I was just going to ask same question...

in the link.(i.e. pdf doc) . it suggest Europe would be using profile 17a upto 100Mbps and Asia 30a upto 200Mbps... but I guess you start conservatively and see if the infrastructure can take it..

In reply to a post by Pgre:

So this is the reason for the 15Mb Min.. HD TV.

It's a slightly pessimistic figure though unless it includes headroom for side activities.

I think most Sky HD channels now broadcast 1080i at 12Mb/s with no complaints - pretty sure ITV HD does. BBC HD is currently broadcasting at 10Mb/s although a few of the more picky viewers aren't happy about it.

Luxe HD broadcasts at 5.5Mb/s and is reckoned to be one of the best pictures available. Then again it doesn't have much content and likely benefits from careful post-processing. It wouldn't surprise me if someone monitors the compression frame by frame to tweak it - they can probably afford to spend a week doing that which most broadcasters can't

Edited by Andrue (Fri 05-Mar-10 13:30:36)

With the compression the analysis you suggest is crucial, as is how the material was originally filmed. A program with heavy strobing can really cause problems with poor encoding.

BBC HD is OK but I believe I noticed the difference, but then I encode material too, so know what to look for. BBC HD can afford to spend a bit of time on its compression too for the non-live material.

Now if Sky VoD were to offer higher than usual bit rates it would be a coup

In reply to a post by bookey:

Thanks for that, i'll bin my graphs and use page 5!

http://www.buckconsult.co.uk/fttx/BT8cProfilesVDSL2.jpg

Any ideas why BT are not using other profiles?

Yep, ANFP.

I must read that one day, when I retire.

In reply to a post by MrSaffron:

BBC HD is OK but I believe I noticed the difference, but then I encode material too, so know what to look for. BBC HD can afford to spend a bit of time on its compression too for the non-live material.

I don't think I have noticed the difference but I don't watch all that much on BBC HD. I'm mostly into documentaries and American imports these days. Last of the Summer Wine will be a good benchmark though and the new series of that is presumably a few months away. Previously that has been hailed as an excellent example (picture-wise at least, granted a lot of people think the show itself is [censored]).

Now if Sky VoD were to offer higher than usual bit rates it would be a coup

Yes. If were given free reign I would implement it as a supplementary tuner and offer an option to restrict downloading to overnight. It wouldn't be VoD but simply avoiding the dreaded 'clash' and not having to play 'shuffle the schedule' with +1 channels would be nice.

Yeh.. in the doc (Which it seems is a US Doc) it does go onto say therefore a typical requirement would be 25Mbps per household.. so I guess HD and then some browsing etc..

But 25Mps per household would be a good min for the government to set right lol (forget this 2 Mbps min)

In reply to a post by Pgre:

Yeh.. in the doc (Which it seems is a US Doc) it does go onto say therefore a typical requirement would be 25Mbps per household.. so I guess HD and then some browsing etc..

Unless I've missed it the doc doesn't mention backhaul either. The upgrades needed to support HD VoD are far reaching

In reply to a post by bookey:

I must read that one day, when I retire.

Grief I didn't read the thing, I just kinda know stuff from people who know stuff and google a bit.

Check the PDF and note the downstream transmit power on 8c and how low it is, has to be low to reduce crosstalk with exchange / CO based DSL else you'd have everyone's ADSL sync rates dropping once a VDSL customer went live.

Edited by Ignitionnet (Fri 05-Mar-10 13:41:12)

Some people have suggested thats happened already in Basingstoke... but as far as I know its still not live.
But maybe there will be some cross talk even with the lower 8c profile powers limits.