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sky hdtv boxes

Discussion in 'Sky Digital TV Forum' started by tigertimtim, Apr 10, 2005.

  1. tigertimtim

    tigertimtim
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    as their going to be pv recorders will the sky hdtv set top boxes when they come out be able to record the programmes off the hdtv channel to play back in the same high def format ?
     
  2. Starburst

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    Yep.

    They will be based on the current SKY+ design but obviously using a mpeg4 chipset (which will also handle SD mpegII broadcasts) with the addition of a higher capacity hard drive and HDMI connection/s and component. I am also hoping that video scaling will be included to improve SD broadcasts when displayed on a HD panel in the same manner as reasonably priced DVD players are quite capable of doing right now.
    It has been said that it will be a 160gig hard drive in line with the current Thomson SKY+ which is reasonable but hardly cutting edge:(
     
  3. alscds

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    from what ive heard its a 160g high def sky plus box and its being released at the same time they announce their new premier high def footy channel
     
  4. supermackem

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    I wish it would hurry up, as the sd at the moment seems to be getting worse. I wonderif its because sky seems to be overloaded with alot of crap channels at the minute.
     
  5. RecordablDVDfan

    RecordablDVDfan
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    Surely recording HD will eat up capaicity so is 160GB enough ? Then it's MPEG4 so I guess so ??
     
  6. Starburst

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    A HD mpeg4 channel would run around 10Mbits/second so while it is more than double the size of a "good" SD channel having 4 times the hard drive capacity more than makes up for it.
    Not to forget HD will only account for perhaps a dozen (SKY, HD1/2 etc) out of 200+ TV channels on the SKY platform so I would still be recording a lot of SD material as I ecpect others would be as well.

    The hard drive capacity hasn't been officially confirmed (little has actually) but some articles/sites give info that does sound reasonable and reliable.
    Personally I would hope for a larger hard drive combined with either a second internal caddy or external data/power links.
     
  7. RecordablDVDfan

    RecordablDVDfan
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    Thanks for info, interesting stuff. I hope the box will not be too expensive as well as the subscription, something like £10 less I guess I will go for, box about £250 ??

    I still wish the main 5 channels or at least the BBC would launch an HD service at the same time Sky do. It would be great to see some UK home grown progs in HD. All Sky will offer is movies and sport 2 things I am not interested in personally...
     
  8. Starburst

    Starburst
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    I think you are going to be in for a shock if you are hoping SKY+ HD will retail for £250 :)
    I don't think SKY will subsidise it since they know that just like SKY D and then SKY+ there will be people willing to pay full retail (plus the premium for all new products) when it is launched. I am expecting it to be offered for around £400 with an additional payment for installation (for new users) which hopefully is waived for SKY+ users upgrading since they have the Quad etc required.

    Just like SKY+ I expect hardware prices to drop significantly over time, question you have to ask is how much do you want High Def:)

    SKY1 of course will have access to a large number of shows that have been made in HD for the last few years as well as virtually all the current US imports (from the major networks and Premium channels).

    Speculation of course but it isn't out of the question for Discovery to offer their HD programming to SKY, they did an exclusive deal with SKY in the early days so the precedent is set. Disney are another that could look to generate a bit of extra revenue by offering some of HD content and it's not out of the question for the BBC to offer some sort of content from it's existing HD library and as the % produced in HD grows a viable full time channel has to be on the cards. ITV, CH4 and Five I think won't dabble in HD for a few years yet but CH4 and Five do have content that is made in HD and seem to be a little more adventerous than ITV these days.
    HD1/HD2 etc will also be broadcasting from 28.2 degrees in mpeg4 so a standalone subscription or bundled deal with SKY is pretty much a certainty:)
     
  9. Stellavision

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    I have heard people mentioning that Sky Hi Def will be broadcasting in 720p, has this been confirmed as definate yet?
    It will be a bit of a pain for people like me with displays (42PD5200) which won't do 720 @ 50hz! :(
     
  10. MikeK

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    It wouldn't be that difficult to incorporate a frame rate converter into the design, to allow 720p to be output at either 50 or 60Hz - whether they'll do it or not though remains to be seen (they may decide to attempt to keep costs as low as possible by stripping out all the "features" and going for the lowest common denominator)

    All the nitty gritty details of the Sky HD system are all just speculation at the moment - they simply haven't released the information (possibly because the design specifics of the delivery system itself haven't been finalised yet)
    All we know really is that it will be HD of some sort (and surely can only be 720/50p or 1080/50i, as they are the proposed standards for European HD) and the receiver will be a PVR device (like Sky+) featuring HDCP protected output in some form!
    Everything else is really speculation (sometimes educated speculation though :) )
     
  11. Dutch

    Dutch
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    I'm fairly sure the HD STB will allow you to select which output you want regardless of the format broadcast as they do in the US. So you could set it to output 1080i50 for your Hitachi. Hope this helps.

