Here's a short sample so you can see for yourself. Sample. I copied the sample from my Ultimo to my PC.
This is happening on SD and HD channels. You can't really see it on your PC but if you view it on the media player of the Ultimo you can see what I'm talking about. So basically I'm seing minor pixellation on all channels but I shouldn't be seing that on the Sly Sports F1 HD channel as the bitrate of the episode is high at 17 Mbps on a non-action scene.