Good news!
MAD now supports the MPEG 2 extension to Lower Sampling Frequencies (24, 22.05, and 16 kHz.)
In addition, the Layer III performance has improved yet again due to a new optimization that avoids the IMDCT calculation when all the inputs would be zero.
I'd appreciate any testing anyone is able to do with respect to MPEG 2 LSF; I have several Layer III streams I could verify but I don't have any Layer I or II streams handy.
The release:
ftp://ftp.mars.org/pub/mpeg/
Cheers, -rob