Yep - every English region/sub-region has a dedicated 24/7 video stream on satellite, carrying identical content for much of the day. The encoding used to happen at each regional site, but I think each regional BBC One variant is backhauled uncompressed 270Mbs and compressed at a central coding and mux centre. When you tune to a BBC One English region you are tuned to the same PIDs 24/7 - no PID switching goes on.
Some of the Nordic channels do the PID switching thing for regional opts - and it is far from a clean switch. Flash, bang, freeze etc. In some cases if your receiver gets confused you end up with nothing...
Some of the Nordic channels do the PID switching thing for regional opts - and it is far from a clean switch. Flash, bang, freeze etc. In some cases if your receiver gets confused you end up with nothing...
That seems to be a major problem with DVB, you can't change any of the basic parameters without causing disruptions in the receiver that may last for several seconds or cause it to freeze. Shame they haven't solved that.
I haven't seen any PID switching on satellite, but on DTT in Sweden there is some picture roll and crackling when its regional news on SVT. I remember seeing something similar on NDR in Germany.
Similar problems have been reported in Norway, where NRK1 attempted to switch between HD and SD in the same stream, causing unacceptable delays as receivers had to readjust.
Some of the Nordic channels do the PID switching thing for regional opts - and it is far from a clean switch. Flash, bang, freeze etc. In some cases if your receiver gets confused you end up with nothing...
That seems to be a major problem with DVB, you can't change any of the basic parameters without causing disruptions in the receiver that may last for several seconds or cause it to freeze. Shame they haven't solved that.
I haven't seen any PID switching on satellite, but on DTT in Sweden there is some picture roll and crackling when its regional news on SVT. I remember seeing something similar on NDR in Germany.
Similar problems have been reported in Norway, where NRK1 attempted to switch between HD and SD in the same stream, causing unacceptable delays as receivers had to readjust.
It isn't a DVB issue AIUI - it's an MPEG issue.
Even if you do clever things with I-frame boundaries it's still going to be tricky to do seamless switching when you are switching between GOP-based compressed streams. You're basically doing a channel change after all.
Some of the Nordic channels do the PID switching thing for regional opts - and it is far from a clean switch. Flash, bang, freeze etc. In some cases if your receiver gets confused you end up with nothing...
I haven't seen any PID switching on satellite, but on DTT in Sweden there is some picture roll and crackling when its regional news on SVT. I remember seeing something similar on NDR in Germany.
What is the point of doing it on terrestrial anyway? I can understand it on satellite, but not on a land based system that can be regionalised easily
Some of the Nordic channels do the PID switching thing for regional opts - and it is far from a clean switch. Flash, bang, freeze etc. In some cases if your receiver gets confused you end up with nothing...
I haven't seen any PID switching on satellite, but on DTT in Sweden there is some picture roll and crackling when its regional news on SVT. I remember seeing something similar on NDR in Germany.
What is the point of doing it on terrestrial anyway? I can understand it on satellite, but not on a land based system that can be regionalised easily
Well, one desirable feature for DTT would be automatic switching between HD and SD for regional opts ?
I ask because proposed plans by the BBC state that there is a possibility that the BBC Two Scotland opt-out service being decommissioned, leaving programmes such as Newsnight Scotland in the dark.
Hurrah, no more Newsnight Scotland! Proper Newsnight instead! (On the downside, I bet they'd put Landward and Beechgrove Garden together in the Countryfile slot, wouldn't they?)
I ask because proposed plans by the BBC state that there is a possibility that the BBC Two Scotland opt-out service being decommissioned, leaving programmes such as Newsnight Scotland in the dark.
Hurrah, no more Newsnight Scotland! Proper Newsnight instead! (On the downside, I bet they'd put Landward and Beechgrove Garden together in the Countryfile slot, wouldn't they?)
I think your added this into the wrong thread Beechgrove has been on BBC on for a while.
I haven't seen any PID switching on satellite, but on DTT in Sweden there is some picture roll and crackling when its regional news on SVT. I remember seeing something similar on NDR in Germany.
What is the point of doing it on terrestrial anyway? I can understand it on satellite, but not on a land based system that can be regionalised easily
It is a bandwidth-efficient way to provide multiple regional variations from a single transmitter. This is done to correct problems where transmitter coverage areas cause people to receive the "wrong" programme.
