Fail init for unknown fft order, to prevent an array overflow
Output sound high-pitched compared to binary. Sample here
http://a1862.g.akamai.net/7/1862/14448/v1/esa.download.akamai.com/13452/qt/ESA_VenusExpress_110K_Stream.mov


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@4724 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b