# All files / src/remux mp4-generator.js

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    1x

     /**
     * Generate MP4 Box
    */

    const UINT32_MAX = Math.pow(2, 32) - 1;

    class MP4 {
      static init () {
        MP4.types = {
          avc1: [], // codingname
          avcC: [],
          btrt: [],
          dinf: [],
          dref: [],
          esds: [],
          ftyp: [],
          hdlr: [],
          mdat: [],
          mdhd: [],
          mdia: [],
          mfhd: [],
          minf: [],
          moof: [],
          moov: [],
          mp4a: [],
          '.mp3': [],
          mvex: [],
          mvhd: [],
          pasp: [],
          sdtp: [],
          stbl: [],
          stco: [],
          stsc: [],
          stsd: [],
          stsz: [],
          stts: [],
          tfdt: [],
          tfhd: [],
          traf: [],
          trak: [],
          trun: [],
          trex: [],
          tkhd: [],
          vmhd: [],
          smhd: []
        };

        let i;
        for (i in MP4.types) {
          if (MP4.types.hasOwnProperty(i)) {
            MP4.types[i] = [
              i.charCodeAt(0),
              i.charCodeAt(1),
              i.charCodeAt(2),
              i.charCodeAt(3)
            ];
          }
        }

        let videoHdlr = new Uint8Array([
          0x00, // version 0
          0x00, 0x00, 0x00, // flags
          0x00, 0x00, 0x00, 0x00, // pre_defined
          0x76, 0x69, 0x64, 0x65, // handler_type: 'vide'
          0x00, 0x00, 0x00, 0x00, // reserved
          0x00, 0x00, 0x00, 0x00, // reserved
          0x00, 0x00, 0x00, 0x00, // reserved
          0x56, 0x69, 0x64, 0x65,
          0x6f, 0x48, 0x61, 0x6e,
          0x64, 0x6c, 0x65, 0x72, 0x00 // name: 'VideoHandler'
        ]);

        let audioHdlr = new Uint8Array([
          0x00, // version 0
          0x00, 0x00, 0x00, // flags
          0x00, 0x00, 0x00, 0x00, // pre_defined
          0x73, 0x6f, 0x75, 0x6e, // handler_type: 'soun'
          0x00, 0x00, 0x00, 0x00, // reserved
          0x00, 0x00, 0x00, 0x00, // reserved
          0x00, 0x00, 0x00, 0x00, // reserved
          0x53, 0x6f, 0x75, 0x6e,
          0x64, 0x48, 0x61, 0x6e,
          0x64, 0x6c, 0x65, 0x72, 0x00 // name: 'SoundHandler'
        ]);

        MP4.HDLR_TYPES = {
          'video': videoHdlr,
          'audio': audioHdlr
        };

        let dref = new Uint8Array([
          0x00, // version 0
          0x00, 0x00, 0x00, // flags
          0x00, 0x00, 0x00, 0x01, // entry_count
          0x00, 0x00, 0x00, 0x0c, // entry_size
          0x75, 0x72, 0x6c, 0x20, // 'url' type
          0x00, // version 0
          0x00, 0x00, 0x01 // entry_flags
        ]);

        let stco = new Uint8Array([
          0x00, // version
          0x00, 0x00, 0x00, // flags
          0x00, 0x00, 0x00, 0x00 // entry_count
        ]);

        MP4.STTS = MP4.STSC = MP4.STCO = stco;

        MP4.STSZ = new Uint8Array([
          0x00, // version
          0x00, 0x00, 0x00, // flags
          0x00, 0x00, 0x00, 0x00, // sample_size
          0x00, 0x00, 0x00, 0x00 // sample_count
        ]);
        MP4.VMHD = new Uint8Array([
          0x00, // version
          0x00, 0x00, 0x01, // flags
          0x00, 0x00, // graphicsmode
          0x00, 0x00,
          0x00, 0x00,
          0x00, 0x00 // opcolor
        ]);
        MP4.SMHD = new Uint8Array([
          0x00, // version
          0x00, 0x00, 0x00, // flags
          0x00, 0x00, // balance
          0x00, 0x00 // reserved
        ]);

