Java ExtractorInput.resetPeekPosition方法代码示例

import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
/**
 * Does a byte by byte search to try and find the next level 1 element. This method is called if
 * some invalid data is encountered in the parser.
 *
 * @param input The {@link ExtractorInput} from which data has to be read.
 * @return id of the next level 1 element that has been found.
 * @throws EOFException If the end of input was encountered when searching for the next level 1
 *     element.
 * @throws IOException If an error occurs reading from the input.
 * @throws InterruptedException If the thread is interrupted.
 */
private long maybeResyncToNextLevel1Element(ExtractorInput input) throws IOException,
    InterruptedException {
  input.resetPeekPosition();
  while (true) {
    input.peekFully(scratch, 0, MAX_ID_BYTES);
    int varintLength = VarintReader.parseUnsignedVarintLength(scratch[0]);
    if (varintLength != C.LENGTH_UNSET && varintLength <= MAX_ID_BYTES) {
      int potentialId = (int) VarintReader.assembleVarint(scratch, varintLength, false);
      if (output.isLevel1Element(potentialId)) {
        input.skipFully(varintLength);
        return potentialId;
      }
    }
    input.skipFully(1);
  }
}
 

import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
/**
 * Skips to the data in the given WAV input stream and returns its data size. After calling, the
 * input stream's position will point to the start of sample data in the WAV.
 * <p>
 * If an exception is thrown, the input position will be left pointing to a chunk header.
 *
 * @param input Input stream to skip to the data chunk in. Its peek position must be pointing to
 *     a valid chunk header.
 * @param wavHeader WAV header to populate with data bounds.
 * @throws ParserException If an error occurs parsing chunks.
 * @throws IOException If reading from the input fails.
 * @throws InterruptedException If interrupted while reading from input.
 */
public static void skipToData(ExtractorInput input, WavHeader wavHeader)
    throws IOException, InterruptedException {
  Assertions.checkNotNull(input);
  Assertions.checkNotNull(wavHeader);

  // Make sure the peek position is set to the read position before we peek the first header.
  input.resetPeekPosition();

  ParsableByteArray scratch = new ParsableByteArray(ChunkHeader.SIZE_IN_BYTES);
  // Skip all chunks until we hit the data header.
  ChunkHeader chunkHeader = ChunkHeader.peek(input, scratch);
  while (chunkHeader.id != Util.getIntegerCodeForString("data")) {
    Log.w(TAG, "Ignoring unknown WAV chunk: " + chunkHeader.id);
    long bytesToSkip = ChunkHeader.SIZE_IN_BYTES + chunkHeader.size;
    // Override size of RIFF chunk, since it describes its size as the entire file.
    if (chunkHeader.id == Util.getIntegerCodeForString("RIFF")) {
      bytesToSkip = ChunkHeader.SIZE_IN_BYTES + 4;
    }
    if (bytesToSkip > Integer.MAX_VALUE) {
      throw new ParserException("Chunk is too large (~2GB+) to skip; id: " + chunkHeader.id);
    }
    input.skipFully((int) bytesToSkip);
    chunkHeader = ChunkHeader.peek(input, scratch);
  }
  // Skip past the "data" header.
  input.skipFully(ChunkHeader.SIZE_IN_BYTES);

  wavHeader.setDataBounds(input.getPosition(), chunkHeader.size);
}
 

import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
/**
 * Skips to the position of the start of the page containing the {@code targetGranule} and
 * returns the granule of the page previous to the target page.
 *
 * @param input the {@link ExtractorInput} to read from.
 * @param targetGranule the target granule.
 * @param currentGranule the current granule or -1 if it's unknown.
 * @return the granule of the prior page or the {@code currentGranule} if there isn't a prior
 *     page.
 * @throws ParserException thrown if populating the page header fails.
 * @throws IOException thrown if reading from the input fails.
 * @throws InterruptedException thrown if interrupted while reading from the input.
 */
//@VisibleForTesting
long skipToPageOfGranule(ExtractorInput input, long targetGranule, long currentGranule)
    throws IOException, InterruptedException {
  pageHeader.populate(input, false);
  while (pageHeader.granulePosition < targetGranule) {
    input.skipFully(pageHeader.headerSize + pageHeader.bodySize);
    // Store in a member field to be able to resume after IOExceptions.
    currentGranule = pageHeader.granulePosition;
    // Peek next header.
    pageHeader.populate(input, false);
  }
  input.resetPeekPosition();
  return currentGranule;
}
 

import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
@Override
public boolean sniff(ExtractorInput input) throws IOException, InterruptedException {
  // Check if file starts with "FLV" tag
  input.peekFully(scratch.data, 0, 3);
  scratch.setPosition(0);
  if (scratch.readUnsignedInt24() != FLV_TAG) {
    return false;
  }

