The streams on a YouTube channel's Live tab — past, in progress and scheduled in one list, and the state of each is not returned. A stream that is live right now carries metrics.watching, the exact number of people watching.

The streams on a YouTube channel's Live tab (served by YouTube at /streams). WARNING: past, in-progress and SCHEDULED streams come in one list and the state of each is NOT returned -- measured badges include LIVE and Upcoming. Call youtube/video by the id and read isLiveContent. No metric is returned: a scheduled stream has no views, and the tab metadata reads "N waiting" or "N watching" -- the second is an exact count of people watching right now, and it still does not fit: metrics has four keys and a concurrent viewer is none of them.