle subtitle = getSubtitleForTestAsset(WITH_CSS_COMPLEX_SELECTORS);
     Spanned firstCueText = getUniqueSpanTextAt(subtitle, /* timeUs= */ 0);
     assertThat(firstCueText).hasUnderlineSpanBetween(0, firstCueText.length());
     assertThat(firstCueText)
@@ -497,26 +436,22 @@ public class WebvttDecoderTest {
     assertThat(firstCueText)
         .hasTypefaceSpanBetween("This should be underlined and ".length(), firstCueText.length())
         .withFamily("courier");
-
     Spanned secondCueText = getUniqueSpanTextAt(subtitle, /* timeUs= */ 2_000_000);
     assertThat(secondCueText)
         .hasTypefaceSpanBetween("This ".length(), secondCueText.length())
         .withFamily("courier");
     assertThat(secondCueText)
         .hasNoForegroundColorSpanBetween("This ".length(), secondCueText.length());
-
     Spanned thirdCueText = getUniqueSpanTextAt(subtitle, /* timeUs= */ 2_500_000);
     assertThat(thirdCueText).hasBoldSpanBetween("This ".length(), thirdCueText.length());
     assertThat(thirdCueText)
         .hasTypefaceSpanBetween("This ".length(), thirdCueText.length())
         .withFamily("courier");
-
     Spanned fourthCueText = getUniqueSpanTextAt(subtitle, /* timeUs= */ 4_000_000);
     assertThat(fourthCueText)
         .hasNoStyleSpanBetween("This ".length(), "shouldn't be bold.".length());
     assertThat(fourthCueText)
         .hasBoldSpanBetween("This shouldn't be bold.\nThis ".length(), fourthCueText.length());
-
     Spanned fifthCueText = getUniqueSpanTextAt(subtitle, /* timeUs= */ 5_000_000);
     assertThat(fifthCueText)
         .hasNoStyleSpanBetween("This is ".length(), "This is specific".length());
@@ -526,26 +461,25 @@ public class WebvttDecoderTest {
 
   @Test
   public void webvttWithCssTextCombineUpright() throws Exception {
-    WebvttSubtitle subtitle = getSubtitleForTestAsset(WITH_CSS_TEXT_COMBINE_UPRIGHT);
-
+    Subtitle subtitle = getSubtitleForTestAsset(WITH_CSS_TEXT_COMBINE_UPRIGHT);
     Spanned firstCueText = getUniqueSpanTextAt(subtitle, 500_000);
     assertThat(firstCueText)
         .hasHorizontalTextInVerticalContextSpanBetween("Combine ".length(), "Combine all".length());
-
     Spanned secondCueText = getUniqueSpanTextAt(subtitle, 3_500_000);
     assertThat(secondCueText)
         .hasHorizontalTextInVerticalContextSpanBetween(
             "Combine ".length(), "Combine 0004".length());
   }
 
-  private WebvttSubtitle getSubtitleForTestAsset(String asset)
-      throws IOException, SubtitleDecoderException {
-    WebvttDecoder decoder = new WebvttDecoder();
+  private Subtitle getSubtitleForTestAsset(String asset) throws IOException {
+    DelegatingSubtitleDecoder decoder =
+        new DelegatingSubtitleDecoder(
+            "DelegatingSubtitleDecoderWithWebvttParser", new WebvttParser());
     byte[] bytes = TestUtil.getByteArray(ApplicationProvider.getApplicationContext(), asset);
-    return (WebvttSubtitle) decoder.decode(bytes, bytes.length, /* reset= */ false);
+    return decoder.decode(bytes, bytes.length, /* reset= */ false);
   }
 
-  private Spanned getUniqueSpanTextAt(WebvttSubtitle sub, long timeUs) {
+  private Spanned getUniqueSpanTextAt(Subtitle sub, long timeUs) {
     return (Spanned) Assertions.checkNotNull(sub.getCues(timeUs).get(0).text);
   }
 }
diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/text/DefaultSubtitleParserFactory.java b/libraries/extractor/src/main/java/androidx/media3/extractor/text/DefaultSubtitleParserFactory.java
index 609756ed31..0c2c80c799 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/text/DefaultSubtitleParserFactory.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/text/DefaultSubtitleParserFactory.java
@@ -25,6 +25,7 @@ import androidx.media3.extractor.text.ssa.SsaParser;
 import androidx.media3.extractor.text.subrip.SubripParser;
 import androidx.media3.extractor.text.tx3g.Tx3gParser;
 import androidx.media3.extractor.text.webvtt.Mp4WebvttParser;
+import androidx.media3.extractor.text.webvtt.WebvttParser;
 import java.util.Objects;
 
 /**
@@ -33,9 +34,10 @@ import java.util.Objects;
  * <p>The formats supported by this factory are:
  *
  * <ul>
+ *   <li>SSA/ASS ({@link SsaParser})
+ *   <li>WebVTT ({@link WebvttParser})
  *   <li>WebVTT (MP4) ({@link Mp4WebvttParser})
  *   <li>SubRip ({@link SubripParser})
- *   <li>SSA/ASS ({@link SsaParser})
  *   <li>TX3G ({@link Tx3gParser})
  *   <li>PGS ({@link PgsParser})
  *   <li>DVB ({@link DvbParser})
@@ -48,6 +50,7 @@ public final class DefaultSubtitleParserFactory implements SubtitleParser.Factor
   public boolean supportsFormat(Format format) {
     @Nullable String mimeType = format.sampleMimeType;
     return Objects.equals(mimeType, MimeTypes.TEXT_SSA)
+        || Objects.equals(mimeType, MimeTypes.TEXT_VTT)
         || Objects.equals(mimeType, MimeTypes.APPLICATION_MP4VTT)
         || Objects.equals(mimeType, MimeTypes.APPLICATION_SUBRIP)
         || Objects.equals(mimeType, MimeTypes.APPLICATION_TX3G)
@@ -62,6 +65,8 @@ public final class DefaultSubtitleParserFactory implements SubtitleParser.Factor
       switch (mimeType) {
         case MimeTypes.TEXT_SSA:
           return new SsaParser(format.initializationData);
+        case MimeTypes.TEXT_VTT:
+          return new WebvttParser();
         case MimeTypes.APPLICATION_MP4VTT:
           return new Mp4WebvttParser();
         case MimeTypes.APPLICATION_SUBRIP:
diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/text/webvtt/WebvttDecoder.java b/libraries/extractor/src/main/java/androidx/media3/extractor/text/webvtt/WebvttParser.java
similarity index 84%
rename from libraries/extractor/src/main/java/androidx/media3/extractor/text/webvtt/WebvttDecoder.java
rename to libraries/extractor/src/main/java/androidx/media3/extractor/text/webvtt/WebvttParser.java
index cb74c2b6ab..3281e74003 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/text/webvtt/WebvttDecoder.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/text/webvtt/WebvttParser.java
@@ -20,19 +20,19 @@ import androidx.annotation.Nullable;
 import androidx.media3.common.ParserException;
 import androidx.media3.common.util.ParsableByteArray;
 import androidx.media3.common.util.UnstableApi;
-import androidx.media3.extractor.text.SimpleSubtitleDecoder;
-import androidx.media3.extractor.text.Subtitle;
-import androidx.media3.extractor.text.SubtitleDecoderException;
+import androidx.media3.extractor.text.CuesWithTiming;
+import androidx.media3.extractor.text.SubtitleParser;
+import com.google.common.collect.ImmutableList;
 import java.util.ArrayList;
 import java.util.List;
 
