Possibly fixes: null pointer dereference
Possibly fixes: 9352/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MP3ADUFLOAT_fuzzer-5146068961460224
Fixes: Heap-use-after-free
Fixes: 9453/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MP3ADUFLOAT_fuzzer-5137954375729152

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by: Michael Niedermayer <michael@niedermayer.cc>