        MP4.STSD = new Uint8Array([
          0x00, // version 0
          0x00, 0x00, 0x00, // flags
          0x00, 0x00, 0x00, 0x01]);// entry_count

        let majorBrand = new Uint8Array([105, 115, 111, 109]); // isom
        let avc1Brand = new Uint8Array([97, 118, 99, 49]); // avc1
        let minorVersion = new Uint8Array([0, 0, 0, 1]);

        MP4.FTYP = MP4.box(MP4.types.ftyp, majorBrand, minorVersion, majorBrand, avc1Brand);
        MP4.DINF = MP4.box(MP4.types.dinf, MP4.box(MP4.types.dref, dref));
      }

      static box (type) {
        let
          payload = Array.prototype.slice.call(arguments, 1),
          size = 8,
          i = payload.length,
          len = i,
          result;
        // calculate the total size we need to allocate
        while (i--) {
          size += payload[i].byteLength;
        }

        result = new Uint8Array(size);
        result[0] = (size >> 24) & 0xff;
        result[1] = (size >> 16) & 0xff;
        result[2] = (size >> 8) & 0xff;
        result[3] = size & 0xff;
        result.set(type, 4);
        // copy the payload into the result
        for (i = 0, size = 8; i < len; i++) {
          // copy payload[i] array @ offset size
          result.set(payload[i], size);
          size += payload[i].byteLength;
        }
        return result;
      }

      static hdlr (type) {
        return MP4.box(MP4.types.hdlr, MP4.HDLR_TYPES[type]);
      }

      static mdat (data) {
        return MP4.box(MP4.types.mdat, data);
      }

      static mdhd (timescale, duration) {
        duration *= timescale;
        const upperWordDuration = Math.floor(duration / (UINT32_MAX + 1));
        const lowerWordDuration = Math.floor(duration % (UINT32_MAX + 1));
        return MP4.box(MP4.types.mdhd, new Uint8Array([
          0x01, // version 1
          0x00, 0x00, 0x00, // flags
          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, // creation_time
          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, // modification_time
          (timescale >> 24) & 0xFF,
          (timescale >> 16) & 0xFF,
          (timescale >> 8) & 0xFF,
          timescale & 0xFF, // timescale
          (upperWordDuration >> 24),
          (upperWordDuration >> 16) & 0xFF,
          (upperWordDuration >> 8) & 0xFF,
          upperWordDuration & 0xFF,
          (lowerWordDuration >> 24),
          (lowerWordDuration >> 16) & 0xFF,
          (lowerWordDuration >> 8) & 0xFF,
          lowerWordDuration & 0xFF,
          0x55, 0xc4, // 'und' language (undetermined)
          0x00, 0x00
        ]));
      }

      static mdia (track) {
        return MP4.box(MP4.types.mdia, MP4.mdhd(track.timescale, track.duration), MP4.hdlr(track.type), MP4.minf(track));
      }

      static mfhd (sequenceNumber) {
        return MP4.box(MP4.types.mfhd, new Uint8Array([
          0x00,
          0x00, 0x00, 0x00, // flags
          (sequenceNumber >> 24),
          (sequenceNumber >> 16) & 0xFF,
          (sequenceNumber >> 8) & 0xFF,
          sequenceNumber & 0xFF // sequence_number
        ]));
      }

      static minf (track) {
        if (track.type === 'audio') {
          return MP4.box(MP4.types.minf, MP4.box(MP4.types.smhd, MP4.SMHD), MP4.DINF, MP4.stbl(track));
        } else {
          return MP4.box(MP4.types.minf, MP4.box(MP4.types.vmhd, MP4.VMHD), MP4.DINF, MP4.stbl(track));
        }
      }