 /**
- * A {@link SimpleSubtitleDecoder} for WebVTT.
+ * A {@link SubtitleParser} for WebVTT.
  *
  * <p>See the <a href="http://dev.w3.org/html5/webvtt">WebVTT specification</a>.
  */
 @UnstableApi
-public final class WebvttDecoder extends SimpleSubtitleDecoder {
+public final class WebvttParser implements SubtitleParser {
 
   private static final int EVENT_NONE = -1;
   private static final int EVENT_END_OF_FILE = 0;
@@ -46,23 +46,22 @@ public final class WebvttDecoder extends SimpleSubtitleDecoder {
   private final ParsableByteArray parsableWebvttData;
   private final WebvttCssParser cssParser;
 
-  public WebvttDecoder() {
-    super("WebvttDecoder");
+  public WebvttParser() {
     parsableWebvttData = new ParsableByteArray();
     cssParser = new WebvttCssParser();
   }
 
   @Override
-  protected Subtitle decode(byte[] data, int length, boolean reset)
-      throws SubtitleDecoderException {
+  public ImmutableList<CuesWithTiming> parse(byte[] data, int offset, int length) {
     parsableWebvttData.reset(data, length);
+    parsableWebvttData.setPosition(offset);
     List<WebvttCssStyle> definedStyles = new ArrayList<>();
 
     // Validate the first line of the header, and skip the remainder.
     try {
       WebvttParserUtil.validateWebvttHeaderLine(parsableWebvttData);
     } catch (ParserException e) {
-      throw new SubtitleDecoderException(e);
+      throw new IllegalArgumentException(e);
     }
     while (!TextUtils.isEmpty(parsableWebvttData.readLine())) {}
 
@@ -73,7 +72,7 @@ public final class WebvttDecoder extends SimpleSubtitleDecoder {
         skipComment(parsableWebvttData);
       } else if (event == EVENT_STYLE_BLOCK) {
         if (!cueInfos.isEmpty()) {
-          throw new SubtitleDecoderException("A style block was found after the first cue.");
+          throw new IllegalArgumentException("A style block was found after the first cue.");
         }
         parsableWebvttData.readLine(); // Consume the "STYLE" header.
         definedStyles.addAll(cssParser.parseBlock(parsableWebvttData));
@@ -85,9 +84,13 @@ public final class WebvttDecoder extends SimpleSubtitleDecoder {
         }
       }
     }
-    return new WebvttSubtitle(cueInfos);
+    WebvttSubtitle subtitle = new WebvttSubtitle(cueInfos);
+    return subtitle.toCuesWithTimingList();
   }
 
+  @Override
+  public void reset() {}
+
   /**
    * Positions the input right before the next event, and returns the kind of event found. Does not
    * consume any data from such event, if any.
diff --git a/libraries/extractor/src/test/java/androidx/media3/extractor/text/SubtitleExtractorTest.java b/libraries/extractor/src/test/java/androidx/media3/extractor/text/SubtitleExtractorTest.java
index 7a7371c425..fd712ecca7 100644
--- a/libraries/extractor/src/test/java/androidx/media3/extractor/text/SubtitleExtractorTest.java
+++ b/libraries/extractor/src/test/java/androidx/media3/extractor/text/SubtitleExtractorTest.java
@@ -21,8 +21,9 @@ import static org.junit.Assert.assertThrows;
 import androidx.media3.common.Format;
 import androidx.media3.common.MimeTypes;
 import androidx.media3.common.util.Util;
+import androidx.media3.exoplayer.text.DelegatingSubtitleDecoder;
 import androidx.media3.extractor.Extractor;
-import androidx.media3.extractor.text.webvtt.WebvttDecoder;
+import androidx.media3.extractor.text.webvtt.WebvttParser;
 import androidx.media3.test.utils.FakeExtractorInput;
 import androidx.media3.test.utils.FakeExtractorOutput;
 import androidx.media3.test.utils.FakeTrackOutput;
@@ -64,7 +65,8 @@ public class SubtitleExtractorTest {
             .build();
     SubtitleExtractor extractor =
         new SubtitleExtractor(
-            new WebvttDecoder(),
+            new DelegatingSubtitleDecoder(
+                "DelegatingSubtitleDecoderWithWebvttParser", new WebvttParser()),
             new Format.Builder().setSampleMimeType(MimeTypes.TEXT_VTT).build());
     extractor.init(output);
 
