libmad 0.15.1b assertion failure

I accidentally loaded some non-audio data in my application, and I'm
getting:

a.out: layer3.c:2640: mad_layer_III: Assertion `stream->md_len + md_len - si.main_data_begin <= (511 + 2048 + 8)' failed.

I'm using the low-level interface.  I can reproduce this with madlld,
if I change INPUT_BUFFER_SIZE from 5*8192 to 4*8192 or lower (my own
buffer is 16k).

The file (edited down as small as I can get it while still triggering
this) is at:

        http://zewt.org/~glenn/testfile

There's some MPEG-1 video in there, which I suppose MAD is picking up;
that's fine, I just want it to gracefully play garbage or give a fatal
error, without dying.

-- 
Glenn Maynard