Rebuilding Freeview High Definition from 2019 onwards
As Freeview High Definition users in Cornwall already know, the number of TV channels being broadcast in the UK will be cut back in mid-2020 to make way for the fifth generation of mobile phone data services.
This is because the number of multiplexes being broadcast will be cut back to the original six. The extra two were provided as a “interim service”. A Freeview multiplex is a single broadcast of binary data that occupies a 8MHz frequency range. In the UK each of these can carry 24.1, 27.1 or 40.2Mbps or of data.
Because older TV sets and set-top boxes can only work with 24.1 Mbps, it is only possible for the owners of the multiplexes to use the higher capacity modes when every home has switched to Freeview HD capable equipment. This equipment is marked with “DVB-T2”.
As illustrated, the total bitrate (in a home that can receive all the multiplexes) will change over time.
Meet the multiplexes
Not all the multiplexes are the same:
- only three are broadcast to the whole of the UK;
- a different three are broadcast in the better DVB-T2 mode;
- legally, only BBC channels may appear on BBCA
- also, legally, only public service broadcast channels (ITV, C4, C5) can appear on D3&4
- The HD mode multiplexes have more bits and use a more video efficient encoding system (MPEG-4)
- The current license to broadcast have different end-dates
This can be summaries in this table.
Multiplex name |
Expires |
HD mode? |
Coverage |
Mode |
Bitrate today |
||
com7 |
21 June 2020 |
Yes |
76% |
6 |
40.2 |
||
com8 |
21 June 2020 |
Yes |
76% |
6 |
40.2 |
||
D3&4 |
15 November 2022 |
No |
100% |
3 |
24.1 |
||
ARQA |
15 November 2026 |
No |
90% |
8 |
27.1 |
||
ARQB |
15 November 2026 |
No |
90% |
8 |
27.1 |
||
SDN |
15 November 2026 |
No |
90% |
8 |
27.1 |
||
BBCB |
16 November 2026 |
Yes |
100% |
6 |
40.2 |
||
BBCA |
31 December 2027 |
No |
100% |
3 |
24.1 |
Freeview requires about 2.2Mbps for a standard definition channels and three times that for a high definition one (6.7Mbps).
The Freeview HD EPG problem
One problem for people with Freeview HD receivers will note is that HD channels are grouped together in the program guide, rather than appear as replacements for the standard definition channels as viewers expect. This is because the six channels on the BBCB multiplex (BBC One, BBC Two, CBBC, ITV, Channel 4 and Channel 5) can only be seen on newer boxes, making channel number replacement impossible without breaking the oldest Freeview equipment.
Basically the UK-wide BBCA and D3&4 multiplexes can’t change mode until ALL homes can receive them.
The interim position
There is good news, however, for the SDN, ARQA and ARQB multiplexes. They can switch modes to the high definition whenever they feel that it is commercially practical. This might be at a lower level of Freeview HD box use, perhaps 80% or 90%.
By switching to DVB-T2 mode, each of them can increase their capacity from 27.1 to 40.2Mbps and take advantage of MPEG4.
So, of the 80Mbps lost when com7 and com8 close, half of that can be got back by SDN, ARQA and ARQB upgrading, which would be enough for an extra 6 full HD services.
The HD public service channels
This diagram explains what will happen to create space six more Freeview HD channels.
The gains for the BBC when everyone has a DVB-T2 receiver are larger. It will:
- No longer need half of the capacity on the BBCB multiplex (20.1Mbps) as it can move these channels to BBCA
- Gain 16.1 Mbps on BBCA due to the mode change;
- Gain 6.6 Mbps from not simulcasting three services in SD and HD
- Use the “gained 22.1Mbps” Be able to supply all the BBC television channels in HD to all UK homes
For the D3&4 multiplex, the gains are similar:
- No longer need the 20.1Mbps on BBCB, making it available for other UK-wide services.
