I just found:
Quote:
1080i vs 1080p -> MYTH VS REALITY (the ultimate test sequence)!
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Oh no, not another 1080i vs 1080p/60/24 thread...
I know, I know...This has been discussed ad absurdum.
I will spare you the general discussion about this topic - the search function is your friend.
To put it simple: Generally there are two "opinions"/ point of views about the whole matter:
1) 1080i holds all the resolution of the original film frame and is just another method of transfering the picture information (fields vs frames delivery). Given that we talk about film based (24p) content. And given that the display unit or an intermediate video processor is able to restore (-> Inverse Telecine) the original progressive film frames from the 1080i stream. Given the very nature of HD-DVDs pure progressive encoding this should be an easy enough task for just about any modern display device.
THEREFOR 1080i output is indistinguishable from 1080p output. It just doesn't matter and is only a marketing instrument.
2) The other view is to agree with the above arguments BUT also to recognize that in reality things are a little different... I've always been a very STRONG proponent of untouched, unaltered, unprocessed 1080p output (ignoring the inherent HD-DVD 3:2 pulldown flags and decode the native 1080p stream), ideally @ 24p. But does it really matter?
MYTH versus REALITY.
Instead of arguing and picking sides based on beliefs and which expert's opinion one trust is there no real world test sequence that proves beyond any doubt if there is relevance to pure 1080p output or not?
YES, there is.
No, it is not some artificial, strange cadence sequence from a special HD-DVD test disc. It is a sequence from a common disc many of us have right at home.
Mission Impossible III. Chapter 8. Timecode 46:54. The staircase.
Before you ask - NO, this is not an artifact. This is just a real world sequence with very fine, high frequency detail. In movement. That shows how inadequate 1080i processing in reality really is. HD-DVDs are said to be mastered in 1080p - although there really still isn't any way of seeing the native, progressive stream (with the exception of some immature HTPC solution). This this sequence is stored perfectly on the disc. So why is just about anybody seeing moire and "shimmering" artifacts???
My test setup: Toshiba XE1 (= rebadged european XA2, I use the term "XA2" in the following to avoid misunderstandings), HDMI connection to a Sharp Z20000 native 1080p DLP front projector (it is fair to call it state of the art...).
Test 1: XA2 set to 1080i output, Sharp Z20k does the "deinterlacing"/IVTC. This (=1080i output from A1, A2, E1) certainly is the most common configuration among HD-DVD users.
result: Very disturbing moire and interlacing artifacts, nomatter which "deinterlacing" mode I choose with the Sharp. The staircase is a real mess. So my display unit is not any good then... Quick reality update -> the Sharp Z20k is a bleeding edge $11,999 unit, introduced to the market Q406, native 1080p resolution (no scaling whatsoever involved, perfect 1:1 pixel mapping). It may not have the very best internal processing out there (no hyped Gennum or HQV processor to be found ) BUT is likely far beyond any ordinary HDTV/plasma/LCD set - Greg Rogers (WSR) rates the 1080i IVTC as "flawless" in his review...
Test 2: XA2 set to 1080p output. Film progressive mode selected in setup menu. Straight 1080p HDMI connection to the Sharp Z20k.
result: Obviously better. No excessive moire and interlacing artifacts. BUT far from being perfect - or acceptable for that matter. During this ~ 3 seconds sequence the XA2 1080p mode shows clear "bob/weave interlacing pumping" - it looses cadence track for at least 4 times during this sequence...
Test 3: A friend of mine brings his DVDO VP50 video scaler over. XA2 1080i output to the video scaler. VP50 IVTC and 1080p output straight to the Z20k.
result: Perfection. So this is how this scene is supposed to look like No shimmering of fine details. Full resolution (some distant steps have just ~1 pixel height...). No moire.
Conclusion:
1) In order to get an artifact free picture (even with moving, very fine high frequency details, (vertically) filtered transfers sure don't show this behaviour) out of HD-DVD you need an additional, specialized >$2,990 video processor to do the IVTC. To get the most out of it this is the sad and expensive truth.
2) HD-DVD as a format is 1080i as long as no player out there is able to output the native 1080p stream encoded on the disc. Toshiba with its XA2 dropped the ball big time with its inadequate Silicon Optix REON implementation. Lets hope for a firmware upgrade ASAP. Still the XA2 is just doing the very same 1080i decoding -> internal IVTC/deinterlacing for 1080p output process the Samsung Blu-Ray player was "trashed" for... Even though the REON processor SHOULD be able to do a better job than it does with its current XA2 implementation.
3) The (hopefully) upcoming 1080p/24 upgrade for the XA2 is the chance for Toshiba to finally do it right. Native PROGRESSIVE processing from decoding to output. And please, Toshiba engineers, buy yourself a MI:III disc and make sure the most obvious 1080i interlacing artifacts are avoided with your "state of the art player".
4) THIS is not about one single disc showing some interlacing related artifacts - this "problem" is generally present with any single disc - but this sequence is the most obvious example as it shows unfiltered (thank you for that, Paramount) high frequency detail in movement. Something I would very much enjoy seeing much more often in the future (The Departed is the latest prime example of a filtered mess of a transfer - despite the glowing reviews ) MI:III is "stored correctly" on the disc - but no player (not even the "1080p" XA2) is able to show it this way. You need $2,990 for that...
I encourage everybody to try this at home! Comments are welcome.
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HD DVD Blu-Ray FORMAT NEUTRALITY: Be a discerning customer and NOT a cheerleader. Own both for the total experience - everything else is too much of a compromise for any self-respecting enthusiast!
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Last edited by TheLion : Today at 08:04 AM.
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