Can we get global_quality in AVCodecContext exposed?

[matthewlai]

The flag to enable it is already exposed, but not the global_quality property itself.

https://ffmpeg.org/doxygen/6.0/structAVCodecContext.html#a209f5ec60cb5f0b0a4962f4c5c5bb541

I believe this is currently the only way to do constant quality encoding with VideoToolbox on Apple Silicon1.

Thanks!