RK Audio
RK Audio (RKAU) is a legacy lossless (and lossy) audio codec for the Windows platform. It was developed by Malcolm Taylor together with RK (a general purpose data compressor) and RKim (a lossless image compressor).
Development apparently ceased around year 2000; the author offered it for download until circa 2005 at his new company MSoftware, which then for a while revived the compression suite (including an audio compressor) as the WinRK archiver, now also discontinued.
Testing by ReallyRareWares and Squeezechart indicated excellent compression level by year 2000 standards, at the cost of high CPU usage. Features were few.
Further reading
| Audio codecs: type/usage | for end-users to encode | on physical media etc. | legacy formats |
|---|---|---|---|
| Lossless | (Uncompr. LPCM) • ALAC • FLAC • Monkey's Audio • MPEG-4 ALS • OptimFROG • TAK • TTA • WavPack | MLP/Dolby TrueHD | La • LPAC/LTAC • RealAudio Lossless • RK Audio • Shorten • WMA Lossless • (others) |
| Lossy | (ADPCM formats) • AAC • AC-3 • MP2 • MP3 • Musepack • Opus • Vorbis | AC-3 • DTS • (Bluetooth codecs) | ATRAC • QDesign • Real Audio • RK Audio (lossy modes) • Speex • VQF • WMA |
| Hybrid lossless&lossy | OptimFROG DualStream • WavPack | DTS-HD MA • MPEG-4 SLS | ATRAC Advanced Lossless • mp3HD |