Hi @HoaiThanh,
It looks like Tony may have thought you were using our USB camera, which has onboard H264 encoding.
From QGroundControl’s documentation, it seems like UDP video requires H264 or H265 encoding. You could try using an RTSP stream with MJPG encoding instead, but if that doesn’t work then you may need to receive the video outside of QGroundControl (with the reduced convenience that provides), or get a camera with an H264-encoded output stream option.