qdm2: check array index before use, fix out of array accesses

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit a7ee6281f7ef1c29284e3a4cadfe0f227ffde1ed)
1 file changed