@@ -107,7 +109,8 @@ public class SubtitleExtractorTest {
             .build();
     SubtitleExtractor extractor =
         new SubtitleExtractor(
-            new WebvttDecoder(),
+            new DelegatingSubtitleDecoder(
+                "DelegatingSubtitleDecoderWithWebvttParser", new WebvttParser()),
             new Format.Builder().setSampleMimeType(MimeTypes.TEXT_VTT).build());
     extractor.init(output);
     FakeTrackOutput trackOutput = output.trackOutputs.get(0);
@@ -149,7 +152,8 @@ public class SubtitleExtractorTest {
             .build();
     SubtitleExtractor extractor =
         new SubtitleExtractor(
-            new WebvttDecoder(),
+            new DelegatingSubtitleDecoder(
+                "DelegatingSubtitleDecoderWithWebvttParser", new WebvttParser()),
             new Format.Builder().setSampleMimeType(MimeTypes.TEXT_VTT).build());
     extractor.init(output);
     FakeTrackOutput trackOutput = output.trackOutputs.get(0);
@@ -185,7 +189,10 @@ public class SubtitleExtractorTest {
   public void read_withoutInit_fails() {
     FakeExtractorInput input = new FakeExtractorInput.Builder().setData(new byte[0]).build();
     SubtitleExtractor extractor =
-        new SubtitleExtractor(new WebvttDecoder(), new Format.Builder().build());
+        new SubtitleExtractor(
+            new DelegatingSubtitleDecoder(
+                "DelegatingSubtitleDecoderWithWebvttParser", new WebvttParser()),
+            new Format.Builder().build());
 
     assertThrows(IllegalStateException.class, () -> extractor.read(input, null));
   }
@@ -194,7 +201,10 @@ public class SubtitleExtractorTest {
   public void read_afterRelease_fails() {
     FakeExtractorInput input = new FakeExtractorInput.Builder().setData(new byte[0]).build();
     SubtitleExtractor extractor =
-        new SubtitleExtractor(new WebvttDecoder(), new Format.Builder().build());
+        new SubtitleExtractor(
+            new DelegatingSubtitleDecoder(
+                "DelegatingSubtitleDecoderWithWebvttParser", new WebvttParser()),
+            new Format.Builder().build());
     FakeExtractorOutput output = new FakeExtractorOutput();
 
     extractor.init(output);
@@ -206,7 +216,10 @@ public class SubtitleExtractorTest {
   @Test
   public void seek_withoutInit_fails() {
     SubtitleExtractor extractor =
-        new SubtitleExtractor(new WebvttDecoder(), new Format.Builder().build());
+        new SubtitleExtractor(
+            new DelegatingSubtitleDecoder(
+                "DelegatingSubtitleDecoderWithWebvttParser", new WebvttParser()),
+            new Format.Builder().build());
 
     assertThrows(IllegalStateException.class, () -> extractor.seek(0, 0));
   }
@@ -214,7 +227,10 @@ public class SubtitleExtractorTest {
   @Test
   public void seek_afterRelease_fails() {
     SubtitleExtractor extractor =
-        new SubtitleExtractor(new WebvttDecoder(), new Format.Builder().build());
+        new SubtitleExtractor(
+            new DelegatingSubtitleDecoder(
+                "DelegatingSubtitleDecoderWithWebvttParser", new WebvttParser()),
+            new Format.Builder().build());
     FakeExtractorOutput output = new FakeExtractorOutput();
 
     extractor.init(output);
@@ -226,7 +242,10 @@ public class SubtitleExtractorTest {
   @Test
   public void released_calledTwice() {
     SubtitleExtractor extractor =
-        new SubtitleExtractor(new WebvttDecoder(), new Format.Builder().build());
+        new SubtitleExtractor(
+            new DelegatingSubtitleDecoder(
+                "DelegatingSubtitleDecoderWithWebvttParser", new WebvttParser()),
+            new Format.Builder().build());
     FakeExtractorOutput output = new FakeExtractorOutput();
 
