Fixes: unknown_unknown_19e_414_cov_764838672_bellhamlam.mov

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 053e80f6)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>