Best Free Audio-Editing Software
Windows, macOS, LinuxOpen-source Audacity can record and edit audio files on more tracks than you can imagine. It then outputs exactly what you need. It is perfect for noobs and pros alike, on any desktop OS.
Best Free Video Converter
Windows, macOS, LinuxNo one would call HandBrake simple, but it's hard for any other video transcoder to compete in power and comprehensiveness. Transcode means to convert; Handbrake will turn almost any video format into another video format. It's free, it's open-source, and it has years of practice.
VLC media player
Windows, macOS, Linux, iOS, AndroidThe premier way to watch just about any video, no matter the video's weird codec, VLC media player has features including auto-rotating smartphone videos taken at the wrong orientation and resuming playback from where you stopped. Seriously, VLC plays back anything on all desktop platforms, and it guarantees no ads, tracking, or spyware. (For more, read How to Play DVDs in Windows 10.)