      static moof (sn, baseMediaDecodeTime, track) {
        return MP4.box(MP4.types.moof, MP4.mfhd(sn), MP4.traf(track, baseMediaDecodeTime));
      }
      /**
     * @param tracks... (optional) {array} the tracks associated with this movie
     */
      static moov (tracks) {
        let
          i = tracks.length,
          boxes = [];

        while (i--) {
          boxes[i] = MP4.trak(tracks[i]);
        }

        return MP4.box.apply(null, [MP4.types.moov, MP4.mvhd(tracks[0].timescale, tracks[0].duration)].concat(boxes).concat(MP4.mvex(tracks)));
      }

      static mvex (tracks) {
        let
          i = tracks.length,
          boxes = [];

        while (i--) {
          boxes[i] = MP4.trex(tracks[i]);
        }

        return MP4.box.apply(null, [MP4.types.mvex].concat(boxes));
      }

      static mvhd (timescale, duration) {
        duration *= timescale;
        const upperWordDuration = Math.floor(duration / (UINT32_MAX + 1));
        const lowerWordDuration = Math.floor(duration % (UINT32_MAX + 1));
        let
          bytes = new Uint8Array([
            0x01, // version 1
            0x00, 0x00, 0x00, // flags
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, // creation_time
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, // modification_time
            (timescale >> 24) & 0xFF,
            (timescale >> 16) & 0xFF,
            (timescale >> 8) & 0xFF,
            timescale & 0xFF, // timescale
            (upperWordDuration >> 24),
            (upperWordDuration >> 16) & 0xFF,
            (upperWordDuration >> 8) & 0xFF,
            upperWordDuration & 0xFF,
            (lowerWordDuration >> 24),
            (lowerWordDuration >> 16) & 0xFF,
            (lowerWordDuration >> 8) & 0xFF,
            lowerWordDuration & 0xFF,
            0x00, 0x01, 0x00, 0x00, // 1.0 rate
            0x01, 0x00, // 1.0 volume
            0x00, 0x00, // reserved
            0x00, 0x00, 0x00, 0x00, // reserved
            0x00, 0x00, 0x00, 0x00, // reserved
            0x00, 0x01, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x01, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x40, 0x00, 0x00, 0x00, // transformation: unity matrix
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, // pre_defined
            0xff, 0xff, 0xff, 0xff // next_track_ID
          ]);
        return MP4.box(MP4.types.mvhd, bytes);
      }

      static sdtp (track) {
        let
          samples = track.samples || [],
          bytes = new Uint8Array(4 + samples.length),
          flags,
          i;
        // leave the full box header (4 bytes) all zero
        // write the sample table
        for (i = 0; i < samples.length; i++) {
          flags = samples[i].flags;
          bytes[i + 4] = (flags.dependsOn << 4) |
            (flags.isDependedOn << 2) |
            (flags.hasRedundancy);
        }

        return MP4.box(MP4.types.sdtp, bytes);
      }

      static stbl (track) {
        return MP4.box(MP4.types.stbl, MP4.stsd(track), MP4.box(MP4.types.stts, MP4.STTS), MP4.box(MP4.types.stsc, MP4.STSC), MP4.box(MP4.types.stsz, MP4.STSZ), MP4.box(MP4.types.stco, MP4.STCO));
      }

      static avc1 (track) {
        let sps = [], pps = [], i, data, len;
        // assemble the SPSs

        for (i = 0; i < track.sps.length; i++) {
          data = track.sps[i];
          len = data.byteLength;
          sps.push((len >>> 8) & 0xFF);
          sps.push((len & 0xFF));

