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BBC One Breakdown

Major Technical fault before Panorama - Video on page 11 (November 2020)

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NG
noggin Founding member
Standard UK broadcast bitrate and codec for HD show delivery - as per DPP AS11 - is 100Mbs AVCi100. Add on to that the 1.15Mbs per track bitrate requirement for 48k/24bit PCM uncompressed audio tracks (usually 4 or 16 for stereo and 5.1 shows - so ~4.5 to 18Mbs for audio)

Rule of thumb = 1GB/minute (i.e. 1GigaByte per minute - though it's a bit less for stereo)

So a BBC 30 minute show (~29 minutes) with a standard 2 minute line-up and clock will be around 30GB, and an hour long show will be around 60GB, in HD. This may increase if there are textless elements (often another few minutes on the end) tacked on to the end of the delivered programme.

(SD shows - not that they really exist these days - are 50Mbs for video - using IMX50 I-frame only MPEG2 - with the same bitrates for 24 bit audio - though some 16 bit audio - which will require 2/3 the bitrate - may also be in use)

Also MarkyMark you are making an assumption that you can start playout whilst still recording - whilst that's a standard feature in broadcast video servers like EVS - it may not be for integrated 'channel in a box' systems like Morpheus ICE used by Red Bee... (Red Bee use IP 'channel in a box' for both ITV and BBC playout these days - with no separate playout servers, vision and sound mixers, graphics boxes etc. The 'box' does everything internally in the IP domain - playout, DVE, graphics generation, audio mixing and handles the playout automation stuff too)

**EDIT - I believe delayed playout of a recording is a feature of Morpheus ICE, as it can be used for time shift **

Traditionally Red Bee have required 3x the duration of the show to turn around a line recording as a file for delivery to BBC One or Two playout (So for a 30 minute show you were required to start playout to Red Bee 2 hours before transmission). If you missed that slot you had to be prepared to playout live to network down-the-line. This may have been relaxed since I last checked - but that was the rule of thumb programmes usually worked to in deciding whether they could line-feed to lines-record, or had to line-feed live to NC1 or NC2.
Last edited by noggin on 17 November 2020 12:41pm - 3 times in total
CO
commseng
The rules for file transfers are different for different broadcasters I believe.
Certainly at the weekend I was on late as we couldn't transfer a one hour programme completely 7 hours before transmission!
SP
Steve in Pudsey
Was it a late edit that lead to the whole issue, with a hurried file transfer that had timecode problems causing the playout software to fall over?
If so how did Belfast manage to play it out without the same issues?


NI were showing Panorama an hour later, which implies that they had time to learn from the problems that Network had and fix their copy? Or maybe NI Pres obtained their copy via a different workflow (as an in-house production, maybe they could get it more easily from an internal server?), which didn't suffer from the same issue?
LL
Larry the Loafer
For a clueless layman like myself, can somebody tell me what would've prompted the white screen of death? I don't recall ever seeing that before. Or was it just the first frame from an innocuous trailer or something?
OV
Orry Verducci
Regarding the lack the music, someone asked Duncan last night and he answered with:




So it seems very much a case of multiple things going wrong.

It's been mentioned here by Tony that it was a timecode issue. I'd be interested to know if it was an issue with the timecode on the file, followed by a series of other problems, or if there was a problem with the station timecode from the SPG. Speaking again from experience the loss of main and backup station timecode takes down most video systems and confuses the hell out of the automation, so I wonder if that's what happened here?

For a clueless layman like myself, can somebody tell me what would've prompted the white screen of death? I don't recall ever seeing that before. Or was it just the first frame from an innocuous trailer or something?

I suspect it was the first frame of a video file, I can't think of a video device or source that would by default output white. The ones I expect to see if there's trouble going on are black, bars or a particular shade of green which appears when an SDI link fails.
Last edited by Orry Verducci on 17 November 2020 2:20pm - 2 times in total
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MA
Markymark
You can sometimes end up with white from a device that's having its input being fed from its output
RT
Run_Telecine

I suspect it was the first frame of a video file, I can't think of a video device or source that would by default output white. The ones I expect to see if there's trouble going on are black, bars or a particular shade of green which appears when an SDI link fails.


For SDI you'd either get a pink or green screen, depending on whether it's all 1s or all 0s. I can't remember which way round it is!
MA
Markymark

I suspect it was the first frame of a video file, I can't think of a video device or source that would by default output white. The ones I expect to see if there's trouble going on are black, bars or a particular shade of green which appears when an SDI link fails.


For SDI you'd either get a pink or green screen, depending on whether it's all 1s or all 0s. I can't remember which way round it is!


Green is zeros
DB
dbl
*

The viewers stuck around...ish
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IT
itsrobert Founding member
dbl posted:
*

The viewers stuck around...ish

I didn't know there were so many TV Forumers these days! Seriously, though, we should have a membership drive. It looks as though there are lots of geeks out there.
BE
Bennyboy1984
I think in recent breakdowns if you want to go by how catastrophic they are, this one is definitely up there with the 2018 BGT breakdown.
AN
Andrew Founding member
2m EastEnders fans watching half an episode of Panorama there from 8pm!
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