When will the 720p be outdated?

Answer 1

720p is one of the two main HD resolutions being used. The other is 1080i. The number refers to the number of lines making the picture and the letter refers to the scan type: p for progrsseive scan and i for interlaced. Effectively, 720p runs at 60Hz (USA) or 50Hz (European) and 1080i runs at 30Hz or 25Hz. Broadcasters use one or both of them for current HD broadcasts with 720p being used more for sport and 1080i for drama and features. 720p is likely to be replaced by 1080p in the future but that won't be for a number of years. 1080p currently is not handled by any of the major broadcasters for live material and equipment for 1080p is still at early stages of development. Because it uses twice the bandwith of 720p and 1080i, it requires more storage, more bandwidth on transmission chains and it will be some time before these become common. When 1080i can be handled in live production, stored economically and broadcast without sucking up numerous other channels, we can look forward to high resolution, 60Hz material which will be well placed to push 720p aside. As a very personal prediction, as broadcasters are fight now investing in 720p and 1080i broadcast chains, we should expect them to move to 1080p only when the come to upgrade to new equipment - say, 5 years onwards. Until then, 720p will be a big part of HD content.