Aqualung is a music player for the GNU/Linux operating system. It plays audio files from your filesystem and has the feature of inserting no gaps between adjacent tracks. It also supports high quality sample rate conversion between the file and the output device, when necessary. Almost all sample-based, uncompressed formats (e.g. WAV, AIFF, AU etc.) are supported. Files encoded with FLAC (the Free Lossless Audio Codec), Ogg Vorbis, Ogg Speex, MPEG Audio (including the infamous MP3 format) and MOD audio formats (MOD, S3M, XM, IT, etc.), Musepack are also supported.

Located here is a basic decoder for Apple Lossless Audio Codec files (ALAC). ALAC is a proprietary lossless audio compression scheme. Apple never released any documents on the format. What I provide here is a C implementation of a decoder, written from reverse engineering the file format. It turns out that most of the algorithms in the codec are fairly well known. ALAC uses an adaptive FIR prediction algorithm and stores the error values using a modified rice or golumb algorithm. Further details are in alac.c.

It is true! MP3 format is the most common format we normally use in our everyday applications but MP3 is a lossy compression algorithm and it is not comparable with the quality of uncompressed audio formats as Monkey’s Audio, ALAC, WMA. Nowadays, FLAC is well and constantly supported by many music player producer. We compared FLAC and MP3 formats using the “Brandenburg Concerto No. 3 in G Major - Allegro” by Bach and the results were very interesting. For common listeners (as us) the audio quality was, more or less, the same but when we asked to a couple of friends (authentic music “hooligans”) to describe the difference between the two music files (FLAC and MP3) they spent more than 15 minutes of their (and our) time talking about “tones”, “pizzicato” and something else that I really do not remember at the moment! After the listening, when we compared the file extensions, we discovered that the FLAC file was five times bigger than the MP3 (25.6MB vs 5.1MB)… To conclude, we really think that FLAC represents a fantastic (and the best) lossless format for home stereo systems. On the other side, if you are not a music purist, MP3 could be the best choice for listening music on portable audio devices.