Further cleanup subtitle implementations.

library/src/main/java/com/google/android/exoplayer/C.java

@@ -94,7 +94,7 @@ public final class C {
   /**
    * An element of a custom ExoPlayer WebVTT header. An {@code WEBVTT_OFFSET + value} element can
    * be added to a custom ExoPlayer WebVTT header to specify an offset time (in microseconds) that
-   * should be subtracted from the embedded MPEGTS value.
+   * should be added to the embedded MPEGTS value.
    *
    * @hide
    */

library/src/main/java/com/google/android/exoplayer/chunk/VideoFormatSelectorUtil.java

@@ -132,7 +132,7 @@ public final class VideoFormatSelectorUtil {
       }
     }
 
-    return Util.toIntArray(selectedIndexList);
+    return Util.toArray(selectedIndexList);
   }
 
   /**

library/src/main/java/com/google/android/exoplayer/dash/DashChunkSource.java

@@ -165,8 +165,8 @@ public class DashChunkSource implements ChunkSource {
    *     note that the value sets an upper bound on the length of media that the player can buffer.
    *     Hence a small value may increase the probability of rebuffering and playback failures.
    * @param elapsedRealtimeOffsetMs If known, an estimate of the instantaneous difference between
-   *    server-side unix time and {@link SystemClock#elapsedRealtime()} in milliseconds, specified
-   *    as the server's unix time minus the local elapsed time. It unknown, set to 0.
+   *     server-side unix time and {@link SystemClock#elapsedRealtime()} in milliseconds, specified
+   *     as the server's unix time minus the local elapsed time. It unknown, set to 0.
    */
   public DashChunkSource(ManifestFetcher<MediaPresentationDescription> manifestFetcher,
       int adaptationSetIndex, int[] representationIndices, DataSource dataSource,
@@ -491,23 +491,23 @@ public class DashChunkSource implements ChunkSource {
     DataSpec dataSpec = new DataSpec(segmentUri.getUri(), segmentUri.start, segmentUri.length,
         representation.getCacheKey());
 
-    long presentationTimeOffsetUs = representation.presentationTimeOffsetUs;
+    long sampleOffsetUs = -1 * representation.presentationTimeOffsetUs;
     if (representation.format.mimeType.equals(MimeTypes.TEXT_VTT)) {
-      if (representationHolder.vttHeaderOffsetUs != presentationTimeOffsetUs) {
+      if (representationHolder.vttHeaderOffsetUs != sampleOffsetUs) {
         // Update the VTT header.
         headerBuilder.setLength(0);
         headerBuilder.append(C.WEBVTT_EXO_HEADER).append("=")
-            .append(C.WEBVTT_EXO_HEADER_OFFSET).append(presentationTimeOffsetUs)
+            .append(C.WEBVTT_EXO_HEADER_OFFSET).append(sampleOffsetUs)
             .append("\n");
         representationHolder.vttHeader = headerBuilder.toString().getBytes();
-        representationHolder.vttHeaderOffsetUs = presentationTimeOffsetUs;
+        representationHolder.vttHeaderOffsetUs = sampleOffsetUs;
       }
       return new SingleSampleMediaChunk(dataSource, dataSpec, Chunk.TRIGGER_INITIAL,
           representation.format, startTimeUs, endTimeUs, absoluteSegmentNum, isLastSegment,
           MediaFormat.createTextFormat(MimeTypes.TEXT_VTT), null, representationHolder.vttHeader);
     } else {
       return new ContainerMediaChunk(dataSource, dataSpec, trigger, representation.format,
-          startTimeUs, endTimeUs, absoluteSegmentNum, isLastSegment, 0,
+          startTimeUs, endTimeUs, absoluteSegmentNum, isLastSegment, sampleOffsetUs,
           representationHolder.extractorWrapper, representationHolder.format, drmInitData, true);
     }
   }

library/src/main/java/com/google/android/exoplayer/text/subrip/SubripParser.java

@@ -19,8 +19,8 @@ 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.SubtitleParser;
+import com.google.android.exoplayer.util.LongArray;
 import com.google.android.exoplayer.util.MimeTypes;
-import com.google.android.exoplayer.util.Util;
 
 import android.text.Html;
 import android.text.Spanned;
@@ -36,8 +36,6 @@ import java.util.regex.Pattern;
 
