Type of software that splits an analog or digital signal into multiple signals
A demultiplexer for digital mediafiles, or media demultiplexer, also called a file splitter by laymen or consumer software providers, is software that demultiplexes individual elementary streams of a media file, e.g., audio, video, or subtitles and sends them to their respective decoders for actual decoding. Media demultiplexers are not decoders themselves, but are format container handlers that separate media streams from a (container) file and supply them to their respective audio, video, or subtitles decoders.
libvlc (part of VideoLAN project and VLC Media Player) - demultiplexes many formats e.g. MPEG transport stream, MPEG program stream, MP4, MOV, 3GP, Ogg, OGM, ASF, WMV, WMA, MKV, FLV, etc.
MP4Box, command line MP4 multiplexer/demultiplexer with GUIs like My MP4Box
Playback issues
Playback difficulties (such as no playback, no audio, or no video) may result from several or legacy file splitters for a particular file format being installed on an operating system. This causes decoder-to-file-splitter mismatch resulting in playback failure on media players.