1 files changed, 140 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/ts/TsBinarySearchSeeker.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/ts/TsBinarySearchSeeker.java
new file mode 100644
index 0000000000..136691bdaf
--- /dev/null
+++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/ts/TsBinarySearchSeeker.java
@@ -0,0 +1,140 @@
+/*
+ * Copyright (C) 2018 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.extractor.ts;
+
+import org.mozilla.thirdparty.com.google.android.exoplayer2.C;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.BinarySearchSeeker;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.ExtractorInput;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableByteArray;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.util.TimestampAdjuster;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Util;
+import java.io.IOException;
+
+/**
+ * A seeker that supports seeking within TS stream using binary search.
+ *
+ * <p>This seeker uses the first and last PCR values within the stream, as well as the stream
+ * duration to interpolate the PCR value of the seeking position. Then it performs binary search
+ * within the stream to find a packets whose PCR value is within {@link #SEEK_TOLERANCE_US} from the
+ * target PCR.
+ */
+/* package */ final class TsBinarySearchSeeker extends BinarySearchSeeker {
+
+  private static final long SEEK_TOLERANCE_US = 100_000;
+  private static final int MINIMUM_SEARCH_RANGE_BYTES = 5 * TsExtractor.TS_PACKET_SIZE;
+  private static final int TIMESTAMP_SEARCH_BYTES = 600 * TsExtractor.TS_PACKET_SIZE;
+
+  public TsBinarySearchSeeker(
+      TimestampAdjuster pcrTimestampAdjuster, long streamDurationUs, long inputLength, int pcrPid) {
+    super(
+        new DefaultSeekTimestampConverter(),
+        new TsPcrSeeker(pcrPid, pcrTimestampAdjuster),
+        streamDurationUs,
+        /* floorTimePosition= */ 0,
+        /* ceilingTimePosition= */ streamDurationUs + 1,
+        /* floorBytePosition= */ 0,
+        /* ceilingBytePosition= */ inputLength,
+        /* approxBytesPerFrame= */ TsExtractor.TS_PACKET_SIZE,
+        MINIMUM_SEARCH_RANGE_BYTES);
+  }
+
+  /**
+   * A {@link TimestampSeeker} implementation that looks for a given PCR timestamp at a given
+   * position in a TS stream.
+   *
+   * <p>Given a PCR timestamp, and a position within a TS stream, this seeker will peek up to {@link
+   * #TIMESTAMP_SEARCH_BYTES} from that stream position, look for all packets with PID equal to
+   * PCR_PID, and then compare the PCR timestamps (if available) of these packets to the target
+   * timestamp.
+   */
+  private static final class TsPcrSeeker implements TimestampSeeker {
+
+    private final TimestampAdjuster pcrTimestampAdjuster;
+    private final ParsableByteArray packetBuffer;
+    private final int pcrPid;
+
+    public TsPcrSeeker(int pcrPid, TimestampAdjuster pcrTimestampAdjuster) {
+      this.pcrPid = pcrPid;
+      this.pcrTimestampAdjuster = pcrTimestampAdjuster;
+      packetBuffer = new ParsableByteArray();
+    }
+
+    @Override
+    public TimestampSearchResult searchForTimestamp(ExtractorInput input, long targetTimestamp)
+        throws IOException, InterruptedException {
+      long inputPosition = input.getPosition();
+      int bytesToSearch = (int) Math.min(TIMESTAMP_SEARCH_BYTES, input.getLength() - inputPosition);
+
+      packetBuffer.reset(bytesToSearch);
+      input.peekFully(packetBuffer.data, /* offset= */ 0, bytesToSearch);
+
+      return searchForPcrValueInBuffer(packetBuffer, targetTimestamp, inputPosition);
+    }
+
+    private TimestampSearchResult searchForPcrValueInBuffer(
+        ParsableByteArray packetBuffer, long targetPcrTimeUs, long bufferStartOffset) {
+      int limit = packetBuffer.limit();
+
+      long startOfLastPacketPosition = C.POSITION_UNSET;
+      long endOfLastPacketPosition = C.POSITION_UNSET;
+      long lastPcrTimeUsInRange = C.TIME_UNSET;
+
+      while (packetBuffer.bytesLeft() >= TsExtractor.TS_PACKET_SIZE) {
+        int startOfPacket =
+            TsUtil.findSyncBytePosition(packetBuffer.data, packetBuffer.getPosition(), limit);
+        int endOfPacket = startOfPacket + TsExtractor.TS_PACKET_SIZE;
+        if (endOfPacket > limit) {
+          break;
+        }
+        long pcrValue = TsUtil.readPcrFromPacket(packetBuffer, startOfPacket, pcrPid);
+        if (pcrValue != C.TIME_UNSET) {
+          long pcrTimeUs = pcrTimestampAdjuster.adjustTsTimestamp(pcrValue);
+          if (pcrTimeUs > targetPcrTimeUs) {
+            if (lastPcrTimeUsInRange == C.TIME_UNSET) {
+              // First PCR timestamp is already over target.
+              return TimestampSearchResult.overestimatedResult(pcrTimeUs, bufferStartOffset);
+            } else {
+              // Last PCR timestamp < target timestamp < this timestamp.
+              return TimestampSearchResult.targetFoundResult(
+                  bufferStartOffset + startOfLastPacketPosition);
+            }
+          } else if (pcrTimeUs + SEEK_TOLERANCE_US > targetPcrTimeUs) {
+            long startOfPacketInStream = bufferStartOffset + startOfPacket;
+            return TimestampSearchResult.targetFoundResult(startOfPacketInStream);
+          }
+
+          lastPcrTimeUsInRange = pcrTimeUs;
+          startOfLastPacketPosition = startOfPacket;
+        }
+        packetBuffer.setPosition(endOfPacket);
+        endOfLastPacketPosition = endOfPacket;
+      }
+
+      if (lastPcrTimeUsInRange != C.TIME_UNSET) {
+        long endOfLastPacketPositionInStream = bufferStartOffset + endOfLastPacketPosition;
+        return TimestampSearchResult.underestimatedResult(
+            lastPcrTimeUsInRange, endOfLastPacketPositionInStream);
+      } else {
+        return TimestampSearchResult.NO_TIMESTAMP_IN_RANGE_RESULT;
+      }
+    }
+
+    @Override
+    public void onSeekFinished() {
+      packetBuffer.reset(Util.EMPTY_BYTE_ARRAY);
+    }
+  }
+}