FOX-HD poor quality / macroblocking
For about the last month, I've noticed a significant drop in quality of FOX-HD (KCPQ HD) on Comcast. The main program I record is Gotham, and I frequently see quite a bit of macroblocking appear in scenes (it will come and go). The most visible artifact is that actors faces will appear to be subdivided into blocks. It's somewhat subtle, but I see it whenever it happens, and it's very distracting.
I'm not sure if this is a change on Fox's end, or Comcast's. KCPQ-HD used to be one of the highest quality channels, even though it's only 720p. The bitrate was consistently high (around 13Mbps).
Does anyone else see this as well? Is the upcoming MPEG-4 switchover responsible?