Support MKV embedded SubRip captions.

library/src/androidTest/assets/subrip/no_end_timecodes

+1
+00:00:00,000 -->
+SubRip doesn't technically allow missing end timecodes.
+
+2
+00:00:02,345 -->
+We interpret it to mean that a subtitle extends to the start of the next one.
+
+3
+00:00:03,456 -->
+Or to the end of the media.
\ No newline at end of file

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

@@ -25,13 +25,14 @@ import java.io.InputStream;
  */
 public final class SubripParserTest extends InstrumentationTestCase {
 
-  private static final String TYPICAL_SUBRIP_FILE = "subrip/typical";
-  private static final String EMPTY_SUBRIP_FILE = "subrip/empty";
+  private static final String EMPTY_FILE = "subrip/empty";
+  private static final String TYPICAL_FILE = "subrip/typical";
+  private static final String NO_END_TIMECODES_FILE = "subrip/no_end_timecodes";
 
-  public void testParseNullSubripFile() throws IOException {
+  public void testParseEmptySubripFile() throws IOException {
     SubripParser parser = new SubripParser();
     InputStream inputStream =
-        getInstrumentation().getContext().getResources().getAssets().open(EMPTY_SUBRIP_FILE);
+        getInstrumentation().getContext().getResources().getAssets().open(EMPTY_FILE);
     SubripSubtitle subtitle = parser.parse(inputStream);
     // Assert that the subtitle is empty.
     assertEquals(0, subtitle.getEventTimeCount());
@@ -41,7 +42,7 @@ public final class SubripParserTest extends InstrumentationTestCase {
   public void testParseTypicalSubripFile() throws IOException {
     SubripParser parser = new SubripParser();
     InputStream inputStream =
-        getInstrumentation().getContext().getResources().getAssets().open(TYPICAL_SUBRIP_FILE);
+        getInstrumentation().getContext().getResources().getAssets().open(TYPICAL_FILE);
     SubripSubtitle subtitle = parser.parse(inputStream);
 
     // Test event count.
@@ -60,4 +61,29 @@ public final class SubripParserTest extends InstrumentationTestCase {
     assertEquals(3456000, subtitle.getEventTime(3));
   }
 
+  public void testParseNoEndTimecodes() throws IOException {
+    SubripParser parser = new SubripParser();
+    InputStream inputStream = getInstrumentation().getContext().getResources().getAssets()
+        .open(NO_END_TIMECODES_FILE);
+    SubripSubtitle subtitle = parser.parse(inputStream);
+
+    // Test event count.
+    assertEquals(3, subtitle.getEventTimeCount());
+
+    // Test first cue.
+    assertEquals(0, subtitle.getEventTime(0));
+    assertEquals("SubRip doesn't technically allow missing end timecodes.",
+        subtitle.getCues(subtitle.getEventTime(0)).get(0).text.toString());
+
+    // Test second cue.
+    assertEquals(2345000, subtitle.getEventTime(1));
+    assertEquals("We interpret it to mean that a subtitle extends to the start of the next one.",
+        subtitle.getCues(subtitle.getEventTime(1)).get(0).text.toString());
+
+    // Test third cue.
+    assertEquals(3456000, subtitle.getEventTime(2));
+    assertEquals("Or to the end of the media.",
+        subtitle.getCues(subtitle.getEventTime(2)).get(0).text.toString());
+  }
+
 }

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

@@ -39,7 +39,7 @@ import java.util.regex.Pattern;
  */
 public final class SubripParser implements SubtitleParser {
 
-  private static final Pattern SUBRIP_TIMING_LINE = Pattern.compile("(.*)\\s+-->\\s+(.*)");
+  private static final Pattern SUBRIP_TIMING_LINE = Pattern.compile("(\\S*)\\s*-->\\s*(\\S*)");
   private static final Pattern SUBRIP_TIMESTAMP =
       Pattern.compile("(?:(\\d+):)?(\\d+):(\\d+),(\\d+)");
 
@@ -54,6 +54,7 @@ public final class SubripParser implements SubtitleParser {
     ArrayList<Cue> cues = new ArrayList<>();
     LongArray cueTimesUs = new LongArray();
     BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, C.UTF8_NAME));
+    boolean haveEndTimecode;
     String currentLine;
 
     while ((currentLine = reader.readLine()) != null) {
@@ -65,11 +66,16 @@ public final class SubripParser implements SubtitleParser {
       }
 
       // Read and parse the timing line.
+      haveEndTimecode = false;
       currentLine = reader.readLine();
       Matcher matcher = SUBRIP_TIMING_LINE.matcher(currentLine);
       if (matcher.find()) {
-        cueTimesUs.add(parseTimestampUs(matcher.group(1)));
-        cueTimesUs.add(parseTimestampUs(matcher.group(2)));
+        cueTimesUs.add(parseTimecode(matcher.group(1)));
+        String endTimecode = matcher.group(2);
+        if (!TextUtils.isEmpty(endTimecode)) {
+          haveEndTimecode = true;
+          cueTimesUs.add(parseTimecode(matcher.group(2)));
+        }
       } else {
         throw new ParserException("Expected timing line: " + currentLine);
       }
@@ -85,6 +91,9 @@ public final class SubripParser implements SubtitleParser {
 
       Spanned text = Html.fromHtml(textBuilder.toString());
       cues.add(new Cue(text));
+      if (haveEndTimecode) {
+        cues.add(null);
+      }
     }
 
     Cue[] cuesArray = new Cue[cues.size()];
@@ -98,7 +107,7 @@ public final class SubripParser implements SubtitleParser {
     return MimeTypes.APPLICATION_SUBRIP.equals(mimeType);
   }
 
-  private static long parseTimestampUs(String s) throws NumberFormatException {
+  private static long parseTimecode(String s) throws NumberFormatException {
     Matcher matcher = SUBRIP_TIMESTAMP.matcher(s);
     if (!matcher.matches()) {
       throw new NumberFormatException("has invalid format");

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

@@ -32,8 +32,8 @@ import java.util.List;
   private final long[] cueTimesUs;
 
   /**
-   * @param cues The cues in the subtitle.
-   * @param cueTimesUs Interleaved cue start and end times, in microseconds.
+   * @param cues The cues in the subtitle. Null entries may be used to represent empty cues.
+   * @param cueTimesUs The cue times, in microseconds.
    */
   public SubripSubtitle(Cue[] cues, long[] cueTimesUs) {
     this.cues = cues;
@@ -69,11 +69,11 @@ import java.util.List;
   @Override
   public List<Cue> getCues(long timeUs) {
     int index = Util.binarySearchFloor(cueTimesUs, timeUs, true, false);
-    if (index == -1 || index % 2 == 1) {
-      // timeUs is earlier than the start of the first cue, or corresponds to a gap between cues.
+    if (index == -1 || cues[index] == null) {
+      // timeUs is earlier than the start of the first cue, or we have an empty cue.
       return Collections.<Cue>emptyList();
     } else {
-      return Collections.singletonList(cues[index / 2]);
+      return Collections.singletonList(cues[index]);
     }
   }