FLAC is a Free Lossless Audio Codec. The FLAC format supports streaming, seeking, and archival, and gives 25-75% compression on typical CD audio. Input plugins for Winamp and XMMS are also provided.
FLAC stands for Free Lossless Audio Codec. by encoding audio files with FLAC, the quality is exactly the same as the original audio file's quality is. This is exactly unlike the audio formats such as MP3 and WMA work -- these audio formats are called "lossy" and that means that when the original audio is encoded into the lossy audio format, some of the audio data is lost forever and can't be brought back by any means. ID3 ID3 is a small piece of information stored physically inside the MP3 file (in the beginning or in the end of the file, depends on ID3's version). ID3 tags can contain various information about the MP3, like album name, song name, artist, original artist, genre, composer, releasing year, additional comment fields, etc.. Nowadays ID3s are de facto in audio world and they can be added to most of the audio formats and even to certain video formats in order to provide additional information of the file. View ID3 Tag Editor.
A codec similar to MP3, but "lossless" in that it completely preserves a file's audio fidelity (at the price of a larger file size than "lossy"). FLAC is free and its source code is open, so users and developers are able to view code and extend its functions.