constructor (pts, data, duration, sampleOffset) {
    this.originPts = this.pts = this.dts = pts
    this.data = data
    this.size = data.byteLength
    this.sampleOffset = sampleOffset
    if (duration) this.duration = duration
  }
@param {number} pts
@param {Uint8Array} data
@param {number} [duration=1024]