Fixes: out of array access
Fixes: 16277/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5696629440512000
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 5937f05503)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
tags/n4.2.1