avcodec/bgmc: Check input space in ff_bgmc_decode_init()
Fixes: Infinite loop
Fixes: 16608/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ALS_fuzzer-
5636229827133440
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Thilo Borgmann <thilo.borgmann@mail.de>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit
b54031a6e93d1abc7fb2d0263e0f6c4b639e423f)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>