60fps=30fps+motion blur?

[lentoPastel]

Some people says that 60fps isnt really necessary, that the human eye cannot distinguish more than 30 fps, but to me 60fps looks so much smoother... I was under the impression that that was because at 60fps some kind of motion blur (m.b.) start to happens. Is that right? if that is correct, 30fps + properly done m.b. equals 60fps? is that cheaper (simulating the m.b.) than achieving 60fps (from a computational point of view)? Are there any differences between 60fps and 60fps+m.b to a human? is m.b. just a shortcut to simulate 60fps?

I was reminded from this doubt because a new trailer of Lost planet (XB360) and the amazed people at neogaf (http://www.neogaf.com/forum/showthread.php?t=97050) with the excelent execution of m.b. in that trailer.

greetings
Sebastian

 

[nintenho]

Once you get up to 200fps, the human eye can't see a difference but the difference between the same game without motion blur at 30fps and 60fps is very noticeable. It also depends a lot on the game you're playing. For most games, it doesn't matter but for racing games it makes a huge difference that can make or break the game. That's the reason why there are so many more racing games that are at 60fps then any other genre. Some people say that 60fps is the minimum to make it move like real life.

 

[fellix]

The general issue here with the frame count is that in the computer animation at all (3D games in particular) the scene is being rendered frame-by-frame (dicreete motion), while in real real life (take the human eye or video camcorder, it's not a big difference) the motion is defined by the rate of "snapshots" from a given scene. So if we take a fixed 25/30 snapshot rate for the second case - the more motion is in the scene, the more temporal blur effect will be (more "motion" is exposed for each single "snapshot" - 1/25 ot 1/30 for the case), while to achieve same effect on CG animation/games you'll need some huge (and constant !?) FPS rate to fool the human eye in medium/fast scenes . . . and again the motion won't be so naturall, given the fact that our visual apperception is very sensitive to rapid frame-altering refreshesh.

 

[jlippo]

Sweet spot with motion blur would be somewhere around 60-120fps.

Without motion blur there are cases where you can see problems in motion with framerates well beyond 200hz.
Good example would be small white ball going circles on your screen, one or more revolutions per secound. It is very clear that 60 isn't enough, nor is 120.
To get it look decent, ball shouldn't move more than distance of its own radius, even this could be noticeable, best would be movement in subpixels.

 

[Kaotik]

Once you get up to 200fps, the human eye can't see a difference but the difference between the same game without motion blur at 30fps and 60fps is very noticeable. It also depends a lot on the game you're playing. For most games, it doesn't matter but for racing games it makes a huge difference that can make or break the game. That's the reason why there are so many more racing games that are at 60fps then any other genre. Some people say that 60fps is the minimum to make it move like real life.

Human eye can't really see 200 individual "frames" so to say, it's a continuous flow that our eyes see (and yes, i know the air pilot test where they recognize planes that are only shown for 1/200th second, but the other frames on those tests are blank, put different planes to those 199 other frames and see it all go in a big blur)

edit:
72fps is generally kept as the limit - above that and it's smooth (there's a reason (most) people don't see flickering anymore @ 75Hz for example, but do @ 60Hz)

 

[Nom De Guerre]

It's my opinion that motion blur for in-game play should never be forced (or in a more diplomatic term, implemented). Not even when there's "extra" horsepower (which surely can be better used).

 

[Ailuros]

Sweet spot with motion blur would be somewhere around 60-120fps.

Without motion blur there are cases where you can see problems in motion with framerates well beyond 200hz.
Good example would be small white ball going circles on your screen, one or more revolutions per secound. It is very clear that 60 isn't enough, nor is 120.
To get it look decent, ball shouldn't move more than distance of its own radius, even this could be noticeable, best would be movement in subpixels.

Depends what you mean exactly with motion blur. If it's real temporal antialiasing, then for 4x sample MB, you'd need theoretically 240fps to achieve 60 fps with 4x sample MB. Unless I have understood the whole affair backwards.

If I'm not off track the next best question would be if 4x sample MB is actually adequate, or if a higher sample density would be more ideal.

 

[Jabbah]

Films at the cinema is a good example of low frame rates and motion blur not being acceptable. Try looking at a stationary object with some writing on it in a panning shot. You get a jerky blur. High frame rates are needed with or without motion blur, with motion blur helping the illusion of fluid movement at a given frame rate.

Check out the end of Sneak Peak 2 from Project Offset for a nice demo of motion blur.

 

[Jabbah]

I was reminded from this doubt because a new trailer of Lost planet (XB360) and the amazed people at neogaf (http://www.neogaf.com/forum/showthread.php?t=97050) with the excelent execution of m.b. in that trailer.

Now that is quite pretty.

 

[Xeinon]

The question is more like, Do you need 60fps to have a good sense of speed? Sure, it´s nice to have higher framerate in action games, but racing games should be the ones who would need it the most.

I think PGR3s sense of speed is exellent, i don´t know if it is thanx to the motion blur though.

 

[Kaotik]

The question is more like, Do you need 60fps to have a good sense of speed? Sure, it´s nice to have higher framerate in action games, but racing games should be the ones who would need it the most.

I think PGR3s sense of speed is exellent, i don´t know if it is thanx to the motion blur though.

No, you don't need 60 fps for good sense of speed. Take a look on Geoff Crammond's F1-series of games, which were limited to ~24FPS (GP4 was first to break this I think)

 

[santyhammer]

cd freq

Can be offtopic but... have you wondered why the CDs audio frequency is 44Khz when the human ear work in 20Hz-22Khz frequency or why the typical vertical monitor frequency is 60Hz?

In physics exists a law ( sorry I don't remind the name, is something like Digital sampling theory ) that mentions our senses need to 2x that frecuency to achieve smoother results... If you pass the 2x your senses won't appreciate any change, so if the human eye grabs images at 30Hz then a monitor need to work to 60Hz to achieve good results.

 

[Rodéric]

Subject already discussed, here's a quick summary:

Movies use 24Hz and there's a reason, it's a good cost/performance ratio.
In this case "performance" would rather be "seemingly smooth".

A movie frame = the sum of all that happened in that duration (ie motion blur...)
A computer frame = the state of the world at time t (instantaneous).

If you display the later, you need much higher framerate to have a smooth result, or you can choose to try the former and "simulate" a movie frame with your computer, factoring in motion blur...


And the last point about sound frequency and sound sampling...
That's just that, sampling = how often you get the signal, no matter what the signal is. (ie independant of signal range)