One typical example of the German model is Hamburg, where NDR are using their regional mux to broadcast their main NDR channel with four LCNs mapped to the same video stream. The rest of the space in used to broadcast MDR, WDR and Bayerisches Fernsehen for most of the day, except when there is regional news on NDR, when the other channels go blank to make room for four regional variants of NDR. (Most of Germany's regional public TV channels broadcast regional news in the same timeslots, so viewers don't miss out on any great programming).
Sweden has a slightly different model. SVT are broadcasting two LCNs each for SVT1 and SVT2. They are usually mapped to the same video stream. When there's regional news, the stream is "split" into two streams using the same bandwidth.
One typical example of the German model is Hamburg, where NDR are using their regional mux to broadcast their main NDR channel with four LCNs mapped to the same video stream. The rest of the space in used to broadcast MDR, WDR and Bayerisches Fernsehen for most of the day, except when there is regional news on NDR, when the other channels go blank to make room for four regional variants of NDR. (Most of Germany's regional public TV channels broadcast regional news in the same timeslots, so viewers don't miss out on any great programming).
Ahh I see, interesting
So an equivalent here would be, say, ITV Westcountry having a MUX with it appearing in 4 places on the EPG and then at 6pm closing down ITV2,3 and 4 to use that bandwidth for sub regions?
Quote:
Sweden has a slightly different model. SVT are broadcasting two LCNs each for SVT1 and SVT2. They are usually mapped to the same video stream. When there's regional news, the stream is "split" into two streams using the same bandwidth.
So on one LCN you get regional news and the other you don't?
I suspect the only way you'll get regional programmes on more than one network on DSat would be for LCN 101 to become BBC1 England (a downsampled version of BBC1 HD), LCN 102 remains BBC England. Then each region has its own channel called BBC [Region name], which is switchable between the networks, with the distribution feed to the region being switched before a programme for them to opt out of on cue. They might put up a caption between regional programmes or simply go off air so the bandwidth can be reallocated for red button streams.
For DTT it shouldn't be impossible to opt on any network you want with a bit of reconfiguration of the switching matrix at the coding and mux service.
So an equivalent here would be, say, ITV Westcountry having a MUX with it appearing in 4 places on the EPG and then at 6pm closing down ITV2,3 and 4 to use that bandwidth for sub regions?
So on one LCN you get regional news and the other you don't?
I can't back this up completely, but I believe they are cramming in one extra stream when there's regional news, without closing down other channels. Apparently, the regional news has less bandwidth priority than national programmes, so it doesn't affect the other channels too much. I've been told that national programming on SVT1 and SVT2 typically has 5-6 Mbit/s, while the regional news only gets ~3 Mbit/s.
Whenever I've watched DTT in Stockholm on my laptop, I've had two LCNs for SVT1, and two LCNs for SVT2. One was for the Stockholm "ABC" region, and one was for a different region. All carried on the same mux I think.
It could well be that both LCNs map to a single set of video and audio PIDs for the networked programmes, but one LCN remaps to a different (otherwise empty) set of video and audio PIDs for the split regional content. This would be more bandwith efficient (albeit dropping picture quality in the regional slots) than running two sets of video and audio streams 24/7.
So one LCN (say Stockholm) is mapped to the same video and audio PIDs all day - and carries the Stockholm regional variant during regional opts. The other LCN is mapped to the same PIDs as the Stockholm version for networked programming, but remaps to a normally dormant set of PIDs for the duration of the regional content, carrying different programming.
In an ideal world, the extra video content for the second region would be statmuxed with all the services in the mux I guess - rather than just halving the bandwith of the single stream and giving it to two of them (and you'd avoid opts on both SVT1 and 2 at the same time to avoid 2 extra streams being active at the same time) -
I usually watch SVT1/2 ABC - which I would expect not to switch PIDs - and haven't noticed any nasty crunches on the junctions - and can't say I've noticed terrible picture quality. Will do some TSReader analysis of the muxes when I'm next in Stockholm.
At the moment, SVT1 HD and SVT2 HD on DTT (now carried on DVB-T2 muxes in Sweden) don't carry regional variations at all - wherever you are in Sweden you get the ABC version I think. (They don't bother with replacing the Stockholm regional news in the way that the BBC replace BBC London News on BBC One HD)
(On the downside, I bet they'd put Landward and Beechgrove Garden together in the Countryfile slot, wouldn't they?)
Beechgrove has been on BBC on for a while.