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I'm worried

Discussion in 'Televisions' started by Pecker, Jul 22, 2005.

  1. Pecker

    Pecker
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    I'm a bit worried.

    Having read several articles, both in print and online, it appears pretty clear that HD will start being broadcast soon.

    It's also pretty clear that initial broadcasts will be in 720p.

    It's also pretty clear that HD broadcasts a few years down the line will be 1080i.

    It's also pretty clear that 1080p is not out of the question.

    But the problem is, most new projectors/plasma/LCD sets only go up to 720p.

    Surely, buying a set limited to 720p is madness. Of course, you'll be getting an improved picture, but it's a real dead end purchase if it turns out that some future broadcasts are in 1080, or have I missed something?

    Comments.

    Steve W
     
  2. Starburst

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    HD will indeed be with us in 2006 via SKY and perhaps TW and the BBC.

    720p seems to be favoured by SKY but that by no means indicates that 1080i won't be used by them fdr some content and by other broadcasters.

    1080p is still a few years away thanks to the capacity required even when using the mpeg4 codec and is not part of the EBU proposals.

    Thanks to the limitations of the technology combined with economics of scale the vast majority of displays are closer to 1280*720 than 1920*1080 but over the next couple of years that will change.

    Buying a 720p display is not madness since there is plenty of content out there with more to come and scaling a 1080i down to the native resolution will still give huge benefits over the continuing use of a PAL spec display.

    However if you are happy with PAL broadcasts then by all means wait a few years and the technology will improve and prices drop bringing 1080p panels into the domain of the domestic buyer although broadcast 1080p may be a few years behind which leaves pre-recorded material as the main source.

    So enjoy HD as it is now or deny yourself, the choice is yours:)
     
  3. Dutch

    Dutch
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    It's not clear that initial broadcasts will be 720p, and later ones 1080i - both formats will be used from the start. We may get 1080p broadcasts in a few years - possibly when terrestrial HD starts after analogue is turned off. A couple of 1080p projectors and LCD sets are available at the moment, with more out next year - hopefully they will all actually accept a 1080p signal.

    Steve
     
  4. David Mackenzie

    David Mackenzie
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    1080p broadcasts? That would need a lot of bandwidth and I wouldn't bet on it happening. Wouldn't be surprised if 1080p was for pre-recorded disc formats only.

    I also think 720p and 1080i will co-exist. 720p used for material that relies on clear motion (sports) and 1080i used for greater detail on stuff that doesn't move as much (nature shows maybe). The HD decoder will probably output to the TV in one of the formats and convert SD content and other HD resolutions into whatever output type you have selected.
     
  5. Stephen Neal

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    I think the OP is confused somewhat. It is not clear who will use 720p and who will use 1080i - though it is likely that both could be used at launch. There is unlikely to be a move from 720p to 1080i on the channels that start 720p.

    1080p is not supported as part of the Sky standard.

    HD-DVD and BluRay are expected to support 1080/24p and 1080/25p. I'm not clear if they will support 1080/50p or 1080/60p - or if these will be interlaced at the higher picture rates.

    It is entirely conceivable that MPEG4 will allow 1080/50p or 1080/60p to be broadcast - however there is very little broadcast production kit (VTRs, Vision Mixers, Routers etc.) that currently runs in 1080/50p or 1080/60p - because the bandwith required is greater than that which can be carried via the HD-SDI connection standard.
     
  6. Quickbeam

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    The equipment provided by Sony for Sky's new HDTV studio is multistandard. The cameras are 1920 x 1080p native and can output 720p and 1080i in equally high quality. If the 720p output from these cameras doesn't look good, it never will. (I'm referring to the fact that most Americans say that 1080i always looks better, even though most US channels are 1440 x 1080i, and some are 1280 x 1080i.) Interesting that Sony initially complained about the EBU's recommendation of 720p; these new cameras must have been in development before the EBU's findings were published, so Sony already had its bases covered.

    It's impossible to say whether Sky branded channels will use 720p or 1080i then based on the choice of equipment supplier. I'd be surprised if both are used, but it's possible. The decision will depend on a) which compresses best (lower bit rates mean more HDTV channels per transponder), and b) which format foreign broadcasters prefer (obviously you can convert between 720p and 1080i, but there will be some loss of quality). Unfortunately the answers to a) and b) are not likely to be the same!:)
     
  7. NicolasB

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    Forget about 1080p.

    The question is: if some broadcasts are 1280x720 (p) and some are 1920x1080 (i) right from the start then does it make sense to buy a 1280x720 screen? To my mind the answer is "no", but I know plenty of people disagree with me.

    To be fair, it's not yet clear how much, if any, 1080i material will be available via Sky HD or HD-DVD/BluRay. It's the logical choice for all cinema films - but the AV industry almost invariably goes for the stupid option rather than the logical one. :rolleyes:
     
  8. Stephen Neal

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    Yep - just as Philips (now Thomson/GrassValley) have with the 1920x4320 LDK 6000s that Alfacam use - they downconvert the 4320p to 1080i/p or 720p (as well as 480i and 576p I believe) internally - so they may outperform the Sonys as they will still have more vertical oversampling by whole orders.

