XMedia Recode can convert almost all known audio and video formats.
https://www.xmedia-recode.de/en/

XMedia Recode can convert almost all known audio and video formats.
https://www.xmedia-recode.de/en/
MediaInfo is a convenient unified display of the most relevant technical and tag data for video and audio files.
https://mediaarea.net/en/MediaInfo
Kodi is an award-winning free and open source (GPL) software media player and entertainment hub that can be installed on Linux, OSX, Windows, iOS, tvOS and Android. It is designed around a “10-foot user interface” for use with televisions and remote controls.
Users can play and view most videos, music, podcasts, games and other digital media files from local and network storage media and the internet.
https://kodi.tv
MKVToolNix is a set of tools to create, alter and inspect Matroska files under Linux, other Unices and Windows.
https://mkvtoolnix.download/index.html