Which metric indicates when your video is watched in 50% view for 2 seconds or more, or when someone clicks to expand/unmute your video?

Which metric indicates when your video is watched in 50% view for 2 seconds or more, or when someone clicks to expand/unmute your video?

 

• A 6s/50% pre-roll/video view
• A 3s/100% pre-roll/video view
• A pre-roll view or a video view
• A 15s pre-roll/video