Another excellent test case is the track "Second Bad Vilbel" by Autechre. The rockets at the beginning pose an insurmountable challenge for most codecs. Last I

Another excellent test case is the track "Second Bad Vilbel" by Autechre. The rockets at the beginning pose an insurmountable challenge for most codecs. Last I checked, MP3 at any bitrate couldn't do it, and Ogg Vorbis fell down unless you went up to at least -q7, which is a rather high bitrate (~224kbps).