1 files changed, 186 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/util/TimestampAdjuster.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/util/TimestampAdjuster.java
new file mode 100644
index 0000000000..e824251282
--- /dev/null
+++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/util/TimestampAdjuster.java
@@ -0,0 +1,186 @@
+/*
+ * 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 org.mozilla.thirdparty.com.google.android.exoplayer2.util;
+
+import org.mozilla.thirdparty.com.google.android.exoplayer2.C;
+
+/**
+ * Offsets timestamps according to an initial sample timestamp offset. MPEG-2 TS timestamps scaling
+ * and adjustment is supported, taking into account timestamp rollover.
+ */
+public final class TimestampAdjuster {
+
+  /**
+   * A special {@code firstSampleTimestampUs} value indicating that presentation timestamps should
+   * not be offset.
+   */
+  public static final long DO_NOT_OFFSET = Long.MAX_VALUE;
+
+  /**
+   * The value one greater than the largest representable (33 bit) MPEG-2 TS 90 kHz clock
+   * presentation timestamp.
+   */
+  private static final long MAX_PTS_PLUS_ONE = 0x200000000L;
+
+  private long firstSampleTimestampUs;
+  private long timestampOffsetUs;
+
+  // Volatile to allow isInitialized to be called on a different thread to adjustSampleTimestamp.
+  private volatile long lastSampleTimestampUs;
+
+  /**
+   * @param firstSampleTimestampUs See {@link #setFirstSampleTimestampUs(long)}.
+   */
+  public TimestampAdjuster(long firstSampleTimestampUs) {
+    lastSampleTimestampUs = C.TIME_UNSET;
+    setFirstSampleTimestampUs(firstSampleTimestampUs);
+  }
+
+  /**
+   * Sets the desired result of the first call to {@link #adjustSampleTimestamp(long)}. Can only be
+   * called before any timestamps have been adjusted.
+   *
+   * @param firstSampleTimestampUs The first adjusted sample timestamp in microseconds, or
+   *     {@link #DO_NOT_OFFSET} if presentation timestamps should not be offset.
+   */
+  public synchronized void setFirstSampleTimestampUs(long firstSampleTimestampUs) {
+    Assertions.checkState(lastSampleTimestampUs == C.TIME_UNSET);
+    this.firstSampleTimestampUs = firstSampleTimestampUs;
+  }
+
+  /** Returns the last value passed to {@link #setFirstSampleTimestampUs(long)}. */
+  public long getFirstSampleTimestampUs() {
+    return firstSampleTimestampUs;
+  }
+
+  /**
+   * Returns the last value obtained from {@link #adjustSampleTimestamp}. If {@link
+   * #adjustSampleTimestamp} has not been called, returns the result of calling {@link
+   * #getFirstSampleTimestampUs()}. If this value is {@link #DO_NOT_OFFSET}, returns {@link
+   * C#TIME_UNSET}.
+   */
+  public long getLastAdjustedTimestampUs() {
+    return lastSampleTimestampUs != C.TIME_UNSET
+        ? (lastSampleTimestampUs + timestampOffsetUs)
+        : firstSampleTimestampUs != DO_NOT_OFFSET ? firstSampleTimestampUs : C.TIME_UNSET;
+  }
+
+  /**
+   * Returns the offset between the input of {@link #adjustSampleTimestamp(long)} and its output.
+   * If {@link #DO_NOT_OFFSET} was provided to the constructor, 0 is returned. If the timestamp
+   * adjuster is yet not initialized, {@link C#TIME_UNSET} is returned.
+   *
+   * @return The offset between {@link #adjustSampleTimestamp(long)}'s input and output.
+   *     {@link C#TIME_UNSET} if the adjuster is not yet initialized and 0 if timestamps should not
+   *     be offset.
+   */
+  public long getTimestampOffsetUs() {
+    return firstSampleTimestampUs == DO_NOT_OFFSET
+        ? 0
+        : lastSampleTimestampUs == C.TIME_UNSET ? C.TIME_UNSET : timestampOffsetUs;
+  }
+
+  /**
+   * Resets the instance to its initial state.
+   */
+  public void reset() {
+    lastSampleTimestampUs = C.TIME_UNSET;
+  }
+
+  /**
+   * Scales and offsets an MPEG-2 TS presentation timestamp considering wraparound.
+   *
+   * @param pts90Khz A 90 kHz clock MPEG-2 TS presentation timestamp.
+   * @return The adjusted timestamp in microseconds.
+   */
+  public long adjustTsTimestamp(long pts90Khz) {
+    if (pts90Khz == C.TIME_UNSET) {
+      return C.TIME_UNSET;
+    }
+    if (lastSampleTimestampUs != C.TIME_UNSET) {
+      // The wrap count for the current PTS may be closestWrapCount or (closestWrapCount - 1),
+      // and we need to snap to the one closest to lastSampleTimestampUs.
+      long lastPts = usToPts(lastSampleTimestampUs);
+      long closestWrapCount = (lastPts + (MAX_PTS_PLUS_ONE / 2)) / MAX_PTS_PLUS_ONE;
+      long ptsWrapBelow = pts90Khz + (MAX_PTS_PLUS_ONE * (closestWrapCount - 1));
+      long ptsWrapAbove = pts90Khz + (MAX_PTS_PLUS_ONE * closestWrapCount);
+      pts90Khz =
+          Math.abs(ptsWrapBelow - lastPts) < Math.abs(ptsWrapAbove - lastPts)
+              ? ptsWrapBelow
+              : ptsWrapAbove;
+    }
+    return adjustSampleTimestamp(ptsToUs(pts90Khz));
+  }
+
+  /**
+   * Offsets a timestamp in microseconds.
+   *
+   * @param timeUs The timestamp to adjust in microseconds.
+   * @return The adjusted timestamp in microseconds.
+   */
+  public long adjustSampleTimestamp(long timeUs) {
+    if (timeUs == C.TIME_UNSET) {
+      return C.TIME_UNSET;
+    }
+    // Record the adjusted PTS to adjust for wraparound next time.
+    if (lastSampleTimestampUs != C.TIME_UNSET) {
+      lastSampleTimestampUs = timeUs;
+    } else {
+      if (firstSampleTimestampUs != DO_NOT_OFFSET) {
+        // Calculate the timestamp offset.
+        timestampOffsetUs = firstSampleTimestampUs - timeUs;
+      }
+      synchronized (this) {
+        lastSampleTimestampUs = timeUs;
+        // Notify threads waiting for this adjuster to be initialized.
+        notifyAll();
+      }
+    }
+    return timeUs + timestampOffsetUs;
+  }
+
+  /**
+   * Blocks the calling thread until this adjuster is initialized.
+   *
+   * @throws InterruptedException If the thread was interrupted.
+   */
+  public synchronized void waitUntilInitialized() throws InterruptedException {
+    while (lastSampleTimestampUs == C.TIME_UNSET) {
+      wait();
+    }
+  }
+
+  /**
+   * Converts a 90 kHz clock timestamp to a timestamp in microseconds.
+   *
+   * @param pts A 90 kHz clock timestamp.
+   * @return The corresponding value in microseconds.
+   */
+  public static long ptsToUs(long pts) {
+    return (pts * C.MICROS_PER_SECOND) / 90000;
+  }
+
+  /**
+   * Converts a timestamp in microseconds to a 90 kHz clock timestamp.
+   *
+   * @param us A value in microseconds.
+   * @return The corresponding value as a 90 kHz clock timestamp.
+   */
+  public static long usToPts(long us) {
+    return (us * 90000) / C.MICROS_PER_SECOND;
+  }
+
+}