diff --git a/library/src/main/java/com/google/android/exoplayer/dash/mpd/SegmentBase.java b/library/src/main/java/com/google/android/exoplayer/dash/mpd/SegmentBase.java
index 91093980c6..2f9cb9052f 100644
--- a/library/src/main/java/com/google/android/exoplayer/dash/mpd/SegmentBase.java
+++ b/library/src/main/java/com/google/android/exoplayer/dash/mpd/SegmentBase.java
@@ -301,7 +301,7 @@ public abstract class SegmentBase {
         return DashSegmentIndex.INDEX_UNBOUNDED;
       } else {
         long durationMs = (duration * 1000) / timescale;
-        return startNumber + (int) (periodDurationMs / durationMs);
+        return startNumber + (int) (periodDurationMs / durationMs) - 1;
       }
     }