# All files / src/demux tsdemuxer.js

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    15x

     /**
     * highly optimized TS demuxer:
     * parse PAT, PMT
     * extract PES packet from audio and video PIDs
     * extract AVC/H264 NAL units and AAC/ADTS samples from PES packet
     * trigger the remuxer upon parsing completion
     * it also tries to workaround as best as it can audio codec switch (HE-AAC to AAC and vice versa), without having to restart the MediaSource.
     * it also controls the remuxing process :
     * upon discontinuity or level switch detection, it will also notifies the remuxer so that it can reset its state.
    */

    import * as ADTS from './adts';
    import MpegAudio from './mpegaudio';
    import Event from '../events';
    import ExpGolomb from './exp-golomb';
    import SampleAesDecrypter from './sample-aes';
    // import Hex from '../utils/hex';
    import { logger } from '../utils/logger';
    import { ErrorTypes, ErrorDetails } from '../errors';

    // We are using fixed track IDs for driving the MP4 remuxer
    // instead of following the TS PIDs.
    // There is no reason not to do this and some browsers/SourceBuffer-demuxers
    // may not like if there are TrackID "switches"
    // See https://github.com/video-dev/hls.js/issues/1331
    // Here we are mapping our internal track types to constant MP4 track IDs
    // With MSE currently one can only have one track of each, and we are muxing
    // whatever video/audio rendition in them.
    const RemuxerTrackIdConfig = {
      video: 1,
      audio: 2,
      id3: 3,
      text: 4
    };

    class TSDemuxer {
      constructor (observer, remuxer, config, typeSupported) {
        this.observer = observer;
        this.config = config;
        this.typeSupported = typeSupported;
        this.remuxer = remuxer;
        this.sampleAes = null;
      }

      setDecryptData (decryptdata) {
        if ((decryptdata != null) && (decryptdata.key != null) && (decryptdata.method === 'SAMPLE-AES')) {
          this.sampleAes = new SampleAesDecrypter(this.observer, this.config, decryptdata, this.discardEPB);
        } else {
          this.sampleAes = null;
        }
      }

      static probe (data) {
        const syncOffset = TSDemuxer._syncOffset(data);
        if (syncOffset < 0) {
          return false;
        } else {
          if (syncOffset) {
            logger.warn(`MPEG2-TS detected but first sync word found @ offset ${syncOffset}, junk ahead ?`);
          }

          return true;
        }
      }

      static _syncOffset (data) {
        // scan 1000 first bytes
        const scanwindow = Math.min(1000, data.length - 3 * 188);
        let i = 0;
        while (i < scanwindow) {
          // a TS fragment should contain at least 3 TS packets, a PAT, a PMT, and one PID, each starting with 0x47
          if (data[i] === 0x47 && data[i + 188] === 0x47 && data[i + 2 * 188] === 0x47) {
            return i;
          } else {
            i++;
          }
        }
        return -1;
      }

      /**
       * Creates a track model internal to demuxer used to drive remuxing input
       *
       * @param {string} type 'audio' | 'video' | 'id3' | 'text'
       * @param {number} duration
       * @return {object} TSDemuxer's internal track model
       */
      static createTrack (type, duration) {
        return {
          container: type === 'video' || type === 'audio' ? 'video/mp2t' : undefined,
          type,
          id: RemuxerTrackIdConfig[type],
          pid: -1,
          inputTimeScale: 90000,
          sequenceNumber: 0,
          samples: [],
          len: 0,
          dropped: type === 'video' ? 0 : undefined,
          isAAC: type === 'audio' ? true : undefined,
          duration: type === 'audio' ? duration : undefined
        };
      }

      /**
       * Initializes a new init segment on the demuxer/remuxer interface. Needed for discontinuities/track-switches (or at stream start)
       * Resets all internal track instances of the demuxer.
       *
       * @override Implements generic demuxing/remuxing interface (see DemuxerInline)
       * @param {object} initSegment
       * @param {string} audioCodec
       * @param {string} videoCodec
       * @param {number} duration (in TS timescale = 90kHz)
       */
      resetInitSegment (initSegment, audioCodec, videoCodec, duration) {
        this.pmtParsed = false;
        this._pmtId = -1;

        this._avcTrack = TSDemuxer.createTrack('video', duration);
        this._audioTrack = TSDemuxer.createTrack('audio', duration);
        this._id3Track = TSDemuxer.createTrack('id3', duration);
        this._txtTrack = TSDemuxer.createTrack('text', duration);

