CVE-2021-38171: avformat/adtsenc: return value check for init_get_bits in adts_decode… · FFmpeg/FFmpeg@9ffa494

adts_decode_extradata in libavformat/adtsenc.c in FFmpeg 4.4 does not check the init_get_bits return value, which is a necessary step because the second argument to init_get_bits can be crafted.