You probably may be aware of the browser extension, Video Downloader or the popular download manager youtube-dl that has a CLI and a GUI version to download streaming videos on platforms like Youtube.
Both of those tools can download streaming videos in a choice quality that is available for that video.
Persepolis is a similar download manager but adds some extra options in the mix. Not only it gives you the choice in video quality it can also download the video and audio quality from two different choices and mix them together. With this feature, it is also possible to download video or audio solely.
Persepolis is packed with a lot of other features, like different themes and many more. You can check their Github page for more info.
Persepolis is available in the AUR.