        // flush any partial content
        this.aacOverFlow = null;
        this.aacLastPTS = null;
        this.avcSample = null;
        this.audioCodec = audioCodec;
        this.videoCodec = videoCodec;
        this._duration = duration;
      }

      /**
       *
       * @override
       */
      resetTimeStamp () {}

      // feed incoming data to the front of the parsing pipeline
      append (data, timeOffset, contiguous, accurateTimeOffset) {
        let start, len = data.length, stt, pid, atf, offset, pes,
          unknownPIDs = false;
        this.contiguous = contiguous;
        let pmtParsed = this.pmtParsed,
          avcTrack = this._avcTrack,
          audioTrack = this._audioTrack,
          id3Track = this._id3Track,
          avcId = avcTrack.pid,
          audioId = audioTrack.pid,
          id3Id = id3Track.pid,
          pmtId = this._pmtId,
          avcData = avcTrack.pesData,
          audioData = audioTrack.pesData,
          id3Data = id3Track.pesData,
          parsePAT = this._parsePAT,
          parsePMT = this._parsePMT,
          parsePES = this._parsePES,
          parseAVCPES = this._parseAVCPES.bind(this),
          parseAACPES = this._parseAACPES.bind(this),
          parseMPEGPES = this._parseMPEGPES.bind(this),
          parseID3PES = this._parseID3PES.bind(this);

        const syncOffset = TSDemuxer._syncOffset(data);

        // don't parse last TS packet if incomplete
        len -= (len + syncOffset) % 188;

        // loop through TS packets
        for (start = syncOffset; start < len; start += 188) {
          if (data[start] === 0x47) {
            stt = !!(data[start + 1] & 0x40);
            // pid is a 13-bit field starting at the last bit of TS[1]
            pid = ((data[start + 1] & 0x1f) << 8) + data[start + 2];
            atf = (data[start + 3] & 0x30) >> 4;
            // if an adaption field is present, its length is specified by the fifth byte of the TS packet header.
            if (atf > 1) {
              offset = start + 5 + data[start + 4];
              // continue if there is only adaptation field
              if (offset === (start + 188)) {
                continue;
              }
            } else {
              offset = start + 4;
            }
            switch (pid) {
            case avcId:
              if (stt) {
                if (avcData && (pes = parsePES(avcData)) && pes.pts !== undefined) {
                  parseAVCPES(pes, false);
                }

                avcData = { data: [], size: 0 };
              }
              if (avcData) {
                avcData.data.push(data.subarray(offset, start + 188));
                avcData.size += start + 188 - offset;
              }
              break;
            case audioId:
              if (stt) {
                if (audioData && (pes = parsePES(audioData)) && pes.pts !== undefined) {
                  if (audioTrack.isAAC) {
                    parseAACPES(pes);
                  } else {
                    parseMPEGPES(pes);
                  }
                }
                audioData = { data: [], size: 0 };
              }
              if (audioData) {
                audioData.data.push(data.subarray(offset, start + 188));
                audioData.size += start + 188 - offset;
              }
              break;
            case id3Id:
              if (stt) {
                if (id3Data && (pes = parsePES(id3Data)) && pes.pts !== undefined) {
                  parseID3PES(pes);
                }

                id3Data = { data: [], size: 0 };
              }
              if (id3Data) {
                id3Data.data.push(data.subarray(offset, start + 188));
                id3Data.size += start + 188 - offset;
              }
              break;
            case 0:
              if (stt) {
                offset += data[offset] + 1;
              }

              pmtId = this._pmtId = parsePAT(data, offset);
              break;
            case pmtId:
              if (stt) {
                offset += data[offset] + 1;
              }

              let parsedPIDs = parsePMT(data, offset, this.typeSupported.mpeg === true || this.typeSupported.mp3 === true, this.sampleAes != null);

              // only update track id if track PID found while parsing PMT
              // this is to avoid resetting the PID to -1 in case
              // track PID transiently disappears from the stream
              // this could happen in case of transient missing audio samples for example
              // NOTE this is only the PID of the track as found in TS,
              // but we are not using this for MP4 track IDs.
              avcId = parsedPIDs.avc;
              if (avcId > 0) {
                avcTrack.pid = avcId;
              }

              audioId = parsedPIDs.audio;
              if (audioId > 0) {
                audioTrack.pid = audioId;
                audioTrack.isAAC = parsedPIDs.isAAC;
              }
              id3Id = parsedPIDs.id3;
              if (id3Id > 0) {
                id3Track.pid = id3Id;
              }