          // SPS
          sps = sps.concat(Array.prototype.slice.call(data));
        }

        // assemble the PPSs
        for (i = 0; i < track.pps.length; i++) {
          data = track.pps[i];
          len = data.byteLength;
          pps.push((len >>> 8) & 0xFF);
          pps.push((len & 0xFF));

          pps = pps.concat(Array.prototype.slice.call(data));
        }

        let avcc = MP4.box(MP4.types.avcC, new Uint8Array([
            0x01, // version
            sps[3], // profile
            sps[4], // profile compat
            sps[5], // level
            0xfc | 3, // lengthSizeMinusOne, hard-coded to 4 bytes
            0xE0 | track.sps.length // 3bit reserved (111) + numOfSequenceParameterSets
          ].concat(sps).concat([
            track.pps.length // numOfPictureParameterSets
          ]).concat(pps))), // "PPS"
          width = track.width,
          height = track.height,
          hSpacing = track.pixelRatio[0],
          vSpacing = track.pixelRatio[1];

        return MP4.box(MP4.types.avc1, new Uint8Array([
          0x00, 0x00, 0x00, // reserved
          0x00, 0x00, 0x00, // reserved
          0x00, 0x01, // data_reference_index
          0x00, 0x00, // pre_defined
          0x00, 0x00, // reserved
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00, // pre_defined
          (width >> 8) & 0xFF,
          width & 0xff, // width
          (height >> 8) & 0xFF,
          height & 0xff, // height
          0x00, 0x48, 0x00, 0x00, // horizresolution
          0x00, 0x48, 0x00, 0x00, // vertresolution
          0x00, 0x00, 0x00, 0x00, // reserved
          0x00, 0x01, // frame_count
          0x12,
          0x64, 0x61, 0x69, 0x6C, // dailymotion/hls.js
          0x79, 0x6D, 0x6F, 0x74,
          0x69, 0x6F, 0x6E, 0x2F,
          0x68, 0x6C, 0x73, 0x2E,
          0x6A, 0x73, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, // compressorname
          0x00, 0x18, // depth = 24
          0x11, 0x11]), // pre_defined = -1
        avcc,
        MP4.box(MP4.types.btrt, new Uint8Array([
          0x00, 0x1c, 0x9c, 0x80, // bufferSizeDB
          0x00, 0x2d, 0xc6, 0xc0, // maxBitrate
          0x00, 0x2d, 0xc6, 0xc0])), // avgBitrate
        MP4.box(MP4.types.pasp, new Uint8Array([
          (hSpacing >> 24), // hSpacing
          (hSpacing >> 16) & 0xFF,
          (hSpacing >> 8) & 0xFF,
          hSpacing & 0xFF,
          (vSpacing >> 24), // vSpacing
          (vSpacing >> 16) & 0xFF,
          (vSpacing >> 8) & 0xFF,
          vSpacing & 0xFF]))
        );
      }

      static esds (track) {
        let configlen = track.config.length;
        return new Uint8Array([
          0x00, // version 0
          0x00, 0x00, 0x00, // flags

          0x03, // descriptor_type
          0x17 + configlen, // length
          0x00, 0x01, // es_id
          0x00, // stream_priority

          0x04, // descriptor_type
          0x0f + configlen, // length
          0x40, // codec : mpeg4_audio
          0x15, // stream_type
          0x00, 0x00, 0x00, // buffer_size
          0x00, 0x00, 0x00, 0x00, // maxBitrate
          0x00, 0x00, 0x00, 0x00, // avgBitrate

          0x05 // descriptor_type
        ].concat([configlen]).concat(track.config).concat([0x06, 0x01, 0x02])); // GASpecificConfig)); // length + audio config descriptor
      }

      static mp4a (track) {
        let samplerate = track.samplerate;
        return MP4.box(MP4.types.mp4a, new Uint8Array([
          0x00, 0x00, 0x00, // reserved
          0x00, 0x00, 0x00, // reserved
          0x00, 0x01, // data_reference_index
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00, // reserved
          0x00, track.channelCount, // channelcount
          0x00, 0x10, // sampleSize:16bits
          0x00, 0x00, 0x00, 0x00, // reserved2
          (samplerate >> 8) & 0xFF,
          samplerate & 0xff, //
          0x00, 0x00]),
        MP4.box(MP4.types.esds, MP4.esds(track)));
      }

