nvh264enc and gstreamer

Integration
1

Hi,

I need to send 10 simultaneous videos from the same device.
The only available option is to use hardware-accelerated encoder

I have the following pipeline:

gst-launch-1.0 rtpbin name=rtpbin rtp-profile=avpf \
    videotestsrc is-live=true ! \
    videoconvert ! \
    nvh264enc preset='low-latency-hq' ! \
    "video/x-h264,profile=baseline,level=(string)3.1" ! \
    rtph264pay pt=103 ssrc=2222 ! \
    rtpbin.send_rtp_sink_0 rtpbin.send_rtp_src_0 ! \
    udpsink host=${videoTransportIp} port=${videoTransportPort} rtpbin.send_rtcp_src_0 ! \
    udpsink host=${videoTransportIp} port=${videoTransportRtcpPort} sync=false async=false

the consumer connects but I cannot see any frame.
any tip?