  // Checking reserved flags are set to 0
  input.peekFully(scratch.data, 0, 2);
  scratch.setPosition(0);
  if ((scratch.readUnsignedShort() & 0xFA) != 0) {
    return false;
  }

  // Read data offset
  input.peekFully(scratch.data, 0, 4);
  scratch.setPosition(0);
  int dataOffset = scratch.readInt();

  input.resetPeekPosition();
  input.advancePeekPosition(dataOffset);

  // Checking first "previous tag size" is set to 0
  input.peekFully(scratch.data, 0, 4);
  scratch.setPosition(0);

  return scratch.readInt() == 0;
}
 

import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
private int readSample(ExtractorInput extractorInput) throws IOException, InterruptedException {
  if (sampleBytesRemaining == 0) {
    extractorInput.resetPeekPosition();
    if (!extractorInput.peekFully(scratch.data, 0, 4, true)) {
      return RESULT_END_OF_INPUT;
    }
    scratch.setPosition(0);
    int sampleHeaderData = scratch.readInt();
    if ((sampleHeaderData & HEADER_MASK) != (synchronizedHeaderData & HEADER_MASK)
        || MpegAudioHeader.getFrameSize(sampleHeaderData) == C.LENGTH_UNSET) {
      // We have lost synchronization, so attempt to resynchronize starting at the next byte.
      extractorInput.skipFully(1);
      synchronizedHeaderData = 0;
      return RESULT_CONTINUE;
    }
    MpegAudioHeader.populateHeader(sampleHeaderData, synchronizedHeader);
    if (basisTimeUs == C.TIME_UNSET) {
      basisTimeUs = seeker.getTimeUs(extractorInput.getPosition());
      if (forcedFirstSampleTimestampUs != C.TIME_UNSET) {
        long embeddedFirstSampleTimestampUs = seeker.getTimeUs(0);
        basisTimeUs += forcedFirstSampleTimestampUs - embeddedFirstSampleTimestampUs;
      }
    }
    sampleBytesRemaining = synchronizedHeader.frameSize;
  }
  int bytesAppended = trackOutput.sampleData(extractorInput, sampleBytesRemaining, true);
  if (bytesAppended == C.RESULT_END_OF_INPUT) {
    return RESULT_END_OF_INPUT;
  }
  sampleBytesRemaining -= bytesAppended;
  if (sampleBytesRemaining > 0) {
    return RESULT_CONTINUE;
  }
  long timeUs = basisTimeUs + (samplesRead * C.MICROS_PER_SECOND / synchronizedHeader.sampleRate);
  trackOutput.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, synchronizedHeader.frameSize, 0,
      null);
  samplesRead += synchronizedHeader.samplesPerFrame;
  sampleBytesRemaining = 0;
  return RESULT_CONTINUE;
}
 

import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
/**
 * Peeks ID3 data from the input, including gapless playback information.
 *
 * @param input The {@link ExtractorInput} from which data should be peeked.
 * @throws IOException If an error occurred peeking from the input.
 * @throws InterruptedException If the thread was interrupted.
 */
private void peekId3Data(ExtractorInput input) throws IOException, InterruptedException {
  int peekedId3Bytes = 0;
  while (true) {
    input.peekFully(scratch.data, 0, Id3Decoder.ID3_HEADER_LENGTH);
    scratch.setPosition(0);
    if (scratch.readUnsignedInt24() != Id3Decoder.ID3_TAG) {
      // Not an ID3 tag.
      break;
    }
    scratch.skipBytes(3); // Skip major version, minor version and flags.
    int framesLength = scratch.readSynchSafeInt();
    int tagLength = Id3Decoder.ID3_HEADER_LENGTH + framesLength;

