[trsqr]

Nope, it's not. Whenever the nuc needs to do something else ontop of doing the recording, you get pixelation.

Indeed that seems to be the case. External powered USB hub does not help for this. The following works here for reproducing the issue:

1) Start recording of a channel (I took HD channel) from Tvheadend web UI
2) Start watching another HD channel using XBMC live TV functionality
-- At this point there are 0 errors even if I keep waiting for a few minutes --
3) Open the EPG on top of the live TV channel (EPG is overlaid on top of the picture)
-- At this point I start to get continuity counter errors approx once per minute AND they do happen for both the recorded channel and the live TV channel at exactly the same time. Naturally the picture gets pixelated every time there's such an error. I was watching Yle TV2 and recording Yle Fem and got the following:

Code:

May 01 15:10:35 MediaCenter tvheadend[608]: TS: Sony CXD2820R/Digita: 586,000 kHz/Yle TV2 HD: H264 @ #312: Continuity counter error
May 01 15:10:35 MediaCenter tvheadend[608]: TS: Sony CXD2820R/Digita: 586,000 kHz/Yle Fem HD: H264 @ #315: Continuity counter error

4) Hide the EPG and return to full screen live TV and there are no more error and no pixelation. In general it's not too bad, but I'm still not too happy with it. Especially since I can't use 2 tuners simultanously without the xHCI host dying.

EDIT: I don't seem to get any of these errors if I choose Bob instead of Yadif for deinterlacing (not that it matters that much on a 1080i content). When I have De-interlace (yadif) chosen the CPU does not seem to go anywhere near 100% though. The codec info screen shows me CPU for 4 cores (dual core, 2 threads I guess) and at max one CPU seems to peak around 70% while mainly they hover around 10-20%.

There was also a bit suspicious "leaking memory" message in my log file which might be VAAPI related (or maybe not, it's just that earlier messages from that process are VAAPI related). That's at 15:10:31: http://sprunge.us/GLKF

Regarding my other problem with 2 tuners: Has anyone tried 2 USB tuners on the NUC simultaneously and can confirm that it works ok?

By the way, I noticed that if I plug in an USB 2.0 device on any of the ports, it gets plugged into bus 2 (when checking with lsusb). An USB 3.0 device gets plugged into bus 3. So far I haven't found any way to get the 2 tuners on different buses.