     extractor.init(output);
diff --git a/libraries/extractor/src/test/java/androidx/media3/extractor/text/webvtt/WebvttParserTest.java b/libraries/extractor/src/test/java/androidx/media3/extractor/text/webvtt/WebvttParserTest.java
new file mode 100644
index 0000000000..17e92120b4
--- /dev/null
+++ b/libraries/extractor/src/test/java/androidx/media3/extractor/text/webvtt/WebvttParserTest.java
@@ -0,0 +1,563 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package androidx.media3.extractor.text.webvtt;
+
+import static androidx.media3.test.utils.truth.SpannedSubject.assertThat;
+import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assert.assertThrows;
+
+import android.text.Layout.Alignment;
+import android.text.Spanned;
+import androidx.media3.common.text.Cue;
+import androidx.media3.common.text.TextAnnotation;
+import androidx.media3.common.util.Assertions;
+import androidx.media3.common.util.ColorParser;
+import androidx.media3.extractor.text.CuesWithTiming;
+import androidx.media3.test.utils.TestUtil;
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Iterables;
+import com.google.common.truth.Expect;
+import java.io.IOException;
+import java.util.List;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/** Unit test for {@link WebvttParser}. */
+@RunWith(AndroidJUnit4.class)
+public class WebvttParserTest {
+
+  private static final String TYPICAL_FILE = "media/webvtt/typical";
+  private static final String TYPICAL_WITH_BAD_TIMESTAMPS =
+      "media/webvtt/typical_with_bad_timestamps";
+  private static final String TYPICAL_WITH_IDS_FILE = "media/webvtt/typical_with_identifiers";
+  private static final String TYPICAL_WITH_COMMENTS_FILE = "media/webvtt/typical_with_comments";
+  private static final String WITH_POSITIONING_FILE = "media/webvtt/with_positioning";
+  private static final String WITH_OVERLAPPING_TIMESTAMPS_FILE =
+      "media/webvtt/with_overlapping_timestamps";
+  private static final String WITH_VERTICAL_FILE = "media/webvtt/with_vertical";
+  private static final String WITH_RUBIES_FILE = "media/webvtt/with_rubies";
+  private static final String WITH_BAD_CUE_HEADER_FILE = "media/webvtt/with_bad_cue_header";
+  private static final String WITH_TAGS_FILE = "media/webvtt/with_tags";
+  private static final String WITH_CSS_STYLES = "media/webvtt/with_css_styles";
+  private static final String WITH_FONT_SIZE = "media/webvtt/with_font_size";
+  private static final String WITH_CSS_COMPLEX_SELECTORS =
+      "media/webvtt/with_css_complex_selectors";
+  private static final String WITH_CSS_TEXT_COMBINE_UPRIGHT =
+      "media/webvtt/with_css_text_combine_upright";
+  private static final String WITH_BOM = "media/webvtt/with_bom";
+  private static final String EMPTY_FILE = "media/webvtt/empty";
+
+  @Rule public final Expect expect = Expect.create();
+
+  @Test
+  public void parseEmpty() throws IOException {
+    WebvttParser parser = new WebvttParser();
+    byte[] bytes = TestUtil.getByteArray(ApplicationProvider.getApplicationContext(), EMPTY_FILE);
+    assertThrows(IllegalArgumentException.class, () -> parser.parse(bytes));
+  }
+
+  @Test
+  public void parseTypical() throws Exception {
+    List<CuesWithTiming> allCues = getCuesForTestAsset(TYPICAL_FILE);
+
+    assertThat(allCues).hasSize(2);
+
+    assertThat(allCues.get(0).startTimeUs).isEqualTo(0L);
+    assertThat(allCues.get(0).durationUs).isEqualTo(1_234_000L);
+    Cue firstCue = Iterables.getOnlyElement(allCues.get(0).cues);
+    assertThat(firstCue.text.toString()).isEqualTo("This is the first subtitle.");
+
+    assertThat(allCues.get(1).startTimeUs).isEqualTo(2_345_000L);
+    assertThat(allCues.get(1).durationUs).isEqualTo(3_456_000L - 2_345_000L);
+    Cue secondCue = Iterables.getOnlyElement(allCues.get(1).cues);
+    assertThat(secondCue.text.toString()).isEqualTo("This is the second subtitle.");
+  }
+
+  @Test
+  public void parseWithBom() throws Exception {
+    List<CuesWithTiming> allCues = getCuesForTestAsset(WITH_BOM);
+
+    assertThat(allCues).hasSize(2);
+
+    assertThat(allCues.get(0).startTimeUs).isEqualTo(0L);
+    assertThat(allCues.get(0).durationUs).isEqualTo(1_234_000L);
+    Cue firstCue = Iterables.getOnlyElement(allCues.get(0).cues);
+    assertThat(firstCue.text.toString()).isEqualTo("This is the first subtitle.");
+
+    assertThat(allCues.get(1).startTimeUs).isEqualTo(2_345_000L);
+    assertThat(allCues.get(1).durationUs).isEqualTo(3_456_000L - 2_345_000L);
+    Cue secondCue = Iterables.getOnlyElement(allCues.get(1).cues);
+    assertThat(secondCue.text.toString()).isEqualTo("This is the second subtitle.");
+  }
+
+  @Test
+  public void parseTypicalWithBadTimestamps() throws Exception {
+    List<CuesWithTiming> allCues = getCuesForTestAsset(TYPICAL_WITH_BAD_TIMESTAMPS);
+
+    assertThat(allCues).hasSize(2);
+
+    assertThat(allCues.get(0).startTimeUs).isEqualTo(0L);
+    assertThat(allCues.get(0).durationUs).isEqualTo(1_234_000L);
+    Cue firstCue = Iterables.getOnlyElement(allCues.get(0).cues);
+    assertThat(firstCue.text.toString()).isEqualTo("This is the first subtitle.");
+
+    assertThat(allCues.get(1).startTimeUs).isEqualTo(2_345_000L);
+    assertThat(allCues.get(1).durationUs).isEqualTo(3_456_000L - 2_345_000L);
+    Cue secondCue = Iterables.getOnlyElement(allCues.get(1).cues);
+    assertThat(secondCue.text.toString()).isEqualTo("This is the second subtitle.");
+  }
+
+  @Test
+  public void parseTypicalWithIds() throws Exception {
+    List<CuesWithTiming> allCues = getCuesForTestAsset(TYPICAL_WITH_IDS_FILE);
+
+    assertThat(allCues).hasSize(2);
+
+    assertThat(allCues.get(0).startTimeUs).isEqualTo(0L);
