The attribution was removed by libav while moving the code to libavutil

The original code is from
commit eb4825b5
Author: Loren Merritt <lorenm@u.washington.edu>
Date:   Thu Aug 10 19:06:25 2006 +0000

    sse and 3dnow implementations of float->int conversion and mdct windowing.
    15% faster vorbis.

and

commit 06972056
Author: Loren Merritt <lorenm@u.washington.edu>
Date:   Fri Aug 11 18:19:37 2006 +0000

    vorbis simd tweaks
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>