outside the range of int at libavfilter/vf_dctdnoiz.c

[Suhwan]

Summary of the bug:
There are an outside the range of int and 2 integer division by zero at libavfilter/vf_dctdnoiz.c

I compiled ffmpeg with "--toolchain=clang-usan" to check the undefined-behaviours and attached log file.
How to reproduce:

% ffmpeg_g  -y -i $PoC -filter_complex dctdnoiz -target dv -loglevel 0 -map 0  tmp.epaf

ffmpeg version N-95343-ge835a9d302 Copyright (c) 2000-2019 the FFmpeg developers
built with clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)
configuration: --cc=clang --cxx=clang++ --ld=clang --enable-debug --toolchain=clang-usan

Here's UBSAN log

libavfilter/vf_dctdnoiz.c:593:39: runtime error: division by zero
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior libavfilter/vf_dctdnoiz.c:593:39 in 
libavfilter/vf_dctdnoiz.c:593:15: runtime error: inf is outside the range of representable values of type 'int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior libavfilter/vf_dctdnoiz.c:593:15 in 
libavfilter/vf_dctdnoiz.c:613:45: runtime error: division by zero
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior libavfilter/vf_dctdnoiz.c:613:45 in

Please confirm.
Thanks

[Suhwan]

poc

[Elon Musk]

Fixed in 4a3917c02c428b11128ac3d4a01b780ea44aa53c