              if (unknownPIDs && !pmtParsed) {
                logger.log('reparse from beginning');
                unknownPIDs = false;
                // we set it to -188, the += 188 in the for loop will reset start to 0
                start = syncOffset - 188;
              }
              pmtParsed = this.pmtParsed = true;
              break;
            case 17:
            case 0x1fff:
              break;
            default:
              unknownPIDs = true;
              break;
            }
          } else {
            this.observer.trigger(Event.ERROR, { type: ErrorTypes.MEDIA_ERROR, details: ErrorDetails.FRAG_PARSING_ERROR, fatal: false, reason: 'TS packet did not start with 0x47' });
          }
        }
        // try to parse last PES packets
        if (avcData && (pes = parsePES(avcData)) && pes.pts !== undefined) {
          parseAVCPES(pes, true);
          avcTrack.pesData = null;
        } else {
          // either avcData null or PES truncated, keep it for next frag parsing
          avcTrack.pesData = avcData;
        }

        if (audioData && (pes = parsePES(audioData)) && pes.pts !== undefined) {
          if (audioTrack.isAAC) {
            parseAACPES(pes);
          } else {
            parseMPEGPES(pes);
          }

          audioTrack.pesData = null;
        } else {
          if (audioData && audioData.size) {
            logger.log('last AAC PES packet truncated,might overlap between fragments');
          }

          // either audioData null or PES truncated, keep it for next frag parsing
          audioTrack.pesData = audioData;
        }

        if (id3Data && (pes = parsePES(id3Data)) && pes.pts !== undefined) {
          parseID3PES(pes);
          id3Track.pesData = null;
        } else {
          // either id3Data null or PES truncated, keep it for next frag parsing
          id3Track.pesData = id3Data;
        }

        if (this.sampleAes == null) {
          this.remuxer.remux(audioTrack, avcTrack, id3Track, this._txtTrack, timeOffset, contiguous, accurateTimeOffset);
        } else {
          this.decryptAndRemux(audioTrack, avcTrack, id3Track, this._txtTrack, timeOffset, contiguous, accurateTimeOffset);
        }
      }

      decryptAndRemux (audioTrack, videoTrack, id3Track, textTrack, timeOffset, contiguous, accurateTimeOffset) {
        if (audioTrack.samples && audioTrack.isAAC) {
          let localthis = this;
          this.sampleAes.decryptAacSamples(audioTrack.samples, 0, function () {
            localthis.decryptAndRemuxAvc(audioTrack, videoTrack, id3Track, textTrack, timeOffset, contiguous, accurateTimeOffset);
          });
        } else {
          this.decryptAndRemuxAvc(audioTrack, videoTrack, id3Track, textTrack, timeOffset, contiguous, accurateTimeOffset);
        }
      }

      decryptAndRemuxAvc (audioTrack, videoTrack, id3Track, textTrack, timeOffset, contiguous, accurateTimeOffset) {
        if (videoTrack.samples) {
          let localthis = this;
          this.sampleAes.decryptAvcSamples(videoTrack.samples, 0, 0, function () {
            localthis.remuxer.remux(audioTrack, videoTrack, id3Track, textTrack, timeOffset, contiguous, accurateTimeOffset);
          });
        } else {
          this.remuxer.remux(audioTrack, videoTrack, id3Track, textTrack, timeOffset, contiguous, accurateTimeOffset);
        }
      }

      destroy () {
        this._initPTS = this._initDTS = undefined;
        this._duration = 0;
      }

      _parsePAT (data, offset) {
        // skip the PSI header and parse the first PMT entry
        return (data[offset + 10] & 0x1F) << 8 | data[offset + 11];
        // logger.log('PMT PID:'  + this._pmtId);
      }

      _parsePMT (data, offset, mpegSupported, isSampleAes) {
        let sectionLength, tableEnd, programInfoLength, pid, result = { audio: -1, avc: -1, id3: -1, isAAC: true };
        sectionLength = (data[offset + 1] & 0x0f) << 8 | data[offset + 2];
        tableEnd = offset + 3 + sectionLength - 4;
        // to determine where the table is, we have to figure out how
        // long the program info descriptors are
        programInfoLength = (data[offset + 10] & 0x0f) << 8 | data[offset + 11];
        // advance the offset to the first entry in the mapping table
        offset += 12 + programInfoLength;
        while (offset < tableEnd) {
          pid = (data[offset + 1] & 0x1F) << 8 | data[offset + 2];
          switch (data[offset]) {
          case 0xcf: // SAMPLE-AES AAC
            if (!isSampleAes) {
              logger.log('unkown stream type:' + data[offset]);
              break;
            }
            /* falls through */

