1 files changed, 241 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/ts/PesReader.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/ts/PesReader.java
new file mode 100644
index 0000000000..86afe22563
--- /dev/null
+++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/ts/PesReader.java
@@ -0,0 +1,241 @@
+/*
+ * 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.extractor.ts;
+
+import org.mozilla.thirdparty.com.google.android.exoplayer2.C;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.ParserException;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.ExtractorOutput;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Log;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableBitArray;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableByteArray;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.util.TimestampAdjuster;
+
+/**
+ * Parses PES packet data and extracts samples.
+ */
+public final class PesReader implements TsPayloadReader {
+
+  private static final String TAG = "PesReader";
+
+  private static final int STATE_FINDING_HEADER = 0;
+  private static final int STATE_READING_HEADER = 1;
+  private static final int STATE_READING_HEADER_EXTENSION = 2;
+  private static final int STATE_READING_BODY = 3;
+
+  private static final int HEADER_SIZE = 9;
+  private static final int MAX_HEADER_EXTENSION_SIZE = 10;
+  private static final int PES_SCRATCH_SIZE = 10; // max(HEADER_SIZE, MAX_HEADER_EXTENSION_SIZE)
+
+  private final ElementaryStreamReader reader;
+  private final ParsableBitArray pesScratch;
+
+  private int state;
+  private int bytesRead;
+
+  private TimestampAdjuster timestampAdjuster;
+  private boolean ptsFlag;
+  private boolean dtsFlag;
+  private boolean seenFirstDts;
+  private int extendedHeaderLength;
+  private int payloadSize;
+  private boolean dataAlignmentIndicator;
+  private long timeUs;
+
+  public PesReader(ElementaryStreamReader reader) {
+    this.reader = reader;
+    pesScratch = new ParsableBitArray(new byte[PES_SCRATCH_SIZE]);
+    state = STATE_FINDING_HEADER;
+  }
+
+  @Override
+  public void init(TimestampAdjuster timestampAdjuster, ExtractorOutput extractorOutput,
+      TrackIdGenerator idGenerator) {
+    this.timestampAdjuster = timestampAdjuster;
+    reader.createTracks(extractorOutput, idGenerator);
+  }
+
+  // TsPayloadReader implementation.
+
+  @Override
+  public final void seek() {
+    state = STATE_FINDING_HEADER;
+    bytesRead = 0;
+    seenFirstDts = false;
+    reader.seek();
+  }
+
+  @Override
+  public final void consume(ParsableByteArray data, @Flags int flags) throws ParserException {
+    if ((flags & FLAG_PAYLOAD_UNIT_START_INDICATOR) != 0) {
+      switch (state) {
+        case STATE_FINDING_HEADER:
+        case STATE_READING_HEADER:
+          // Expected.
+          break;
+        case STATE_READING_HEADER_EXTENSION:
+          Log.w(TAG, "Unexpected start indicator reading extended header");
+          break;
+        case STATE_READING_BODY:
+          // If payloadSize == -1 then the length of the previous packet was unspecified, and so
+          // we only know that it's finished now that we've seen the start of the next one. This
+          // is expected. If payloadSize != -1, then the length of the previous packet was known,
+          // but we didn't receive that amount of data. This is not expected.
+          if (payloadSize != -1) {
+            Log.w(TAG, "Unexpected start indicator: expected " + payloadSize + " more bytes");
+          }
+          // Either way, notify the reader that it has now finished.
+          reader.packetFinished();
+          break;
+        default:
+          throw new IllegalStateException();
+      }
+      setState(STATE_READING_HEADER);
+    }
+
+    while (data.bytesLeft() > 0) {
+      switch (state) {
+        case STATE_FINDING_HEADER:
+          data.skipBytes(data.bytesLeft());
+          break;
+        case STATE_READING_HEADER:
+          if (continueRead(data, pesScratch.data, HEADER_SIZE)) {
+            setState(parseHeader() ? STATE_READING_HEADER_EXTENSION : STATE_FINDING_HEADER);
+          }
+          break;
+        case STATE_READING_HEADER_EXTENSION:
+          int readLength = Math.min(MAX_HEADER_EXTENSION_SIZE, extendedHeaderLength);
+          // Read as much of the extended header as we're interested in, and skip the rest.
