I've noticed strange effect with the SNR bar. Every time when UNC counter increased SNR bar becomes more and more red. In the same time hex and percent values are fine. Combined screenshot from femon plugin: http://www.pictureshack.ru/images/95487_unc.jpg It's not plugin depended. The same behavior can be observed on standard VDR's channel LCARS skin info bar.
Why UNC occurred, it's a different story. Currently I can't explain why viewing some (not all!) HD channels lead to the UNC (disturbance are visible too). Is it bitrate or something else, I don't know. It seems only 1080i suffer, not 720p and BER stays always on zero. If somebody have any method to debug and find reason of this, I will be thankful for sharing.
My configuration: DD Cine S2 v6.5 (endriss media_buid), kernel 3.12.17, vdr-2.1.6, last softhddevice and GeForce GT520 HDMI for output.