FFmpeg - Open source multimedia suite for conversion, playback, profiling, and streaming.
Ant Media Server - Scalable, Ultra Low Latency & Adaptive WebRTC Streaming Ant Media Server provides Scalable Ultra-low latency (0.5 seconds) Adaptive Live Streaming with WebRTC. It supports RTMP, RTSP, Zixi, WebRTC, Adaptive Bitrate, HLS and MP4 recording.
Xvid - Xvid is an open-source research project focusing on video compression and is a collaborative...
Red5 - Red5 is an open source Flash media server for live streaming solutions of all kinds.
FLAC - A free, open source codec for lossless audio compression and decompression
Nimble Streamer - Light-weight media server that is freemium, pay for control panel if you need it.