Media starts

The Media starts metric counts every media session that began. It is incremented as soon as the backend receives a media.sessionStart event, even if the viewer drops out during pre-roll ads, buffering, or before any main content plays. Use it as the broadest top-of-funnel metric for media reporting; pair it with Content starts to measure ad and buffer drop-off.

How this metric is calculated

The media backend sets mediaReporting.sessionDetails.isViewed = true when a media.sessionStart event is received. The reported metric is 1 per session. Media starts is reported on the start call, not the close call. It is the only Phase 1 metric that does not wait for session close.