- Gain 16.1 Mbps on D3&4 due to the mode change;
- Gain 6.6 Mbps from not simulcasting three services in SD and HD
- Be able to broadcast ITV, C4 and C5 in HD to all UK homes
I hope that's as clear as possible! Any qestions?
3:28 PM
I like how clearly and simply this article paints the picture. However, it fails to consider the fact that, when an SD channel is moved from the DVB-T to the DVB-T2 standard, it only requires about half the bandwidth (around 1.1Mbps). The more modern MPEG4 encoding is about twice as efficient as the older MPEG2.
This means that in channel carrying capacity, the 'interim' solution almost exactly matches the current situation. The 'final' solution has the capacity for around an extra 8 HD or 48 SD channels.
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4:07 PM
I really think it's time those with old DVB-T1 boxes or TVs [non Freeview HD] are encouraged to replace their equipment with DVB-T2/Freeview HD boxes or TVs. BBC need to set a date on a migration to DVB-T2. Majority of people know they need to upgrade to HD equipment, even if they don't have coverage of HD channels, as the switch over will eventually come. I just feel Ofcom are dragging it out & need to push things along now. Let's sort the capacity issue.
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8:01 PM
It would be great, albeit highly unlikely, if the Government would speed up the switch over to the Final all-DVB-T2 solution by providing free HD boxes to less well-off viewers, in the same way that it did by providing SD boxes to enable and speed up the analogue switch-off in 2012.
After all, the Government is raking in multi-billions by selling off the spectrum, first at 800MHz for 4G mobile, and then at 700MHz for 5G. So doesn't the population deserve some small proportion of this back by way of free or subsidised HD boxes to reduce the time that the current viewers of Com7 and Com8 channels will have to suffer some of their favourite channels off being off-air?
Incidentally, if the response to complaints about losing these Com7 and Com8 channels is "go watch them on satellite instead", then there needs to be some free or subsidised satellite kit for people currently without, and, not least, some money to get Channel 4, 4HD, 4Seven and 4+1 back on Freesat as well.
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8:24 AM
It's all very well having BBC1 in HD and removing the SD channels, but even on satellite they only broadcast BBC London in HD, the local regions lose out on the local news.
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Chris: Clearly, the whole point of this is to have the local BBC One and ITV/STV/UTV services on Freeview HD.
Doing this would not dictate changes to the outputs of the satellite services.
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42Jon: Yes, you are correct, there is also the gains made from moving SD channels to MPEG4.
I had included those calculations in the spreadsheet I had made that I based the article on, but I though that there was only a certain level of complexity to the numbers that would leave the article understandable.
The main upshot of this is that it would be possible for the BBCA and D3&4 multiplexes to upgrade a few more channels to full HD (BBC Four HD, BBC News HD, BBC Scotland HD) or a mixture of HD and SD+1 channels (ITV 2 HD and ITV 2+1).
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Colin R: I guess it's worth remembering that the at800 | 4G & Freeview | 4G interference | 4G Filters | 800 MHz people have been paid for by the mobile broadband companies as part of their deals to get the former TV broadcast frequencies.
They have provided, over time, free filters and sometime free Freesat equipment, as well as the necessary support. Which you might expect as they paid 2,341m that they paid them.
The problem here is that any additional benefits from changing to DVB-T2 don't accrue to HMG, but to the multiplex owners. I can't see that Lord Hall of Birkenhead, for example, really has shown the ability to understand this kind of commercial situation, given his previous well-documented actions.
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12:08 PM
Yeah would be good if tv company was transmitting in hd at least when you see Japanese are trying to go to 8000 lines is it? When how many are doing basic hd. Even sky has not got many uhd yet
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12:28 PM
Hi,
Will 5G interfere with the TV signal? It has already been necessary for us to fit a 4G filter, 4G filter, due to loss of reception quality.
Thanks
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12:58 PM
What plans are there to improve the coverage of Free view in the Scottish Highlands. My caravan is located at Gairlochy and coverage is very poor
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