    if (metadata == null) {
      byte[] id3Data = new byte[tagLength];
      System.arraycopy(scratch.data, 0, id3Data, 0, Id3Decoder.ID3_HEADER_LENGTH);
      input.peekFully(id3Data, Id3Decoder.ID3_HEADER_LENGTH, framesLength);
      // We need to parse enough ID3 metadata to retrieve any gapless playback information even
      // if ID3 metadata parsing is disabled.
      Id3Decoder.FramePredicate id3FramePredicate = (flags & FLAG_DISABLE_ID3_METADATA) != 0
          ? GaplessInfoHolder.GAPLESS_INFO_ID3_FRAME_PREDICATE : null;
      metadata = new Id3Decoder(id3FramePredicate).decode(id3Data, tagLength);
      if (metadata != null) {
        gaplessInfoHolder.setFromMetadata(metadata);
      }
    } else {
      input.advancePeekPosition(framesLength);
    }

    peekedId3Bytes += tagLength;
  }

  input.resetPeekPosition();
  input.advancePeekPosition(peekedId3Bytes);
}
 

import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
private void skipToPageOfGranule(ExtractorInput input, long granule,
    long elapsedSamplesExpected) throws IOException, InterruptedException {
  DefaultOggSeeker oggSeeker = new DefaultOggSeeker(0, input.getLength(), new FlacReader());
  while (true) {
    try {
      assertEquals(elapsedSamplesExpected, oggSeeker.skipToPageOfGranule(input, granule, -1));
      return;
    } catch (FakeExtractorInput.SimulatedIOException e) {
      input.resetPeekPosition();
    }
  }
}
 

import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
/**
 * Peeks data from the input and parses ID3 metadata.
 *
 * @param input The {@link ExtractorInput} from which data should be peeked.
 * @param out The {@link GaplessInfoHolder} to populate.
 * @throws IOException If an error occurred peeking from the input.
 * @throws InterruptedException If the thread was interrupted.
 */
public static void parseId3(ExtractorInput input, GaplessInfoHolder out)
    throws IOException, InterruptedException {
  ParsableByteArray scratch = new ParsableByteArray(10);
  int peekedId3Bytes = 0;
  while (true) {
    input.peekFully(scratch.data, 0, 10);
    scratch.setPosition(0);
    if (scratch.readUnsignedInt24() != ID3_TAG) {
      break;
    }

    int majorVersion = scratch.readUnsignedByte();
    int minorVersion = scratch.readUnsignedByte();
    int flags = scratch.readUnsignedByte();
    int length = scratch.readSynchSafeInt();
    if (!out.hasGaplessInfo() && canParseMetadata(majorVersion, minorVersion, flags, length)) {
      byte[] frame = new byte[length];
      input.peekFully(frame, 0, length);
      parseGaplessInfo(new ParsableByteArray(frame), majorVersion, flags, out);
    } else {
      input.advancePeekPosition(length);
    }

    peekedId3Bytes += 10 + length;
  }
  input.resetPeekPosition();
  input.advancePeekPosition(peekedId3Bytes);
}
 

import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
@Override
public boolean sniff(ExtractorInput input) throws IOException, InterruptedException {
  // Skip any ID3 headers.
  ParsableByteArray scratch = new ParsableByteArray(10);
  ParsableBitArray scratchBits = new ParsableBitArray(scratch.data);
  int startPosition = 0;
  while (true) {
    input.peekFully(scratch.data, 0, 10);
    scratch.setPosition(0);
    if (scratch.readUnsignedInt24() != ID3_TAG) {
      break;
    }
    scratch.skipBytes(3);
    int length = scratch.readSynchSafeInt();
    startPosition += 10 + length;
    input.advancePeekPosition(length);
  }
  input.resetPeekPosition();
  input.advancePeekPosition(startPosition);

