The type of event that initiated video playback, or "unspecified" if the event is unknown.
Possible autoplay values include:
- Page load with sound on
- Page load with sound off by default
- Mouse-over with sound on
- Entering viewport with sound on
- Entering viewport with sound off by default
Possible click to play values include:
- Click with sound on
Publishers must include the dc_vpm parameter in placement tags for data to populate in this dimension.