The Ultra HD movement has taken many twists and turns since its inception, with a gradual switch in emphasis towards better pixels rather than just higher resolution. With the best of intentions there has admittedly been some confusion not just among consumers but also pay TV operators, content owners and broadcasters, some of whom seem unsure about whether and when to commit to a given version of ultra HD at a time of flux.

Source: Ultra HD crystallizes around Phase A – Ultra HD Forum