Var debate 2019/20

[cleavers]

Allison Rudd(I know) was very pro var on the guardian podcast and they were told it would only be used on clear and obvious errors. So it seems to me mixed messages are coming from inside that camp.

Again if you read the thread, "clear and obvious" doesn't apply to offside, and that's in the brief from PL.

 

[simon23]

That’s a perfectly legitimate point and one Lineker raises as well. My understanding is it when the foot touches the ball hence the Sterling goal being onside.

By that point the jesus one that was disallowed should have also stood then as when Silva's boot first touches the ball sterling is onside

The fact that we are talking about millimetres and micro seconds however is the bit that is concerning I guess...will it stop the naturalness / fluidity of the game???? It all seems a bit too forensic to me...

I'm all for VAR stopping the divers and cheaters (ie boly scoring with his hand last year or Salah endlessly diving- though I'm not convinced it will stop that as they seem to seem any contact, even the slightest, enough reason to justify an attacker throwing himself to the floor.....on that the Lanzini should have been booked at weekend at least once yet VAR didn't pick it up (maybe that's not one of its purposes; I don't know...if it's not it should be)

 

[cleavers]

I also want to know how 2 incidents at United’s game did not get var checked.

They did, all goals are checked, not every VAR check is notified if there is nothing wrong, they're doing checks now while the game is in play to prevent the stupid delays, so if a goal is given, it will be checked before kick off, if there's no real reason to do anything the game will just restart, not everything is a conspiracy against City.

 

[simon23]

We also defend with a high line which means it will help at the back and so long as our defenders do their job then there’s no relying on a middle aged guy trying to keep up.

Last season, we could hold a perfect line pushing up, catch a player offside and the flag doesn’t go up as the lino couldn’t watch two things 40 yards apart at the same time. So we’ve done our job, played a great offside, it’s not given and we go a goal down.

I’d always take accuracy over that.

I think it will definitely aid us more than hinder us...supporters are just going to have to get used to a few goals not standing.....I can think of one incident last season where sterling kicked the ground and the ref gave us a penalty....sterling didn't even appeal and it was clearly a bad decision and mistake by the ref.....but on the other side there was the willy boly handball vs wolves where we would have won but dropped 2 pts ...

 

[BlueAnorak]

If what @SWP's back has posted above, its not 25 frames per second its far above that, we don't know, because they haven't bothered to tell us here yet.

It's not it's N channels (N = Number of cameras) with each camera providing a stream of 50Hz MPEG4 video at 25 FPS. The broadcast technology doesnt exist to deliver anything better in the available network bandwidth from Caneras deployed to English stadiums.
See DVB-T2 and MPEG4 specifications
Max screen refresh frequency = 60Hz (used in germany), next best = 50Hz used in the UK for all TV channels.

The only improvement is using H.264 standard rather than MPEG4 which doubles the compression on MPEG4. It doesn't change the frequency/frame rate.

 

[cleavers]

It's not it''s N channels (N = Number of cameras) with each camera providing 50Hz MPEG4 video at 25 FPS. The broadcast technology doesnt exist to deliver anything better in the available network bandwidth from Caneras deployed to English stadiums.
See DVB-T2 and MPEG4 specifications
Max screen refresh frequency = 60Hz (used in germany), next best = 50Hz used in the UK for all TV channels.

He describes what they said on his broadcast of the game, I'm not arguing with you or him, just stating what he said. I've no reason to call him a liar, or Walton who said something similar yesterday without giving the same detail.

The managers and captains had it demonstrated to them last week, and were apparently "very happy" with it, so maybe its you that is not up to date, but as we (UK viewers) haven't been given the same detail, that's quite understandable.

 

[GOULDYBOBS]

Am I missing something here, I play computer games at 60fps and have been doing for around 2 years now. Why cant they use that?

Hope your on PC otherwise you bought the marketing campaign

 

[BlueAnorak]

He describes what they said on his broadcast of the game, I'm not arguing with you or him, just stating what he said. I've no reason to call him a liar, or Walton who said something similar yesterday without giving the same detail.

