Freeview HD multiplex to be renewed until November 2026
Brian Butterworth published on UK Free TV Following an earlier consolation, Ofcom has now agreed to renew the licence for the "BBCB" multiplex (known as Multiplex B before switchover).
As this is used to carry the high definition versions of public services to 98.5% of the population of the UK, Ofcom will not be making a charge to BBC Free-to-View Limited.
Ofcom has also removed some of the requirements to fund Digital UK and promote digital switchover, as this will be complete shortly.
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Tuesday, 25 September 2012
When will there be more HD channels on Freeview?
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Stuart's: mapS's Freeview map terrainS's terrain plot wavesS's frequency data S's Freeview Detailed Coverage
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Mark Fletcher12:21 PM
Halifax
Stuart Swaine,Bradford.A tricky question to answer,but come 2050 onwards the likely possibility of 1,000+ UHD channels via terrestrial aerial on only 1 multiplex will be the norm.Bearing in mind normal SD and 1080p HD broadcasts will be switched off by then,that is advanced technology progressing with the times.
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Mark's: mapM's Freeview map terrainM's terrain plot wavesM's frequency data M's Freeview Detailed Coverage
Mark A.
6:13 PM
6:13 PM
98.5% !
I assume that the 1.5% can't get any terrestrial TV,
as BBC-B will be transmitted from all transmitters by 24/10/2012.
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Mark A.: yes, the 1.5% are cratered to by satellite. they are beyond the economic reach of DVB-T2
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Stuart Swaine: There is a "fifth" slot, which had the Olympic Interactive HD service in it, and this was to be used by Channel 5, but they changed their minds at the last moment.
Quite who else *qualifies* to run an HD service on the public-service Freeview multiplex, is a good question.
The contenders might be the likes of ITV-2 HD or E4 HD if Channel 5 HD can't be persuaded.
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trevorjharris11:36 PM
Very brave of Ofcom who clearly believe that the BBC will still exist in 2026. Our hotel room in Italy only had 2 English channels and they were BBC 1 and BBC 2. We soon realised how awfuly it was to be restricted to those 2 channels. 80% of the programing was house hunting or antique shows. Most of the rest was absolutly mind numbing.
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Friday, 28 September 2012
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Mike Dimmick4:46 PM
Mark Fletcher: Rubbish. Unless Claude Shannon's Theory of Information is wrong - which is unlikely - the maximum bitrate achievable for the conditions that the HD multiplex currently operates in (8 MHz channel, minimum 17.8 dB signal-to-noise ratio for a random white-noise channel) would be approximately 47.27 Mbit/s. The HD multiplex currently achieves 40.21 Mbit/s. The improvement is subject to diminishing return - you need more and more processing power to handle the error-correcting codes that deliver the increased capacity. Low-density parity check (LDPC) codes already approach the Shannon limit (to 0.04 dB) with block lengths of 10 million bits - rather longer than the 64,800 bits used in DVB-T2.
The only way to increase capacity further from the same bandwidth is to adopt multiple input-multiple output (MIMO) transmission. This requires the end customer to have multiple aerials pointing at the same transmitter, and the broadcasters to install multiple transmitting aerials and transmitters. Basically, it means doubling (trebling, etc) the costs, to both transmitters and receivers, for less than double (treble) the throughput.
The compression ratios may well increase, but it's worth pointing out that it's taken 14 years for the compression ratios on Freeview to allow twice the number of channels per multiplex as at onDigital's launch - and many channels on the multiplexes that do have 12 simultaneous channels are now running in reduced resolution (544x576 rather than the proper 720x576) and that many viewers consider the compression artifacts unacceptable. MPEG-4 AVC is more efficient than MPEG-2 Visual, but HD channels still average around 8 Mbit/s compared to an SD channel's 2 Mbit/s, with five times as many pixels to handle. Call it an improved efficiency factor of 20%, which allows for the fact that the level of compression artifacts (and the acceptable level) on HD at present is low.
Ultra HD would be expected, for 4K mode, to deliver 4.27x the number of pixels compared to HD. Let's say the next-generation compressor can again deliver 20% improvement compared to AVC. You still need 3.4x as much capacity as for an HD channel. That means probably not achieving even two UHD channels per multiplex.
For a technology comparison, yes, LTE Advanced (the 4G mobile phone standard) is quoted at over 1 Gbit/s, but that is achieved through wider bandwidth, up to 100 MHz, about one-third the width of the entire Freeview broadcast spectrum; deeper MIMO, up to 8x8 (8 transmitters, 8 receivers); and that is the best possible performance for receivers very close to the transmitter. In practice users will be much further away from the cell tower and won't get anything like that performance. You're also sharing the capacity with other users. 802.11n Wi-Fi similarly gets its best capacity at far higher signal-to-noise ratios, using 40 MHz bandwidth, and using MIMO techniques. DVB-T2 gets better bitrates (bits/sec/Hz) than either if you consider the SNR available, the bandwidth available, and the fact that as currently deployed, it only uses single in-single out; it can use deeper error-correcting codes, and greater modulation depth (256QAM vs 128QAM, for example), because it is expecting fixed-position mains-powered receivers rather than battery-operated mobile devices (so can require more computation power) and doesn't have to accommodate rate-adaptation because it is broadcast, rather than trying to adapt to the best rate for the targetted mobile device.
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Monday, 1 October 2012
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trevorjharris10:58 AM
@Mike
Actually the new MPEG H265 codec is expected to double the compression rate compared with H264.
I don't think that Ultra HD is going to be viable on terestrial. Just look at the problems they are having with HD. It is going to be along time before any free to air company will be able to provide a Ultra HD service.
Satallite has always seemed to me to be the future of television. Satallite already has 65 HD channels and one 3D channel. The extra 24 HD channels for the Olympics demonstrated the superiority of Satellite.
Of course Fibre to the Home could provide these services but BT has been pushing Fibre to the Box which can only be a short term statergy.
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Tuesday, 23 October 2012
Sunday, 10 February 2013
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conor6:35 PM
freeview will not get ultra hd due to bandwith constraints satilite will be the way to go bbc might do ultra hd next year on freesat and cable and sky if there boxes can do it i am saving up for a freesat ultra hd box at the nomment
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