[Pete]

Why do channels still broadcast in SD? Surely its more of a clart these days to have SD streaming infrastructure.

I understand things like regional BBC centres still having SD studios, but for something like The Box which is surely just run off a server at Red Bee why on earth is it still in SD? See also MTV.

[Allanbuzzy]

Short answer: Broadcast capacity can't fit loads of HD channels and would require upgrades to the pre-existing satellites/cable/terrestrial systems. Unless they make internet feeds of their channels, it ain't happening.

Long answer: It would require entire upgrades to their infrastructure, be even more costly to run and probably be a waste of space if it's something like 4Music or MTV Music. I mean, you can watch music videos for free and in 4K through YouTube or XITE/Vevo on Sky Q. For channels like E4 Extra, would the benefit really be there for a repeats channel? I guess you could argue Talking Pictures TV could be a much better channel in quality with the upgrade but a lot of those old films are low quality anyway so what difference will that make?

Personally, with the advent of internet-based television, I do think there will be more default HD channels cropping up (given that the BBC are pushing to give viewers at least some way to watch HD feeds of their channels through iPlayer on Freeview despite COM7's closure and bandwidth taken by their local channels). Hell, I'm sure Paramount are just as close as to just putting their music feeds instead onto Pluto TV, running automated and in better quality. Having, for instance, the whole of Freeview being streamed and in 720/1080p default on phones and tablets would be the dream. Of course, it isn't gonna happen.

[Spencer]

I suspect we’ll soon see other broadcasters doing the same as BBC One on DSat, and closing their SD simulcast channels. I would imagine others are watching keenly to see if the Beeb’s move goes without any major impact to viewers. Clearing the SD simulcasts from transponders might free up some space for the likes of ITV Be and 4Seven to go HD on satellite.

[James2001]

That's been happening on Virgin for quite a while, most SD simulcasts have long closed (Sky Arts & News seem to be the only ones remaining). Though they took all their SD only boxes out of commission years ago, unlike other platforms where they're still hanging round.

[Orry Verducci]

As someone who works in the industry and has dealt with distribution I can tell you that it mainly comes down to mainly one thing: cost.

Most channels are played out in HD now, but downscaled to SD at the point of distribution.

From the point of view of satellite, HD services need to be broadcast at higher bitrates than SD services and as such take up more space on the mutiplexes/transponders they're on. As such the uplink and connectivity providers charge more, which not all broadcasters are willing to pay for all services. When you consider that many broadcasters still simulcast in SD and HD, which means paying for two services for each channel, the costs go up very quickly. It's only in the last few years that use of SD Sky/Freesat boxes has dropped off to the point that we can now safely do away with SD services.

This is why for many years lots of the HD services were behind the Sky paywall, as by doing so Sky would offset the costs of providing the HD service. As those contracts with Sky are expiring some broadcasters are now choosing to switch their HD services to FTA, such as ITV did late last year.

Freeview is a much more complicated situation. A variety of political and commercial factors means that HD capacity on the platform is currently extremely limited. The HD capacity that does exist is taken up entirely by the PSB broadcasters for their main channels.

[Allanbuzzy]

In my original post, I seemed to have forgotten that AV1 formatting could definitely reduce the amount of space these channels could take. AV1 seems to be the future of digital online video, but you could just as easily run a service of channels in HD given the amount of free space given from this codec. Could Freeview adapt to this format? Time will tell with DVB-I in planning at the moment.

[Technologist]

DVB - is entirely codec agnostic ..is a super EPG system over multiple delivery technologies.
There are a increasing range of codecs available now with different properties and more efficient
and increasingly symmetric ……So you could say that it is only the patent free nature of AV1
that makes it attractive to big tech … (software)
But broadcasting has tv sets (hardware) and there are many codec developers of that heritage …..
and is it worth changing everyone TV / stb to cope with a new codec
and multiple illuminate over a transition for a system
Which may last say 10 to 15 years …??
But something could replace HEVC for UHD perhaps .. but ATSC 3???
But I cannot see emission of SD and HD being anything other than MPEG2 and AVC ..
And it’s interesting to see how much web streaming is still AVC …

[SunburntRock89]

In my original post, I seemed to have forgotten that AV1 formatting could definitely reduce the amount of space these channels could take. AV1 seems to be the future of digital online video, but you could just as easily run a service of channels in HD given the amount of free space given from this codec. Could Freeview adapt to this format? Time will tell with DVB-I in planning at the moment.

Judging by how we're still broadcasting in MPEG2 for SD channels, I don't see AV1 taking over on Freeview any time soon.

AV1 is still making its way out there on Desktop platforms (with only the latest CPUs/GPUs from Intel, AMD and Nvidia supporting AV1 encode and decode) - imagine how long it will take for it to trickle down to budget TVs.

The next step for TV is probably the closure of DVB-S and T mutliplexes and replacing them with DVB-S2 and T2 multiplexes, along with switching to the more efficient H.264 (AVC) codec to give us more breathing room. Again though, this all comes down to cost.

[Orry Verducci]

AV1 being used to deliver broadcast TV in the UK is extremely unlikely.

Firstly the broadcast industry has largely gone with the MPEG codecs (i.e. HEVC) instead of AV1. As such there are many more smart TV's on the market supporting those codecs than those with AV1, which I think is available on only some the very newest TV's on the market.

Any decision to introduce a new codec would also be caught up in the same politics that is preventing Freeview from moving over to DVB-T2 with more HD services, like many of our European neighbours have.

Due to the limited capacity such services can only be introduced if existing services are dropped, which the stakeholders (i.e. broadcasters, Ofcom, etc) are very reluctant to do as that will mean a large chunk of the population with incompatible receivers won't have access to the services. For everyone other than the BBC that means less viewers and less ad income. So when it comes to Freeview everyone is extremely conservative about making changes.

[IndigoTucker]

H265/HEVC is already much easier to implement atm, theres already a wealth of hardware encoders/decoders (even my laptop has a hardware chip that can encode at faster than realtime for HD).