Camera stream working on website, but not iOS app

I am using the amcrest camera integration (with all the default settings) and I can get a live broadcast on the HA web site, but cannot get a live broadcast on the iOS app to work reliably. When I first go into full screen it may take 5-10 seconds to update. But it quickly stops auto updating and the only way to get the camera feed to update is to hit the +15 sec button.

For the amcrest integration, the default stream_source is snapshot. To get live broadcast working better on iOS, do I need to switch to rtsp or mjpeg?

Here are my various versionings:
HA Supervisor v 209, Host system HassOS 3.12
iPhone 11, iOS 13.3
Amcrest with latest firmware
V2.622.00AC000.0.R, Build Date: 2019-10-24