Live TV ends in login console

[IriDium]

Ok nothing strange there.

So it's definiely an Addon/PVR issue.

xbmc.log shows certain ffmpeg errors.

You could try installing ffmpeg and see if that improves things. sudo apt-get install ffmpeg.
Then change streaming method from TSreader to FFmpeg.
Also check your MPEG license is correct. sudo vcgencmd codec_enabled MPG2

Apart from that I have no idea. Best to wait and see if anyone else has MediaPortal or post a question on their forum.