In reference to the recent clarification of the Sky HD service which has been talked about in relatively vague terms for some time now.
People have been wanting to know whether the service will be either 720p or 1080i
it seems that Sky are going to fence sit and support both formats.
This will probably mean the worst of both worlds. Unless you are using a top notch CRT projector (very expensive and only really appropriate for movie viewing) then anyone with a fixed pixel panel device (LCD or plasma) will have to buy a compromise screen (or two screens !).
720p is made up of 720 lines, 1080i is made up of 1080 lines (broadcast alternately in two batches of 540). To make the most of what will undoubtedly be a very high quality picture quality transmission standard one would need a screen with EITHER 720 lines OR 1080 lines (or a multiple of the two
a 2160 line screen anyone !)
Leaving aside the fact that you cant currently actually buy a plasma screen with exactly 720 lines
No doubt screens will become available in 1080 line sizes
but they may be designed as interlaced screens and be unable to show 720p (at least, not without converting it to 1080i first
definitely the worst of both worlds).
Even a fully flexible 1080 line screen will have to scale 720 line images up to 1080 lines. Think what this would mean in the simple case of filming an image of 360 black horizontal bars. The 720p system would register a pin sharp image of a black TV lines followed by a white one, etc, etc,. It would look fantastic and clean and absolutely superb on a 720 line monitor. Leaving aside the interlacing, the display on a 1080 screen (which you might think should be better, having more lines) is scaled up by 1.5. So two adjacent lines (one black, one white) have to be displayed on three lines. Im guessing that this would come out as one black, one grey and one white. So black / white / black / white becomes black / grey / white / black / grey / white. So all the sharpness of the original 720 line image will be lost as approximately one third of the lines on the 1080 image will be a mushy grey (a colour not even present in the original !)
Im not saying that any of the above resulting TV pictures will look really BAD
in fact it will probably look a bit better than todays TV
what I am saying is that it will fall short of the potential of a true HD system.
There is of course another limit which I just touched upon
that of the human eye. There are many reasoned arguments that the greater pixel count of HD is only really useful for very large screens. At normal viewing distances from a sensible screen we are already creating images which the human eye cannot fault. Unless you are creating a home cinema with a 100 inch projected image and you want to sit up close to it for an immersive experience, then why do we need more resolution ? Wouldnt it be a bit like getting a stereo to go above 20 KHz (when anyone over the age of about 30 cant hear anything above 15 KHz) ?
And do we NEED HD for news, current affairs and makeover programmes ?
Granted it will be nice for dramas
but it is really going to push up the cost of production (not only with the need for new hardware, but also the fact that the sets will have to be much better or else all the fake stuff they use now is going to look silly the BBC have already discovered this with their current productions which are being filmed HD compliant). Who ends up paying for that ? Us !
These new channels are going to take up approximately 4x the bandwidth. Theres another cost. More worrying is the pressure that this is going to place on broadcasters to apply more compression.
It makes me laugh that digital broadcasting got where it is today by riding roughshod over picture quality (you would be surprised at how many people either switch to Sky Digital or buy a bigger TV and then notice problems which are in fact simply symptoms of MPEG and/or over-compression) and now, all of a sudden, HD picture quality is the way ahead. More likely it is one of the few ways that Sky can gain an advantage over terrestrial broadcasters
both digital terrestrial and cable simply do not have access to the sort of bandwidth needed to launch a decent HD service.
PQ I can remember when all TV PQ problems were down to reception. An individual could spend as much money as they wanted (or where able) to in upgrading aerials, head end amplifiers, cabling and TV sets. Each time they would find an improvement in their TV image. Nowadays virtually all PQ problems are down to broadcast issues.
Broadcast problems that bug me :
- incorrect (or mixed) aspect ratios (especially in historical documentaries)
- superimposed logos (sometimes coloured, sometimes moving !!!)
- superimposed red dots
- re-broadacsters (e.g. UK Gold) who, on second showing, dont show the 16:9 original
- MPEG artifacts (all of which can be blamed on simple over compression)
With the exception of red dots, there is nothing I can do to address any of these (and why should I have to keep jumping up to press backup ?)
