I believe currently live streaming via browser using Vera UI requires support for flv-streams which Amcrest cameras don't support.
I fiddled around with the MJPEG stream from the Amcrest (http://<camera IP>/cgi-bin/mjpg/video.cgi?channel=0&subtype=1) but it won't work with Vera.
One can define those flv-streams via the same Streams-variable that enables RTSP streams like this :
flv,http,/cgi-bin/mjpg/video.cgi?channel=0&subtype=1;flv_low,http,/cgi-bin/mjpg/video.cgi?channel=0&subtype=1;rtsp,rtsp,/cam/realmonitor?channel=1&subtype=0;rtsp_low,rtsp,/cam/realmonitor?channel=1&subtype=1
After adding the flv anf flv_low parts, Vera will open the flash based stream player in the web UI when live but since the HTTP stream from Amcrest is MJPEG, the flash based player cannot play it.
Those flv and flv_low parts need to be removed to get frame by frame *streaming* back.
I suppose Vera web UI could support the native H.264 RTSP streams via web UI if they implemented a RTSP to WebRTC proxy in the Vera and had HTML5 web UI that can play those webRTC streams. Naturally the used browser should support displaying H.264 via WebRTC as Vera lacks the CPU power to transcode H.264 to something else.
Since openluup allows for much more powerful hardware, I would imagine adding that kind of RTSP to WebRTC proxy with optional transcoding functionality could be implemented into openluup and AltUI. I suppose giving a hint to the openluup and ALTUI develops might be enough

There seems to be some discussion around the subject of streaming RTSP via web pages
https://flashphoner.com/7-ways-to-stream-rtsp-on-the-page/