[magmastonealex]

Yes, ATSC in North America generally uses MPEG-2 video, in an MPEG-2 transport stream (often with AC-3 as the audio codec).

There are provisions to use h.264 within that transport stream, but I'm not sure if any stations actually broadcast with that.

[mrpippy]

Some cable systems (Comcast has been migrating I believe) do use H.264, but I don’t know of any OTA usage. There is “Mobile DTV” AKA ATSC-M/H which uses H264 and is designed for mobile reception, but stations are rare and commercial adoption is nonexistent.