Rewrite the SBR decoder QMF analysis filter on top of the IMDCT instead of the RDFT.
This is based on a procedure to implement the filterbank on the DCT-IV described in
Hsu, H.W. et al. "A Complex Quadrature Mirror Filterbanks for MPEG-4 HE-AAC"
Originally committed as revision 23516 to svn://svn.ffmpeg.org/ffmpeg/trunk