The managers and captains had it demonstrated to them last week, and were apparently "very happy" with it, so maybe its you that is not up to date, but as we (UK viewers) haven't been given the same detail, that's quite understandable.

It's not whether he's a liar (he isnt), its the way the information presented. 2 cameras provide 2 channels and twice the information 4 cameras 4 times the information. Hawkeye (a Sony UK company) whose systems are used by VAR uses a system that combines the images of multiple cameras (channels) to provide a higher accuracy on the presented offside image.
Eventually you will have a complete 3D image that can be moved around to give any view of the game you want.
I know for a fact they are working on AI to combine the images of 8 cameras to give a a 3D image that you can use to give a view of any incident from any angle.
At the moment you are still relying on the video analyst to pick the point where the player touches the ball. AI will resolve this within a few years.

 

[Marvin]

As has been posted Andy Gray's piece is not accurate, he's basing his opinion on the pictures shown, but its not, its technology based and @SWP's back has posted an explanation of said technology, its there if you want to read it, this was also explained by Walton yesterday, but not no examples given, which PL managers and captains were shown in detail last week.

I watched Peter Walton's brief explanation on BT Sport. He didn't really say how it worked.

I agree this discussion is a bit unrewarding as we're discussing a process we don't understand. That's pretty poor. The game is supposed to accept VAR without question, so then explain it.

The delay of 2 mins makes me think it's a manual process which raises questions.

The frame per second argument is relevant if they are advancing frame by frame, but that still does not get round the point that the moment when a ball is played, is not a moment but a finite period of time, and then you have to determine and measure that moment and you also have to measure the distance between players at that 'moment'. You will have an error budget, however it is done, so Phil Neville's black and white call of a player being offisde or not offside maybe the call that the law demands but it may not be possible to determine. In practise this error maybe so small that this issue is just pedantic and irrelevant, or it maybe significant. It depends on the precision of their measurements which we can only guess at the moment. I don't see why we should just have blind faith in officialdom though. Why have all these VAR ambassadors and arguments, when a 15 minute explanation of how they arrived at the West Ham v City offside calls would probably do the job. The fact that this has not been done makes me suspicious. On the other hand football clubs have bought into it. This affects fans though, so explain it to us. Maybe we would not understand, but I bet there will be some fans who do and will know what questions to ask etc.

 

[cleavers]

2 cameras provide 2 channels

Sorry its not his post, but @edinburgh123 post that says 33 camera's @120 frames per second, no idea where he got that from to be fair so don't know if that's real, but if it is its significant increase, but even @SWP's back says SkyQ is filmed at 50fps on 4k (and I would imagine that BT UHD is the same), so I assume he's correct, but the point is its not some referee viewing an image (or 10) its a computer looking at it, that was what Walton said yesterday.

I watched Peter Walton's brief explanation on BT Sport. He didn't really say how it worked.

He did say it was a computer derived decision.

 

[Da_Blu_Moona]

why are we expecting machine level accuracy from a human sport, watched and played by..... humans. Why can't we have fallible human officiating. The sport has lasted this long without it.

The increasing mechanisation of the world....

There is an inherent beauty in imperfection in and of itself.

 

[Marvin]

Sorry its not his post, but @edinburgh123 post that says 33 camera's @120 frames per second, no idea where he got that from to be fair so don't know if that's real, but if it is its significant increase, but even @SWP's back says SkyQ is filmed at 50fps on 4k (and I would imagine that BT UHD is the same), so I assume he's correct, but the point is its not some referee viewing an image (or 10) its a computer looking at it, that was what Walton said yesterday.


He did say it was a computer derived decision.

That doesn't mean anything. Computers can derive rubbish.

The frames per second does not get round the problem that there is no single moment in which the foot strikes the ball. If they are advancing frame by frame, whether they use 24 or 6000 they still have to select the image and then manipulate it. Not worth speculating too much but I think that's the point. I find it surprising that with all the hysteria with VAR we can be this far into it all, and no one seems to know what they do. They must have done presentations to lots of people but it hasn't worked its way into the public domain yet

 

[City Raider]

That doesn't mean anything. Computers can derive rubbish.

