AC3Filter: DirectShow AC3 filter.
Free Lossless Audio Coder: FLAC is an open source lossless audio codec, supports streaming, seeking and archival.
MPE Secure Media: Secure streaming media format giving authors, songwriters and publishers complete control over products distributed through the internet.
Musepack: Open audio compression format also known as MPC or MPEGPlus/MP+. Based on MPEG1 Layer-2/MP2 algorithms.
OptimFROG: Loseless audio compression supporting IEEE Float audio data.
Speex: Open audio codec designed for speech, part of the Xiph.org Foundation.
Study on Audio Compression: Detailed comparison of various audio compression algorithms including ASF, RealAudio, MP3, Ogg Vorbis, MOV, and VQF.
The Void: PC Audio Resource: Information about computer audio formats and sound cards.
True Audio: Open lossless audio codec developed with the main requirements of reasonable compression level and high operation speed.
Vianix Corporation: Developed MASC technology (Managed Audio Sound Compression) memory-efficient audio compression algorithm providing voice emulation.
WavPack: Open audio codec facilitating both loseless compression and a unique hybrid compression mode.