Video quality in YouTube downloader

YouTube Downloader always downloads videos as 720p. Use this to know what are quality iTags on YouTube https://gist.github.com/sidneys/7095afe4da4ae58694d128b1034e01e2#comprehensive-list-of-youtube-format-code-itags. And try to fix this. In ideal case either the video should be downloaded in best possible resolution or the user should be given options to choose one quality.