Tremor Video announced earlier today that in June it served 98.3% of its in-stream video ads in players that were 400 pixels or bigger. Tremor has found that the bigger-sized players drive double the engagement rate and also boost completion rates for ads. Based on its own analytics, Tremor found that for ads appearing in 400-500 pixel players, 62% of viewers watched to completion and for ads appearing in a 500-700 pixel player, completion jumped to 75%.

Tremor believes that as player sizes get bigger the viewing experience becomes more TV-like, therefore inducing users to relax and be more prone to sit through ads. Looking ahead, this bodes well for ads on connected TVs, where the content and ads are seen in full screen. Tremor said that it is advising publishing partners to increase the size of their players in order to deliver improved ad performance.

Related, Hulu must also be finding similar results; back in March it increased the size of its video player by 55% to a beefy 900x500.