load (seg, audioSeg, loadInit, loadAudioInit = loadInit) {
    const toLoad = []
    if (seg) toLoad[0] = this.loadVideoSegment(seg, loadInit)
    if (audioSeg) toLoad[1] = this.loadAudioSegment(audioSeg, loadAudioInit)
    return Promise.all(toLoad)
  }
@param {MediaSegment} seg
@param {MediaSegment} audioSeg
@param {boolean} loadInit
@param {boolean} loadAudioInit