There are some advance people, trying to warm up the audience. From what I heard, she couldn't get an enthusiastic "Hoo-rah" or whatever the Army equivalent is, out of the crowd. The presidential seal has already been affixed to the podium. I don't see the TOTUS (Teleprompter of the US) in sight.
Either no one is saying anything (no music, either), or the feed is silent. My guess is the feed is not sending audio at this time.
The troops appear to be in wait mode - chatting with friends, standing around. No one is pressing to be close to the front.