 /**
  * A simple SubRip parser.
- * <p/>
- * @see <a href="https://en.wikipedia.org/wiki/SubRip">Wikipedia on SubRip</a>
  */
 public final class SubripParser implements SubtitleParser {
 
@@ -53,9 +51,9 @@ public final class SubripParser implements SubtitleParser {
 
   @Override
   public SubripSubtitle parse(InputStream inputStream, String inputEncoding, long startTimeUs)
-          throws IOException {
+      throws IOException {
     ArrayList<Cue> cues = new ArrayList<>();
-    ArrayList<Long> cueTimesUs = new ArrayList<>();
+    LongArray cueTimesUs = new LongArray();
     BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, C.UTF8_NAME));
     String currentLine;
 
@@ -90,12 +88,9 @@ public final class SubripParser implements SubtitleParser {
       cues.add(new Cue(text));
     }
 
-    reader.close();
-    inputStream.close();
-
     Cue[] cuesArray = new Cue[cues.size()];
     cues.toArray(cuesArray);
-    long[] cueTimesUsArray = Util.toLongArray(cueTimesUs);
+    long[] cueTimesUsArray = cueTimesUs.toArray();
     return new SubripSubtitle(startTimeUs, cuesArray, cueTimesUsArray);
   }
 

library/src/main/java/com/google/android/exoplayer/text/tx3g/Tx3gParser.java

@@ -35,12 +35,8 @@ public final class Tx3gParser implements SubtitleParser {
   public Subtitle parse(InputStream inputStream, String inputEncoding, long startTimeUs)
       throws IOException {
     DataInputStream dataInputStream  = new DataInputStream(inputStream);
-    try {
-      String cueText = dataInputStream.readUTF();
-      return new Tx3gSubtitle(startTimeUs, new Cue(cueText));
-    } finally {
-      dataInputStream.close();
-    }
+    String cueText = dataInputStream.readUTF();
+    return new Tx3gSubtitle(startTimeUs, new Cue(cueText));
   }
 
   @Override

library/src/main/java/com/google/android/exoplayer/text/webvtt/WebvttParser.java

@@ -59,7 +59,7 @@ public class WebvttParser implements SubtitleParser {
   private static final Pattern WEBVTT_CUE_SETTING = Pattern.compile(WEBVTT_CUE_SETTING_STRING);
 
   private static final Pattern MEDIA_TIMESTAMP_OFFSET =
-      Pattern.compile(C.WEBVTT_EXO_HEADER_OFFSET + "\\d+");
+      Pattern.compile(C.WEBVTT_EXO_HEADER_OFFSET + "\\-?\\d+");
   private static final Pattern MEDIA_TIMESTAMP = Pattern.compile("MPEGTS:\\d+");
 
   private static final String NON_NUMERIC_STRING = ".*[^0-9].*";
@@ -135,7 +135,7 @@ public class WebvttParser implements SubtitleParser {
           throw new ParserException("X-TIMESTAMP-MAP doesn't contain media timestamp: " + line);
         } else {
           mediaTimestampUs = (Long.parseLong(timestampMatcher.group().substring(7)) * 1000)
-              / SAMPLING_RATE - mediaTimestampOffsetUs;
+              / SAMPLING_RATE + mediaTimestampOffsetUs;
         }
         mediaTimestampUs = getAdjustedStartTime(mediaTimestampUs);
       }
@@ -237,10 +237,7 @@ public class WebvttParser implements SubtitleParser {
       subtitles.add(cue);
     }
 
-    webvttData.close();
-    inputStream.close();
-    WebvttSubtitle subtitle = new WebvttSubtitle(subtitles, mediaTimestampUs);
-    return subtitle;
+    return new WebvttSubtitle(subtitles, mediaTimestampUs);
   }
 
   @Override

library/src/main/java/com/google/android/exoplayer/util/LongArray.java

@@ -20,7 +20,7 @@ import java.util.Arrays;
 /**
  * An append-only, auto-growing {@code long[]}.
  */
-public class LongArray {
+public final class LongArray {
 
   private static final int DEFAULT_INITIAL_CAPACITY = 32;
 
