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Rkolsen2,721 posts since 20 Jan 2014
BBC World
For FreeView which appears to use Stat Muxing do they channels have a guaranteed amount of bandwidth? Here in the US our networks like to have around an average 12-16Mbps while most of SD subchannels ideally would like 4 Mbps but will settle for no less than 1 Mbps (this is all ATSC 1.0 and MPEG-2]. There are some stations thanks to the spectrum auction are carrying 2 1080i feeds + 2 SD feeds - the 1080is average around 8Mbps each and SD around 1Mbps each.

What is transmitted on BBC One and ITV during opts? Is it just color bars or in the case of BBC One the tune to SD Barker? In the US during commercial breaks some networks may transmit nothing but I think NBC and ABC Show an animated logo slide. During local time it’s usualky just black with some sort of channel identification or color bars with the number to NOC.

Finally, when people discuss a TV show do they say I saw it on BBC One or just BBC?
Don’t let anyone treat you like you’re a VO/SOT when you’re a PKG.
Inspector Sands13,595 posts since 25 Aug 2004

What is transmitted on BBC One and ITV during opts? Is it just color bars or in the case of BBC One the tune to SD Barker?

During the regional opt outs the relevant regional programme/ad break is transmitted. On the HD version of BBC1 there's a red slate, although in the 18:30 regional news slot there is normally the red slate followed by a barker of programme highlights


During the opt outs the 'network version' of BBC1 leaving Red Bee carries the News Channel during the day and BBC London News during Breakfast, but this isn't normally seen. If a region fails to opt out or has to stop early then that is what is seen in that region, though an alternative region can be arranged if there's enough warning

Quote:
Finally, when people discuss a TV show do they say I saw it on BBC One or just BBC?

They'll say the channel they saw it on. There might be a few people who will say they saw something last week on 'Westward' or 'Central' but these are increasingly rare as the memory of those channels diminishes
623058
I still hear people say thingy was on GMTV today...
noggin14,318 posts since 26 Jun 2001
For FreeView which appears to use Stat Muxing do they channels have a guaranteed amount of bandwidth? Here in the US our networks like to have around an average 12-16Mbps while most of SD subchannels ideally would like 4 Mbps but will settle for no less than 1 Mbps (this is all ATSC 1.0 and MPEG-2]. There are some stations thanks to the spectrum auction are carrying 2 1080i feeds + 2 SD feeds - the 1080is average around 8Mbps each and SD around 1Mbps each.


The UK and US OTA systems are based on two totally different concepts.

In the US each station has a 6MHz channel of its own - which it then carves up between channels. Each 6MHz ATSC 8VSB mux can carry 19.2Mbs of video and audio - and MPEG2 is the dominant codec for SD and HD. The system was originally designed to allow one 1080i or 720p HD service, to mirror the existing 6MHz NTSC-M SD analogue service a station was allocated, though the system allowed for a reduction of bitrate to allow for additional SD sub-channels (and as encoders have improved, more/HD subchannels became an option)

In the UK the BBC were given one 8MHz DVB-T mux (later a second was gifted), iTV and C4 shared a DVB-T mux etc. - so there isn't a direct mapping from analogue channels to digital muxes.

The 24MHz BBCA mux (aka PSB1) carries BBC One, BBC Two, CBBC, CBeebies/BBC Four, BBC News Channel, BBC Parliament, BBC Red Button video and BBC Radio services (plus BBC Alba and BBC Scotland in Scotland) These are all 16:9 SD MPEG2 services.

ITV/C4's mux (D3/4 aka PSB2) is similar.

The second BBC mux, (PSB3 aka BBCB) switched to DVB-T2 at 40.25Mbs and carries BBC One HD, BBC Two HD, CBBC HD, ITV HD, C4 HD, C5 HD - all 1080i h.264 (which is a lot more efficient than MPEG2). The BBC handles coding and mux for this mux - with ITV, C4 and C5 paying for carriage (but the BBC don't use this to make money)

Everything is statmuxed - with a pretty equitable system of everyone averaging roughly the same bitrate of 4.5Mbs with a peak of 16.5Mbs

http://en.digitalbitrate.com/dtv.php?liste=1&live=9&lang=en&mux=BBCB-PSB3 is useful to see how European DVB services operate.

You'll see Germany is using DVB-T2 but with h.265/HEVC and 1080p50 (not 1080i25) and with even lower average bitrates. The US system is using a 20+ year old codec - until ATSC 3.0 hits that is (if it does)

Quote:

What is transmitted on BBC One and ITV during opts?