    I'd be surprised if Sky were to chose 720p for an HD film channel - as there is no point running a 50p standard when the source material will be 25p. 1080/50i would be a better choice - as this is effectively a 1080/25p format with a slight vertical resolution drop...

    I would expect any Sky commissioned drama to be 1080/25p - but I suspect they will go 720/50p for sport as it does seem to compress better at lower bit rates.

    Given that most of their US imports are going to be 1080/24p mastered (a few US series are 720/24p - but not many) - a general Sky HD version of Sky One would make sense in 1080/50i - however we'll just have to wait and see!
     
  9. Quickbeam

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    Arguably what is more of an issue is the fact that there are comparatively few 1280 x 720 native screens. The vast majority of new LCD screens are 1366 x 768 resolution. Scaling a 1280 x 720p broadcast to 1366 x 768 isn't going to do the image quality any favours. This is why 1080p screens are appealing, even if all the TV broadcasts are 720p.

    1080p, not 1080i, is actually the logical choice for feature films on HD-DVD/Blu-ray. The problem with encoding a film in 1080i - apart from the loss of vertical resolution due to interlacing - is that almost none of the current generation progressive HDTV displays deinterlace 1080i film sources correctly: they take each 540 line field and scale it to the display's resolution, instead of merging it with the other field. If you encode in 1080p and the display accepts 1080p then it will show the whole frame whether or not it deinterlaces 1080i correctly.
     
  10. Pecker

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    Well, here I am at a forum of experts, people 'in the know', and probably the country's early adopters.

    And there's no agreement as to whether there will be any 1080 (i or p) broadcasts from the start, or at all.

    RE:

    "Buying a 720p display is not madness since there is plenty of content out there with more to come and scaling a 1080i down to the native resolution will still give huge benefits over the continuing use of a PAL spec display."

    But if (for example) you but a 720 screen this year, and 1080 takes off in early '07, you are going to either (A) watch a display with significantly lower resolution than that being broadcast, or (B) shell out a fortune for the 2nd time in 2 or 3 years.

    Let's hope the general public don't get to hear about this.

    Because if they do, the sale of new 'HD Ready' 720 sets will grind to an absolute halt.

    Steve W
     
  11. Stephen Neal

    Stephen Neal
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    1080/50p is not on the cards. Sky HD receivers will not have 1080p outputs.

    1080/50i and 720/50p are the two HD formats supported by the Sky HD receiver - and are the two HD-ready display formats mandated (in addition to 1080/60i and 720/60p which is also part of the HD-ready spec)

    It is likely that most high-end HD drama, or "film"-like production, will be in 1080/25p - however this is not a proposed broadcast format - and will be converted to 1080/50i or 720/50p for broadcast (though 1080/50i makes a lot more sense in horizontal resolution terms, and 720/50p has no frame rate advantage)

    Whether sport and other "video"-like productions are captured and/or broadcast 1080/50i (as the BBC are currently running for their HD sport and music OBs) or 720/50p is not yet clear. 1080/50i and 720/50p have roughly similar vertical resolutions (1080/50i delivers about 800 lines of vertical resolution - so pretty close to 720/50p) - 720/50p has better movement detail, 1080/50i has better horizontal detail.

    For broadcasts 1080/50i and 720/50p are the only imminent HD standards. A 720 line display will deliver good results on both inputs - scaling and de-interlacing quality permitting. However some 720p displays actually treat 1080i as 540p apparently, rather than de-interlacing to 1080p and scaling...

    For pre-recorded material it is possible that 1080/25p may be used - however I don't believe many HD displays will accept a 1080/25p video signal - so the HD-DVD or BluRay player will have to convert to 1080/50i (by interlacing), 720/50p (by scaling) or 1080/50p (by frame doubling). The latter is the only format not supported as part of the HD-Ready standard.

    I think people are over-exaggerating the 1080 issue. Sure 1080/25p may contain more vertical and horizontal resolution than a 720p display can display. Sure 1080/50i may contain more horizontal resolution than a 720p display (but not more vertical information).

    For that matter some HD-ready displays - such as 1024x720 (Panasonic) and 1024x1024 panels - don't have the spec to display a 1280x720 720p signal at full resolution. However there is more to a display than resolution - greyscale performance, contrast, black leve etc. are all as important. One of the best HD plasmas I've seen has been the 1024x720 Panasonic 500 series - which is technically quite low resolution. However the issues other than resolution played a big part in this.

    For screen sizes below 50" and normal viewing distances the difference between 720 and 1080 line displays is quite difficult to perceive according to BBC R&D research (720 begins to look noticably better than 576 on screens larger than 27" at average viewing distances)

    If you want a BIG screen - say a 70" display - then 1080 is going to be the way to go (Sony have the Qualia 006 1920x1080 display at this size). However if you are in the 37-42" size range then 720p is likely to be fine - significantly better than 576 displays and not noticably worse than 1080p displays at normal viewing distances.
     