  // Try to find four or more consecutive AAC audio frames, exceeding the MPEG TS packet size.
  int headerPosition = startPosition;
  int validFramesSize = 0;
  int validFramesCount = 0;
  while (true) {
    input.peekFully(scratch.data, 0, 2);
    scratch.setPosition(0);
    int syncBytes = scratch.readUnsignedShort();
    if ((syncBytes & 0xFFF6) != 0xFFF0) {
      validFramesCount = 0;
      validFramesSize = 0;
      input.resetPeekPosition();
      if (++headerPosition - startPosition >= MAX_SNIFF_BYTES) {
        return false;
      }
      input.advancePeekPosition(headerPosition);
    } else {
      if (++validFramesCount >= 4 && validFramesSize > 188) {
        return true;
      }

      // Skip the frame.
      input.peekFully(scratch.data, 0, 4);
      scratchBits.setPosition(14);
      int frameSize = scratchBits.readBits(13);
      // Either the stream is malformed OR we're not parsing an ADTS stream.
      if (frameSize <= 6) {
        return false;
      }
      input.advancePeekPosition(frameSize - 6);
      validFramesSize += frameSize;
    }
  }
}
 

import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
@Override
public boolean sniff(ExtractorInput input) throws IOException, InterruptedException {
  // Skip any ID3 headers.
  ParsableByteArray scratch = new ParsableByteArray(10);
  int startPosition = 0;
  while (true) {
    input.peekFully(scratch.data, 0, 10);
    scratch.setPosition(0);
    if (scratch.readUnsignedInt24() != ID3_TAG) {
      break;
    }
    scratch.skipBytes(3);
    int length = scratch.readSynchSafeInt();
    startPosition += 10 + length;
    input.advancePeekPosition(length);
  }
  input.resetPeekPosition();
  input.advancePeekPosition(startPosition);

  int headerPosition = startPosition;
  int validFramesCount = 0;
  while (true) {
    input.peekFully(scratch.data, 0, 5);
    scratch.setPosition(0);
    int syncBytes = scratch.readUnsignedShort();
    if (syncBytes != AC3_SYNC_WORD) {
      validFramesCount = 0;
      input.resetPeekPosition();
      if (++headerPosition - startPosition >= MAX_SNIFF_BYTES) {
        return false;
      }
      input.advancePeekPosition(headerPosition);
    } else {
      if (++validFramesCount >= 4) {
        return true;
      }
      int frameSize = Ac3Util.parseAc3SyncframeSize(scratch.data);
      if (frameSize == C.LENGTH_UNSET) {
        return false;
      }
      input.advancePeekPosition(frameSize - 5);
    }
  }
}
 

import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
/**
 * Returns a position converging to the {@code targetGranule} to which the {@link ExtractorInput}
 * has to seek and then be passed for another call until a negative number is returned. If a
 * negative number is returned the input is at a position which is before the target page and at
 * which it is sensible to just skip pages to the target granule and pre-roll instead of doing
 * another seek request.
 *
 * @param targetGranule the target granule position to seek to.
 * @param input the {@link ExtractorInput} to read from.
 * @return the position to seek the {@link ExtractorInput} to for a next call or
 *     -(currentGranule + 2) if it's close enough to skip to the target page.
 * @throws IOException thrown if reading from the input fails.
 * @throws InterruptedException thrown if interrupted while reading from the input.
 */
//@VisibleForTesting
public long getNextSeekPosition(long targetGranule, ExtractorInput input)
    throws IOException, InterruptedException {
  if (start == end) {
    return -(startGranule + 2);
  }

  long initialPosition = input.getPosition();
  if (!skipToNextPage(input, end)) {
    if (start == initialPosition) {
      throw new IOException("No ogg page can be found.");
    }
    return start;
  }

  pageHeader.populate(input, false);
  input.resetPeekPosition();

  long granuleDistance = targetGranule - pageHeader.granulePosition;
  int pageSize = pageHeader.headerSize + pageHeader.bodySize;
  if (granuleDistance < 0 || granuleDistance > MATCH_RANGE) {
    if (granuleDistance < 0) {
      end = initialPosition;
      endGranule = pageHeader.granulePosition;
    } else {
      start = input.getPosition() + pageSize;
      startGranule = pageHeader.granulePosition;
      if (end - start + pageSize < MATCH_BYTE_RANGE) {
        input.skipFully(pageSize);
        return -(startGranule + 2);
      }
    }

    if (end - start < MATCH_BYTE_RANGE) {
      end = start;
      return start;
    }

    long offset = pageSize * (granuleDistance <= 0 ? 2 : 1);
    long nextPosition = input.getPosition() - offset
        + (granuleDistance * (end - start) / (endGranule - startGranule));

    nextPosition = Math.max(nextPosition, start);
    nextPosition = Math.min(nextPosition, end - 1);
    return nextPosition;
  }

