MPlayer

MPlayer was the best video player for a long time. Then a fork happened and many developers left for MPlayer2. That was in turn abandoned for mpv which is now the most updated and feature-rich branch. MPlayer is still updated and alive but updates are essentially just small fixes to make sure it still compiles against modern versions of ffmpeg.

MPlayer comes with a video conversion tool called mencoder. This has also not been more than barely maintained for decades.

The modern alternatives

• mpv is a better and more updated stand-alone player than mplayer (and mplayer2)
• SMPlayer is a better choice than GMPlayer if you want a video player with a graphical interface
• ffmpeg is a far better tool for converting audio or video than mencoder.

Links

• mplayer's website: http://www.mplayerhq.hu/
• mplayer and mencoder manual
• http://www.mplayerhq.hu/DOCS/man/en/mplayer.1.html

Alternatives

Program	rating	framework	backend	highlights
Celluloid		GTK	mpv	Has a playlist. Otherwise very limited.
GNOME Videos		GTK/GNOME	gstreamer	Useless GUI, problems playing a lot of files
mpv			libmpv	On-screen controls. No playlist, no GUI. Plays everything.
VLC			libvlc	Fully featured. Playlist, advanced playback options, video conversion, live stream recording
SMPlayer		Qt	mpv	Fully featured. Playlist, advanced playback options, easy to use.

discontinued: Xine | GMPlayer | MPlayer