            // ISO/IEC 13818-7 ADTS AAC (MPEG-2 lower bit-rate audio)
          case 0x0f:
            // logger.log('AAC PID:'  + pid);
            if (result.audio === -1) {
              result.audio = pid;
            }

            break;

            // Packetized metadata (ID3)
          case 0x15:
            // logger.log('ID3 PID:'  + pid);
            if (result.id3 === -1) {
              result.id3 = pid;
            }

            break;

          case 0xdb: // SAMPLE-AES AVC
            if (!isSampleAes) {
              logger.log('unkown stream type:' + data[offset]);
              break;
            }
            /* falls through */

            // ITU-T Rec. H.264 and ISO/IEC 14496-10 (lower bit-rate video)
          case 0x1b:
            // logger.log('AVC PID:'  + pid);
            if (result.avc === -1) {
              result.avc = pid;
            }

            break;

            // ISO/IEC 11172-3 (MPEG-1 audio)
            // or ISO/IEC 13818-3 (MPEG-2 halved sample rate audio)
          case 0x03:
          case 0x04:
            // logger.log('MPEG PID:'  + pid);
            if (!mpegSupported) {
              logger.log('MPEG audio found, not supported in this browser for now');
            } else if (result.audio === -1) {
              result.audio = pid;
              result.isAAC = false;
            }
            break;

          case 0x24:
            logger.warn('HEVC stream type found, not supported for now');
            break;

          default:
            logger.log('unkown stream type:' + data[offset]);
            break;
          }
          // move to the next table entry
          // skip past the elementary stream descriptors, if present
          offset += ((data[offset + 3] & 0x0F) << 8 | data[offset + 4]) + 5;
        }
        return result;
      }

      _parsePES (stream) {
        let i = 0, frag, pesFlags, pesPrefix, pesLen, pesHdrLen, pesData, pesPts, pesDts, payloadStartOffset, data = stream.data;
        // safety check
        if (!stream || stream.size === 0) {
          return null;
        }

        // we might need up to 19 bytes to read PES header
        // if first chunk of data is less than 19 bytes, let's merge it with following ones until we get 19 bytes
        // usually only one merge is needed (and this is rare ...)
        while (data[0].length < 19 && data.length > 1) {
          let newData = new Uint8Array(data[0].length + data[1].length);
          newData.set(data[0]);
          newData.set(data[1], data[0].length);
          data[0] = newData;
          data.splice(1, 1);
        }
        // retrieve PTS/DTS from first fragment
        frag = data[0];
        pesPrefix = (frag[0] << 16) + (frag[1] << 8) + frag[2];
        if (pesPrefix === 1) {
          pesLen = (frag[4] << 8) + frag[5];
          // if PES parsed length is not zero and greater than total received length, stop parsing. PES might be truncated
          // minus 6 : PES header size
          if (pesLen && pesLen > stream.size - 6) {
            return null;
          }

          pesFlags = frag[7];
          if (pesFlags & 0xC0) {
            /* PES header described here : http://dvd.sourceforge.net/dvdinfo/pes-hdr.html
                as PTS / DTS is 33 bit we cannot use bitwise operator in JS,
                as Bitwise operators treat their operands as a sequence of 32 bits */
            pesPts = (frag[9] & 0x0E) * 536870912 +// 1 << 29
              (frag[10] & 0xFF) * 4194304 +// 1 << 22
              (frag[11] & 0xFE) * 16384 +// 1 << 14
              (frag[12] & 0xFF) * 128 +// 1 << 7
              (frag[13] & 0xFE) / 2;
            // check if greater than 2^32 -1
            if (pesPts > 4294967295) {
              // decrement 2^33
              pesPts -= 8589934592;
            }
            if (pesFlags & 0x40) {
              pesDts = (frag[14] & 0x0E) * 536870912 +// 1 << 29
                (frag[15] & 0xFF) * 4194304 +// 1 << 22
                (frag[16] & 0xFE) * 16384 +// 1 << 14
                (frag[17] & 0xFF) * 128 +// 1 << 7
                (frag[18] & 0xFE) / 2;
              // check if greater than 2^32 -1
              if (pesDts > 4294967295) {
                // decrement 2^33
                pesDts -= 8589934592;
              }
              if (pesPts - pesDts > 60 * 90000) {
                logger.warn(`${Math.round((pesPts - pesDts) / 90000)}s delta between PTS and DTS, align them`);
                pesPts = pesDts;
              }
            } else {
              pesDts = pesPts;
            }
          }
          pesHdrLen = frag[8];
          // 9 bytes : 6 bytes for PES header + 3 bytes for PES extension
          payloadStartOffset = pesHdrLen + 9;