      static mp3 (track) {
        let samplerate = track.samplerate;
        return MP4.box(MP4.types['.mp3'], new Uint8Array([
          0x00, 0x00, 0x00, // reserved
          0x00, 0x00, 0x00, // reserved
          0x00, 0x01, // data_reference_index
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00, // reserved
          0x00, track.channelCount, // channelcount
          0x00, 0x10, // sampleSize:16bits
          0x00, 0x00, 0x00, 0x00, // reserved2
          (samplerate >> 8) & 0xFF,
          samplerate & 0xff, //
          0x00, 0x00]));
      }

      static stsd (track) {
        if (track.type === 'audio') {
          if (!track.isAAC && track.codec === 'mp3') {
            return MP4.box(MP4.types.stsd, MP4.STSD, MP4.mp3(track));
          }

          return MP4.box(MP4.types.stsd, MP4.STSD, MP4.mp4a(track));
        } else {
          return MP4.box(MP4.types.stsd, MP4.STSD, MP4.avc1(track));
        }
      }

      static tkhd (track) {
        let id = track.id,
          duration = track.duration * track.timescale,
          width = track.width,
          height = track.height,
          upperWordDuration = Math.floor(duration / (UINT32_MAX + 1)),
          lowerWordDuration = Math.floor(duration % (UINT32_MAX + 1));
        return MP4.box(MP4.types.tkhd, new Uint8Array([
          0x01, // version 1
          0x00, 0x00, 0x07, // flags
          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, // creation_time
          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, // modification_time
          (id >> 24) & 0xFF,
          (id >> 16) & 0xFF,
          (id >> 8) & 0xFF,
          id & 0xFF, // track_ID
          0x00, 0x00, 0x00, 0x00, // reserved
          (upperWordDuration >> 24),
          (upperWordDuration >> 16) & 0xFF,
          (upperWordDuration >> 8) & 0xFF,
          upperWordDuration & 0xFF,
          (lowerWordDuration >> 24),
          (lowerWordDuration >> 16) & 0xFF,
          (lowerWordDuration >> 8) & 0xFF,
          lowerWordDuration & 0xFF,
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00, // reserved
          0x00, 0x00, // layer
          0x00, 0x00, // alternate_group
          0x00, 0x00, // non-audio track volume
          0x00, 0x00, // reserved
          0x00, 0x01, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x01, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00,
          0x40, 0x00, 0x00, 0x00, // transformation: unity matrix
          (width >> 8) & 0xFF,
          width & 0xFF,
          0x00, 0x00, // width
          (height >> 8) & 0xFF,
          height & 0xFF,
          0x00, 0x00 // height
        ]));
      }

      static traf (track, baseMediaDecodeTime) {
        let sampleDependencyTable = MP4.sdtp(track),
          id = track.id,
          upperWordBaseMediaDecodeTime = Math.floor(baseMediaDecodeTime / (UINT32_MAX + 1)),
          lowerWordBaseMediaDecodeTime = Math.floor(baseMediaDecodeTime % (UINT32_MAX + 1));
        return MP4.box(MP4.types.traf,
          MP4.box(MP4.types.tfhd, new Uint8Array([
            0x00, // version 0
            0x00, 0x00, 0x00, // flags
            (id >> 24),
            (id >> 16) & 0XFF,
            (id >> 8) & 0XFF,
            (id & 0xFF) // track_ID
          ])),
          MP4.box(MP4.types.tfdt, new Uint8Array([
            0x01, // version 1
            0x00, 0x00, 0x00, // flags
            (upperWordBaseMediaDecodeTime >> 24),
            (upperWordBaseMediaDecodeTime >> 16) & 0XFF,
            (upperWordBaseMediaDecodeTime >> 8) & 0XFF,
            (upperWordBaseMediaDecodeTime & 0xFF),
            (lowerWordBaseMediaDecodeTime >> 24),
            (lowerWordBaseMediaDecodeTime >> 16) & 0XFF,
            (lowerWordBaseMediaDecodeTime >> 8) & 0XFF,
            (lowerWordBaseMediaDecodeTime & 0xFF)
          ])),
          MP4.trun(track,
            sampleDependencyTable.length +
                        16 + // tfhd
                        20 + // tfdt
                        8 + // traf header
                        16 + // mfhd
                        8 + // moof header
                        8), // mdat header
          sampleDependencyTable);
      }

