static async checkVideoSupport_(videoConfig) {
    // Use 'shaka.media.Capabilities.isTypeSupported' to check if
    // the stream is supported.
    // Cast platforms will additionally check canDisplayType(), which
    // accepts extended MIME type parameters.
    // See: https://github.com/shaka-project/shaka-player/issues/4726
    const device = shaka.device.DeviceFactory.getDevice();
    const deviceType = device.getDeviceType();
    if (deviceType === shaka.device.IDevice.DeviceType.CAST) {
      const isSupported =
          await shaka.polyfill.MediaCapabilities.canCastDisplayType_(
              videoConfig);
      return isSupported;
    }
    return shaka.media.Capabilities.isTypeSupported(videoConfig.contentType);
  }
@param {!VideoConfiguration} videoConfig The 'video' field of the
  MediaDecodingConfiguration.
@return {!Promise<boolean>}
@private