          stream.size -= payloadStartOffset;
          // reassemble PES packet
          pesData = new Uint8Array(stream.size);
          for (let j = 0, dataLen = data.length; j < dataLen; j++) {
            frag = data[j];
            let len = frag.byteLength;
            if (payloadStartOffset) {
              if (payloadStartOffset > len) {
                // trim full frag if PES header bigger than frag
                payloadStartOffset -= len;
                continue;
              } else {
                // trim partial frag if PES header smaller than frag
                frag = frag.subarray(payloadStartOffset);
                len -= payloadStartOffset;
                payloadStartOffset = 0;
              }
            }
            pesData.set(frag, i);
            i += len;
          }
          if (pesLen) {
            // payload size : remove PES header + PES extension
            pesLen -= pesHdrLen + 3;
          }
          return { data: pesData, pts: pesPts, dts: pesDts, len: pesLen };
        } else {
          return null;
        }
      }

      pushAccesUnit (avcSample, avcTrack) {
        if (avcSample.units.length && avcSample.frame) {
          const samples = avcTrack.samples;
          const nbSamples = samples.length;
          // only push AVC sample if starting with a keyframe is not mandatory OR
          //    if keyframe already found in this fragment OR
          //       keyframe found in last fragment (track.sps) AND
          //          samples already appended (we already found a keyframe in this fragment) OR fragment is contiguous
          if (!this.config.forceKeyFrameOnDiscontinuity ||
              avcSample.key === true ||
              (avcTrack.sps && (nbSamples || this.contiguous))) {
            avcSample.id = nbSamples;
            samples.push(avcSample);
          } else {
            // dropped samples, track it
            avcTrack.dropped++;
          }
        }
        if (avcSample.debug.length) {
          logger.log(avcSample.pts + '/' + avcSample.dts + ':' + avcSample.debug);
        }
      }

      _parseAVCPES (pes, last) {
        // logger.log('parse new PES');
        let track = this._avcTrack,
          units = this._parseAVCNALu(pes.data),
          debug = false,
          expGolombDecoder,
          avcSample = this.avcSample,
          push,
          spsfound = false,
          i,
          pushAccesUnit = this.pushAccesUnit.bind(this),
          createAVCSample = function (key, pts, dts, debug) {
            return { key: key, pts: pts, dts: dts, units: [], debug: debug };
          };
        // free pes.data to save up some memory
        pes.data = null;

        // if new NAL units found and last sample still there, let's push ...
        // this helps parsing streams with missing AUD (only do this if AUD never found)
        if (avcSample && units.length && !track.audFound) {
          pushAccesUnit(avcSample, track);
          avcSample = this.avcSample = createAVCSample(false, pes.pts, pes.dts, '');
        }

        units.forEach(unit => {
          switch (unit.type) {
          // NDR
          case 1:
            push = true;
            if (!avcSample) {
              avcSample = this.avcSample = createAVCSample(true, pes.pts, pes.dts, '');
            }

            if (debug) {
              avcSample.debug += 'NDR ';
            }

            avcSample.frame = true;
            let data = unit.data;
            // only check slice type to detect KF in case SPS found in same packet (any keyframe is preceded by SPS ...)
            if (spsfound && data.length > 4) {
              // retrieve slice type by parsing beginning of NAL unit (follow H264 spec, slice_header definition) to detect keyframe embedded in NDR
              let sliceType = new ExpGolomb(data).readSliceType();
              // 2 : I slice, 4 : SI slice, 7 : I slice, 9: SI slice
              // SI slice : A slice that is coded using intra prediction only and using quantisation of the prediction samples.
              // An SI slice can be coded such that its decoded samples can be constructed identically to an SP slice.
              // I slice: A slice that is not an SI slice that is decoded using intra prediction only.
              // if (sliceType === 2 || sliceType === 7) {
              if (sliceType === 2 || sliceType === 4 || sliceType === 7 || sliceType === 9) {
                avcSample.key = true;
              }
            }
            break;
            // IDR
          case 5:
            push = true;
            // handle PES not starting with AUD
            if (!avcSample) {
              avcSample = this.avcSample = createAVCSample(true, pes.pts, pes.dts, '');
            }

            if (debug) {
              avcSample.debug += 'IDR ';
            }

            avcSample.key = true;
            avcSample.frame = true;
            break;
            // SEI
          case 6:
            push = true;
            if (debug && avcSample) {
              avcSample.debug += 'SEI ';
            }

            expGolombDecoder = new ExpGolomb(this.discardEPB(unit.data));