+    assertThat(allCues.get(0).durationUs).isEqualTo(1_234_000L);
+    Cue firstCue = Iterables.getOnlyElement(allCues.get(0).cues);
+    assertThat(firstCue.text.toString()).isEqualTo("This is the first subtitle.");
+
+    assertThat(allCues.get(1).startTimeUs).isEqualTo(2_345_000L);
+    assertThat(allCues.get(1).durationUs).isEqualTo(3_456_000L - 2_345_000L);
+    Cue secondCue = Iterables.getOnlyElement(allCues.get(1).cues);
+    assertThat(secondCue.text.toString()).isEqualTo("This is the second subtitle.");
+  }
+
+  @Test
+  public void parseTypicalWithComments() throws Exception {
+    List<CuesWithTiming> allCues = getCuesForTestAsset(TYPICAL_WITH_COMMENTS_FILE);
+
+    assertThat(allCues).hasSize(2);
+
+    assertThat(allCues.get(0).startTimeUs).isEqualTo(0L);
+    assertThat(allCues.get(0).durationUs).isEqualTo(1_234_000L);
+    Cue firstCue = Iterables.getOnlyElement(allCues.get(0).cues);
+    assertThat(firstCue.text.toString()).isEqualTo("This is the first subtitle.");
+
+    assertThat(allCues.get(1).startTimeUs).isEqualTo(2_345_000L);
+    assertThat(allCues.get(1).durationUs).isEqualTo(3_456_000L - 2_345_000L);
+    Cue secondCue = Iterables.getOnlyElement(allCues.get(1).cues);
+    assertThat(secondCue.text.toString()).isEqualTo("This is the second subtitle.");
+  }
+
+  @Test
+  public void parseWithTags() throws Exception {
+    List<CuesWithTiming> allCues = getCuesForTestAsset(WITH_TAGS_FILE);
+
+    assertThat(allCues).hasSize(4);
+
+    assertThat(allCues.get(0).startTimeUs).isEqualTo(0L);
+    assertThat(allCues.get(0).durationUs).isEqualTo(1_234_000L);
+    Cue firstCue = Iterables.getOnlyElement(allCues.get(0).cues);
+    assertThat(firstCue.text.toString()).isEqualTo("This is the first subtitle.");
+
+    assertThat(allCues.get(1).startTimeUs).isEqualTo(2_345_000L);
+    assertThat(allCues.get(1).durationUs).isEqualTo(3_456_000L - 2_345_000L);
+    Cue secondCue = Iterables.getOnlyElement(allCues.get(1).cues);
+    assertThat(secondCue.text.toString()).isEqualTo("This is the second subtitle.");
+
+    assertThat(allCues.get(2).startTimeUs).isEqualTo(4_000_000L);
+    assertThat(allCues.get(2).durationUs).isEqualTo(5_000_000L - 4_000_000L);
+    Cue thirdCue = Iterables.getOnlyElement(allCues.get(2).cues);
+    assertThat(thirdCue.text.toString()).isEqualTo("This is the third subtitle.");
+
+    assertThat(allCues.get(3).startTimeUs).isEqualTo(6_000_000L);
+    assertThat(allCues.get(3).durationUs).isEqualTo(7_000_000L - 6_000_000L);
+    Cue fourthCue = Iterables.getOnlyElement(allCues.get(3).cues);
+    assertThat(fourthCue.text.toString()).isEqualTo("This is the <fourth> &subtitle.");
+  }
+
+  @Test
+  public void parseWithPositioning() throws Exception {
+    List<CuesWithTiming> allCues = getCuesForTestAsset(WITH_POSITIONING_FILE);
+
+    assertThat(allCues).hasSize(8);
+
+    assertThat(allCues.get(0).startTimeUs).isEqualTo(0L);
+    assertThat(allCues.get(0).durationUs).isEqualTo(1_234_000L);
+    Cue firstCue = Iterables.getOnlyElement(allCues.get(0).cues);
+    assertThat(firstCue.text.toString()).isEqualTo("This is the first subtitle.");
+    assertThat(firstCue.position).isEqualTo(0.6f);
+    assertThat(firstCue.positionAnchor).isEqualTo(Cue.ANCHOR_TYPE_END);
+    assertThat(firstCue.textAlignment).isEqualTo(Alignment.ALIGN_NORMAL);
+    assertThat(firstCue.size).isEqualTo(0.35f);
+
+    // Unspecified values should use WebVTT defaults
+    assertThat(firstCue.line).isEqualTo(-1f);
+    assertThat(firstCue.lineType).isEqualTo(Cue.LINE_TYPE_NUMBER);
+    assertThat(firstCue.verticalType).isEqualTo(Cue.TYPE_UNSET);
+
+    assertThat(allCues.get(1).startTimeUs).isEqualTo(2_345_000L);
+    assertThat(allCues.get(1).durationUs).isEqualTo(3_456_000L - 2_345_000L);
+    Cue secondCue = Iterables.getOnlyElement(allCues.get(1).cues);
+    assertThat(secondCue.text.toString()).isEqualTo("This is the second subtitle.");
+    // Position is invalid so defaults to 0.5
+    assertThat(secondCue.position).isEqualTo(0.5f);
+    assertThat(secondCue.textAlignment).isEqualTo(Alignment.ALIGN_OPPOSITE);
+
+    assertThat(allCues.get(2).startTimeUs).isEqualTo(4_000_000L);
+    assertThat(allCues.get(2).durationUs).isEqualTo(5_000_000L - 4_000_000L);
+    Cue thirdCue = Iterables.getOnlyElement(allCues.get(2).cues);
+    assertThat(thirdCue.text.toString()).isEqualTo("This is the third subtitle.");
+    assertThat(thirdCue.line).isEqualTo(0.45f);
+    assertThat(thirdCue.lineType).isEqualTo(Cue.LINE_TYPE_FRACTION);
+    assertThat(thirdCue.lineAnchor).isEqualTo(Cue.ANCHOR_TYPE_END);
+    assertThat(thirdCue.textAlignment).isEqualTo(Alignment.ALIGN_CENTER);
+    // Derived from `align:middle`:
+    assertThat(thirdCue.positionAnchor).isEqualTo(Cue.ANCHOR_TYPE_MIDDLE);
+
+    assertThat(allCues.get(3).startTimeUs).isEqualTo(6_000_000L);
+    assertThat(allCues.get(3).durationUs).isEqualTo(7_000_000L - 6_000_000L);
+    Cue fourthCue = Iterables.getOnlyElement(allCues.get(3).cues);
+    assertThat(fourthCue.text.toString()).isEqualTo("This is the fourth subtitle.");
+    assertThat(fourthCue.line).isEqualTo(-10f);
+    assertThat(fourthCue.lineAnchor).isEqualTo(Cue.ANCHOR_TYPE_START);
+    assertThat(fourthCue.textAlignment).isEqualTo(Alignment.ALIGN_CENTER);
+    // Derived from `align:middle`:
+    assertThat(fourthCue.position).isEqualTo(0.5f);
+    assertThat(fourthCue.positionAnchor).isEqualTo(Cue.ANCHOR_TYPE_MIDDLE);
+
+    assertThat(allCues.get(4).startTimeUs).isEqualTo(8_000_000L);
+    assertThat(allCues.get(4).durationUs).isEqualTo(9_000_000L - 8_000_000L);
+    Cue fifthCue = Iterables.getOnlyElement(allCues.get(4).cues);