    Steve
     
  12. Stephen Neal

    Stephen Neal
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    Sky have confirmed that their receivers will cope with 720/50p and 1080/50i broadcasts - though they haven't confirmed what their own HD channels will run in.

    It is expected that the Sky boxes will allow for a fixed HD output and will cross-convert HD material in the other standard to this - allowing you to run with a fixed 720p or 1080i output irrespective of the HD broadcast being received (as is the case in the US)

    I'd be VERY surprised if field/frame rate conversion (to allow 50Hz stuff to be displayed on 60Hz only displays) were included though - as to do this properly at HD requires converters costing $10ks to $100ks - and even then the quality suffers (and doing it on a pre-compressed signal will be even harder). Just adding an extra 10 fields/frames by repeating frames certainly won't enhance the HD experience...
     
  13. NicolasB

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    How exactly can you convert 720p to 1080i without it looking terrible? Surely you've either got to throw away every alternate frame or downscale it vertically to 540 lines?

    For that matter, to convert 1080i to 720p wouldn't be easy, either. Downscaling 1080p to 720p is possible, but the initial deinterlacing of 1080i to 1080p is quite computationally intensive (unless you can count on it being inherently progressive source material like a film). I mean, okay, nearly all hi-def displays are going to have to do that to display 1080i at all, but how many of them can actually do it well is another question. :) I suppose maybe there won't be much 1080i material that wasn't originally shot on film....
     
  14. Stellavision

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    Slightly reassuring guys, thanks.
     
  15. Stephen Neal

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    No - far easier to upconvert the 720/50p to 1080/50p internally (so 1:1 frame mapping with a scaling) - then interlace the 1080/50p stream to 1080/50i for output (possibly by doing a line-offset average for each field)

    In fact going this way is more difficult - as it is far easier to interlace a progressive source than de-interlace an interlaced one.

    Well if you assume it is film and 2:2 pull-down then there is no de-interlacing to do - the source is progressive (albeit filtered vertically to avoid interlace flicker)

    De-interlacing a 50i source is much more difficult - and to do it well you need a lot of power (effectively you have to interpolate new frames from the fields - and guess what this would look like!)

    That is why the EBU and Sky are suggesting 720/50p - as it removes the low-cost/low-performance de-interlacing requirement from the display.

    A lot of 1080 drama is shot 1080/24p or 1080/25p (for that "film" look) if it isn't shot on film, but 1080/50i IS used for sport and entertainment shows, as well as some news (NHK run HD News I believe)
     
  16. NicolasB

    NicolasB
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    Yes, that's exactly what I said. :rolleyes: You scale up 720p to 1080p. That then gives you twice as many unique frames per second as you can actually display, so somehow you have to divide the number of frames by two.

    What's a "line-offset average"?
     
  17. Stephen Neal

    Stephen Neal
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    Sorry - but you said :

    Neither of which are the case...

    You take your 50 x 720 line frames, scale each and every one of them to 50 x 1080 line frames, and then interlace - just as a broadcast TV camera does.

    Broadcast CCDs are inherently progressive capture devices - as they capture every line during every capture period. To convert this 50 frame captured video to 50 fields interlaced video - they average lines 1 and 2, 3 and 4, 5 and 6 etc in each frame to create the alternate lines that make up the field (doing so generates a degree of vertical filtering as well -reducing interline flicker)

    Now this might seem that you are running a 540 line resolution - and if you only consider one field that is the case. However for the next field you average lines 2 and 3, lines 4 and 5 etc. you have a line-offset, so your 540 line field contains a "half-line" vertical offset.

    That is how both standard and high def broadcast CCD cameras generate their interlaced outputs from their progressive sensors these days I believe.

    (Tubed cameras were different, they actually altered the scanning positions between fields on the camera tubes, so scanned different picture area between fields)
     

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