Hardware H264 encoding resolution limit

I have a hat that produces a raw GRAY8 5120x800 video and I’d like to stream that using Gstreamer. What’s the highest resolution (WidthxHeight) can the Jetson Nano/Xavier hardware encode?

The maximum width is 4096 for Jetson Nano. 5120 should be OK for Jetson Xavier.
GRAY8 is not supported in encoding. Please convert it to YUV420or NV12.