Where's best for HD TV?
MORE than three quarters of UK homes own an HD-ready TV according to Ofcom's 2015 Communications Market Review, just behind the 78% of us who have broadband at home.
But just because we have HD-ready TVs, that doesn't mean we're watching HD programming: while even the most basic TVs on sale are HD-ready these days, Ofcom say just 57% of households are signed up to a proper HD TV package.
There's a degree of chicken and egg to this issue, however: many people are waiting for HD to really take off before committing to a package, but broadcasters and providers need us to watch to justify further investment.
Not that we're all that limited for viewing: since the BBC started broadcasting in HD in 2006, the number of HD channels has grown to more than 90.
Who's best for HD TV?
Sky is arguably the best provider for HD TV, although Virgin Media really aren't that far behind anymore.
For quick comparison, here are the TV packages offering the most HD channels as standard from each provider:
Sky offer the joint largest number of HD channels, providing 50 to their Box Sets Bundle customers. Original and Variety Bundle customers can access 11 HD channels as long as they have one of the provider's HD-capable boxes.
Only those who've been with Sky for a very long time and have never updated their set top box are likely to miss out, as the standard Sky+ box, and the multiroom box are both HD-capable - and one of the Sky Q boxes is Ultra HD-compatible as well.
Virgin Media now also offer 50 HD channels, although it's taken them a while to get there - and the selection does differ slightly. Again, only those with the top tier TV deal will get all 50: that's Full House TV for new or upgrading customers, and what older customers might know as TV XL.
Among the HD channels available to Virgin Media customers are those from BT Sport. Full House / TV XL customers will find that they get both SD and HD versions included in their subscriptions.
Both Sky and Virgin Media customers can add more HD channels if they subscribe to one of the premium Sky channel packs - Sky Cinema or Sky Sports.
Those subscribing to Sky Cinema will get both the SD and HD versions of all 11 live channels as standard, but those wanting Sky Sports will need to add a separate HD pack - and if they're with Sky, they can only get that by upgrading to the Box Sets Bundle first.
Youview from TalkTalk only offers the 12 HD channels it's possible to get with Freeview; the basic Youview packages from BT and Plusnet are the same.
BT and Plusnet offer HD packs including at least another 13 channels for a little extra per month - customers who also take BT Sport will get those four channels in HD as well. That makes a grand total of 29 HD channels.
BT do also offer Sky Sports 1 and 2 in HD, for an extra £5 a month - but no one with Youview can get Sky Cinema in HD.
About this time last year, however, BT raised the game with the launch of BT Sport Ultra HD.
We go into Ultra HD in more detail below - but here it's enough to say that people with BT's Total Entertainment TV package get this channel plus the other 29 HD channels.
Sky have done a great job of driving demand for HD - across all providers - with their sports channels.
It's somewhat arguable that people who want to watch movies in HD are more likely to seek out blu-ray discs than view them on TV.
That's because, depending on whether we have HD-ready or "true HD" TV, we may only be seeing pictures with a resolution of 720p, whereas blu-ray operates at 1080p - and blu-ray players can "upscale" SD DVDs to make them appear sharper.
Sport, on the other hand, kind of needs to be live.
Sky isn't the cheapest way to get Sky Sports, but it's often argued to be the best place to go: they have the most sports channels, and they're all available in HD too.
In January 2010, the BVA released research that showed 6.5 million of us hoping to catch the World Cup in HD weren't actually viewing high definition content; we just thought we were. That's one in 10 of us.
Back in 2007 Ofcom released similar findings when their Mystery Shopping report into the sale of HD-ready TVs found that 41% of people buying a HD-ready TV were being given potentially misleading advice about what the set could do.
HD-ready versus "true HD"
For those who want HD TV, the obvious place to start is an HD or HD-ready TV set. As mentioned above, almost all TVs sold these days are at least HD ready - which means they have a resolution of 720p. For now that might well be enough.
That's because most HD TV channels are broadcast in 1020i - a little short of the "true HD" standard of 1080p. The "i" stands for "interlaced scan", the "p" for "progressive scan".
When 1080i channels are broadcast, we're actually seeing two sets of images alternating rapidly - first the odd numbered columns of pixels, then the even numbered columns, and back again. It's done too quickly for our eyes to detect, but it is noticeable - think about how TV screens and computer monitors appear to flicker when seen on TV.
