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HDTV for us all.

Discussion in 'Projectors, Screens & Video Processors' started by rigman, Dec 31, 2001.

  1. rigman

    rigman
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    Hiya all,

    was just sat here thinking about the HDTV and how it is so unfair that the yanks and the japs have it and we dont and are not likely to for a long time.

    Question is

    if you use a video processor or a HCPC to scale the image to get 720p or 960p then are you now turning the source into what is effectively HDTV, be it DVD, satellite or OTA through a suitable projector that could cope with the higher resolutions. Or am I missing something.

    If that is the case then all you have to do is spend a few grand and you can have HDTV anytime you want.

    Darren
     
  2. Stuart Wright

    Stuart Wright
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    Yes, that sounds about right.
     
  3. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    The reality is slightly different though. This interpolated information is not as accurate as the real thing.....I have never seen a DVD look like it has as much detail as a HiDef source in 1080i or 720P. Think about this.

    Does PAL VHS tape look as good scaled to 1440 x 720P or whatever, compared to NTSC DVD's....Yet the PAL video tape is 567i and the DVD is 480i...so why should the lower res DVD look better.... in fact, why don't they look as good as each other if they are being output at the same resolution.

    As is always the case with these things there is more to it than meets the eye. One for Event2 perhaps.

    Richard Ansell is the man to explain this one for us.

    Gordon
     
  4. uncle eric

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    Yes and no, but mostly no.
    Basicly a Pal or NTSC source be it DVD or (Pal)Sky Digital has a much lower native resolution than either Hi Def modes, 720p or 1080i.
    While a good CRT capable of accurately displaying massaged lower interlaced rates and converting them to 720p or even 960p from a non Hi Def source such as the above can look very good. Its still way behind the image a 720p or 1080i Hi Def source will produce.

    The latter interlaced 1080i being the best mode for several reasons.
    Firstly, contrary to popular belief, it offers more resolution than the 720 progressive mode. The 1080i mode is produced at a lower scan rate than 720p thus making display equipement less costly to produce. 1080i will prevail, much to the distaste of 720p fans like Joe Kane.
    Thats not to say 1080i cannot be improved upon. It can. Frankly speaking though, the choice of display equipement than can manage the conversion from 1080i to 1080 progressive is limited to the very best 9" CRT's. I saw a few attempts with 8" machines only to see bad overlap.

    Getting back on track, simply explained, you cannot add information thats not there. In the old days when de-interlacers were first introduced, magazines refered to them as 'Line Doublers' that would "Guess the information in between and fill in the gaps".
    This misconception is now rife with the advent of scalers. Many now assume that if 720p can be achieved it automatically becomes Hi Def TV.
    Believe me, if it were, good old Murdoch would charge for it.

    Normal low res PAL and NTSC sources such as DVD and DTV just does not have the native resolution that true Hi Def has.

    Going sideways slightly, while Japanese Hi Def is also NTSC its perfomance is better than the USA version.
    The Japanese use the latest generation Hi Def broadcasting equipement while the americans are somewhat reluctant to spend many more millions of dollars when their first investment is yet to see full fruition.

    Eric

    P.S. I'm not Richard A :eek:
     
  5. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Eric isn't Richard which is probably good news for both of them hahahaha.

    He has got close to answering though. The answer is in the Horizontal resolution of these native sources...and some other stuff but mainly that I'd say. There are also issues with the colour gammut afforded by each of these standards too.

    1080i has a larger perceived vertical resolution as Eric says. Everytime I've seen it though I have seen interlace artifacts. Just they are so small as to make them harder to see.

    Eric: Although Japan uses NTSC as its TV standard I think that there HiDef standard is something completely different.

    In the US the stadards for HiDef and NTSC are completely different things altogether. I would expect this would be the same the world over. Japan's HiDef standards are, from what I remember, higher than the ones currently implimented by US.

    Gordon
     
  6. rigman

    rigman
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    Oh well just a thought. Looks like I will have to save a bit harder to try and retire to Florida earlier than what I had originally intended.

    If hi-definition DVD's eventually come out in the states sometime in the future then I suppose we will could always import that instead.
     
  7. ReTrO

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    Are the Japs or Yanks going to ever stream Hi-Def Tv over the net? It would require a good connection, like people in good offices have. Only for demo uses etc, if it were good enough it could even persuade TV people in Europe to think about it.

