Fixes: timeout (243sec -> a few ms) Fixes: 25716/clusterfuzz-testcase-minimized-ffmpeg_IO_DEMUXER_fuzzer-5764093666131968 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>