RTSP stream working fine on web but showing a static image on Android app

I configure my reolink RLC-411WS stream in Vera:
rtsp://usr:password@mycam:554/h264Preview_01_sub

Encoding for the channel is set to 640x360 at 4fps (max 128kbps) with Main H.264 Profile.
Set those pretty low to limit the bandwith over mobile network.

The stream works quite well on the web, but on the Android mobile, I only get a static image.
Any idea why or how to what the encoding values should be to make it work on mobile too?