Audio Formats Supported by Windows Media Player 11
Audio formats may be considered as uncompressed, lossless and compressed. For more information on this, see my article at http://www.brighthub.com/electronics/home-theater/articles/36347.aspx. The completely uncompressed audio formats supported by WMP11 are .cda, as used on audio CDs, .wav the native uncompressed format for Windows and .aiff which is the native uncompressed format for the Apple Macintosh platform.
Lossless compression offers the chance of smaller file sizes without information loss. Lossless formats include WMA Lossless supported by WMP11, Apple Lossless used by users of iTunes who require high quality audio, and FLAC, an open source alternative. Neither of the latter two formats is supported by WMP11 by default.
A wide range of compressed audio formats are supported by WMP11 in a range of resolutions and sampling rates. It is important that many of the audio file formats are file containers, and can be used with a variety of codecs (coder/decoders). Thus .wav files are container files and can support a range of compressed formats using different codecs, provided that your WMP installation has the appropriate codec installed.
WMP 11 supports a wide range of audio codecs including .mp3 and mp2. It can also play MIDI files widely used in digital music creation.
However, if your chosen format is not part of the default installation, in some cases, you can add an add-on to handle additional formats. I use Windows Media Player to successfully to access my FLAC-encoded audio files using an add-on at http://dfn.dl.sourceforge.net/sourceforge/flac/flac-1.2.1b.exe.