            // skip frameType
            expGolombDecoder.readUByte();

            var payloadType = 0;
            var payloadSize = 0;
            var endOfCaptions = false;
            var b = 0;

            while (!endOfCaptions && expGolombDecoder.bytesAvailable > 1) {
              payloadType = 0;
              do {
                b = expGolombDecoder.readUByte();
                payloadType += b;
              } while (b === 0xFF);

              // Parse payload size.
              payloadSize = 0;
              do {
                b = expGolombDecoder.readUByte();
                payloadSize += b;
              } while (b === 0xFF);

              // TODO: there can be more than one payload in an SEI packet...
              // TODO: need to read type and size in a while loop to get them all
              if (payloadType === 4 && expGolombDecoder.bytesAvailable !== 0) {
                endOfCaptions = true;

                let countryCode = expGolombDecoder.readUByte();

                if (countryCode === 181) {
                  let providerCode = expGolombDecoder.readUShort();

                  if (providerCode === 49) {
                    let userStructure = expGolombDecoder.readUInt();

                    if (userStructure === 0x47413934) {
                      let userDataType = expGolombDecoder.readUByte();

                      // Raw CEA-608 bytes wrapped in CEA-708 packet
                      if (userDataType === 3) {
                        let firstByte = expGolombDecoder.readUByte();
                        let secondByte = expGolombDecoder.readUByte();

                        let totalCCs = 31 & firstByte;
                        let byteArray = [firstByte, secondByte];

                        for (i = 0; i < totalCCs; i++) {
                          // 3 bytes per CC
                          byteArray.push(expGolombDecoder.readUByte());
                          byteArray.push(expGolombDecoder.readUByte());
                          byteArray.push(expGolombDecoder.readUByte());
                        }

                        this._insertSampleInOrder(this._txtTrack.samples, { type: 3, pts: pes.pts, bytes: byteArray });
                      }
                    }
                  }
                }
              } else if (payloadSize < expGolombDecoder.bytesAvailable) {
                for (i = 0; i < payloadSize; i++) {
                  expGolombDecoder.readUByte();
                }
              }
            }
            break;
            // SPS
          case 7:
            push = true;
            spsfound = true;
            if (debug && avcSample) {
              avcSample.debug += 'SPS ';
            }

            if (!track.sps) {
              expGolombDecoder = new ExpGolomb(unit.data);
              let config = expGolombDecoder.readSPS();
              track.width = config.width;
              track.height = config.height;
              track.pixelRatio = config.pixelRatio;
              track.sps = [unit.data];
              track.duration = this._duration;
              let codecarray = unit.data.subarray(1, 4);
              let codecstring = 'avc1.';
              for (i = 0; i < 3; i++) {
                let h = codecarray[i].toString(16);
                if (h.length < 2) {
                  h = '0' + h;
                }

                codecstring += h;
              }
              track.codec = codecstring;
            }
            break;
            // PPS
          case 8:
            push = true;
            if (debug && avcSample) {
              avcSample.debug += 'PPS ';
            }

            if (!track.pps) {
              track.pps = [unit.data];
            }

            break;
            // AUD
          case 9:
            push = false;
            track.audFound = true;
            if (avcSample) {
              pushAccesUnit(avcSample, track);
            }

            avcSample = this.avcSample = createAVCSample(false, pes.pts, pes.dts, debug ? 'AUD ' : '');
            break;
            // Filler Data
          case 12:
            push = false;
            break;
          default:
            push = false;
            if (avcSample) {
              avcSample.debug += 'unknown NAL ' + unit.type + ' ';
            }

            break;
          }
          if (avcSample && push) {
            let units = avcSample.units;
            units.push(unit);
          }
        });
        // if last PES packet, push samples
        if (last && avcSample) {
          pushAccesUnit(avcSample, track);
          this.avcSample = null;
        }
      }

      _insertSampleInOrder (arr, data) {
        let len = arr.length;
        if (len > 0) {
          if (data.pts >= arr[len - 1].pts) {
            arr.push(data);
          } else {
            for (let pos = len - 1; pos >= 0; pos--) {
              if (data.pts < arr[pos].pts) {
                arr.splice(pos, 0, data);
                break;
              }
            }
          }
        } else {
          arr.push(data);
        }
      }

