Addon Mediaportal PVR Client Audio and Video problems

I have a htpc with Windows 7 and Mediaportal. Live TV with Mediaportal is working on the htpc. Some weeks ago I tested live tv with a raspberry pi 3 b+ with LibreELEC (Leia Beta 4) and Mediaportal PVR Client addon and everything has been working fine.
Now I have to different TV boxes. Both with S905X chip and 2GB and 16GB. On both boxes I have installed CoreELEC 8.95.4.1
Both boxes have the same problem: when watching HD Content (ZDF HD, ARD HD and so on) the sound is on and off and on and off and the Video is stuttering. On the Screen I get a bar with a percent scale titleld with “Zwischenspeichern” (in english something like “buffering”). All the tv channels with this Problem has 720p Resolution. For example the tv channel “Servus tv hd Deutschland” has 1080i Resolution and here live tv is working great.
When I start live tv on my htpc and I share the live tv stream and I play this shared live tv stream with CoreELEC everything is working fine too.
Someone an idea what to do?

Here you’ll find the Kodi.LOG
Kodi LOG

A few days ago I tested my tv box with CoreELEC 8.95.7 Still the same issue. When watching Live-tv HD channels (german HD channels ZDF HD, ARD HD and so on) the audio goes on and off and on and off and the Video is stuttering. On the Screen I get a bar with a percent scale titleld with “Zwischenspeichern” (in english something like “buffering”). All the tv channels with this problem has 720p Resolution. Have other people the same issue? Is there a solution?

I have no experience with the Mediaportal pvr addon.
With TVH every HD channel is working smooth here.

But looking at your old log at Kodinerds, you have a lot of addons and skins installed.
I assume you also updated directly from LibreELEC or imported a LibreELEC backup into your CoreELEC installation.

Please try a fresh CoreELEC installation on a separate SD card and don’t modify anything except installing and configuring your pvr client.

Hi relkai
a few weeks ago with 8.95.5 I tried this already a fresh CoreELEC install on SD without changing anything else except installing mediaportal pvr Client addon and still this buffering issues.

Okay, then I can’t help you, I’m afraid.
Maybe someone, who uses the same pvr client is able to help you.