But yes, when it says available in HD, you can change to the corresponding HD channel (Fox, NBC, etc…) and it should be the HD broadcast. The HD channels have a slight delay on them, but some will be close to simultaneous.
there’s 2 discovery hd channels. one is discovery hd and the other is discovery hd theatre. it should be below channel 200… comcast added a couple more channels this past month or two. tbs, usa, discovery