      _getLastNalUnit () {
        let avcSample = this.avcSample, lastUnit;
        // try to fallback to previous sample if current one is empty
        if (!avcSample || avcSample.units.length === 0) {
          let track = this._avcTrack, samples = track.samples;
          avcSample = samples[samples.length - 1];
        }
        if (avcSample) {
          let units = avcSample.units;
          lastUnit = units[units.length - 1];
        }
        return lastUnit;
      }

      _parseAVCNALu (array) {
        let i = 0, len = array.byteLength, value, overflow, track = this._avcTrack, state = track.naluState || 0, lastState = state;
        let units = [], unit, unitType, lastUnitStart = -1, lastUnitType;
        // logger.log('PES:' + Hex.hexDump(array));

        if (state === -1) {
        // special use case where we found 3 or 4-byte start codes exactly at the end of previous PES packet
          lastUnitStart = 0;
          // NALu type is value read from offset 0
          lastUnitType = array[0] & 0x1f;
          state = 0;
          i = 1;
        }

        while (i < len) {
          value = array[i++];
          // optimization. state 0 and 1 are the predominant case. let's handle them outside of the switch/case
          if (!state) {
            state = value ? 0 : 1;
            continue;
          }
          if (state === 1) {
            state = value ? 0 : 2;
            continue;
          }
          // here we have state either equal to 2 or 3
          if (!value) {
            state = 3;
          } else if (value === 1) {
            if (lastUnitStart >= 0) {
              unit = { data: array.subarray(lastUnitStart, i - state - 1), type: lastUnitType };
              // logger.log('pushing NALU, type/size:' + unit.type + '/' + unit.data.byteLength);
              units.push(unit);
            } else {
              // lastUnitStart is undefined => this is the first start code found in this PES packet
              // first check if start code delimiter is overlapping between 2 PES packets,
              // ie it started in last packet (lastState not zero)
              // and ended at the beginning of this PES packet (i <= 4 - lastState)
              let lastUnit = this._getLastNalUnit();
              if (lastUnit) {
                if (lastState && (i <= 4 - lastState)) {
                  // start delimiter overlapping between PES packets
                  // strip start delimiter bytes from the end of last NAL unit
                  // check if lastUnit had a state different from zero
                  if (lastUnit.state) {
                    // strip last bytes
                    lastUnit.data = lastUnit.data.subarray(0, lastUnit.data.byteLength - lastState);
                  }
                }
                // If NAL units are not starting right at the beginning of the PES packet, push preceding data into previous NAL unit.
                overflow = i - state - 1;
                if (overflow > 0) {
                  // logger.log('first NALU found with overflow:' + overflow);
                  let tmp = new Uint8Array(lastUnit.data.byteLength + overflow);
                  tmp.set(lastUnit.data, 0);
                  tmp.set(array.subarray(0, overflow), lastUnit.data.byteLength);
                  lastUnit.data = tmp;
                }
              }
            }
            // check if we can read unit type
            if (i < len) {
              unitType = array[i] & 0x1f;
              // logger.log('find NALU @ offset:' + i + ',type:' + unitType);
              lastUnitStart = i;
              lastUnitType = unitType;
              state = 0;
            } else {
              // not enough byte to read unit type. let's read it on next PES parsing
              state = -1;
            }
          } else {
            state = 0;
          }
        }
        if (lastUnitStart >= 0 && state >= 0) {
          unit = { data: array.subarray(lastUnitStart, len), type: lastUnitType, state: state };
          units.push(unit);
          // logger.log('pushing NALU, type/size/state:' + unit.type + '/' + unit.data.byteLength + '/' + state);
        }
        // no NALu found
        if (units.length === 0) {
          // append pes.data to previous NAL unit
          let lastUnit = this._getLastNalUnit();
          if (lastUnit) {
            let tmp = new Uint8Array(lastUnit.data.byteLength + array.byteLength);
            tmp.set(lastUnit.data, 0);
            tmp.set(array, lastUnit.data.byteLength);
            lastUnit.data = tmp;
          }
        }
        track.naluState = state;
        return units;
      }

      /**
       * remove Emulation Prevention bytes from a RBSP
       */
      discardEPB (data) {
        let length = data.byteLength,
          EPBPositions = [],
          i = 1,
          newLength, newData;