  12. Stephen Neal

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    Yep - though 1080/24/25/30p or 1080/50/60p aren't part of the HD-ready display spec are they - so any 1080p (rather than 1080i or 720p) outputs from a BluRay/HD-DVD player would require a display with additional input specs over and above those required for HD-ready certification. These may well appear - and as long as the player also supports 1080i and 720p as well it wouldn't be an issue I guess...

    I would imagine that the current treatment of 1080i as 540p would be improved upon, and 1080/50i interconnects (but possibly with optional vertical pre-filtering in the player if the on-disc recording hasn't been filtered) be used - surely 25p film-mode detection will be implemented in higher-end 720p and 1080p displays pretty quickly - as it will be a quality issue that would allow differentiation from lower end displays that treat 1080i as 540p?
     
  13. Starburst

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    Well 1080i is an approved resolution for the EU broadcasters and is widespread in the US where the selection of panels is just as restricted thanks to the manufacturing and economic limitations as they are in the UK.
    Doesn't seem to have caused HD sales to suffer too badly.

    As for 1080p there is no road map for broadcasting in that format although it is the "holy grail" so to speak and thanks to optical disk capacity pre-recorded movies are likely to support that format even when there are no viable domestic displays at a realistic price.

    HD1 and HD2 will certainly be broadcasting in 1080i and it wouldn't surprise me if Discovery HD Theatre launches (they have a license) they to would use 1080i as they does in the US.



    If you but a 720 screen now then you will get a huge benefit over normal PAL spec broadcasts and source material assuming you also invest in the HD STB/Player and in some cases subscriptions.
    Simply put for those who spend that sort of money now the downside of perhaps replacing the panel with a native 1920*1080 res version may not be much of an issue and again even if they put it off for a few years the qaulity of 1080i on a 720p is still stunning and makes PAL spec digital broadcasts look pathetic.


    I don't think the general public as a whole gives a monkies about HD and perhaps won't until we see major movement by the traditional PSB's and by the time they do then the display technology will hopefully meet the requirment for native 1920*1080.
    If mr and mrs bloggs are not impressed with a 720p broadcast on a suitable panel then they are not going to be that impressed a few years later with 1080i native:)

    The intended market for HD is not Mr & Mrs Bloggs and won't be for many years, those who buy into HD nwo or in the next 6-12 months know or will know the situation.
     
  14. probedb

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    Well I'm buying a 720p screen (Viewsonic with native res of 1280x720) mainly for watching 1080i material that I have. I think the step up in quality that people will get will be huge. Seeing 1080i material on a 720p screen usually ends up looking fantastic as it's able to use the full resolution even though it's being downscaled. IMHO anyways!
     
  15. Tarbat

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    And one of the most important factors affecting display quality is the level and quality of MPEG compression. Certainly for broadcast, the trade-off between higher resolutions (1920x1080i) and bandwidth will be critically important. For the same amount of bandwidth, I would imagine a 1280x720p broadcast may actually be better quality than a 1920x1080i broadcast. Isn't an interlaced signal more challenging for MPEG4 codecs?
     
  16. Pecker

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    I have a 28" CRT, a 32" CRT and a DLP projector showing a 6 foot wide image.

    The DLP projector is a Themescene (I think H56), which isd compatible with 480p, 576p, 1080i & 720p, but has a resolution of 1024 pixels x 768 lines.

    I watch TV & DVD on it, with both signals being sent from my Denon amp via component cables. My Denon DVD goes into the amp via component, and the TV signal comes from my NTL digital box in RGB, into an RGB-Component convertor, then to the amp.

    The difference in quality between the TV picture and the DVD picture is huge.

    As far as I can tell, this is mainly due to my TV signal being interlaced & the DVD being progressive.

    I'm looking forward to seeing what an HD picture is like through it. But doubtless NTL will be the last broadcasters to go HD.

    Steve W
     
  17. Stephen Neal

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    DVD will usually be compressed at higher bit rates than digital satellite, cable and freeview, so there will be fewer compression artefacts. DVDs are also often mastered using multiple passes of MPEG2 compression that can be optimised - and film DVDs are often sourced from HD transfers (that will be clearer and cleanert than SD ones) Though the same MPEG2 compression system is used for DVD and digital TV - digital TV often looks a lot worse as it is usually compressed by between twice and three times as much. (DVD maxes out at around 9Mbs - DVB TV runs at between 2 and 5Mbs typically)

    DVD itself is not inherently progressive or interlaced - and can carry either interlaced or progressive video information. Film material in PAL land is very simple to de-interlace (it isn't inherently interlaced though can be stored in this format) and in theory it is just as easy to de-interlace to progressive either in the DVD player or a progressive display (though not all de-interlacers are equal) - though CRT displays won't neccessarily de-interlace as they can display in native interlaced mode. (Flat panel devices will need to de-interlace to progressive though - so the quality of de-interlacing is important in these situations)
     

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