+          if (continueRead(data, pesScratch.data, readLength)
+              && continueRead(data, null, extendedHeaderLength)) {
+            parseHeaderExtension();
+            flags |= dataAlignmentIndicator ? FLAG_DATA_ALIGNMENT_INDICATOR : 0;
+            reader.packetStarted(timeUs, flags);
+            setState(STATE_READING_BODY);
+          }
+          break;
+        case STATE_READING_BODY:
+          readLength = data.bytesLeft();
+          int padding = payloadSize == -1 ? 0 : readLength - payloadSize;
+          if (padding > 0) {
+            readLength -= padding;
+            data.setLimit(data.getPosition() + readLength);
+          }
+          reader.consume(data);
+          if (payloadSize != -1) {
+            payloadSize -= readLength;
+            if (payloadSize == 0) {
+              reader.packetFinished();
+              setState(STATE_READING_HEADER);
+            }
+          }
+          break;
+        default:
+          throw new IllegalStateException();
+      }
+    }
+  }
+
+  private void setState(int state) {
+    this.state = state;
+    bytesRead = 0;
+  }
+
+  /**
+   * Continues a read from the provided {@code source} into a given {@code target}. It's assumed
+   * that the data should be written into {@code target} starting from an offset of zero.
+   *
+   * @param source The source from which to read.
+   * @param target The target into which data is to be read, or {@code null} to skip.
+   * @param targetLength The target length of the read.
+   * @return Whether the target length has been reached.
+   */
+  private boolean continueRead(ParsableByteArray source, byte[] target, int targetLength) {
+    int bytesToRead = Math.min(source.bytesLeft(), targetLength - bytesRead);
+    if (bytesToRead <= 0) {
+      return true;
+    } else if (target == null) {
+      source.skipBytes(bytesToRead);
+    } else {
+      source.readBytes(target, bytesRead, bytesToRead);
+    }
+    bytesRead += bytesToRead;
+    return bytesRead == targetLength;
+  }
+
+  private boolean parseHeader() {
+    // Note: see ISO/IEC 13818-1, section 2.4.3.6 for detailed information on the format of
+    // the header.
+    pesScratch.setPosition(0);
+    int startCodePrefix = pesScratch.readBits(24);
+    if (startCodePrefix != 0x000001) {
+      Log.w(TAG, "Unexpected start code prefix: " + startCodePrefix);
+      payloadSize = -1;
+      return false;
+    }
+
+    pesScratch.skipBits(8); // stream_id.
+    int packetLength = pesScratch.readBits(16);
+    pesScratch.skipBits(5); // '10' (2), PES_scrambling_control (2), PES_priority (1)
+    dataAlignmentIndicator = pesScratch.readBit();
+    pesScratch.skipBits(2); // copyright (1), original_or_copy (1)
+    ptsFlag = pesScratch.readBit();
+    dtsFlag = pesScratch.readBit();
+    // ESCR_flag (1), ES_rate_flag (1), DSM_trick_mode_flag (1),
+    // additional_copy_info_flag (1), PES_CRC_flag (1), PES_extension_flag (1)
+    pesScratch.skipBits(6);
+    extendedHeaderLength = pesScratch.readBits(8);
+
+    if (packetLength == 0) {
+      payloadSize = -1;
+    } else {
+      payloadSize = packetLength + 6 /* packetLength does not include the first 6 bytes */
+          - HEADER_SIZE - extendedHeaderLength;
+    }
+    return true;
+  }
+
+  private void parseHeaderExtension() {
+    pesScratch.setPosition(0);
+    timeUs = C.TIME_UNSET;
+    if (ptsFlag) {
+      pesScratch.skipBits(4); // '0010' or '0011'
+      long pts = (long) pesScratch.readBits(3) << 30;
+      pesScratch.skipBits(1); // marker_bit
+      pts |= pesScratch.readBits(15) << 15;
+      pesScratch.skipBits(1); // marker_bit
+      pts |= pesScratch.readBits(15);
+      pesScratch.skipBits(1); // marker_bit
+      if (!seenFirstDts && dtsFlag) {
+        pesScratch.skipBits(4); // '0011'
+        long dts = (long) pesScratch.readBits(3) << 30;
+        pesScratch.skipBits(1); // marker_bit
+        dts |= pesScratch.readBits(15) << 15;
+        pesScratch.skipBits(1); // marker_bit
+        dts |= pesScratch.readBits(15);
+        pesScratch.skipBits(1); // marker_bit
+        // Subsequent PES packets may have earlier presentation timestamps than this one, but they
+        // should all be greater than or equal to this packet's decode timestamp. We feed the
+        // decode timestamp to the adjuster here so that in the case that this is the first to be
+        // fed, the adjuster will be able to compute an offset to apply such that the adjusted
+        // presentation timestamps of all future packets are non-negative.
+        timestampAdjuster.adjustTsTimestamp(dts);
+        seenFirstDts = true;
+      }
+      timeUs = timestampAdjuster.adjustTsTimestamp(pts);
+    }
+  }
+
+}