  // position accepted (before target granule and within MATCH_RANGE)
  input.skipFully(pageSize);
  return -(pageHeader.granulePosition + 2);
}
 

import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
private boolean synchronize(ExtractorInput input, boolean sniffing)
    throws IOException, InterruptedException {
  int validFrameCount = 0;
  int candidateSynchronizedHeaderData = 0;
  int peekedId3Bytes = 0;
  int searchedBytes = 0;
  int searchLimitBytes = sniffing ? MAX_SNIFF_BYTES : MAX_SYNC_BYTES;
  input.resetPeekPosition();
  if (input.getPosition() == 0) {
    peekId3Data(input);
    peekedId3Bytes = (int) input.getPeekPosition();
    if (!sniffing) {
      input.skipFully(peekedId3Bytes);
    }
  }
  while (true) {
    if (!input.peekFully(scratch.data, 0, 4, validFrameCount > 0)) {
      // We reached the end of the stream but found at least one valid frame.
      break;
    }
    scratch.setPosition(0);
    int headerData = scratch.readInt();
    int frameSize;
    if ((candidateSynchronizedHeaderData != 0
        && (headerData & HEADER_MASK) != (candidateSynchronizedHeaderData & HEADER_MASK))
        || (frameSize = MpegAudioHeader.getFrameSize(headerData)) == C.LENGTH_UNSET) {
      // The header doesn't match the candidate header or is invalid. Try the next byte offset.
      if (searchedBytes++ == searchLimitBytes) {
        if (!sniffing) {
          throw new ParserException("Searched too many bytes.");
        }
        return false;
      }
      validFrameCount = 0;
      candidateSynchronizedHeaderData = 0;
      if (sniffing) {
        input.resetPeekPosition();
        input.advancePeekPosition(peekedId3Bytes + searchedBytes);
      } else {
        input.skipFully(1);
      }
    } else {
      // The header matches the candidate header and/or is valid.
      validFrameCount++;
      if (validFrameCount == 1) {
        MpegAudioHeader.populateHeader(headerData, synchronizedHeader);
        candidateSynchronizedHeaderData = headerData;
      } else if (validFrameCount == 4) {
        break;
      }
      input.advancePeekPosition(frameSize - 4);
    }
  }
  // Prepare to read the synchronized frame.
  if (sniffing) {
    input.skipFully(peekedId3Bytes + searchedBytes);
  } else {
    input.resetPeekPosition();
  }
  synchronizedHeaderData = candidateSynchronizedHeaderData;
  return true;
}
 

import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
/**
 * Returns a {@link Seeker} to seek using metadata read from {@code input}, which should provide
 * data from the start of the first frame in the stream. On returning, the input's position will
 * be set to the start of the first frame of audio.
 *
 * @param input The {@link ExtractorInput} from which to read.
 * @throws IOException Thrown if there was an error reading from the stream. Not expected if the
 *     next two frames were already peeked during synchronization.
 * @throws InterruptedException Thrown if reading from the stream was interrupted. Not expected if
 *     the next two frames were already peeked during synchronization.
 * @return a {@link Seeker}.
 */
private Seeker setupSeeker(ExtractorInput input) throws IOException, InterruptedException {
  // Read the first frame which may contain a Xing or VBRI header with seeking metadata.
  ParsableByteArray frame = new ParsableByteArray(synchronizedHeader.frameSize);
  input.peekFully(frame.data, 0, synchronizedHeader.frameSize);

  long position = input.getPosition();
  long length = input.getLength();
  int headerData = 0;
  Seeker seeker = null;

