Fixes: runtime error: index 16 out of bounds for type 'int [16]'
Fixes: 2209/clusterfuzz-testcase-minimized-5012343912136704
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 1cb4ef526dd1e5f547d0354efb0831d07e967919)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>