VLC player for most desktop operating systems, and also has versions for Android and iOS mobile devices.

VLC Linux as a media player capable of streaming and playing media over a LAN network (after all, VLC stands for Video LAN client), but it soon became popular on Windows, mainly because it could play most file types, due to its built-in codecs.
It was also one of the first media players to support subtitle files.
But what most people don't know is that VLC has several additional features, which we will present below.
1. Download YouTube videos
One of the important and useful features of VLC is that it can download video files from YouTube.
Select and copy the URL from the video you want (without the “s” if it is in the format https:// and paste it, in the menu: Media > Open Network Stream, and press Play. Then in the Tools menu, select Codec Information and in the window that opens, select the link in the Location field. Copy and paste this into your browser and press Enter. This is the link from YouTube's servers where, during playback, by right-clicking on the video you can save the video to your computer (save video as…).
2. Desktop recording
Quite a useful feature for those who create video tutorials, or if you want to show someone what problem you are facing.
Go to the Media->Open Capture Device menu and in the Capture Mode menu select Desktop, while in the lower field change the f/s to 15f/s which is a satisfactory number for recording the desktop. In the Play option, select the arrow on the right and click on Convert. On the next screen, select the file type from Profile (select mp4) and save it to the desired computer folder. Finally, select Start.
3. Convert video files
A useful feature is the conversion of video files, especially for those who have devices that do not support all file types.
Go to the Media->Convert/Save menu and in the window that opens, select the file you want to convert with Add. After selecting the file, select Convert/Save and in the new window, you have the settings as before, regarding the type of exported file and the storage folder.
Source: e-pcmag.gr