Transmitted - i.e. what is sent from the transmitters to people at home? On BBC One and ITV SD you get your local regional news. On BBC One HD you will get a slate telling you to switch to BBC One, followed by a BBC promotional barker reel. ITV HD carries some regions (but I think you may not get the correct region on ITV HD and have to switch to SD to guarantee this)

If you mean distributed to each station (rather than transmitted) - then the BBC these days usually carry the News Channel on their network feed for the longer opts on the feed send to each regional centre - which they opt away from. This is known as 'Network sustaining' and is designed to be passed on to the transmitters should a region fail to opt-out.

ITV don't run an opt-out system - so they don't have to send ITV to each local studio, instead the local studio output is fed to ITV Playout North and South, and they cut them into the correct transmitter feed at the correct time. As coding and mux is now centralised for transmitters this makes sense.
Quote:
Is it just color bars or in the case of BBC One the tune to SD Barker? In the US during commercial breaks some networks may transmit nothing but I think NBC and ABC Show an animated logo slide. During local time it’s usualky just black with some sort of channel identification or color bars with the number to NOC.


US stations run with a central network feed sent to affiliates for local modification. UK commercial broadcasters no longer really do that as they are all played out centrally (though STV in Scotland hang off an ITV feed I guess)

Quote:

Finally, when people discuss a TV show do they say I saw it on BBC One or just BBC?


Either 'I saw it on BBC One' or 'I saw it on THE BBC'

Unlike US three-letter broadcasters (ABC, NBC, CBS, PBS), the BBC takes a definite article, but ITV and Channel Four don't...

"I saw it on THE BBC" "I saw it on ITV"...


(Yep - doesn't make sense...)
Rkolsen2,721 posts since 20 Jan 2014
BBC World

What is transmitted on BBC One and ITV during opts? Is it just color bars or in the case of BBC One the tune to SD Barker?

During the regional opt outs the relevant regional programme/ad break is transmitted. On the HD version of BBC1 there's a red slate, although in the 18:30 regional news slot there is normally the red slate followed by a barker of programme highlights


During the opt outs the 'network version' of BBC1 leaving Red Bee carries the News Channel during the day and BBC London News during Breakfast, but this isn't normally seen. If a region fails to opt out or has to stop early then that is what is seen in that region, though an alternative region can be arranged if there's enough warning


Okay the latter sounds like what I was wondering as to what does the BBC transmit to regions who are currently opting.

So from your saying and based on what I understand the BBC sends a network feed (with the NC during the times they should opt) to the regions who then manually opt and then back to where ever it’s coded. So if for what ever reason they don’t opt, the region will by default get the NC.
Don’t let anyone treat you like you’re a VO/SOT when you’re a PKG.
Rkolsen2,721 posts since 20 Jan 2014
BBC World
For FreeView which appears to use Stat Muxing do they channels have a guaranteed amount of bandwidth? Here in the US our networks like to have around an average 12-16Mbps while most of SD subchannels ideally would like 4 Mbps but will settle for no less than 1 Mbps (this is all ATSC 1.0 and MPEG-2]. There are some stations thanks to the spectrum auction are carrying 2 1080i feeds + 2 SD feeds - the 1080is average around 8Mbps each and SD around 1Mbps each.


The UK and US OTA systems are based on two totally different concepts.

In the US each station has a 6MHz channel of its own - which it then carves up between channels. Each 6MHz ATSC 8VSB mux can carry 19.2Mbs of video and audio - and MPEG2 is the dominant codec for SD and HD. The system was originally designed to allow one 1080i or 720p HD service, to mirror the existing 6MHz NTSC-M SD analogue service a station was allocated, though the system allowed for a reduction of bitrate to allow for additional SD sub-channels (and as encoders have improved, more/HD subchannels became an option)

In the UK the BBC were given one 8MHz DVB-T mux (later a second was gifted), iTV and C4 shared a DVB-T mux etc. - so there isn't a direct mapping from analogue channels to digital muxes.

The 24MHz BBCA mux (aka PSB1) carries BBC One, BBC Two, CBBC, CBeebies/BBC Four, BBC News Channel, BBC Parliament, BBC Red Button video and BBC Radio services (plus BBC Alba and BBC Scotland in Scotland) These are all 16:9 SD MPEG2 services.

ITV/C4's mux (D3/4 aka PSB2) is similar.

The second BBC mux, (PSB3 aka BBCB) switched to DVB-T2 at 40.25Mbs and carries BBC One HD, BBC Two HD, CBBC HD, ITV HD, C4 HD, C5 HD - all 1080i h.264 (which is a lot more efficient than MPEG2). The BBC handles coding and mux for this mux - with ITV, C4 and C5 paying for carriage (but the BBC don't use this to make money)

Everything is statmuxed - with a pretty equitable system of everyone averaging roughly the same bitrate of 4.5Mbs with a peak of 16.5Mbs

http://en.digitalbitrate.com/dtv.php?liste=1&live=9&lang=en&mux=BBCB-PSB3 is useful to see how European DVB services operate.

