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Will Sky go 1080i 50Hz or 60Hz?

Discussion in 'Televisions' started by mattmarsden, Nov 8, 2004.

  1. mattmarsden

    mattmarsden
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    I think 60Hz makes sense as the vast amount of their programming is from the states, also is more compatible with existing hardware.
     
  2. Laura

    Laura
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    That would be my hope too. I wonder whether the digibox would support downscaling to PAL resolution, which might make them favour a 50Hz signal :(
     
  3. Dutch

    Dutch
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    Hi,

    I think Sky will go for 720p50, although 1080p50 would be better! ;) I'm sure the HD STBs will allow a range of output resolutions to choose from.

    Steve
     
  4. StevenBagley

    StevenBagley
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    It'll be 1080i50, there are too many technical problems about running 60i in the UK (or 50i in the US for that matter -- try filming with a UK video camera in the US and watch the images flicker in the right sort of lighting) -- especially when they'll need to produce 576i50 downconverts for normal viewers.

    As for most HD programming about, it's all 1080p24 within a 1080i60 carrier (ie 3:2 pulldown), this can just as easily be transmitted as 1080i50 with no difference in quality (if anything it'll look smoother). Also I suspect at first HD wil be limited to events via PPV (e.g. the World Cup) or moviews anyway. Do not expect SkyOneHD in 2006, it might happen but I suspect not.

    The bigger question is, will SKy use MPEG2 (I hope not)

    Steven
     
  5. mray

    mray
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    Any idea when Sky will announce, or make up their mind which format to go with please?
     
  6. Starburst

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    I suspect SKY and their manufacturing partners (PACE and maybe Thompson) are pretty close to finalising the specs right now, it may not be made public due to the licensing and contracts. You only have to look at the SKY+160 to see how close they play it to their chest at times although that may be down to the fact it was noothing to brag about:)
     
  7. mray

    mray
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    Thanks Starburst.
    I get the impression sometimes from these forums, that they've already made up their minds!
     
  8. CKNA

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    Most HD programming is 1080i60. You can't shoot sports in 24p. Only shows that are filmed or are made to look like film use 1080p24. When using 1080p24 you have to speed it up to play it at 1080i50 and have no loss in quality. If you convert electronically 60Hz to 50Hz you lose about 20% of quality as 10 fields have to be removed every second.

    Sky will definitely use 50Hz as it too much of a problem using 60Hz in a country where everything is 50Hz.
     
  9. Quickbeam

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    Mexico and Chile both use NTSC despite the fact that their electricity frequency is 50Hz. I read somewhere that the notion that fluorescent lights flicker at the line rate is a myth: they actually flicker at twice the line rate (100/120Hz). Modern lighting that uses electronic ballasts flickers at 20,000 to 60,000Hz, which is surely undetectable. Note that I don't claim to be an authority on this subject; it's just what I read.

    As for Sky using 60Hz, even showing ads in widescreen is currently beyond them, so the idea that they would use anything other than 50Hz HD is just wishful thinking. Anyone hoping for 60Hz HD broadcasts in Europe should emigrate to the US or Japan.

    What I really want to know is whether Sky will use 720p or 1080i. Anyone taking bets?
     
  10. loadsofleads

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    Surely most of the American shows that Sky One broadcast are 1080i aren't they. This will be the decideing factor imho, more American programmes are shown on sky than European ones. I think and hope 1080i, 1080p would be nice but let's not get carried away.

    loadsofleads :thumbsup:
     
  11. CKNA

    CKNA
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    Mexico uses 120V/60Hz for electricity, just like US.
     
  12. Wayne Moule

    Wayne Moule
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    MPEG 2 is fine (take DVD for example) if the bitrate is high enough, surely. Unlike the blocky pictures digital TV puts out now, what ever the platform.
     
  13. vonhosen

    vonhosen
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    It is MPEG-2 they send out now (MPEG-2 Program Stream) , that's the problem.
     
  14. Quickbeam

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    Okay, obviously my source was inaccurate, but I found several sources that state that Chile is 50Hz but uses NTSC, unless you can show otherwise. The other point is that NTSC/720p/1080i does not operate at the line rate, but at 59.94Hz, so it is no exactly in sync with the electricity system anyway.

    MPEG-2 would be fine for Sky's HD provided the bit rate is high enough.
     