By comparison, 1080p TVs show every line of pixels simultaneously. It doesn't look much different to us as viewers, but broadcasting in 1080p takes far more data. In fact, it's been suggested that it's highly unlikely that cable and satellite TV providers will ever send 1080p over the air.
So "true HD" TVs, able to display 1080p, are likely to only ever fulfil their potential with a blu-ray player, or certain games consoles.
There's more on what to look for in a new TV in our buyer's guide.
Other HD requirements
For anything more than the Freeview HD channels available through the TV, viewers will also need a set top box that can receive HD content. Most can these days, but there are still SD-only Freeview boxes on sale, and those who still have older Sky+ boxes will be left frustrated.
Lastly, almost all the pay TV providers charge for extra HD services. We've already mentioned the BT and Plusnet HD packs, but to get the most HD channels on Sky and Virgin means signing up to their most expensive TV packages - and spending even more on top of that for Sky Sports in HD.
Freeview only requires an HD capable set top box, but those who already have a satellite dish can always use that to get HD content via Freesat. Our guide to these platforms goes into more detail on the services they offer.
HD TV has seen a relatively slow take up, perhaps mostly as a result of to the limited number of channels being made available.
While Sky Sports - and now BT Sport - are clearly the main attraction, a huge number of people aren't that interested in sports coverage and to get them on board a much wider variety of HD channels will be needed.
It's been the case until now that the competition between Sky and Virgin has been responsible for pushing up the amount of HD content on offer.
In 2012 for example, Sky rolled out Sky Sports F1 in HD, as well as doubling the amount of HD content available via what was then known as their Anytime+ service.
Since 2013, Virgin Media have largely relied on Sky and BT Sport to boost the number of HD channels they can offer, but in the past year they've added a couple more entertainment channels to their HD line up as well.
At the time of this update, however, we're also seeing the first stirrings of competition in the Ultra HD arena.
Ultra HD, or 4K TV, is so called because it offers four times the detail of HD, with a frame rate of 50 frames per second (fps) compared to the 25fps of SD and HD.
As mentioned above, in summer 2015, BT launched the UK's first Ultra HD channelbeating Sky to the punch.
But Sky were biding their time for a reason, as when they launched their Sky Q service in February 2016, they made a point of telling us that the 2TB version of the new boxes was Ultra HD-ready.
In August, they started broadcasting their own Ultra HD content: Sky Multiscreen 2TB subscribers should all be able to access a growing range of entertainment programmes and documentaries on demand.
Those with Sky Cinema (once Sky Movies) will also find between 70 and 100 films available to view on demand in Ultra HD; those with Sky Sports will be able to watch 124 Premier League fixtures live (or record them) in 4K HD.
That puts BT's efforts slightly to shame.
They win points for getting there first, and for offering live sport in Ultra HD - but even with the BT Sport Ultra HD, they can only offer 30 better-than-SD channels in total - and only those willing to subscribe to the Ultra HD service get them included.
What happened to 3D TV?
3D TV launched in 2010. Initial interest was good: there were 700,000 3D-ready TV sets sold in 2011. But by 2013, Sky said just 400,000 subscribers were accessing their 3D channel - less than 8% of their HD subscribers.
The timing of HD was fortunate too, coming as it did at the same time as the boom in flat screen TVs. It was easy enough to upgrade to an HD-ready TV when getting rid of the bulky old set - but not many people have been willing to upgrade quite so soon again in order to get a 3D-compatible TV.
Virgin Media offer 3D content on demand - mostly movies - and their basic V HD Box is capable of receiving 3D content. All viewers need is a 3D-ready TV and some specs.
In May 2015, Barb - the organisation that records and researches British TV viewing habits - said they believed 3D TV was all but dead. The BBC stopped producing content in 3D in 2013, and in autumn 2014 Sky said they were no longer going to offer Premier League games in 3D.
As we've already seen, sport is key to pushing new services and ways of watching - so although Sky still offer 3D on demand content, Barb concluded that "the party is essentially over".
Most TV manufacturers have concluded similar, moving their focus to other developments like the aforementioned Ultra HD, and OLED screens.