You can download MV videos with some useful third-party downloaders, such as EaseUS Video Downloader. EaseUS Video Downloader is available for Windows and macOS and supports downloading online videos from over 1000 sites, including YouTube, which publishes music videos. You just need to copy the URL of the music video and use the downloader's built-in browser to navigate to the playback page of the MV, and download the corresponding video or audio in the quality and format of your choice!