  15. vonhosen

    vonhosen
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    Chile does use NTSC & 220/50Hz mains
    Mexico uses NTSC & 110-125/60Hz mains
     
  16. Wayne Moule

    Wayne Moule
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    Why?
     
  17. Dutch

    Dutch
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    Sky and the rest of the European broadcasters have the opportunity to go with MPEG4 AVC HP instead of out-dated MPEG2. Let's hope they see sense.

    Steve
     
  18. Wayne Moule

    Wayne Moule
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    Why?
     
  19. Laura

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    Because the new codecs like MPEG4 make better use of the bandwidth, so conequently you don't need so much bandwidth for a good picture.
     
  20. Starburst

    Starburst
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    To the end user there is little difference between mpegII and the more modern codecs, High Def video will still look as good regardless.
    The advantage of the new breed of codecs are higher compression and hence lower bitrates which translates to lower transmission costs or more channels for the same outlay. The countries that have HD right now had little practical option but to adopt the very mature mpegII standard, it works perfectly well and in the US hasn't made any obvious impact on the expansion of their various providors.
    In Europe they/we have a viable option with the new codecs being much closer to a mass produced and proven platform and it would not surprise me in the least if HD1 was the only "mainstream" channel of mpegII HD in western Europe.
     
  21. Cliff

    Cliff
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    I seem to remember Chile uses 625/50 but uses the NTSC colour modulation system. So there would be no flicker with mains lighting.
     
  22. Rimmer

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    It's NTSC-M, 525/60. Evidently they must have found a way to cope with the flicker, assuming there is any.:)

    Speaking of codecs, I think France has made a very bad decision in choosing MPEG-2 for their terrestial DTV. This decision rules out terrestial HDTV broadcasting in France for 15 years or more, something which will no doubt please the cable and satellite companies.
     
  23. Wayne Moule

    Wayne Moule
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    Is that the same for the UK also then?

    I don't think using a codec that compresses even more so than MPEG 2 is a good thing, especially for HD, as picture quality will be affected to a lower standard.
     
  24. vonhosen

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    http://www.alkenmrs.com/video/wwsce.html#C
     
  25. Starburst

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    You are assuming or have more intimate knowledge of the capacity of the DTT network in France and how it compares to the UK.
    Our system is crippled by not being able to infringe on the analogue network which means reduced power and coverage not to mention that there are simply no frequencies that could give additional nationwide muxes until analogue has gone.
    The French may not be handicapped in this manner and as such a proven and cheap mpegII system can offer HD to the masses via mpegII in addition to a bunch of standard definition broadcasts.

    I have no doubt that the decision was made with full knowledge of the benefits of the system choosen when compared to what may be viable in the next 12-36 months.
     
  26. Starburst

    Starburst
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    The compression percentage achieved between say mpegII and mpeg4 should not be considered as a guide to PQ, they are two totally different algorithms and as such only the PQ results have any real comparison value.
    The result is that a HD movie compressed with mpeg4 could be nearly 50% smaller than the corrosponding mpegII version with NO obvious difference in quality when viewed on a high end domestic 1920*1080 display.

    It's true that if you compress a video file to a greater extent using the same codec the results will be poorer but use a different codec and the results change dramatically.

    Bottom line is that the codec used has very little effect on the overall picture quality IF the encoding process is done correctly with care and attention to detail. If any doubt go to the MS website and download some of their HD samples using their wm9 codec, very small file sizes and very impressive PQ at the two accepted HD resolutions.
     
  27. Wayne Moule

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    That's good then and the Windows HD clips are brilliant.
     
  28. NinjaShredder

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    On viewing several US HDTV streams (MPEG-2), I have noticed some very large blocking artifacts for a split second after scene changes. But the bit rate for normal action sequences seems adequate.

    I also seem to recall something to do with newer MPEG-4 type codecs handling cuts between scenes better, by allowing new key frames at arbitrary moments. This seems to me to be a good reason to want newer codecs, even if you have a fair amount of bit rate to play with.
     
  29. Kenny Glasgow

    Kenny Glasgow
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    There is NO WAY Sky will use 60Hz. Their main earner is the Premier League footie, not US TV shows!
     
  30. RecordablDVDfan

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    I hope that BBC and ITV also will start HD in 2006 via Sky seeing as a number of BBC progs are made in HD anyway...what are the chances ?
     

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