always perilous suggesting non-perl in the monastery particularly when eminent monks have pointed out the uses of binmode but i would use

od -c mumblefile

to scan through that mumble-provoking file of yours, then use

strings mumblefile

to extract all human readable content. those 2 have worked nicely for me previously on binary & corrupt files.

there have been rumours strings in particular occasionally yields interesting results when pointed at binary files.

ermmm, you need cygwin for this, which i presume is already installed, mumble mumble...