The frames per second does not get round the problem that there is no single moment in which the foot strikes the ball. If they are advancing frame by frame, whether they use 24 or 6000 they still have to select the image and then manipulate it. Not worth speculating too much but I think that's the point. I find it surprising that with all the hysteria with VAR we can be this far into it all, and no one seems to know what they do. They must have done presentations to lots of people but it hasn't worked its way into the public domain yet

I agree with this. Maybe they can work out the margin of error of foot striking ball and equate that to a distance beyond which is offside.

But then I’m pissed.

 

[caseball]

Maybe it shouldn't be used for offside unless to prove a clear and obvious error.

Anything else is claiming a level of infallibility that's either impossible or undesirable. The claim has come from someone that it's possible to judge offside by a millimetre. I'm not sure who has said this but that appears to be the claim. It's a bit ridiculous if that's the level of precision they're working to.

Someone correct me here if my reasoning is wrong.

Two players walking in opposite directions at 1 m/s are each moving 1000 mm/s. For a given point on an attacker to move from onside to offside by 1 mm requires each player to move only 0.5 mm. This movement will occur in 0.5 millisecond ... at walking speed. When a player kicks a football, contact between ball and foot has been measured to last between about 7.5 milliseconds and 8.5 milliseconds, depending on the force applied: I believe the smaller the force applied, the longer the time of contact. Clearly, to be accurate according to the laws of football, the offside position of our given point has to be judged at the first half millisecond of that time interval. That, I believe, is the implication of claiming that the system can judge offside to the millimetre. The margin of error is huge, 1600%. And that when two players are moving at walking speed in opposite directions.

https://dspace.lboro.ac.uk/dspace-j...ime in Short Duration Sports Ball Impacts.pdf

Please, somebody prove me wrong.

 

[SWP's back]

HDTV on all UK TV channels is DVB-T2 + MPEG4 50Hz or 25 frames a second be it 1080p or 4320p (4k).
Germany although using DVB-T2 + MPEG4 operates using slight different parameters at 60Hz or 30 frames a second.
Transmission to the VAR decision office probably uses DVB-T2 - So each channel wont be any quicker than 25 frames a second.

That’s incorrect, it’s 50 FPS. I posted three links previous stating that.

 

[SWP's back]

It's not it's N channels (N = Number of cameras) with each camera providing a stream of 50Hz MPEG4 video at 25 FPS. The broadcast technology doesnt exist to deliver anything better in the available network bandwidth from Caneras deployed to English stadiums.
See DVB-T2 and MPEG4 specifications
Max screen refresh frequency = 60Hz (used in germany), next best = 50Hz used in the UK for all TV channels.

The only improvement is using H.264 standard rather than MPEG4 which doubles the compression on MPEG4. It doesn't change the frequency/frame rate.

Incorrect.

https://www.sky.com/help/articles/watching-sky-q-in-ultra-hd

“Ultra HD is an innovative new video format, with a picture resolution of 3840x2160 pixels at 50 frames per second, which is 4 times the number of HD TV. This allows you to watch Sky TV shows and movies with greater clarity and detail.”


https://uk.pcmag.com/sky-sports/82988/sky-sports-ultra-hd-vs-bt-sport-ultra-hd-whats-the-difference

“Sky Sports Ultra HD vs BT Sport Ultra HD: What about frame rates and colour depth?
At the time of writing, both broadcasters' 4k Ultra HD coverage will be shown in/at:

• Resolution: 3,840×2,160
• Frame rate: 50 frames per second
• Colour depth: 10-bits (1,024 shades per primary colour)

Specifications-wise, you'll also need a 4k Ultra HD TV set with at least one HDMI 2.0 port; older sets with the outdated HDMI 1.4 spec - which can only support 4k video at up to 30fps - won't work with either service.”


https://recombu.com/digital/article...k-uhd-on-sky-q-ultra-hd-shows-movies-channels

“Sky has secured 124 Premier League football games which it will air in 4K UHD. That means that it will be broadcast live to your dish at 50 frames per second for super fast action captured clearly.”


https://www.hdtvtest.co.uk/n/BT-Spo...tmos-To-Live-Premier-League-Football-Coverage

“The new channel, which is really just a rebrand of the BT Sport 4K UHD channel, will broadcast live Premier League action at 50 frames per second in 4K resolution, with support for High Dynamic Range and Dolby Atmos sound.”

