A stream is impacted when it fails to meet one or more of the Streaming Performance Index (SPI) KPI settings. The Overview dashboard shows both the number and percent of impacted streams for the selected period.
Because an impacted stream can be associated with several Improvement Opportunities — such as High Rebuffering leading to a Playback Error (VPF-T) — the percent of impacted sessions may not equal the sum of the individual Improvement Opportunity percentages.
For engagement context: impacted and non-impacted streaming times show the average playing times of the related sessions in minutes. Impacted streaming time is calculated as the sum of impacted session minutes in the current interval divided by the number of impacted sessions. The Impacted stream widget shows a value only when the number of good sessions exceeds bad sessions by 10 percent; otherwise it displays "Engagement difference low."
For the full SPI framework and the specific KPI settings a stream is measured against, see the Overview dashboard and the SPI Introduction.