720p or 1080i


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Aug 10, 2019
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Which format is best, overall? I would have thought 720p would be better as its effectively got more than double the detail per frame than 1080i, unless im misunderstood about how interlacing works. Does the even feild from the previous frame stay up when the odd feild from the following frame is displayed?

Andrew Everard

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May 30, 2007
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It can really vary from screen to screen. Some 1080i-capable screens look better with 1080i, others with 720p. Whatever the technicalities - and it's to do with the way the fields are drawn alternately in interlaced, with persistence of vision doing the rest - I'd advise a 'suck it and see' approach when deciding which is best for your set-up.


Bear in mind 1080i as a signal used in broadcast can come about one of two ways:

1 - film which was originally 1080p (24 or 25 frames) is interlaced into 1080i (50 or 60 frames). In this case, a GOOD TV can perform what is known as cadence detection, and can reassemble the frames without any loss.

2 - video which was recorded using a 1080i film camera directly as 1080i 50 or 60 frames. In this case each frame is from a slightly different point in time (rather than above where each pair of frames has been created from a single, whole frame). Here you can get deinterlacing artefacts which I won't go into detail here or I will be here forever!!

For me personally, HD sport should have been 720p50. This means the signal will have a TEMPORAL RESOLUTION advantage i.e. there are 1280x720 pixels, times 50 unique frames a second. If you ever get a chance to see 720p50 you will be amazed just how fluid the image is. 1080i50 has a SPATIAL RESOLUTION advantage i.e. there are more pixels a frame, but half the amount of frames a second. This better where detail is more important over movement.

(HD-DVD and Blu-Ray are 1080p24 disc, the output is either interlaced to 1080i or downscaled to 720p. 1080p50/60 isn't something we can get on disc or over the airwaves)