function tweakDrmInfos(callback) {
    if (manifest.variants[0].video.encrypted) {
      callback(manifest.variants[0].video.drmInfos);
    }
    if (manifest.variants[0].audio.encrypted) {
      callback(manifest.variants[0].audio.drmInfos);
    }
  }
@param {function(!Array<shaka.extern.DrmInfo>)} callback