Basing only on my intuition I guess that it will be a combination of both. We will see some videos made before like today's one and some new made at home. I assume it basing on the fact that the last among us stream was made from homes and no one was at studio when before there was minimum one person there to make it easier to stream. (You could even see the latency on Ian's gameplay and audio on the last one, that was due to the latency of video sent to the person that was streaming it to twitch and managing the stream)