gstreamer - GStreamer is a library for constructing graphs of media-handling components. The applications it supports range from simple Ogg/Vorbis playback, audio/video streaming to complex audio (mixing) and video (non-linear editing) processing.
FFmpeg - Open source multimedia suite for conversion, playback, profiling, and streaming.
HandBrake - HandBrake allows users to easily convert video files into a wide variety of different formats.
Adobe Media Encoder CC - Create optimized video for any screen size and resolution with Adobe Media Encoder. Available only in Adobe Creative Cloud.
MPlayer - MPlayer is a movie player which runs on many systems (see the documentation).
PipeWire - Low-latency multimedia framework for Linux audio and video, supporting PulseAudio, JACK, ALSA and GStreamer applications