Mediaportal PVR client for Kodi Live TV worked fine with LibreELEC 7.90.003, but in the following alpha versions it became worse; after some seconds the image was freezing, including Kodi.
In Kodi -> Player settings -> enable „Sync player to display“.
On Rpi1 and Rpi3 it can help to enable OMX Player hardware acceleration instead. Unfortunately, it did not show any effect on my Rpi2.
If you deploy settings using advancedsettings.xml, you can use this configuration part: