I need to download videos/playlists from YouTube in x265/ HEVC format in an easy manner using an android app/software on Windows OS. Do recommended one.
Although YouTube supports the h.265/HEVC format, this format is rarely used on YouTube. Most YouTube videos, including most YouTube 4K videos, are not available in this format. The most commonly used format for high definition YouTube videos is mp4. Is there any reason why you prefer to use an Android app to download rare h.265/HEVC format videos from YouTube in Windows? There is software for Windows that is perfectly capable of downloading YouTube videos, either individual videos or downloading entire playlists, but some of your requirements are impractical, in particular the using your Android phone as a workhorse device to download huge videos part.
Don't use your Android phone to download huge 4K videos. You're probably not going to be watching these videos on your phone, but rather either on your Windows computer or on your TV. Enable bookmark syncing between your web browsers on Android and Windows, and save a bookmark of the YouTube video on your phone so that you can download it later from Windows. Then you can watch it either from Windows or connect Windows to your TV and watch it on your TV. This is the best workflow to use in this case, because if you download too many huge videos from your phone you'll waste too much money on your phone's expensive data plan. So be smart and save money by saving only the YouTube video's bookmark from your phone, not the entire 4K video. You can use Firefox's Send Tab to Device feature to send a link to a tab to Firefox on any other of your devices that has Firefox installed in it, including your phone. Use your Windows computer for a workhorse and use your phone for saving links.
youtube-dl is a small command-line program to download videos from YouTube.com and other sites that don't provide direct links to the videos served. I noticed from researching your Stack Overflow account that you are familiar with the youtube-dl program, but you may not be familiar with all its powerful capabilities including downloading playlists, channels, and sections of the aforementioned between start of section and end of section. You can also download YouTube videos from a custom batch download list.
youtube-dl allows the user, among other things, to choose a specific video quality to download (if available) or let the program automatically determine the best (or worst) quality video to grab. It supports downloading entire playlists and all videos from a given user.
link to Windows executable
youtube-dl -f FORMAT -ciw -o "%(title)s.%(ext)s" -v <url-of-playlist>
<url-of-playlist> is replaced by the URL of the playlist and replace
FORMAT with any available video format, for example
18. You can use the
-F option to see all valid formats like this:
youtube-dl -F 'http://www.youtube.com/some-alphanumeric-string'