This information can be gleaned by examining the encoding used on the various C-band satellites used to distribute the feeds for networks to cable providers. Look at all this MPEG-4 on Galaxy 13
, AMC 11
, and AMC 10
(there are even more satellites than these three that supply providers but these three carry a huge chunk of the cable networks).
These satellites are where Verizon gets the networks. They retrieve them with their satellite dish farms at their Super Head-ends in Illinois and Florida, re-encode them to MPEG-2, and then pass them on to their VHOs via their fiber optics backbone.
Would be nice if we could just use our own C-band satellite dishes and subscribe to the networks directly, but nope, we've gotta go through obnoxious middlemen like Verizon, the cable providers, and DirecTV/Dish Network with their stupid "pizza pan" dishes. The networks will only sell receivers with access to these encrypted feeds to cable providers, not end users.
The days of being able to pick your channels a la carte and watch the network feeds directly from the source are long gone; cable industry and pizza pan satellite greed killed that business model off long ago.