As to over-compression, the Beeb actually turned down the wick back in 2000 (during the Olympics I think) until too many complaints were received
and then they turned it back up just a notch to a barely acceptable level. Is it just me, or is this completely back to front ? Shouldnt the boffins at TV centre be determining the point at which ANY artifacts are showing up on a top-notch system and then ensuring that this is the standards bar below which no programmes should be broadcast ?
Finally, in defence of MPEG, this is the standard used on DVDs. Have you ever seen the sort of poor TV pictures we see on DSat repicated on a DVD ? I certainly havent.
Oh, and cost. All new HD boxes are going to by a sort of Sky+ box. So straight away they are going to cost in the region of £300. But wait, that is the cost based upon the standard design of current digibox with volumes in the millions. These are completely new boxes. They will need MPEG4 decoders and circuitry to deal with something other than the good old tried and tested PAL (576i). PAL has been around since before the transistor was invented chipsets to handle it must be two a penny (they are certainly used in every TV, VCR, DVD, games console and many PCs). Suddenly we need chipsets to deal with 720p and 1080i and, initially at least, there wont be anything like the level of demand. At present the number of people with HDCP enabled screens with significantly more than 576 lines can be best described as low. In the short term only people who can afford to buy screens like yours can even join that group again, I would say, low. And dont forget, they will need whopping hard disks if they want to record HD material and need to be faster at reading and writing too. Expensive.
Sky were prepared to subsidise the original boxes in order to :-
- kill off digital terrestrial (which was seen as a potential major competitive threat)
- charge more per customer (on the basis of there being more channels)
- switch off analogue broadcasting and save ALL analogue transponder costs
The latter was costing as much, if not more, than the proposed cost of digital broadcasting and was only affecting about 3m households. In the event, the switch over to digital went well and the analogue service was switched off gradually, eventually being gone (I think) during 2001. At that point about 200,000 homes fell off the system.
This time around the environment is different :
- the number of households is almost 8m.
- new HD transponder costs will be much greater (4x ?) than the potential savings by turning of the current transponders
- the unit cost of HD boxes will be much greater (remember, they are effectively Sky+ boxes as well as being new tech)
- it will be much harder to get people with normal TVs (i.e. most people) to think that this applies to them
- this will be especially true if there is an enhanced subscription needed (both for the Sky+ elements as well as the HD)
- there is no immediate serious and credible competitive threat (no one else is about to launch a service)
On the latter point, you may recall that back in 1998 DTT and DSat launched at the same time (Oct/Nov) and were seen by many as being mutually exclusive. If Sky didnt mop up the rush to digital TV then it was feared that OnDigital would. In the event OnDigital subsequently collapsed many would say that its financial failure was brought on by the need to match the Sky free box offer.
Lets say the HD boxes go on sale for £500 and there is a requirement for a monthly subscription of £50 (plus any multi room etc). Would you go for that ? £1,100 per annum ? My guess is that some probably would. But ask yourself the question, would you have been as able or willing to, say 5 years ago ? Perhaps not. And I put it to you that there are a lot of people in the UK who are not QUITE as well off as some........
So, in a typical Catch 22 type situation, I dont see how this can become mass-market and therefore attractive enough to Sky to subsidise it
and without the subsidies it wont take off
Yes, I know that the circle could be broken if Sky provided the sudsidies, but it is a different world now. Sky has plateaued out and is no longer growing voraciously. It is a lot more circumspect and controlled by more sober minded individuals. Rupert Murdoch simply cant be so cavalier about how he instructs the company to do his bidding. Much more money would be needed this time around and there is no competitor to place pressure on Sky. Last time BT got involved with a subsidy for the Interactive Services element of the digibox. Much of this was down to the box being connected to the phone line. Well, as existing digiboxes ARE connected aleady, then there is no advantage to BT in moving to HD digiboxes. Plus, here in 2005, BT are much more interested in DSL (something which simply didnt exist back in 1997 which digital TV was being thrashed out).
So I watch with interest.