I have a Vero 4K that, apart from streaming, I use to watch for the postman via CCTV. When streaming from a HikVision camera with hardware H264 enabled, the image will go black a few seconds after the stream starts.
I went through most of the older images in the downloads section and images vero3_20191118 through to vero3_20201227 stream fine with hardware H264 enabled, so this seems to be a bug with the latest software.
I am using an RTSP stream and have tested the output on an HDMI monitor and an LG 4K TV at various resolutions and frame rates with the same result.