16:9 (Landscape)
SizesThe wide horizontal ratio of TV and monitors, standard at 1920×1080 px. It's the native shape for YouTube in-stream video and fits landscape in-feed placements and display banners. On mobile feeds it renders smaller than square or vertical, so it's strongest where the player is already wide.
Example
A 1920×1080 MP4 is the standard upload for a YouTube pre-roll ad.