        // Find all `Emulation Prevention Bytes`
        while (i < length - 2) {
          if (data[i] === 0 &&
              data[i + 1] === 0 &&
              data[i + 2] === 0x03) {
            EPBPositions.push(i + 2);
            i += 2;
          } else {
            i++;
          }
        }

        // If no Emulation Prevention Bytes were found just return the original
        // array
        if (EPBPositions.length === 0) {
          return data;
        }

        // Create a new array to hold the NAL unit data
        newLength = length - EPBPositions.length;
        newData = new Uint8Array(newLength);
        let sourceIndex = 0;

        for (i = 0; i < newLength; sourceIndex++, i++) {
          if (sourceIndex === EPBPositions[0]) {
            // Skip this byte
            sourceIndex++;
            // Remove this position index
            EPBPositions.shift();
          }
          newData[i] = data[sourceIndex];
        }
        return newData;
      }

      _parseAACPES (pes) {
        let track = this._audioTrack,
          data = pes.data,
          pts = pes.pts,
          startOffset = 0,
          aacOverFlow = this.aacOverFlow,
          aacLastPTS = this.aacLastPTS,
          frameDuration, frameIndex, offset, stamp, len;
        if (aacOverFlow) {
          let tmp = new Uint8Array(aacOverFlow.byteLength + data.byteLength);
          tmp.set(aacOverFlow, 0);
          tmp.set(data, aacOverFlow.byteLength);
          // logger.log(`AAC: append overflowing ${aacOverFlow.byteLength} bytes to beginning of new PES`);
          data = tmp;
        }
        // look for ADTS header (0xFFFx)
        for (offset = startOffset, len = data.length; offset < len - 1; offset++) {
          if (ADTS.isHeader(data, offset)) {
            break;
          }
        }
        // if ADTS header does not start straight from the beginning of the PES payload, raise an error
        if (offset) {
          let reason, fatal;
          if (offset < len - 1) {
            reason = `AAC PES did not start with ADTS header,offset:${offset}`;
            fatal = false;
          } else {
            reason = 'no ADTS header found in AAC PES';
            fatal = true;
          }
          logger.warn(`parsing error:${reason}`);
          this.observer.trigger(Event.ERROR, { type: ErrorTypes.MEDIA_ERROR, details: ErrorDetails.FRAG_PARSING_ERROR, fatal: fatal, reason: reason });
          if (fatal) {
            return;
          }
        }

        ADTS.initTrackConfig(track, this.observer, data, offset, this.audioCodec);
        frameIndex = 0;
        frameDuration = ADTS.getFrameDuration(track.samplerate);

        // if last AAC frame is overflowing, we should ensure timestamps are contiguous:
        // first sample PTS should be equal to last sample PTS + frameDuration
        if (aacOverFlow && aacLastPTS) {
          let newPTS = aacLastPTS + frameDuration;
          if (Math.abs(newPTS - pts) > 1) {
            logger.log(`AAC: align PTS for overlapping frames by ${Math.round((newPTS - pts) / 90)}`);
            pts = newPTS;
          }
        }

        // scan for aac samples
        while (offset < len) {
          if (ADTS.isHeader(data, offset) && (offset + 5) < len) {
            let frame = ADTS.appendFrame(track, data, offset, pts, frameIndex);
            if (frame) {
              // logger.log(`${Math.round(frame.sample.pts)} : AAC`);
              offset += frame.length;
              stamp = frame.sample.pts;
              frameIndex++;
            } else {
              // logger.log('Unable to parse AAC frame');
              break;
            }
          } else {
            // nothing found, keep looking
            offset++;
          }
        }

        if (offset < len) {
          aacOverFlow = data.subarray(offset, len);
          // logger.log(`AAC: overflow detected:${len-offset}`);
        } else {
          aacOverFlow = null;
        }

        this.aacOverFlow = aacOverFlow;
        this.aacLastPTS = stamp;
      }

      _parseMPEGPES (pes) {
        let data = pes.data;
        let length = data.length;
        let frameIndex = 0;
        let offset = 0;
        let pts = pes.pts;

        while (offset < length) {
          if (MpegAudio.isHeader(data, offset)) {
            let frame = MpegAudio.appendFrame(this._audioTrack, data, offset, pts, frameIndex);
            if (frame) {
              offset += frame.length;
              frameIndex++;
            } else {
              // logger.log('Unable to parse Mpeg audio frame');
              break;
            }
          } else {
            // nothing found, keep looking
            offset++;
          }
        }
      }

      _parseID3PES (pes) {
        this._id3Track.samples.push(pes);
      }
    }

    export default TSDemuxer;