But yeah, you’re right and me and all these links are wrong.

 

[SWP's back]

The frames per second does not get round the problem that there is no single moment in which the foot strikes the ball. If they are advancing frame by frame, whether they use 24 or 6000 they still have to select the image and then manipulate it

It’s highly relevant as the more frames per second they have available to them, then obviously, the more accurate it can be in terms of being able to pick the correct frame when the player touches the ball (not when it leaves his foot).

 

[jollylescott]

It’s highly relevant as the more frames per second they have available to them, then obviously, the more accurate it can be in terms of being able to pick the correct frame when the player touches the ball (not when it leaves his foot).

That might be the case but I'm certain I have seen more than one frame where Silva touches the ball and Raz is onside.

 

[Dribble]

Maybe it shouldn't be used for offside unless to prove a clear and obvious error.

Anything else is claiming a level of infallibility that's either impossible or undesirable. The claim has come from someone that it's possible to judge offside by a millimetre. I'm not sure who has said this but that appears to be the claim. It's a bit ridiculous if that's the level of precision they're working to.

Someone correct me here if my reasoning is wrong.

Two players walking in opposite directions at 1 m/s are each moving 1000 mm/s. For a given point on an attacker to move from onside to offside by 1 mm requires each player to move only 0.5 mm. This movement will occur in 0.5 millisecond ... at walking speed. When a player kicks a football, contact between ball and foot has been measured to last between about 7.5 milliseconds and 8.5 milliseconds, depending on the force applied: I believe the smaller the force applied, the longer the time of contact. Clearly, to be accurate according to the laws of football, the offside position of our given point has to be judged at the first half millisecond of that time interval. That, I believe, is the implication of claiming that the system can judge offside to the millimetre. The margin of error is huge, 1600%. And that when two players are moving at walking speed in opposite directions.

https://dspace.lboro.ac.uk/dspace-jspui/bitstream/2134/11470/7/Measurement of Contact Time in Short Duration Sports Ball Impacts.pdf

Please, somebody prove me wrong.

You'll get no arguments from me fella... :-)

BTW I totally agree. It never occurred to me until I saw Andy Gray's summary for BEIN Sports. It has to be clarified when offside is judged from EG:

1. The moment the ball leaves the boot

2. The moment the ball touches the boot

At the speeds involved, millimetres become crucial. A prime example of where millimetres matter is the 100m track event. It's impossible to have that level of technology around a football pitch as we don't where a potential offside could take place, but this shows the level of tech needed to determine these fine margins.

@Marvin In terms of video clarity, frame rate matters a helluva lot mate. The more frames per second, the more frames can be viewed to judge point one or two above.

After much consideration, these are the crucial points we need clarification on. Sterling's 2nd goal looked more offside than the second from Jesus which was disallowed.

As Andy Gray pointed out, the crucial differences were the frames where the offside was judged from. For the disallowed goal it was judged when the ball left the boot but for Sterling's second, it was when the ball was first struck.

Lineker alluded to similar reservations on MoTD, so hopefully the powers that be will monitor & evaluate these issues and create a fair standard.

This now brings into question, what are FIFA's standards & UEFA's standards, because apparently they're all different to each other.

 

[SWP's back]

It has to be clarified when offside is judged from EG:

1. The moment the ball leaves the boot

2. The moment the ball is struck

FIFA have it on their website. It is the moment the ball is touched or played so point 2.

https://www.fifa.com/mm/document/afdeveloping/refereeing/law_11_offside_en_47383.pdf