@@ -74,4 +74,13 @@ public class LongArray {
     return size;
   }
 
+  /**
+   * Copies the current values into a newly allocated primitive array.
+   *
+   * @return The primitive array containing the copied values.
+   */
+  public long[] toArray() {
+    return Arrays.copyOf(values, size);
+  }
+
 }

library/src/main/java/com/google/android/exoplayer/util/Util.java

@@ -459,7 +459,7 @@ public final class Util {
    * @param list A list of integers.
    * @return The list in array form, or null if the input list was null.
    */
-  public static int[] toIntArray(List<Integer> list) {
+  public static int[] toArray(List<Integer> list) {
     if (list == null) {
       return null;
     }
@@ -471,24 +471,6 @@ public final class Util {
     return intArray;
   }
 
-  /**
-   * Converts a list of longs to a primitive array.
-   *
-   * @param list A list of longs.
-   * @return The list in array form, or null if the input list was null.
-   */
-  public static long[] toLongArray(List<Long> list) {
-    if (list == null) {
-      return null;
-    }
-    int length = list.size();
-    long[] longArray = new long[length];
-    for (int i = 0; i < length; i++) {
-      longArray[i] = list.get(i);
-    }
-    return longArray;
-  }
-
   /**
    * On platform API levels 19 and 20, okhttp's implementation of {@link InputStream#close} can
    * block for a long time if the stream has a lot of data remaining. Call this method before

library/src/test/assets/webvtt/live_typical

@@ -0,0 +1,9 @@
+EXO-HEADER=OFFSET:-5000000
+WEBVTT
+X-TIMESTAMP-MAP=LOCAL:00:00.000,MPEGTS:450000
+
+00:00.000 --> 00:01.234
+This is the first subtitle.
+
+00:02.345 --> 00:03.456
+This is the second subtitle.

library/src/test/java/com/google/android/exoplayer/text/subrip/SubripParserTest.java

@@ -25,7 +25,7 @@ import java.io.InputStream;
 /**
  * Unit test for {@link SubripParser}.
  */
-public class SubripParserTest extends InstrumentationTestCase {
+public final class SubripParserTest extends InstrumentationTestCase {
 
   private static final String TYPICAL_SUBRIP_FILE = "subrip/typical";
   private static final String EMPTY_SUBRIP_FILE = "subrip/empty";

library/src/test/java/com/google/android/exoplayer/text/webvtt/WebvttParserTest.java

@@ -30,6 +30,7 @@ public class WebvttParserTest extends InstrumentationTestCase {
   private static final String TYPICAL_WEBVTT_FILE = "webvtt/typical";
   private static final String TYPICAL_WITH_IDS_WEBVTT_FILE = "webvtt/typical_with_identifiers";
   private static final String TYPICAL_WITH_TAGS_WEBVTT_FILE = "webvtt/typical_with_tags";
+  private static final String LIVE_TYPICAL_WEBVTT_FILE = "webvtt/live_typical";
   private static final String EMPTY_WEBVTT_FILE = "webvtt/empty";
 
   public void testParseNullWebvttFile() throws IOException {
@@ -131,4 +132,28 @@ public class WebvttParserTest extends InstrumentationTestCase {
     assertEquals(startTimeUs + 7000000, subtitle.getEventTime(7));
   }
 
+  public void testParseLiveTypicalWebvttFile() throws IOException {
+    WebvttParser parser = new WebvttParser();
+    InputStream inputStream =
+        getInstrumentation().getContext().getResources().getAssets().open(LIVE_TYPICAL_WEBVTT_FILE);
+    WebvttSubtitle subtitle = parser.parse(inputStream, C.UTF8_NAME, 0);
+
+    // test start time and event count
+    long startTimeUs = 0;
+    assertEquals(startTimeUs, subtitle.getStartTime());
+    assertEquals(4, subtitle.getEventTimeCount());
+
+    // test first cue
+    assertEquals(startTimeUs, subtitle.getEventTime(0));
+    assertEquals("This is the first subtitle.",
+        subtitle.getCues(subtitle.getEventTime(0)).get(0).text.toString());
+    assertEquals(startTimeUs + 1234000, subtitle.getEventTime(1));
+
+    // test second cue
+    assertEquals(startTimeUs + 2345000, subtitle.getEventTime(2));
+    assertEquals("This is the second subtitle.",
+        subtitle.getCues(subtitle.getEventTime(2)).get(0).text.toString());
+    assertEquals(startTimeUs + 3456000, subtitle.getEventTime(3));
+  }
+
 }