CELT is a very low delay audio codec designed for high-quality
communications. Traditional full-bandwidth  codecs such as Vorbis and
AAC can offer high quality but they require codec delays of hundreds
of milliseconds, which makes them unsuitable  for real-time
interactive applications like teleconferencing. Speech targeted
codecs, such as Speex or G.722, have lower 20-40ms delays but their
speech focus and limited sampling rates restricts their quality,
especially for music.