I told it to use RGBA8 struct instead of `num_pixels` and it got it:
fn convert\_pixels(y\_plane: &mut \[u16\], cb\_plane: &mut \[u16\], cr\_plane: &mut \[u16\], rgba\_pixels: &\[RGBA8\]).and I told it to use aarch64 instead of x86_86, and it converted it!
I'm impressed.