Thread 27 has EXC_BAD_ACCESS somewhere in libavcodec (no symbols) while thread 1 is in ~Image (called by ~PlayerVideo in FFmpegEncoder::go)

Looks like it's nothing to do with the ~Image; the crash is exactly repeatable even with all the memory deallocation disabled.

Seems to be in x264_8_cabac_block_residual_rd_internal_ssse3_lzcnt

./ffmpeg -i ~/workspace/src/dcpomatic/test/data/test.mp4 foo.mp4 segfaults too.

Also happens with a relatively new FFmpeg revision 3f4ce004b8afa915499c367e78ae080bc457624c

Build from https://evermeet.cx/ffmpeg/ is fine

Xcode 12.2 gives Apple clang version 12.0.0 (clang-1200.0.32.29)

It looks like it's the nasm version; 2.15.05 seems to fix it.