You'll see Germany is using DVB-T2 but with h.265/HEVC and 1080p50 (not 1080i25) and with even lower average bitrates. The US system is using a 20+ year old codec - until ATSC 3.0 hits that is (if it does)

Quote:

What is transmitted on BBC One and ITV during opts?


Transmitted - i.e. what is sent from the transmitters to people at home? On BBC One and ITV SD you get your local regional news. On BBC One HD you will get a slate telling you to switch to BBC One, followed by a BBC promotional barker reel. ITV HD carries some regions (but I think you may not get the correct region on ITV HD and have to switch to SD to guarantee this)

If you mean distributed to each station (rather than transmitted) - then the BBC these days usually carry the News Channel on their network feed for the longer opts on the feed send to each regional centre - which they opt away from. This is known as 'Network sustaining' and is designed to be passed on to the transmitters should a region fail to opt-out.

ITV don't run an opt-out system - so they don't have to send ITV to each local studio, instead the local studio output is fed to ITV Playout North and South, and they cut them into the correct transmitter feed at the correct time. As coding and mux is now centralised for transmitters this makes sense.
Quote:
Is it just color bars or in the case of BBC One the tune to SD Barker? In the US during commercial breaks some networks may transmit nothing but I think NBC and ABC Show an animated logo slide. During local time it’s usualky just black with some sort of channel identification or color bars with the number to NOC.


US stations run with a central network feed sent to affiliates for local modification. UK commercial broadcasters no longer really do that as they are all played out centrally (though STV in Scotland hang off an ITV feed I guess)

Quote:

Finally, when people discuss a TV show do they say I saw it on BBC One or just BBC?


Either 'I saw it on BBC One' or 'I saw it on THE BBC'

Unlike US three-letter broadcasters (ABC, NBC, CBS, PBS), the BBC takes a definite article, but ITV and Channel Four don't...

"I saw it on THE BBC" "I saw it on ITV"...


(Yep - doesn't make sense...)

Thanks for the explanation. I knew about the US stuff being an American but not so much the UK. And your right the sustaining feed was what I was thinking of.
Don’t let anyone treat you like you’re a VO/SOT when you’re a PKG.
Steve in Pudsey9,995 posts since 4 Jan 2003
Yorkshire Look North (Yorkshire)
Either 'I saw it on BBC One' or 'I saw it on THE BBC'

Unlike US three-letter broadcasters (ABC, NBC, CBS, PBS), the BBC takes a definite article, but ITV and Channel Four don't...

"I saw it on THE BBC" "I saw it on ITV"...


(Yep - doesn't make sense...)


It kind of makes sense if you expand the initials. "The British Broadcasting Corporation" makes sense gramatically, "The Independent Television" perhaps doesn't.

Not entirely sure the origins of "Now on the UTV" though Smile
Write that down in your copybook now.
3
Si-Co, chevron and bilky asko gave kudos
Orry Verducci1,639 posts since 1 Feb 2005
Anglia (West) Look East
Okay the latter sounds like what I was wondering as to what does the BBC transmit to regions who are currently opting.

So from your saying and based on what I understand the BBC sends a network feed (with the NC during the times they should opt) to the regions who then manually opt and then back to where ever it’s coded. So if for what ever reason they don’t opt, the region will by default get the NC.

That's correct, if a region fails to opt out for some reason the viewers at home will see the News Channel (London News during Breakfast). It's uncommon but has happened. HD opts out of this to show the slate telling viewers to switch to SD.


In the past when the regions opted out this would be sent straight from the regional site to the transmitters, but this has since changed, so now all the regional feeds are sent back to 'Central Coding and Mux' in London. Therefore if a region is having a problem that prevents them from going to air, they can warn CCM who can now switch output to another region to fill the gap.

The nations (Wales, Scotland, NI) are slightly different as they generally receive a clean feed with only the programming on. Between the programmes that feed usually shows this animation:


In ITV's case they do still have a clean network feed which is provided to STV. During breaks this shows a static ITV logo, as seen yesterday when STV cut to the network at the wrong time:


For the English ITV regions and UTV, as said these are played out centrally by Red Bee alongside the network feed, the regional sites aren't involved. As a result there's never really been a situation where the slate has gone to air as the breaks are triggered on all the regions simultaneously by the network automation playlist, or if it has it's an extremely rare occurance.

The feeds from the regions to London/Leeds carrying the regional news do have a similar holding slate when not in use for the news, which is just the ITV logo with the region name under it on a black background, usually with a moving block, as briefly seen 27 seconds in to this promo video for Red Bee:
Last edited by Orry Verducci on 17 March 2019 11:46am
3
Rkolsen, Si-Co and Inspector Sands gave kudos
Josh916 posts since 21 Dec 2014
Besides from announcing programme links, what do Continuity Announcers do?
My tweet was read out on BBC Four's Eurovision coverage and Rylan Clark-Neal replied to it. That's all.