    (What am I saying, it's not going to ahppen for years...:rolleyes: )
     
  8. uncle eric

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    Gordon,
    This is the main gripe from Video Guru's such as Kane. As the 1080 format is interlaced, the main problem would be stairstepping during movement. Although as you mention, its very fairly difficult to see due to much smaller gaps between the scanlines.

    For my next impression..........??????

    Happy New Year to All
    Eric
     
  9. Steve at NMI

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    The data rate of DVD varies but is limited to a maximum of 9.8Mbps. Digital TV is between 2 and 4Mbps.

    ADSL to the home is struggling at 2Mbps. A good (shared) office network might just handle 10Mbps.

    We can't even deliver DVD quality to the home by any route -other than receivng physical disks by snailmail, and a majority of those come from the US - nor has video-on-demand happened with any effect. It will take years yet. However compression algoritihms are improving all the time so the quality will get better.

    Uncompressed SD TV is 270Mbps. HDTV is 1.5Gbps. So trying to deliver anything other than a pretty basic, highly compressed picture is out of the question until fibre reaches right into the home, courtesy of the almost bankrupt ntl: or Telewest.

    The powers that be in the UK decided to use the 'new' digital bandwidth for multi-channel broadcasting of lo-res SD. The Americans, who have had multi-channels for years, preferred to go for a few, higher resolution HD channels. Who made the right choice?

    Best bet is probably to retire to Florida. Even if you are only 18 years old!

    So while Scaling can't match HDTV - it can approach the quality and far exceed unscaled images on a large screen.
     
  10. RichardA

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    As Eric has said the main problem is that you can't create detail that isn't there in the original - so up-converted SD will not be as good as native HD.

    However it is possible to get pretty close if you treat the material in the right way and store the SD material properly - this generally means when transfering a film it should be telecined to HD (1080P24) and then down converted to SD rather than transfering directly to SD. There is a significant difference between scanning an image at lower res and mathematically reducing the resolution of a high res image - particularly if you understand the maths used and can use this knowledge in the upconversion.

    The biggest problem for us all as Home Cinema types is that we don't have access to the high quality SD material - what we get on DVD or Digital TV is way below the quality of 'true' SD - this layering of compression (down conversion is just another form of compression after all) makes it much harder to recover any usable picture information.

    Proper up-conversion can make SD sources high watchable in a cinema or HD environment (as an example the BBC's Blue Planet has been sold as an HD programme even though it was actually edited as an SD programme - it was upconverted using our Alchemist Platinum) but once you see true HD you'll see what you are missing!

    HD transmissions in the US are using about 20Mb/s. This may seem surprisingly low but HD is easier to compress than SD - as an example 'lossless' SD compression is around 3:1 while at HD it's around 20:1.

    I would suggest that visually 720P and 1080i are pretty much the same - the progressive 'resolution' of an interlace source is usually considered to be about 2/3 the total active lines while using half the data rate ( i.e. 1080i has the apparent resolution of 1080 * 2/3 = 720P but the data rate of 1080/2 = 540P) - this is the point of using Interlace in television systems from the start - you get more bang for the buck!


    Hope this helps!

    (p.s. Welcome Steve M to the forums!)
     
  11. uncle eric

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    I think for the time being, the closest us Brits will get to HDTV is in the form of pre-recorded digital tape.
    While we are on the subject, a while ago, a few people mentioned something regarding sales of the above.
    Gordon, I think you also mentioned a source. Does anyone know what happend with this. Did they get the green light. Or are they still stuck on amber like most of the industry.

    Eric
     
  12. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Mark Cuban owner of a US Baseball team and TV Network, I think, had this idea. I'm still monitoring the situation. His TV Network specialises in broadcasting Sport in HiDef and Playboy Beauty Pageants.....etc....

    He seems a sensible bloke having read interviews with him so I would expect that if it can happen he'll make it happen.

    We'll see.

    Gordon

    P.S. Hello Steve! For those who don't know Steve is the chap who distributes Rock Video Porcessors and other TAW stuff.
     
  13. Steve at NMI

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    Thanks Gordon.

    As used at The Event last year.

    And maybe at the next one?
     

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