Future of TV?

[andygrif]

Not really sure which category this post should go in, so mods, please feel free to read and move accordingly!

Here's an interesting story....

http://www.digitalspy.co.uk/article/ds14311.html

It talks of the BBC spearheading the 'possible' future of HDTV in the UK, but also about the digital switchover, due by 2010.

OK...so a couple of points arise from this:

How would ntl deliver this kind of service? It's clear that right now the present boxes (and maybe even infrastructure) would not be able to deliver HDTV signals to your TV. I guess the next obvious question is...who would pay for it? The government, NTL, the BBC or the customer?

How does it work in places like Japan and the US, where they already have such a service - are viewers paying even more for HDTV versions of their channels/programmes?

Would broadband be the way to deliver this? (I would guess broad-er band than available right now)

The next issue for me is why the BBC announce this now, why they are linking it to switchovers (then saying people that would take HDTV would not contribute to the switchover, becuase they would be likely to have switched over already), but mostly - why are they not combining the two projects?

By that I mean that realistically we should have an HDTV offer available now, so that take up is strong come 2010 should we not?

Discuss?

I understood that HDTV and Digital were not rolled out together in this country because of the large costs involved.

A further consideration might be that the Government wants to switch off analogue TV broadcasts so it can make a fortune selling licences to broadcast other signals on those frequencies. If it is to switch off analogue TV, everyone must move to digital. The best way of moving everyone to digital is to allow the majority of people to continue receiving their TV signals through an aerial, just the way they always have. Yet HDTV cannot effectively be delivered in this way, according to the article you linked to.

So, you give everyone the choice of either digital HDTV by cable/satellite or nothing at all, or, you allow people to choose standard-definition digital TV from cable/satellite/aerial. The majority of people in this country will never subscribe to pay-TV services, so the latter is the only viable option, in the absence of a Free-Sat service (which, co-incidentally, the BBC has also started talking about today, according to this morning's Telegraph).

In the future, the BBC clearly hopes data compression technology will improve to the extent that HDTV through a rooftop aerial will become a viable proposition. If it does, the BBC appears to be signalling that it might take the lead in the roll-out, in much the same way as the 'digital revolution' of standard-definition has only gained real momentum since they stepped in to salvage Freeview from the wreckage of on/ITV Digital.

Can i ask something? I'm not very clued up with all this, but what does High Definition TV actually do? Is it just better quality, which i thought DTV was meant to giv anyway

Originally Posted by col d

Can i ask something? I'm not very clued up with all this, but what does High Definition TV actually do? Is it just better quality, which i thought DTV was meant to giv anyway

Digital TV just allows you to deliver your standard 625 lines of picture information in a different way, that is less prone to interference.

High-Definition TV improves the resolution of the picture you watch, so instead of being made up of 625 lines of picture information, it is made of rather more - somewhere over 1,000, IIRC.

The lines of information that make up your picture are drawn horizontally, so it doesn't matter whether you have an old 4:3 or a new 16:9 (widescreen) aspect ratio TV, the picture is only 625 lines.

Originally Posted by towny

Digital TV just allows you to deliver your standard 625 lines of picture information in a different way, that is less prone to interference.

High-Definition TV improves the resolution of the picture you watch, so instead of being made up of 625 lines of picture information, it is made of rather more - somewhere over 1,000, IIRC.

The lines of information that make up your picture are drawn horizontally, so it doesn't matter whether you have an old 4:3 or a new 16:9 (widescreen) aspect ratio TV, the picture is only 625 lines.

576 lines actually The other lines are known as the vertical blanking interval (VBI) and are not sent. Your STB re-generates the VBI lines in order for your TV to lock onto the pics.

[Ramrod]

have a look here

Originally Posted by Ramrod

have a look here

Looks like he's not hosting the images any more.

Proppin - thanks! Things I never knew I never knew! How are these Vertical Blanking Interval lines used to allow a TV to 'lock on' to a picture?

[andygrif]

There were a couple of images still there - and they clearly look fantastic!

I am supposing that HDTV will further coverge traditional broadcast into computer territory (or should that be the other way around?)

So this is in reality what the guys with their flashy plasmas are wanting to pump into their DVI ports?

Originally Posted by towny

Looks like he's not hosting the images any more.

Proppin - thanks! Things I never knew I never knew! How are these Vertical Blanking Interval lines used to allow a TV to 'lock on' to a picture?

Theres timing information in some of them which tells the TV that its the start of a field and whether its an odd or even field etc. The pics wouldn't be very good if the TV couldn't find the top of the fields!

They are also used to pass on analogue teletext, analogue test signals (VITS), the first half of line 23 also signals AFD/Aspect ratio info to your TV.

The horizontally blanked parts of the analogue picture data (sync pulses, and colour burst etc) is also not sent within MPEG. The STB produces the signalling the TV needs.

[andygrif]

Does anyone know how much bandwidth HDTV takes up?

Originally Posted by andygrif

Does anyone know how much bandwidth HDTV takes up?

The article linked in the original post says that digital broadcasting is split into a number of 'multiplexes', and that at standard definition each multiplex can carry 4-6 channels. It goes on to say that a single HDTV broadcast would require an entire multiplex to itself. What this amounts to in bitrate terms I don't know, but comparitively the answer seems to be 'up to six times more than a standard-definition broadcast'.

[SMHarman]

If you double the size of the picture then you quadruple the number of pixels in that image 1x1=1 2x2=4 etc. Plus I imagine better sound and transmission overhead links nicely back to the 5-6 times more bandwidth.

[andygrif]

All getting a little teccie for me!! I was having a snoop round the BBC's Research dept to see if there was any info on there - there is but most of it's 5 years old now - good to see they were ahead in the r&d!

It talks on there about DVD quality - which I guess is around 10mbps. Would the current ntl infrastructure be able to cope with minimal additional investment?

[SMHarman]

Googled this and this on digital spy came back

http://forum.digitalspy.co.uk/board/...d.php?t=119698

Indicates the combined digital radio bandwidth is 8Mb/s
An average DTV channel is 4Mbs
A quality one is already 8Mb/s
And an Analogue on is 36Mb/s

There are 40 odd analogue channels transmitted, switching off the analogue broadcast will free up 1440Mb/s of bandwidth that could be used for HDTV. I'm sure Proppin will come along and correct my guesstimates, but it looks like NTL will be able to carry the signals. You just need a new STB to decode them.

Not really ntl related - moved to Technology forum.