getManifestIsEncrypted_(manifest) {
    return manifest.variants.some((variant) => {
      const videoEncrypted = variant.video && variant.video.encrypted;
      const audioEncrypted = variant.audio && variant.audio.encrypted;
      return videoEncrypted || audioEncrypted;
    });
  }
@param {shaka.extern.Manifest} manifest
@return {boolean}
@private