      /**
       * Generate a track box.
       * @param track {object} a track definition
       * @return {Uint8Array} the track box
       */
      static trak (track) {
        track.duration = track.duration || 0xffffffff;
        return MP4.box(MP4.types.trak, MP4.tkhd(track), MP4.mdia(track));
      }

      static trex (track) {
        let id = track.id;
        return MP4.box(MP4.types.trex, new Uint8Array([
          0x00, // version 0
          0x00, 0x00, 0x00, // flags
          (id >> 24),
          (id >> 16) & 0XFF,
          (id >> 8) & 0XFF,
          (id & 0xFF), // track_ID
          0x00, 0x00, 0x00, 0x01, // default_sample_description_index
          0x00, 0x00, 0x00, 0x00, // default_sample_duration
          0x00, 0x00, 0x00, 0x00, // default_sample_size
          0x00, 0x01, 0x00, 0x01 // default_sample_flags
        ]));
      }

      static trun (track, offset) {
        let samples = track.samples || [],
          len = samples.length,
          arraylen = 12 + (16 * len),
          array = new Uint8Array(arraylen),
          i, sample, duration, size, flags, cts;
        offset += 8 + arraylen;
        array.set([
          0x00, // version 0
          0x00, 0x0f, 0x01, // flags
          (len >>> 24) & 0xFF,
          (len >>> 16) & 0xFF,
          (len >>> 8) & 0xFF,
          len & 0xFF, // sample_count
          (offset >>> 24) & 0xFF,
          (offset >>> 16) & 0xFF,
          (offset >>> 8) & 0xFF,
          offset & 0xFF // data_offset
        ], 0);
        for (i = 0; i < len; i++) {
          sample = samples[i];
          duration = sample.duration;
          size = sample.size;
          flags = sample.flags;
          cts = sample.cts;
          array.set([
            (duration >>> 24) & 0xFF,
            (duration >>> 16) & 0xFF,
            (duration >>> 8) & 0xFF,
            duration & 0xFF, // sample_duration
            (size >>> 24) & 0xFF,
            (size >>> 16) & 0xFF,
            (size >>> 8) & 0xFF,
            size & 0xFF, // sample_size
            (flags.isLeading << 2) | flags.dependsOn,
            (flags.isDependedOn << 6) |
              (flags.hasRedundancy << 4) |
              (flags.paddingValue << 1) |
              flags.isNonSync,
            flags.degradPrio & 0xF0 << 8,
            flags.degradPrio & 0x0F, // sample_flags
            (cts >>> 24) & 0xFF,
            (cts >>> 16) & 0xFF,
            (cts >>> 8) & 0xFF,
            cts & 0xFF // sample_composition_time_offset
          ], 12 + 16 * i);
        }
        return MP4.box(MP4.types.trun, array);
      }

      static initSegment (tracks) {
        if (!MP4.types) {
          MP4.init();
        }

        let movie = MP4.moov(tracks), result;
        result = new Uint8Array(MP4.FTYP.byteLength + movie.byteLength);
        result.set(MP4.FTYP);
        result.set(movie, MP4.FTYP.byteLength);
        return result;
      }
    }

    export default MP4;