Function egl_import_fourcc 

fn egl_import_fourcc(code: Fourcc) -> Fourcc

The NVENC packed input format whose byte order is a dmabuf’s: the XR24 / AR24 family is B,G,R,A in memory (NVENC’s word-ordered ARGB), the XB24 / AB24 family R,G,B,A (ABGR). None for any other fourcc — nothing NVENC reads as packed 8-bit RGB. The fourcc a dmabuf is described with for CUDA’s EGL import: the alpha-carrying twin of an X-format, since the NVIDIA driver refuses XRGB/XBGR images there while the bytes lie identically and NVENC ignores the alpha channel of ARGB/ABGR input.