The highest quality free audio codec is known as FLAC. It is lossless and has no compression, so when you listen to the music you are able to hear all the instruments with clarity.

Free Lossless Audio Codec.

By 'lossless' it means that when you rip a CD to .flac, no data is lost during the ripping process (unlike mp3, ogg vorbis, wma, etc)

DTS-HD Master Audio is a lossless audio codec found on many devices. It is often found with Blu-ray and is the standard Blu-ray lossless audio format.

FLAC files are free lossless audio codec files. You can listen to these files by downloading WinAmp onto your computer and then downloading the FLAC Plugin.

FLAC, stands for Free Lossless Audio Codec. It's a Lossless codec, which means that the resulting data from a transcode be exactly/close to same as the original.

Many uncommon Portable Media players offer FLAC codec support, however it's rare to use them since Lossless files always tend to be over 100mb.

There are Many media players out there that will play .flac files, such as winamp, jetaudio, foobar2000, vlc, kmediaplayer, Xion, and much more.