NvDecoderGL with 4:4:4 subsampling

Hi,
In the decoder sample (NvDecoderGL)why is not possible to decode .h264 video with a 4:4:4 subsampling?
Does it exist a mean / code modification for including this possibility? Maybe by changing the NV12ToRGBA file?
Because in NVDecoderGL sample, just the 4:2:0 is assumed
Thank you.

OS