VLC is a free and open source cross-platform multimedia player and framework that plays most multimedia files as well as DVDs, Audio CDs, VCDs, and various streaming protocols.
VLC Media Player vs KMPlayer opinions
Not so powerful and easy to use as KMPlayer.
No shovelware, ads or other unwanted crap.
Lite weight and supports many video formats.
SMPlayer intends to be a complete front-end for MPlayer, from basic features like playing videos, DVDs, and VCDs to more advanced features like support for MPlayer filters and more. SMPlayer remembers the settings of all files you play.
Audacious is an advanced audio player. It is free, lightweight, based on GTK+, runs on Linux and many other *nix platforms and is focused on audio quality and supporting a wide range of audio codecs. There is also support for several visual styles from Winamp.
Audacious vs KMPlayer opinions
its just for audio file not video
MPlayer is a movie player which runs on many systems (see the documentation). It plays most MPEG/VOB, AVI, Ogg/OGM, VIVO, ASF/WMA/WMV, QT/MOV/MP4, RealMedia, Matroska, NUT, NuppelVideo, FLI, YUV4MPEG, FILM, RoQ, PVA files, supported by many native, XAnim, and Win32 DLL codecs.
MPlayer vs KMPlayer opinions
Miro (formerly Democracy Player) is a free and open source internet TV application, media library, and video player.
No updates since 2013. Youtube intergration broken because of no updates since youtube API changed. See changelog: http://ftp.osuosl.org/pub/pculture.org/Miro/
Videos (previously Totem) is the official movie player of the GNOME desktop environment based on xine-lib or GStreamer. It features a playlist, a full-screen mode, seek and volume controls, as well as keyboard navigation.
SVP allows you to watch any video on your PC file with frame interpolation (like you can watch it on high-end TVs and projectors). It increases frame rate by generating intermediate animation frames between existing ones to produce very smooth, fluid and clear motion.
Musique unclutters your music listening experience with a clean interface that keeps you focused on what really matters: music.