Why 60FPS? (1 Viewer)

[Scott Varney]

I think I asked this on here before but never saw an answer. Since most TV's (with the exception of what this group probably has) can only display 30 frames per second, why do game reviews tout games that can supposedly run at great than 30 FPS. I mean, even PS2 games are said to run at 60 FPS and there is no way to even get that out of the PS2... it has no high-bandwidth component output. Even if the PS2 can generate 60 FPS (which I'm sure it can), neither it nor most TV's on the market can display it.

Are reviewers confusing fields for frames? Why is it so important for a game to run at 60 FPS if the TV can only display 30 FPS? Is it control issues?

Thanks,

Scott

 

[Shayne Lebrun]

60 interlaced frames per second, you mean, which answers your question.

 

[Dave F]

This post from Bjoern should be helpful.
-Dave

 

[Scott L]

Actually Tekken 4 on the PS2 can do progressive so that's a whole new ballpark opened up for specs and developers. For comparitive purposes GT3 does 60fps and GTA III does 30. Notice the differences in smoothness?

 

[Scott Varney]

This post from Bjoern should be helpful.

This does explain why it would be beneficial to lock it into a sustainable framerate. But, it doesn't explain, assuming that with two otherwise similar games, one locked at 30 FPS and and the other at 60 FPS, the one running at 60 FPS should look 'smoother' than the 30 FPS on a standard 30 FPS TV.

 

[Andrew s wells]

lemme see.. Xbox examples (just off the top of my head here).. Halo and amped are both 30fps while metropolis and ralisport are both 60fps. good comaprison examples if you have them to compare.

 

[Gary King]

Because TVs aren't 30Hz.

They can update half of the image at 60Hz. Although this isn't as good as updating the full image at 60Hz for a number of reasons, it does give the visual system a bit more temporal information, which allows your brain to perceive the motion as smoother.

 

[Scott Varney]

Because TVs aren't 30Hz. They can update half of the image at 60Hz. Although this isn't as good as updating the full image at 60Hz for a number of reasons, it does give the visual system a bit more temporal information, which allows your brain to perceive the motion as smoother.

Which is just to say that they display 60 fields per second, not frames.

So, the question still remains, with the exception of those systems/games that can display progressive on HDTV's or monitors, why does anything more than 30 FPS matter?

 

[Gary King]

For *exactly* the reason I mentioned.

TVs can display 60 unique fields every second, and consoles can produce 60 unique fields every second. When a game runs at 60fps, it gives your visual system twice as much temporal resolution as a game running at 30fps, which you perceive as being smoother.

When referring to console frame rate, 60fps is the same thing as 60 fields/second on an interlaced display, is the same as 60Hz.

 

[Scott Varney]

When referring to console frame rate, 60fps is the same thing as 60 fields/second on an interlaced display, is the same as 60Hz.

So, are we being misled by game developers? Because by this response... what is being said is that when a game developer states 60 FPS, they actually mean 60 fields per second, not full frames.

 

[BrianB]

No, Scott. The game logic is still updating 60 times per second.

 

[Iain Lambert]

For my attempt I'll try to explain it as that in a 60fps game the field is being rendered independantly of the previous one, while a 30fps game will only do one game display update for the entire frame. Basically, things look smoother because they aren't doing what would be a 2:1 pulldown in the film world.

The reason that 24fps film still looks fine is because its got built-in motion blur by way of being shot live action - notice how when you watch old Harryhausen stop-motion films that the live action stuff looks smoother than the models.

 

[Shayne Lebrun]

*sigh* Renders at 60 FRAMES per second, HALF of EACH FRAME is displayed to the NTSC television every 1/60th of a second. So for EACH FRAME rendered, HALF gets displayed to the NTSC television.

Plug the same game into the right TV, or an SVGA montior, and suddenly you get each FULL frame displayed every 1/60th of a second.

 

[Scott Varney]

I realize this is beginning to sound like trolling, and it really truly isn't, I'm just trying to understand what's going on here.

And for the matter of this discussion, I think that perhaps we should avoid anything other than the standard 60Hz TV that can be purchased at WalMart (I know, most of us in the group have an HDTV, but the inclusion of such sets just comlicates the matter).

For my attempt I'll try to explain it as that in a 60fps game the field is being rendered independantly of the previous one, while a 30fps game will only do one game display update for the entire frame. Basically, things look smoother because they aren't doing what would be a 2:1 pulldown in the film world.

Iain, I'm certainly not trying to knock this logic. But if each field were rendered seperately from the last, would this not produce some horrendous interlacing artifacts as objects in motion would have moved between fields? It would seem to me at least that there would be horrible tearing on anything in motion.

 

[Iain Lambert]

No Scott, there is no tearing at all. Just watch the news, or anything else either shot on video or broadcast live rather than on film. That is also using a per-field capture method rather than per-frame. It works fine as long as the image is being regularly updated, and indeed pans are actually smoother. If you take a screen grab then it will look horrible though, yes.

 

[Scott Varney]

No Scott, there is no tearing at all. Just watch the news, or anything else either shot on video or broadcast live rather than on film. That is also using a per-field capture method rather than per-frame. It works fine as long as the image is being regularly updated, and indeed pans are actually smoother. If you take a screen grab then it will look horrible though, yes.

Indeed you are correct on this point. I wasn't thinking that, until very recently with some models, video cameras captured in fields, not frames. It's beginning to make sense.

 

[Gary King]

No Scott, there is no tearing at all

Actually, this is incorrect. You need look no farther than Ridge Racer V to see some pretty awful tearing artifacts.

For most games, though, developers are familiar enough with what can and can not be done on a TV so that the tearing artifacts are minimized.

 

[Iain Lambert]

I might be wrong (read - I'm probably wrong), but most of the time tearing is nasty when they don't use double buffering (a technique that doubles the video memory used, and so an early PS2 game is the exact place I'd expect to find the problem) to do the entire screen's update during the vertical blanking interrupt. This means you can start the field draw with one internal frame of image, but finish on a different one, with the tear appearing at the join.

 

[Sean Moon]

My question is how can Tekken 4 be progressive, as I remember reading that the video output on the PS2 was not capable of producing a progressive signal, unless it is doing it somehow through software??????.

 

[Simon J]

My mate used to work for sony, developing PS2 games.

He reckoned developers have the choice of whether a game runs at 25 or 50 fps.

Twice the speed means less processing time for fancier graphics, so there is a trade-off.

Racing games, fine go for 50 fps, adventure games, sure 25 fps. But what for other types of games.

He pointed out the difference between MSR at 25 fps, and F355 at 50 fps.