The 24fps effect... is it the monitor or our eyes?

[Awatef]

I was just wondering why scrolling text @ 24fps is totally blurry.

Is it a limitation of the monitors technology or a "feature" of our eyes?

[ppera2]

It is bad made, nothing else.
By correct made video you will have clear pic.

[Awatef]

non sense

Anybody who knows what I'm talking about?

The effect is not only by fast scrolling text, but also with fast scrolling figures in anime, etc

[ppera2]

Ehmmm.... I ask one FAST excuse from you :D

[jggimi]

This reply is for both of you. Before this goes any further, please review Rules 4 and 12 (http://forum.doom9.org/forum-rules.htm). Thank you.

[Awatef]

jggimi... always disturbing the mood ¬.¬

[ppera2]

Originally posted by jggimi
This reply is for both of you. Before this goes any further, please review Rules 4 and 12 (http://forum.doom9.org/forum-rules.htm). Thank you.

Sorry, but I didn't break any of mentioned rules (at least not in this thread). My second reply was little back-handed. Do you have something against humor here?

[Slogra]

24fps is a very low framerate. Have you ever played a videogame at 24fps? It won't be very smooth at all. But if you blur the picture a bit will look more smooth. When things move fast, their will be more blur. This is called motion blur. So that's why your text is blurred.

I hope you know what i'm talking about...

[auenf]

Originally posted by ppera2
Sorry, but I didn't break any of mentioned rules (at least not in this thread). My second reply was little back-handed. Do you have something against humor here?

we have nothing against humor, but sarcasm is hard to use in written words properly due to the fact that it usually needs a certain tone of voice, or facial expression.

Enf...

[ppera2]

Usually I don't like discuss with moderators, but in this case I must say that intervention was wrong. Why you didn't noted Awatef to make more specific question?
He started with offending tone, and I reacted as I like - sarcastic.

Would it better from me to just remain silent? I don't think so...

P.S. I thought that smileys are invented with some purpose.

[avih]

ppera2: point taken. now, just put it aside pls.

Awatef:
can u pls supply a screenshot so we can understand what r u talking about?

thanx.

[Mango Madness]

24fps should be adequate enough to provide a good movie experience. Monitor technology is far, FAR ahead of tvs but the problem is that it's so far ahead that you can sometimes get tearing or flicker in the movie. Because if you play a 24FPS movie at 100hz refresh rate (24x4=96) you will get a 4 HZ or 1 FPS "error" in the playback.

Another point to consider is the difference between 24 and 30 (or 29.97) FPS. If you've ever watched a movie encoded both ways, the 30 FPS is much smoother and fluid in movement, pans, ect. Regardless, 24 FPS shouldn't make anything unwatchable and it sounds like you have either a bad encode or a bad setup.

[Awatef]

OK, I think nobody understood what I'm talking about, except probably one or two.

OK guys, look, take a 24fps file, and get it through this avisynth script:

avisource("filename.avi")
Animate(1,100,"Subtitle", last,"TEXT SCROLLING AT 24 FRAMES PER SECOND",-100,100,0,99999,"Arial",24, last,"TEXT SCROLLING AT 24 FRAMES PER SECOND",1000,100,0,99999,"Arial",24)

and encode the first 10 seconds

When you play, you almost can't read the text, if you pause the text is damn sharp.
So my question is: is it the monitor or our eyes?

[wmansir]

How about:

blankclip(240)
Animate(1,100,"Subtitle", last,"TEXT SCROLLING AT 24 FRAMES PER SECOND",-100,100,0,99999,"Arial",24, last,"TEXT SCROLLING AT 24 FRAMES PER SECOND",1000,100,0,99999,"Arial",24)

so it doesn't depend on an avi source, and it's 10 seconds long.

I still haven't encoded it yet, but it should help others trying it out.

[avih]

it could be both. how does it play in 25fps? how does it play in your monitor's refresh rate, or a full fraction of it? (i.e. if your monitor is @ 60Hz, how does it look in 30fps).

do u use lcd?
what's your monitor refresh rate?

more details still needed.

[Awatef]

I have a normal CRT monitor.
24 or 25fps is pretty much the same.
Refresh rate from 85Hz to 120Hz, no difference (you don't expect me to put it on 60Hz don't you, I still need my eyes ;))

Well, test it on your equipment, I don't see any reason why it should be any different by you.

[CaptainCarrot]

I can notice the effect very clearly, and i might have an explanation for it:
Your eyes (well, not yours only, the human eyes in general) are to slow. It takes the eye usually about 1/15th of a second to recover from a picture, and even longer for very high contrast (which you definitely have). So let's say for the given example it takes your eye about 1/10th of a second to recover from a picture. Then you can see ~3 frames at the same time, the one that's just playing plus the two last frames before that. So to fix this you got to get yourself a new pair of eyes :D .

Regards

EDIT: try blinking with your eyes very fast when watching the clip, and it'll be sharp ;)

[Zhnujm]

As Slogra said, motion blur. Encode it with higer fps and you see it even better: now you have smooth motion with the blurring.

[Awatef]

What CC said makes sense, but to make sure, I took now the advice of Zhnujm and done a 48fps encode and to my surprise, it was not much better.

So I'm now thinking it may have something to do with progressive and interlaced (or may be monitor and TV?!), because on normal PAL 50Hz TVs, you know the text that scrolls at the bottom of the screen on most news channels, I don't see any blurring.

And Zhnujm, it has nothing to do with motion blur, you missed the point like most people that posted before my avs script.

[Zhnujm]

funny, as my definition of motion blur is exactly what CaptainCarrot describes..
But anyway, you will have twice as much fields per second on your TV and the scrolling texts are mostly much slower than that of the avs script. If you change the fps to 60 and the end frame parameter to 300 it runs without blurring and with a more realistic speed.

[Awatef]

Oh, I see, I thought you were talking about motion blur used in movies.

Anyway, actually with 300, it looks with 24fps quite fine too.

Well, that explanation with the reaction time of the eyes makes sense, I cannot even focus...

[CaptainCarrot]

One idea to convince you, take a picture of your screen with fast enough shutter, there shouldn't be any blur on the picture. I just took a picture with my digicam at 1/90s shutter speed, and the text is perfectly sharp. So it's definitely an eyes only effect.