Mass Media & Technology

25, 30, 60 Frames Per Second

Will we ever be able to capture motion in it's truest form? (December 2016)

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NG
noggin Founding member
james-2001 posted:
noggin posted:
And it's possible to tell 59.94i/p from 50i/p too...


I find it harder to tell that difference. Though I can tell when it's 50hz shown on a 60hz monitor (like watching a DVD or the iPlayer through a PC)- I guess due to the 50>60 conversion.


I can't watch 50Hz on a 60Hz screen for any length of time. The motion judder caused by repeating every 5th frame makes it unwatchable.
CI
cityprod
davidhorman posted:


Why on earth do you think anyone even broadcasts at 50/60fps if no-one could tell the difference from 24fps?


Nobody does broadcast at 50fps. It's 25 fps in most of the world and 30 fps in places like North America and Japan.

Quote:
I know what I'm talking about.


Yeah, when you make a simple mistake like the one above, it does undermine your credibility.
NG
noggin Founding member
cityprod posted:
james-2001 posted:
Try shooting something at 24p with a fast shutter and very little motion blur and see how smooth it looks!


I don't have to. I go to the cinema often enough, and used to back in the days when they actually showed film, rather than digital cinema which is what most cinemas are now. I can't make out individual frames in a 24 fps movie. It's one thing to say that something looks demonstrably smoother, but quite another to actually prove it. And by the way, if you work it out, 1/24th of a second is actually longer than 40 milliseconds.


One reason for this is that most decent cinematographers are aware of the limitation of 24p and shoot around it.

I have zero difficulty spotting 24p, 24p at 60p with 3:2, 25p and 50p apart. 50p vs 60p is trickier, but I'm usually right.

25p vs 50i native content is dead easy.
NG
noggin Founding member
cityprod posted:
davidhorman posted:


Why on earth do you think anyone even broadcasts at 50/60fps if no-one could tell the difference from 24fps?


Nobody does broadcast at 50fps.


Err - tell that to NRK (Norway), SVT (Sweden), DR (Denmark), ARD and ZDF (Germany) who all broadcast 720/50p in Europe. That is 1280x720 at 50 frames per second...

iPlayer is also 720/50p and 540/50p at its maximum quality on some platforms (PCs, Chromecast etc.)

Quote:

It's 25 fps in most of the world and 30 fps in places like North America and Japan.


It's 25 'interlaced' frames per second or 29.97 interlaced frames in 60Hz regions - though many US broadcasters (Fox, ABC, ESPN etc.) use 720/59.4p (59.94fps)

25 interlaced frames are 50 separate images per second - captured potentially 1/50th second apart NOT 1/25th - so you can see 1080i25 as 540p50 on fast motion... It's vital to understand that two consecutive fields in an interlaced frame are NOT captured at the same time. If you don't understand that you don't understand why 25p (aka p25) and 50i (aka i25) will look so different to each other.

Quote:

Quote:
I know what I'm talking about.


Yeah, when you make a simple mistake like the one above, it does undermine your credibility.


Yes... When people make mistakes it does...
JA
james-2001
noggin posted:
Err - tell that to NRK, SVT, ARD, ZDF who all broadcast 720/50p.


Don't forget ABC and Fox in the US (well, 60p rather than 50).
NG
noggin Founding member
cityprod posted:
davidhorman posted:
Quote:
A difference of around 40 milliseconds, cannot be percieved by the human eye, so it appears to be identical, happening at the same time. Hence why 24 frames a second (the standard movie frame rate) looks fairly smooth.


That's demonstrably untrue, since 50fps looks quite different to - far smoother than - 24fps. Anecdotally, I find I can tell the difference between 60fps and 50fps. I've never seen 120fps.


Ah, but did it really? Or did you know in advance that you were watching something shot at 50fps? If you did, then you basically pre-programmed your brain to automatically think it was better. We humans are amazingly good at fooling ourselves. When you start to think critically, that's when you notice things you didn't notice before, such as how we can program ourselves to believe something is better because it has more pixels or more frames.


Lots of us can easily spot the difference between 25p and 50i (which has the same motion capture as 50p (but with some vertical temporal spectrum folding on fine detail - which is what causes twitter on fine detail in interlaced systems) native content without being told or prepped.
NG
noggin Founding member
Should also add that at least one German broadcaster has started 1080p50 (aka 1080/50p) - thats 1920x1080 at 50fps - on their new DVB-T2 H265/HEVC platform that is replacing their SD DVB-T 576i25 (aka 576/50i) terrestrial standard. Others are sticking with 1280x720 at 50fps, which is the standard used on satellite.

http://www.daserste.de/service/kontakt-und-service/das-erste-hd/ard-beteiligt-sich-an-dvb-t2-hd-100.html

Quote:
Das Erste HD in 1080p50/Full-HD
That's 1080p at 50fps...

Although the article says it is due early next year, there are test muxes up and running already.
Last edited by noggin on 11 December 2016 11:04pm
DA
davidhorman
cityprod posted:
Did that, and smell a rat.


What is with your attitude? Even if it's unintentional, could you at least try to use some common courtesy in discussion, instead of using words that make it sound like you're calling me a liar?

Quote:
I checked how it looked as well at 30 fps, by watching it on the standard 480p setting. At that speed, they shouldn't look any different but the left hand looked far worse at 30 fps.


There's a minor frame rate issue with that video, but since the point of it was to demonstrate the difference between 60fps and 30fps, you're really picking at straws. Watch it in 720p60, as I asked you to do so, and then say whether or not you can see the difference, which is what is in question here.

Quote:
Sorry. Not buying what you're selling.


There's no need to be so obnoxious.

cityprod posted:
davidhorman posted:

Why on earth do you think anyone even broadcasts at 50/60fps if no-one could tell the difference from 24fps?


Nobody does broadcast at 50fps. It's 25 fps in most of the world and 30 fps in places like North America and Japan.

Quote:
I know what I'm talking about.


Yeah, when you make a simple mistake like the one above, it does undermine your credibility.


You've just overwhelmingly demonstrated your own ignorance. "Nobody broadcasts at 50fps"? (and don't hide behind interlacing - for the purposes of this discussion, 50i is 50fps, as should be obvious)

All sport is 50/60fps. 99% of news output is 50/60fps. All game shows are 50/60fps. The "classic" (UK) and "cheap" (US) soaps are 50/60fps. Most daytime shows, like Bargain Hunt et al, are 50fps.
NG
noggin Founding member
davidhorman posted:

cityprod posted:
davidhorman posted:

Why on earth do you think anyone even broadcasts at 50/60fps if no-one could tell the difference from 24fps?


Nobody does broadcast at 50fps. It's 25 fps in most of the world and 30 fps in places like North America and Japan.

Quote:
I know what I'm talking about.


Yeah, when you make a simple mistake like the one above, it does undermine your credibility.


You've just overwhelmingly demonstrated your own ignorance. "Nobody broadcasts at 50fps"? (and don't hide behind interlacing - for the purposes of this discussion, 50i is 50fps, as should be obvious)

All sport is 50/60fps. 99% of news output is 50/60fps. All game shows are 50/60fps. The "classic" (UK) and "cheap" (US) soaps are 50/60fps. Most daytime shows, like Bargain Hunt et al, are 50fps.


Yep - and there are plenty of native 50p (and 59.94p) broadcasters -unlike the UK, many countries use a mix of 50i and 50p or 59.94i and 59.94p (50i = i25, 59.94i = i29.97)

And yes - 50i and 50p deliver very similar motion (with a vertical resolution loss on motion at 50i compared to 50p)

The US has plenty of 720/59.94p outlets, and Europe has many 720/50p broadcasters (though some Alchemist cross-convert from 1080/50i internally)
Last edited by noggin on 11 December 2016 11:18pm
DA
davidhorman
Eurosport used to be all 720p50, didn't it?

Another YouTube comparison video of 60fps vs. 30fps:



The problem with the previous clip may be because it was uploaded in the early days of YouTube's 60fps roll-out. The 720p60 version is fine, but the 30fps versions (480p, etc) have had the frames culled in an irregular manner.

Caveat: some combinations of operating system, graphics card and browser may not play it absolutely perfectly. Smart telly might be the best bet. Edit: but not smart set top box, as it will be probably stay in 50Hz and ruin the effect.
Last edited by davidhorman on 11 December 2016 11:39pm - 2 times in total
NG
noggin Founding member
davidhorman posted:
Eurosport used to be all 720p50, didn't it?

Not sure - I've only seen it in 1080i25 on broadcast HD platforms.
GE
thegeek Founding member
cityprod posted:
davidhorman posted:


Why on earth do you think anyone even broadcasts at 50/60fps if no-one could tell the difference from 24fps?


Nobody does broadcast at 50fps. It's 25 fps in most of the world and 30 fps in places like North America and Japan.

A little late to this discussion here, but both Sky Sports and BT Sport are producing content and broadcasting it in 2160p50.

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