Fixes: Timeout
Fixes: 63661/clusterfuzz-testcase-minimized-ffmpeg_dem_LAF_fuzzer-6615365234589696

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpegReviewed-by: Sean McGovern <gseanmcg@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>