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Standard User Pgre
(committed) Fri 05-Mar-10 12:25:34
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Re: FTTC distance from cabinet speed deterioration


[re: bookey] [link to this post]
 
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..

Regards PGre
Standard User Andrue
(knowledge is power) Fri 05-Mar-10 13:17:13
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Re: FTTC distance from cabinet speed deterioration


[re: Pgre] [link to this post]
 
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 smile

Andrue Cope
Brackley, UK

Just because he can smile

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

Administrator MrSaffron
(staff) Fri 05-Mar-10 13:23:27
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Re: FTTC distance from cabinet speed deterioration


[re: Andrue] [link to this post]
 
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

Andrew Ferguson, [email protected]
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.


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Standard User Ignitionnet
(fountain of knowledge) Fri 05-Mar-10 13:27:41
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Re: FTTC distance from cabinet speed deterioration


[re: bookey] [link to this post]
 
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.

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Standard User bookey
(experienced) Fri 05-Mar-10 13:29:32
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Re: FTTC distance from cabinet speed deterioration


[re: Ignitionnet] [link to this post]
 
I must read that one day, when I retire. laugh

Paul
Standard User Andrue
(knowledge is power) Fri 05-Mar-10 13:34:08
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Re: FTTC distance from cabinet speed deterioration


[re: MrSaffron] [link to this post]
 
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.

Andrue Cope
Brackley, UK

Just because he can smile
Standard User Pgre
(committed) Fri 05-Mar-10 13:34:41
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Re: FTTC distance from cabinet speed deterioration


[re: Andrue] [link to this post]
 
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 smile lol (forget this 2 Mbps min)

Regards PGre
Standard User Andrue
(knowledge is power) Fri 05-Mar-10 13:36:39
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Re: FTTC distance from cabinet speed deterioration


[re: Pgre] [link to this post]
 
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 smile

Andrue Cope
Brackley, UK

Just because he can smile
Standard User Ignitionnet
(fountain of knowledge) Fri 05-Mar-10 13:37:31
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Re: FTTC distance from cabinet speed deterioration


[re: bookey] [link to this post]
 
In reply to a post by bookey:
I must read that one day, when I retire. laugh


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.

Stuck on the One Way Internet?

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

Standard User Pgre
(committed) Fri 05-Mar-10 13:39:35
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Re: FTTC distance from cabinet speed deterioration


[re: Ignitionnet] [link to this post]
 
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.

Regards PGre
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