  // Check if there is a Xing header.
  int xingBase = (synchronizedHeader.version & 1) != 0
      ? (synchronizedHeader.channels != 1 ? 36 : 21) // MPEG 1
      : (synchronizedHeader.channels != 1 ? 21 : 13); // MPEG 2 or 2.5
  if (frame.limit() >= xingBase + 4) {
    frame.setPosition(xingBase);
    headerData = frame.readInt();
  }
  if (headerData == XING_HEADER || headerData == INFO_HEADER) {
    seeker = XingSeeker.create(synchronizedHeader, frame, position, length);
    if (seeker != null && !gaplessInfoHolder.hasGaplessInfo()) {
      // If there is a Xing header, read gapless playback metadata at a fixed offset.
      input.resetPeekPosition();
      input.advancePeekPosition(xingBase + 141);
      input.peekFully(scratch.data, 0, 3);
      scratch.setPosition(0);
      gaplessInfoHolder.setFromXingHeaderValue(scratch.readUnsignedInt24());
    }
    input.skipFully(synchronizedHeader.frameSize);
  } else if (frame.limit() >= 40) {
    // Check if there is a VBRI header.
    frame.setPosition(36); // MPEG audio header (4 bytes) + 32 bytes.
    headerData = frame.readInt();
    if (headerData == VBRI_HEADER) {
      seeker = VbriSeeker.create(synchronizedHeader, frame, position, length);
      input.skipFully(synchronizedHeader.frameSize);
    }
  }

  if (seeker == null || (!seeker.isSeekable()
      && (flags & FLAG_ENABLE_CONSTANT_BITRATE_SEEKING) != 0)) {
    // Repopulate the synchronized header in case we had to skip an invalid seeking header, which
    // would give an invalid CBR bitrate.
    input.resetPeekPosition();
    input.peekFully(scratch.data, 0, 4);
    scratch.setPosition(0);
    MpegAudioHeader.populateHeader(scratch.readInt(), synchronizedHeader);
    seeker = new ConstantBitrateSeeker(input.getPosition(), synchronizedHeader.bitrate, length);
  }

  return seeker;
}
 

import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
private boolean synchronize(ExtractorInput input, boolean sniffing)
    throws IOException, InterruptedException {
  int validFrameCount = 0;
  int candidateSynchronizedHeaderData = 0;
  int peekedId3Bytes = 0;
  int searchedBytes = 0;
  int searchLimitBytes = sniffing ? MAX_SNIFF_BYTES : MAX_SYNC_BYTES;
  input.resetPeekPosition();
  if (input.getPosition() == 0) {
    Id3Util.parseId3(input, gaplessInfoHolder);
    peekedId3Bytes = (int) input.getPeekPosition();
    if (!sniffing) {
      input.skipFully(peekedId3Bytes);
    }
  }
  while (true) {
    if (!input.peekFully(scratch.data, 0, 4, validFrameCount > 0)) {
      // We reached the end of the stream but found at least one valid frame.
      break;
    }
    scratch.setPosition(0);
    int headerData = scratch.readInt();
    int frameSize;
    if ((candidateSynchronizedHeaderData != 0
        && (headerData & HEADER_MASK) != (candidateSynchronizedHeaderData & HEADER_MASK))
        || (frameSize = MpegAudioHeader.getFrameSize(headerData)) == C.LENGTH_UNSET) {
      // The header doesn't match the candidate header or is invalid. Try the next byte offset.
      if (searchedBytes++ == searchLimitBytes) {
        if (!sniffing) {
          throw new ParserException("Searched too many bytes.");
        }
        return false;
      }
      validFrameCount = 0;
      candidateSynchronizedHeaderData = 0;
      if (sniffing) {
        input.resetPeekPosition();
        input.advancePeekPosition(peekedId3Bytes + searchedBytes);
      } else {
        input.skipFully(1);
      }
    } else {
      // The header matches the candidate header and/or is valid.
      validFrameCount++;
      if (validFrameCount == 1) {
        MpegAudioHeader.populateHeader(headerData, synchronizedHeader);
        candidateSynchronizedHeaderData = headerData;
      } else if (validFrameCount == 4) {
        break;
      }
      input.advancePeekPosition(frameSize - 4);
    }
  }
  // Prepare to read the synchronized frame.
  if (sniffing) {
    input.skipFully(peekedId3Bytes + searchedBytes);
  } else {
    input.resetPeekPosition();
  }
  synchronizedHeaderData = candidateSynchronizedHeaderData;
  return true;
}