+    assertThat(fifthCue.text.toString()).isEqualTo("This is the fifth subtitle.");
+    assertThat(fifthCue.textAlignment).isEqualTo(Alignment.ALIGN_OPPOSITE);
+    // Derived from `align:right`:
+    assertThat(fifthCue.position).isEqualTo(1.0f);
+    assertThat(fifthCue.positionAnchor).isEqualTo(Cue.ANCHOR_TYPE_END);
+
+    assertThat(allCues.get(5).startTimeUs).isEqualTo(10_000_000L);
+    assertThat(allCues.get(5).durationUs).isEqualTo(11_000_000L - 10_000_000L);
+    Cue sixthCue = Iterables.getOnlyElement(allCues.get(5).cues);
+    assertThat(sixthCue.text.toString()).isEqualTo("This is the sixth subtitle.");
+    assertThat(sixthCue.textAlignment).isEqualTo(Alignment.ALIGN_CENTER);
+    // Derived from `align:center`:
+    assertThat(sixthCue.position).isEqualTo(0.5f);
+    assertThat(sixthCue.positionAnchor).isEqualTo(Cue.ANCHOR_TYPE_MIDDLE);
+
+    assertThat(allCues.get(6).startTimeUs).isEqualTo(12_000_000L);
+    assertThat(allCues.get(6).durationUs).isEqualTo(13_000_000L - 12_000_000L);
+    Cue seventhCue = Iterables.getOnlyElement(allCues.get(6).cues);
+    assertThat(seventhCue.text.toString()).isEqualTo("This is the seventh subtitle.");
+    assertThat(seventhCue.positionAnchor).isEqualTo(Cue.ANCHOR_TYPE_START);
+
+    assertThat(allCues.get(7).startTimeUs).isEqualTo(14_000_000L);
+    assertThat(allCues.get(7).durationUs).isEqualTo(15_000_000L - 14_000_000L);
+    Cue eighthCue = Iterables.getOnlyElement(allCues.get(7).cues);
+    assertThat(eighthCue.text.toString()).isEqualTo("This is the eighth subtitle.");
+    assertThat(eighthCue.positionAnchor).isEqualTo(Cue.ANCHOR_TYPE_END);
+  }
+
+  @Test
+  public void parseWithOverlappingTimestamps() throws Exception {
+    List<CuesWithTiming> allCues = getCuesForTestAsset(WITH_OVERLAPPING_TIMESTAMPS_FILE);
+
+    assertThat(allCues).hasSize(6);
+
+    assertThat(allCues.get(0).startTimeUs).isEqualTo(0);
+    assertThat(allCues.get(0).durationUs).isEqualTo(1_000_000);
+    Cue firstCue = Iterables.getOnlyElement(allCues.get(0).cues);
+    assertThat(firstCue.text.toString()).isEqualTo("Displayed at the bottom for 3 seconds.");
+    assertThat(firstCue.line).isEqualTo(-1f);
+    assertThat(firstCue.lineType).isEqualTo(Cue.LINE_TYPE_NUMBER);
+
+    assertThat(allCues.get(1).startTimeUs).isEqualTo(1_000_000);
+    assertThat(allCues.get(1).durationUs).isEqualTo(1_000_000);
+    ImmutableList<Cue> firstAndSecondCue = allCues.get(1).cues;
+    assertThat(firstAndSecondCue).hasSize(2);
+    assertThat(firstAndSecondCue.get(0).text.toString())
+        .isEqualTo("Displayed at the bottom for 3 seconds.");
+    assertThat(firstAndSecondCue.get(0).line).isEqualTo(-1f);
+    assertThat(firstAndSecondCue.get(0).lineType).isEqualTo(Cue.LINE_TYPE_NUMBER);
+    assertThat(firstAndSecondCue.get(1).text.toString())
+        .isEqualTo("Appears directly above for 1 second.");
+    assertThat(firstAndSecondCue.get(1).line).isEqualTo(-2f);
+    assertThat(firstAndSecondCue.get(1).lineType).isEqualTo(Cue.LINE_TYPE_NUMBER);
+
+    assertThat(allCues.get(2).startTimeUs).isEqualTo(2_000_000);
+    assertThat(allCues.get(2).durationUs).isEqualTo(1_000_000);
+    Cue thirdCue = Iterables.getOnlyElement(allCues.get(2).cues);
+    assertThat(thirdCue.text.toString()).isEqualTo("Displayed at the bottom for 3 seconds.");
+    assertThat(thirdCue.line).isEqualTo(-1f);
+    assertThat(thirdCue.lineType).isEqualTo(Cue.LINE_TYPE_NUMBER);
+
+    assertThat(allCues.get(3).startTimeUs).isEqualTo(4_000_000);
+    assertThat(allCues.get(3).durationUs).isEqualTo(1_000_000);
+    Cue fourthCue = Iterables.getOnlyElement(allCues.get(3).cues);
+    assertThat(fourthCue.text.toString()).isEqualTo("Displayed at the bottom for 2 seconds.");
+    assertThat(fourthCue.line).isEqualTo(-1f);
+    assertThat(fourthCue.lineType).isEqualTo(Cue.LINE_TYPE_NUMBER);
+
+    assertThat(allCues.get(4).startTimeUs).isEqualTo(5_000_000);
+    assertThat(allCues.get(4).durationUs).isEqualTo(1_000_000);
+    ImmutableList<Cue> fourthAndFifth = allCues.get(4).cues;
+    assertThat(fourthAndFifth).hasSize(2);
+    assertThat(fourthAndFifth.get(0).text.toString())
+        .isEqualTo("Displayed at the bottom for 2 seconds.");
+    assertThat(fourthAndFifth.get(0).line).isEqualTo(-1f);
+    assertThat(fourthAndFifth.get(0).lineType).isEqualTo(Cue.LINE_TYPE_NUMBER);
+    assertThat(fourthAndFifth.get(1).text.toString())
+        .isEqualTo("Appears directly above the previous cue, then replaces it after 1 second.");
+    assertThat(fourthAndFifth.get(1).line).isEqualTo(-2f);
+    assertThat(fourthAndFifth.get(1).lineType).isEqualTo(Cue.LINE_TYPE_NUMBER);
+
+    assertThat(allCues.get(5).startTimeUs).isEqualTo(6_000_000);
+    assertThat(allCues.get(5).durationUs).isEqualTo(1_000_000);
+    Cue sixthCue = Iterables.getOnlyElement(allCues.get(5).cues);
+    assertThat(sixthCue.text.toString())
+        .isEqualTo("Appears directly above the previous cue, then replaces it after 1 second.");
+    assertThat(sixthCue.line).isEqualTo(-1f);
+    assertThat(sixthCue.lineType).isEqualTo(Cue.LINE_TYPE_NUMBER);
+  }
+
+  @Test
+  public void parseWithVertical() throws Exception {
+    List<CuesWithTiming> allCues = getCuesForTestAsset(WITH_VERTICAL_FILE);
+
+    assertThat(allCues).hasSize(3);
+
+    assertThat(allCues.get(0).startTimeUs).isEqualTo(0L);
+    assertThat(allCues.get(0).durationUs).isEqualTo(1_234_000L);
+    Cue firstCue = Iterables.getOnlyElement(allCues.get(0).cues);
+    assertThat(firstCue.text.toString()).isEqualTo("Vertical right-to-left (e.g. Japanese)");
+    assertThat(firstCue.verticalType).isEqualTo(Cue.VERTICAL_TYPE_RL);
