[noggin]

Not seeing the pixellation issue with regular Progressive 2160p 10bit HEVC, it does show up on some 2160p 10 bit Interlaced Satellite TV test clips I have with the C2. Something to do with B Frames and motion I have been told if my memory is correct.

There is no 2160p interlaced standard... The clue is in the p of 2160p (the p stands for progressive )

If it is 2160lines then it is progressive. There is no interlaced 2160 line standard AIUI.

At one point H265/HEVC was going to be entirely progressive - but when it became clear how efficient it was, it became clear that there were real benefits to introducing it for current and close-to-launch platforms that were still going to use SD and HD interlaced formats, so interlacing was added. However unlike H264/AVC I believe there isn't the same amount of interlaced optimisation (MBAFF, PAFF etc.) and instead the two fields are effectively encoded as two successive half-res progressive frames? (I believe this toolset is also in AVC but once PAFF and MBAFF arrived the benefits of them with H264 were enough to make them worth using?)

If you have a 2160p clip with fluid motion it is likely to be 2160/50p or 2160/59.94p which are the two current UHD1 implementations used for broadcast TV (BT Sport in the UK use 2160/50p for their '4K' IPTV network which launched last year and carries high quality live Premiere League Football coverage. The US Masters in '4K' on DirecTV in the US is 2160/59.94p - distributed as both satellite and IP I believe ?) If the clip has 'film look' motion it is likely to be 2160/23.976p or 24p or 2160/25p. (I suspect, as with HD, 29.97p/30p content will be unusual)