I'll agree with the above. I really don't want to be an apologist for interlace as such, just agree that the attitude of the broadcasters here (that it may be the lesser of two evils) has some merit. Especially if much programming is 1080p/25 anyway. But roll on 1080p/50(60) indeed.Barry_Green said:
It's also worth noting that much of what the EBU stated 18 months ago was based on a previous document nearly two years ago, itself based largely on previous BBC research into screen size, viewing distance and resolution - http://www.ebu.ch/en/technical/trev/trev_home.html , then item 300 ("High Definition for Europe — a progressive approach")
Perhaps key to that whole document is the first paragraph of their conclusions. "The EBU Technical Committee recommends progressive scanning for HD delivery, for a number of reasons. The principal reason is that it removes the need for interlace-to progressive display conversion at the receiver, and it makes the delivery system more future-proof."
It was in that context that Yves Faroudja made his comments. A 1080i signal fed to a 1080 resolution screen needs no such display conversion.
It is also important to note that the EBU is primarily recommending progressive - not 720p/50. They go on to then recommend 720p/50 later (on the basis of the BBC research) but with the key proviso of: "......GIVEN THE ASSUMPTION THAT (the HD viewer) HAS A WIDEXGA DISPLAY." (My capitals.)
So what's going on? Why, two years later, is the BBC seemingly going against it's own research, and itself requiring only 1080 delivery? Quite simply, display technology has advanced far, far quicker than nearly anybody foresaw, and the expectation is that by the time HD broadcasting reaches a significant number of people in the UK, 1080 resolution screens will be the norm, not WideXGA - so scaling of 1080 signals will not be an issue.
Secondly, the cost of the displays has plummeted as their quality has improved, and the public has shown an appetite for much larger screens than was envisaged in that research. The assumption was made (top of page 7) that "the vast majority of large flat screens for European homes will be in the range 30 to 40 inches". Go into any large UK electrical retailers today, and you will see that this assumption is no longer valid. Screens of 42" - 50" boasting "HDReady" are very common. Hence the conclusions now being drawn from the BBC research are very different - 720p/50 is no longer adequate for a much larger percentage of viewers than originally thought, only a couple of years ago.
Half way down page 2 the author says: "The display manufacturers tell us that the "core" flat panel - the "design target" for broadcasting - should be the "WideXGA" flat panel, which is a 768-line progressively-scanned display. This is a key assumption, and it should be clearly stated that we have to rely here on information received from outside sources." It's generally accepted now that this assumption is no longer valid. The core panel is increasingly likely to be 1080 resolution, especially in the larger sizes where this has most relevance anyway.
Hence the feeling now is still for progressive, but much less 720p - it's now seen as too incremental a change - more 1080p for the future.
Regarding the HVX, then yes, Barry is spot on, the image is true progressive, but carried over an interlace system. As such, the true terminology is "psf", but the important thing to appreciate is that psf to p conversion (and vice versa) is totally transparent (unlike scaling, or true i to p conversion). It's exactly the same as a film telecined for interlace transmission.
