What is a media impression and impression rate?

A media impression is counted each time a visitor loads a page that contains video or audio content. An impression does not mean the media was played. It only means the media was present on the page. When a visitor starts playing the video or audio, Matomo tracks this as a Play Event.

The impression rate shows how often a specific media item appears relative to your audience size. It is calculated by dividing the number of impressions by the number of unique visitors for the selected period. For example, if a video appears on pages viewed by 100 unique visitors and generates 200 impressions, the impression rate is 2 impressions per visitor.

The impression rate is available only for periods where the Unique Visitors metric is supported.

How is this different from the play rate?

The play rate measures engagement, not visibility. It represents the percentage of visitors who played the media compared to those who loaded a page containing it. For example, if 100 visitors loaded a page with a video and 30 of them played it, the play rate is 30%.