Jetson Nano - h264 encoder support Y444 input?

Is there h264 encoder can work with Y444 input on Jetson Nano ? I am using L4T r32.3.1.
From documents and gst-inspect, I know omxh264enc supports only I420 & NV12, nvv4l2h264enc supports only I420, NV12, P010_10LE. While gst-inspect shows that x264enc supports Y444, my test always fail when set appsrc caps as x264enc.

The big background is we need encode source video losslessly on Nano and streaming out to remote server. Even an h264enc supports lossless encode, we need to use Y444 from appsrc to x264enc to avoid color space conversion that is lossy.

Here is example of my test: GST_DEBUG=4 gst-launch-1.0 -v videotestsrc ! video/x-raw,format=Y444 ! x264enc speed-preset=1 ! video/x-h264, stream-format=byte-stream, alignment=au, profile=high ! rtph264pay ! udpsink host=127.0.0.1 port=5500

It gives error like this:
0:00:00.078706771 20242 0x5595994000 FIXME default gstutils.c:3981:gst_pad_create_stream_id_internal:videotestsrc0:src Creating random stream-id, consider implementing a deterministic way of creating a stream-id
0:00:00.079056146 20242 0x5595994000 INFO x264enc gstx264enc.c:227:gst_x264_enc_add_x264_chroma_format: 8-bit depth supported
0:00:00.079285677 20242 0x5595994000 INFO x264enc gstx264enc.c:252:gst_x264_enc_add_x264_chroma_format: 10-bit depth supported
0:00:00.079481406 20242 0x5595994000 WARN basesrc gstbasesrc.c:3055:gst_base_src_loop: error: Internal data stream error.
0:00:00.079582083 20242 0x5595994000 WARN basesrc gstbasesrc.c:3055:gst_base_src_loop: error: streaming stopped, reason not-negotiated (-4)
0:00:00.079717656 20242 0x5595994000 INFO GST_ERROR_SYSTEM gstelement.c:2145:gst_element_message_full_with_details: posting message: Internal data stream error.
0:00:00.079879375 20242 0x5595994000 INFO GST_ERROR_SYSTEM gstelement.c:2172:gst_element_message_full_with_details: posted error message: Internal data stream error.
ERROR: from element /GstPipeline:pipeline0/GstVideoTestSrc:videotestsrc0: Internal data stream error.
Additional debug info:
gstbasesrc.c(3055): gst_base_src_loop (): /GstPipeline:pipeline0/GstVideoTestSrc:videotestsrc0:
streaming stopped, reason not-negotiated (-4)
ERROR: pipeline doesn’t want to preroll.
Setting pipeline to NULL …

Appreciate for any help or suggestion that can achieve lossless coding (without color space conversion).

Hi,
It is not supported on Jetson Nano. Need to use TX2 or Xavier. The commands for verifying the function: