HD : Is it better to watch an HD news channel in the event of an imminent nuclear attack?

[spiderplant]

Originally Posted by RichardCoulter

But by the time it's changed channel and tuned into it, the delay will probably have passed!

Just flick between them using the LastCh button. It's easy to tell which is ahead, especially on the news channels that have a ticker.

I've just checked a few, and in every case the SD channel is ahead (7 seconds ahead in the case of Channel 4). I suspect the MPEG4 encoding processing delay is the biggest factor. ITV HD, which is still MPEG2 in my region, is only very slightly behind the SD version.

Originally Posted by muppetman11

And the award for most pointless thread goes to.........

Maybe not entirely pointless. I recall a similar thread many years ago that was started by someone who was into real-time gambling. He liked analogue TV because it had the least delay.

[Raider999]

Agreed, SD channels are ahead of HD channels.

[joglynne]

Off topic in a way but .... If it was possible to get a full 4 minute warning I would love to hear what people would do.

Besides kissing my husband I hope I would have a large cream cake handy that I could consume without worrying about the calories.

[SnoopZ]

Originally Posted by muppetman11

And the award for most pointless thread goes to.........

I thought that when i saw it last night...... some people just post crap for the sake of posting....

The next thread from him will be, how do you butter your toast or tie your shoe laces! lol

[Raider999]

Personally, I would rather not know and die in ignorant bliss as 4 minutes is not enough time for anything

[devilincarnate]

Originally Posted by Raider999

Personally, I would rather not know and die in ignorant bliss as 4 minutes is not enough time for anything

Not what our lass says to me lol

[Mad Max]

Originally Posted by devilincarnate

Not what our lass says to me lol

[heero_yuy]

The only people that will get a 4 minute warning are the party apparatchiks and their rich friends. Rest of us will die in blissful ignorance. (Probably still watching Jeremy Kyle)

[weenie]

Originally Posted by joglynne

Off topic in a way but .... If it was possible to get a full 4 minute warning I would love to hear what people would do.

Besides kissing my husband I hope I would have a large cream cake handy that I could consume without worrying about the calories.

The selfish part of me would want my hubby and son's with me and the unselfish part of me would want my eldest to be with his one true love his fiancée as I know that is what and whom he would want.

[RichardCoulter]

Originally Posted by spiderplant

Just flick between them using the LastCh button. It's easy to tell which is ahead, especially on the news channels that have a ticker.

I've just checked a few, and in every case the SD channel is ahead (7 seconds ahead in the case of Channel 4). I suspect the MPEG4 encoding processing delay is the biggest factor. ITV HD, which is still MPEG2 in my region, is only very slightly behind the SD version.


Maybe not entirely pointless. I recall a similar thread many years ago that was started by someone who was into real-time gambling. He liked analogue TV because it had the least delay.

Cheers for that SP, so my theory has been disproved and the SD channels are the most up to date because of other factors.

Interesting that it could actually be of importance to gamblers.[COLOR="Silver"]



---------- Post added at 15:53 ---------- Previous post was at 15:52 ----------

Originally Posted by Raider999

Personally, I would rather not know and die in ignorant bliss as 4 minutes is not enough time for anything

Me too, the 4 minute warning is totally pointless.

---------- Post added at 15:53 ---------- Previous post was at 15:53 ----------

Originally Posted by weenie

The selfish part of me would want my hubby and son's with me and the unselfish part of me would want my eldest to be with his one true love his fiancée as I know that is what and whom he would want.

❤

[Qtx]

Originally Posted by spiderplant

I've just checked a few, and in every case the SD channel is ahead (7 seconds ahead in the case of Channel 4). I suspect the MPEG4 encoding processing delay is the biggest factor. ITV HD, which is still MPEG2 in my region, is only very slightly behind the SD version.

I figured encoding would make a difference but wasn't sure how it works out. Although SD has less information, I wondered if it would take longer due to being a higher definition source re-encoded on the fly to lower resolution/bitrate and codec type or something similar.


That would have made the SD slower so obviously not the case but interested to know how the SD/HD channels are actually done and if it all relies on digital hardware or if any old analogue stuff is used.


In the future the answer to which is faster could potentially change according to hardware encoding/decoding and broadcasting specs. 4k could potentially get to someone quicker than SD.

[spiderplant]

Originally Posted by Qtx

That would have made the SD slower so obviously not the case but interested to know how the SD/HD channels are actually done and if it all relies on digital hardware or if any old analogue stuff is used.

The answer is "it varies". But I think it's all digital these days.

Originally Posted by Qtx

In the future the answer to which is faster could potentially change according to hardware encoding/decoding and broadcasting specs. 4k could potentially get to someone quicker than SD.

Advanced codecs take longer to encode because they work on many video frames in parallel. The allows them to find common patterns across mutiple frames, and so increase the compression. But the more frames they scan, the more they have to buffer, so the delay increases. It's unlikely to ever get quicker, as this would reduce the compression or compromise picture quality.

[multiskilled]

Originally Posted by RichardCoulter

Interesting that it could actually be of importance to gamblers.

Think I would rather have the extra delay before I find out I had just blown the mortgage payment on the 2:30 at Kempton

[RichardCoulter]

Originally Posted by spiderplant

The answer is "it varies". But I think it's all digital these days.


Advanced codecs take longer to encode because they work on many video frames in parallel. The allows them to find common patterns across mutiple frames, and so increase the compression. But the more frames they scan, the more they have to buffer, so the delay increases. It's unlikely to ever get quicker, as this would reduce the compression or compromise picture quality.

You never know, over the years they've managed to increase compression efficiencies on Freeview to squeeze in more channels into the same amount of capacity.

---------- Post added at 16:42 ---------- Previous post was at 16:41 ----------

Originally Posted by multiskilled

Think I would rather have the extra delay before I find out I had just blown the mortgage payment on the 2:30 at Kempton

Ha ha, wouldn't it be useful if the bookie was using a two minute delayed system and you weren't 🤗

On a slightly related note, a couple of milliseconds can make a difference (and a lot of money).

https://www.telegraph.co.uk/finance/...-millions.html

Lewis, whose previous books include Liar’s Poker and The Big Short, gets inside the world of high-frequency traders (HFTs) who install ultra-fast fibre-optic data connections between their systems and modern stock exchanges, giving them a minuscule speed advantage over rival traders. This advantage, while just milliseconds (thousandths of a second), allows HFTs to see other buyers’ orders before they are executed.

At the most basic level, they use this time advantage to buy the stock before the first deal has been processed and sell it on to the original purchaser at a slightly higher price, a process known as “front-running”...

...What was previously thought of as fast - before 2007 - just wouldn’t cut it for HFTs. What was fast then was the fastest a human could go. Now there was no man in the loop.

“The response of many of them suggested that their entire commercial existence depended on being faster than the rest of the stock market,” writes Lewis revealing that some of them “would sell their grandmothers for a microsecond [a millionth of a second]”.

No wonder that Spread Networks, the company building the fibre-optic connection, proudly boasted: “Round-trip travel time from Chicago to New Jersey has been cut to 13 milliseconds.”

And HFTs were willing to pay through the nose to use it, with the first 200 to sign up forking out $2.8bn between them.