+
+    assertThat(allCues.get(1).startTimeUs).isEqualTo(2_345_000L);
+    assertThat(allCues.get(1).durationUs).isEqualTo(3_456_000L - 2_345_000L);
+    Cue secondCue = Iterables.getOnlyElement(allCues.get(1).cues);
+    assertThat(secondCue.text.toString()).isEqualTo("Vertical left-to-right (e.g. Mongolian)");
+    assertThat(secondCue.verticalType).isEqualTo(Cue.VERTICAL_TYPE_LR);
+
+    assertThat(allCues.get(2).startTimeUs).isEqualTo(4_000_000L);
+    assertThat(allCues.get(2).durationUs).isEqualTo(5_000_000L - 4_000_000L);
+    Cue thirdCue = Iterables.getOnlyElement(allCues.get(2).cues);
+    assertThat(thirdCue.text.toString()).isEqualTo("No vertical setting (i.e. horizontal)");
+    assertThat(thirdCue.verticalType).isEqualTo(Cue.TYPE_UNSET);
+  }
+
+  @Test
+  public void parseWithRubies() throws Exception {
+    List<CuesWithTiming> allCues = getCuesForTestAsset(WITH_RUBIES_FILE);
+
+    assertThat(allCues).hasSize(4);
+
+    // Check that an explicit `over` position is read from CSS.
+    Cue firstCue = Iterables.getOnlyElement(allCues.get(0).cues);
+    assertThat(firstCue.text.toString()).isEqualTo("Some text with over-ruby.");
+    assertThat((Spanned) firstCue.text)
+        .hasRubySpanBetween("Some ".length(), "Some text with over-ruby".length())
+        .withTextAndPosition("over", TextAnnotation.POSITION_BEFORE);
+
+    // Check that `under` is read from CSS and unspecified defaults to `over`.
+    Cue secondCue = Iterables.getOnlyElement(allCues.get(1).cues);
+    assertThat(secondCue.text.toString())
+        .isEqualTo("Some text with under-ruby and over-ruby (default).");
+    assertThat((Spanned) secondCue.text)
+        .hasRubySpanBetween("Some ".length(), "Some text with under-ruby".length())
+        .withTextAndPosition("under", TextAnnotation.POSITION_AFTER);
+    assertThat((Spanned) secondCue.text)
+        .hasRubySpanBetween(
+            "Some text with under-ruby and ".length(),
+            "Some text with under-ruby and over-ruby (default)".length())
+        .withTextAndPosition("over", TextAnnotation.POSITION_BEFORE);
+
+    // Check many <rt> tags with different positions nested in a single <ruby> span.
+    Cue thirdCue = Iterables.getOnlyElement(allCues.get(2).cues);
+    assertThat(thirdCue.text.toString()).isEqualTo("base1base2base3.");
+    assertThat((Spanned) thirdCue.text)
+        .hasRubySpanBetween(/* start= */ 0, "base1".length())
+        .withTextAndPosition("over1", TextAnnotation.POSITION_BEFORE);
+    assertThat((Spanned) thirdCue.text)
+        .hasRubySpanBetween("base1".length(), "base1base2".length())
+        .withTextAndPosition("under2", TextAnnotation.POSITION_AFTER);
+    assertThat((Spanned) thirdCue.text)
+        .hasRubySpanBetween("base1base2".length(), "base1base2base3".length())
+        .withTextAndPosition("under3", TextAnnotation.POSITION_AFTER);
+
+    // Check a <ruby> span with no <rt> tags.
+    Cue fourthCue = Iterables.getOnlyElement(allCues.get(3).cues);
+    assertThat(fourthCue.text.toString()).isEqualTo("Some text with no ruby text.");
+    assertThat((Spanned) fourthCue.text).hasNoSpans();
+  }
+
+  @Test
+  public void parseWithBadCueHeader() throws Exception {
+    List<CuesWithTiming> allCues = getCuesForTestAsset(WITH_BAD_CUE_HEADER_FILE);
+
+    assertThat(allCues).hasSize(2);
+
+    assertThat(allCues.get(0).startTimeUs).isEqualTo(0L);
+    assertThat(allCues.get(0).durationUs).isEqualTo(1_234_000L);
+    Cue firstCue = Iterables.getOnlyElement(allCues.get(0).cues);
+    assertThat(firstCue.text.toString()).isEqualTo("This is the first subtitle.");
+
+    assertThat(allCues.get(1).startTimeUs).isEqualTo(4_000_000L);
+    assertThat(allCues.get(1).durationUs).isEqualTo(5_000_000L - 4_000_000L);
+    Cue secondCue = Iterables.getOnlyElement(allCues.get(1).cues);
+    assertThat(secondCue.text.toString()).isEqualTo("This is the third subtitle.");
+  }
+
+  @Test
+  public void parseWithCssFontSizeStyle() throws Exception {
+    List<CuesWithTiming> allCues = getCuesForTestAsset(WITH_FONT_SIZE);
+
+    assertThat(allCues).hasSize(6);
+
+    assertThat(allCues.get(0).startTimeUs).isEqualTo(0L);
+    assertThat(allCues.get(0).durationUs).isEqualTo(2_000_000L);
+    Cue firstCue = Iterables.getOnlyElement(allCues.get(0).cues);
+    assertThat(firstCue.text.toString()).isEqualTo("Sentence with font-size set to 4.4em.");
+    assertThat((Spanned) firstCue.text)
+        .hasRelativeSizeSpanBetween(0, "Sentence with font-size set to 4.4em.".length())
+        .withSizeChange(4.4f);
+
+    assertThat(allCues.get(1).startTimeUs).isEqualTo(2_100_000L);
+    assertThat(allCues.get(1).durationUs).isEqualTo(2_400_000L - 2_100_000L);
+    Cue secondCue = Iterables.getOnlyElement(allCues.get(1).cues);
+    assertThat(secondCue.text.toString()).isEqualTo("Sentence with bad font-size unit.");
+    assertThat((Spanned) secondCue.text).hasNoSpans();
+
+    assertThat(allCues.get(2).startTimeUs).isEqualTo(2_500_000L);
+    assertThat(allCues.get(2).durationUs).isEqualTo(4_000_000L - 2_500_000L);
+    Cue thirdCue = Iterables.getOnlyElement(allCues.get(2).cues);
+    assertThat(thirdCue.text.toString()).isEqualTo("Absolute font-size expressed in px unit!");
+    assertThat((Spanned) thirdCue.text)
+        .hasAbsoluteSizeSpanBetween(0, "Absolute font-size expressed in px unit!".length())
+        .withAbsoluteSize(2);
+
+    assertThat(allCues.get(3).startTimeUs).isEqualTo(4_500_000L);
+    assertThat(allCues.get(3).durationUs).isEqualTo(6_000_000L - 4_500_000L);
+    Cue fourthCue = Iterables.getOnlyElement(allCues.get(3).cues);
