Windows Media Audio Lossless is a proprietary lossless audio codec created by Microsoft as a variant on the (lossy) WMA format. It is one of the four codecs supported by the Windows Media Audio Encoder.
While the format specification has never been publicly released, it has been reverse-engineered and both ffmpeg and libav support the format to some degree.
In addition to the software listed below, WMA Lossless also has hardware support on several platforms including Xbox 360 and Microsoft's Zune portable media player. See the Wikipedia article for more.
- MSDN - Windows Media Audio Encoder
- Sustainability of Digital Formats - Windows Media Audio File with WMA9 Lossless Codec
- MultimediaWiki - Windows Media Audio 9 Lossless
- Microsoft's Digital Rights Management Scheme - Technical Details
- FFmpeg's Windows Media Audio Lossless decoder
- FFmpeg (cross-platform, open source)
- An example WMA Lossless file (luckynight.wma)
- My Experience with WMA Lossless and the Implications Thereof - a brief look at ripping and encoding a CD with WMA Lossless