tfdt_(streamInfo) {
    const Mp4Generator = shaka.util.Mp4Generator;
    const baseMediaDecodeTime =
        streamInfo.data ? streamInfo.data.baseMediaDecodeTime : 0;
    const upperWordBaseMediaDecodeTime =
      Math.floor(baseMediaDecodeTime / (Mp4Generator.UINT32_MAX_ + 1));
    const lowerWordBaseMediaDecodeTime =
      Math.floor(baseMediaDecodeTime % (Mp4Generator.UINT32_MAX_ + 1));
    const bytes = new Uint8Array([
      0x01, // version 1
      0x00, 0x00, 0x00, // flags
      ...this.breakNumberIntoBytes_(upperWordBaseMediaDecodeTime, 4),
      ...this.breakNumberIntoBytes_(lowerWordBaseMediaDecodeTime, 4),
    ]);
    return Mp4Generator.box('tfdt', bytes);
  }
Generate a TFDT box

@param {shaka.util.Mp4Generator.StreamInfo} streamInfo
@return {!Uint8Array}
@private