+    assertThat(fourthCue.text.toString()).isEqualTo("Relative font-size expressed in % unit!");
+    assertThat((Spanned) fourthCue.text)
+        .hasRelativeSizeSpanBetween(0, "Relative font-size expressed in % unit!".length())
+        .withSizeChange(0.035f);
+
+    assertThat(allCues.get(4).startTimeUs).isEqualTo(6_100_000L);
+    assertThat(allCues.get(4).durationUs).isEqualTo(6_400_000L - 6_100_000L);
+    Cue fifthCue = Iterables.getOnlyElement(allCues.get(4).cues);
+    assertThat(fifthCue.text.toString()).isEqualTo("Sentence with bad font-size value.");
+    assertThat((Spanned) secondCue.text).hasNoSpans();
+
+    assertThat(allCues.get(5).startTimeUs).isEqualTo(6_500_000L);
+    assertThat(allCues.get(5).durationUs).isEqualTo(8_000_000L - 6_500_000L);
+    Cue sixthCue = Iterables.getOnlyElement(allCues.get(5).cues);
+    assertThat(sixthCue.text.toString())
+        .isEqualTo("Upper and lower case letters in font-size unit.");
+    assertThat((Spanned) sixthCue.text)
+        .hasAbsoluteSizeSpanBetween(0, "Upper and lower case letters in font-size unit.".length())
+        .withAbsoluteSize(2);
+  }
+
+  @Test
+  public void webvttWithCssStyle() throws Exception {
+    List<CuesWithTiming> allCues = getCuesForTestAsset(WITH_CSS_STYLES);
+
+    Spanned firstCueText = getUniqueSpanTextAt(allCues.get(0));
+    assertThat(firstCueText.toString()).isEqualTo("This is the first subtitle.");
+    assertThat(firstCueText)
+        .hasForegroundColorSpanBetween(0, firstCueText.length())
+        .withColor(ColorParser.parseCssColor("papayawhip"));
+    assertThat(firstCueText)
+        .hasBackgroundColorSpanBetween(0, firstCueText.length())
+        .withColor(ColorParser.parseCssColor("green"));
+
+    Spanned secondCueText = getUniqueSpanTextAt(allCues.get(1));
+    assertThat(secondCueText.toString()).isEqualTo("This is the second subtitle.");
+    assertThat(secondCueText)
+        .hasForegroundColorSpanBetween(0, secondCueText.length())
+        .withColor(ColorParser.parseCssColor("peachpuff"));
+
+    Spanned thirdCueText = getUniqueSpanTextAt(allCues.get(2));
+    assertThat(thirdCueText.toString()).isEqualTo("This is a reference by element");
+    assertThat(thirdCueText).hasUnderlineSpanBetween("This is a ".length(), thirdCueText.length());
+
+    Spanned fourthCueText = getUniqueSpanTextAt(allCues.get(3));
+    assertThat(fourthCueText.toString()).isEqualTo("You are an idiot\nYou don't have the guts");
+    assertThat(fourthCueText)
+        .hasBackgroundColorSpanBetween(0, "You are an idiot".length())
+        .withColor(ColorParser.parseCssColor("lime"));
+    assertThat(fourthCueText)
+        .hasBoldSpanBetween("You are an idiot\n".length(), fourthCueText.length());
+  }
+
+  @Test
+  public void withComplexCssSelectors() throws Exception {
+    List<CuesWithTiming> allCues = getCuesForTestAsset(WITH_CSS_COMPLEX_SELECTORS);
+    Spanned firstCueText = getUniqueSpanTextAt(allCues.get(0));
+    assertThat(firstCueText).hasUnderlineSpanBetween(0, firstCueText.length());
+    assertThat(firstCueText)
+        .hasForegroundColorSpanBetween(
+            "This should be underlined and ".length(), firstCueText.length())
+        .withColor(ColorParser.parseCssColor("violet"));
+    assertThat(firstCueText)
+        .hasTypefaceSpanBetween("This should be underlined and ".length(), firstCueText.length())
+        .withFamily("courier");
+
+    Spanned secondCueText = getUniqueSpanTextAt(allCues.get(1));
+    assertThat(secondCueText)
+        .hasTypefaceSpanBetween("This ".length(), secondCueText.length())
+        .withFamily("courier");
+    assertThat(secondCueText)
+        .hasNoForegroundColorSpanBetween("This ".length(), secondCueText.length());
+
+    Spanned thirdCueText = getUniqueSpanTextAt(allCues.get(2));
+    assertThat(thirdCueText).hasBoldSpanBetween("This ".length(), thirdCueText.length());
+    assertThat(thirdCueText)
+        .hasTypefaceSpanBetween("This ".length(), thirdCueText.length())
+        .withFamily("courier");
+
+    Spanned fourthCueText = getUniqueSpanTextAt(allCues.get(3));
+    assertThat(fourthCueText)
+        .hasNoStyleSpanBetween("This ".length(), "shouldn't be bold.".length());
+    assertThat(fourthCueText)
+        .hasBoldSpanBetween("This shouldn't be bold.\nThis ".length(), fourthCueText.length());
+
+    Spanned fifthCueText = getUniqueSpanTextAt(allCues.get(4));
+    assertThat(fifthCueText)
+        .hasNoStyleSpanBetween("This is ".length(), "This is specific".length());
+    assertThat(fifthCueText)
+        .hasItalicSpanBetween("This is specific\n".length(), fifthCueText.length());
+  }
+
+  @Test
+  public void webvttWithCssTextCombineUpright() throws Exception {
+    List<CuesWithTiming> allCues = getCuesForTestAsset(WITH_CSS_TEXT_COMBINE_UPRIGHT);
+
+    Spanned firstCueText = getUniqueSpanTextAt(allCues.get(0));
+    assertThat(firstCueText)
+        .hasHorizontalTextInVerticalContextSpanBetween("Combine ".length(), "Combine all".length());
+
+    Spanned secondCueText = getUniqueSpanTextAt(allCues.get(1));
+    assertThat(secondCueText)
+        .hasHorizontalTextInVerticalContextSpanBetween(
+            "Combine ".length(), "Combine 0004".length());
+  }
+
+  private List<CuesWithTiming> getCuesForTestAsset(String asset) throws IOException {
+    WebvttParser parser = new WebvttParser();
+    byte[] bytes = TestUtil.getByteArray(ApplicationProvider.getApplicationContext(), asset);
+    return parser.parse(bytes);
+  }
+
+  private Spanned getUniqueSpanTextAt(CuesWithTiming cuesWithTiming) {
+    return (Spanned) Assertions.checkNotNull(cuesWithTiming.cues.get(0).text);
+  }
+}