Fixes out of array read
Fixes: 544/clusterfuzz-testcase-5936536407244800.f8bd9b24_8ba77916_70c2c7be_3df6a2ea_96cd9f14
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit b1e21920)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>