diff --git a/library/src/main/java/com/google/android/exoplayer/util/Util.java b/library/src/main/java/com/google/android/exoplayer/util/Util.java
index 95f9576d41..4d51fda9b0 100644
--- a/library/src/main/java/com/google/android/exoplayer/util/Util.java
+++ b/library/src/main/java/com/google/android/exoplayer/util/Util.java
@@ -55,7 +55,7 @@ public final class Util {
       + "([Zz]|((\\+|\\-)(\\d\\d):(\\d\\d)))?");
 
   private static final Pattern XS_DURATION_PATTERN =
-      Pattern.compile("^P(([0-9]*)Y)?(([0-9]*)M)?(([0-9]*)D)?"
+      Pattern.compile("^(-)?P(([0-9]*)Y)?(([0-9]*)M)?(([0-9]*)D)?"
           + "(T(([0-9]*)H)?(([0-9]*)M)?(([0-9.]*)S)?)?$");
 
   private Util() {}
@@ -275,21 +275,23 @@ public final class Util {
   public static long parseXsDuration(String value) {
     Matcher matcher = XS_DURATION_PATTERN.matcher(value);
     if (matcher.matches()) {
+      boolean negated = !TextUtils.isEmpty(matcher.group(1));
       // Durations containing years and months aren't completely defined. We assume there are
       // 30.4368 days in a month, and 365.242 days in a year.
-      String years = matcher.group(2);
+      String years = matcher.group(3);
       double durationSeconds = (years != null) ? Double.parseDouble(years) * 31556908 : 0;
-      String months = matcher.group(4);
+      String months = matcher.group(5);
       durationSeconds += (months != null) ? Double.parseDouble(months) * 2629739 : 0;
-      String days = matcher.group(6);
+      String days = matcher.group(7);
       durationSeconds += (days != null) ? Double.parseDouble(days) * 86400 : 0;
-      String hours = matcher.group(9);
+      String hours = matcher.group(10);
       durationSeconds += (hours != null) ? Double.parseDouble(hours) * 3600 : 0;
-      String minutes = matcher.group(11);
+      String minutes = matcher.group(12);
       durationSeconds += (minutes != null) ? Double.parseDouble(minutes) * 60 : 0;
-      String seconds = matcher.group(13);
+      String seconds = matcher.group(14);
       durationSeconds += (seconds != null) ? Double.parseDouble(seconds) : 0;
-      return (long) (durationSeconds * 1000);
+      long durationMillis = (long) (durationSeconds * 1000);
+      return negated ? -durationMillis : durationMillis;
     } else {
       return (long) (Double.parseDouble(value) * 3600 * 1000);
     }