Fixes assertion failure
Fixes: 03e0abe721b1174856d41a1eb5d6a896/signal_sigabrt_7ffff6ae7cc9_3813_e71bf3541abed3ccba031cd5ba0269a4.avi

This fix is choosen to be simple to backport, better solution
for master is planed

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>