(Pocket-lint) - This has been one of the best World Cup tournaments we can remember - even with England's exit at the semi-final stage - and the BBC is offering the opportunity to watch the final in 4K.
All the BBC's games have been available on certain, 4K HDR-supporting smart TVs via the BBC iPlayer app and the final is no exception. Here's why - and how you can get the stream.
Why now for a 4K World Cup?
The FIFA World Cup is one of the "crown jewels" of sport - events that have to be available on free-to-air TV under UK law. The BBC and ITV share the coverage as usual and that means all the games are being shown live on BBC iPlayer or the ITV Hub as well as the highlights shows.
In Brazil four years ago, only three games were filmed in 4K. You can experience the 2014 final in 4K UHD on YouTube, but this is the first tournament where every game will be filmed in 4K and will be available to the mass of World Cup broadcasters in that format.
The BBC has been experimenting with 4K delivery on iPlayer for several months now. It also teamed up with Sky to show its Blue Planet II 4K footage through that platform, too. It then moved onto live 4K HDR streaming with a Rugby League game in April, followed by the FA Cup Final in May.
These experiments were about proving the technology could handle high-bandwidth streams from an event such as the World Cup, where the demand is significant and the amount of coverage plentiful. There hasn't been a lot of live, on-the-fly encoding of 4K content as yet and that is a challenge for the BBC, but one it is clearly beginning to master.
The BBC developed a live HDR workflow for the Royal Wedding too, which you can read more about if you're interested. The BBC's main aim there was to record the event in 4K HDR for posterity.
As on that day, the BBC studio presentation at the World Cup is upscaled from Full HD - it's only the global match feed which is in native 4K.
How to stream the World Cup in 4K HDR
ITV isn't yet experimenting publicly with 4K so it's only the BBC games that are available in 4K HDR at present. And the BBC games won't be available in 4K HDR on your phone or tablet (that's HD depending on the quality of your stream) so you will need a television that's on the BBC list of compatible smart TVs.
The Ultra HD stream will be available from the BBC iPlayer home screen as soon as programme coverage begins – it will be displayed until the trial is full for that match. The stream will only be available to a set number of users on a first-come, first-served basis – somewhere in the region of “tens of thousands” according to the BBC, although we haven't heard of anybody locked out as yet.
There are some drawbacks. Note that you won’t be able to rewind or restart the stream as with other, standard, iPlayer streams. Because of the encoding time required currently, we've found the stream runs behind behind normal coverage by 30 seconds or even more - some have reported several minutes and others have mentioned commentary not being synchronised with the picture.
A delay is OK if you're watching something you're not that fussed about, but if it's your team your phone will probably buzz with a goal before you've watched it. There were also numerous reports of buffering during the England vs Tunisia game which led to the stream being really delayed - probably because the trial was filling up (even though we didn't hear of people having problems accessing it).
What quality of 4K stream can you expect?
Note that whether you can get completely unadulterated 4K depends on your internet connection. For the full 3840 pixel Ultra HD, you'll need at least a 36Mbps connection. That means if your connection is below that, you’ll get a downgraded version - 2560 pixel Ultra HD or less.
You will probably need a 20Mbps and above connection to get the trial. It may be possible with a slightly slower connection, but we just don't know.
Here's what the BBC says you'll get depending on your internet speed - there are only four streams available of this content because of the increased bitrates required for live HEVC 4K encoding. The top stream quality is the same as Blue Planet II was presented in, but even if you could see that stream you may not be able to get this one because of the increased bitrates required for streaming live.
- 3840x2160p50 36Mbit/s
- 2560x1440p50 16Mbit/s
- 1920x1080p50 10Mbit/s
- 1280x720p50 7Mbit/s
Why does the BBC believe HLG is the way forward?
Part of what the BBC is trialling at the World Cup isn't actually its own capabilities, but the capability of the open UK internet to support live 4K streams.
The BBC streams use the HLG version of HDR, while all footage will be shown at 50 frames per second and audio AAC-LC at 192 kbit/s. The BBC worked on HLG, known as Hybrid Log-Gamma with Japanese broadcaster NHK. NHK also worked with the BBC on the highly experimental 8K footage recorded of the 2012 Olympics.
The World Cup's Host Broadcaster Services is not using HLG, so the BBC converts it.
When it streamed Blue Planet II via the iPlayer, the BBC's Phil Layton said, "Due to the way HLG represents light, audiences get the most natural colours possible on their televisions at home... it [also] fits very well and reliably into existing live production workflows."
The BBC claims that HLG "provides a great picture not only to HDR devices, but to standard dynamic range (SDR) devices that support the BT.2020 wide colour gamut as well". Obviously, there's an advantage there because the BBC doesn't have to use a separate stream for SDR TVs.
The 4K UHD content so far witnessed has been of excellent quality, but it has been a disadvantage that you're unable to pause it or handle it like another BBC iPlayer stream.
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