Motion Blur - Temporal Antiliasing

[davepermen]

just because the image is blurred doesn't mean our eyes and our brain takes them as blurred ..

i have some homevideos of a carusel at home (hence homevideo ). it rotates quite fast. you can look at it, see the horses, cars, dragons turn around in circles, and kids sitting on top of it. you don't have any problems seeing all of them. until you stop the movie. _every_ of the frames is blurred. motion blurred. because it rotates so fast, the camera wasn't able to capture a still image, with sharp pictures of the circulating items. still, if you watch the video, it all looks sharp to you.

it's quite interesting as actually it's just a brainfake. but it works, and it works very well. at least in my brain .. so motionblur works in my case very well, too.. as i will still see the stuff sharp.

but i don't know if thats just my brain that is sort of f**ed up (then again. hey, it's useful that way)

 

[Jabbah]

This is why I would like to have a demo to test the effects of motion blur at different frame rates and at different velocities. It could be that low frame rates are just pretty bad with or wothout motion blur (slightly better with) and faster frame rates are needed with motion blur helping in a variety of cases, maybe most.

One case with home video to remember though is that more likely than not your camera is recording at 50fps PAL or 60fps NTSC encoding each frame in the seperate fields. In motion you will get a very good picture due to the high frame rate but when paused you will be flicking back a forth between the two fields giving the impression of greater amounts of motion blur than there actually are.

 

[davepermen]

hm.. sure.. interlacing does affect the impression as well, i'd guess.. then again, it's nearly 100% horizontal motion (blur) in the video, and thus, the half resolution vertically in a lonely frame shouldn't really affect that. but this is just guessing..

but so far, i always had a bether feeling watching something with motionblur than something without. it just never looked that natural to me without.

 

[Mate Kovacs]

IMO, Multisampling Temporal AA is necessary only when the renderer is capable of (at least) twice the frequency as the display device. (Say, it's capable of 180FPS, and the vsync is only 85Hz.)

 

[DemoCoder]

We're not talking about ATI's "temporal" AA, but real temporal AA.


Again, I think the issue of someone "eye tracking" fast moving objects onscreen is a canard. In most cases, when playing say FPS games, the player's attention (i.e. eye focus) is going to be focused on a small neighborhood around the target reticle, he uses his peripheral vision to look for other enemies, sometimes shifting his eyes to quickly investigate something in the periphery. If a fast moving object is running past him, he will "track" most of the time not by sitting still with the mouse and using his eyes, but moving the target reticle and his eyes at the same time.

The behavior I've seen of most FPS players is to immediately and quickly, almost by reflex, snap the target reticle onto anything moving that looks like an enemy.

So like I said, let's focus on the common case. if 90% of the time, the user's eyes would be such that an image would be blurred, and 10% of the time, he might track using eyes only (not reticle), I say, focus on the 90% case. The 10% of the time, he wil see an image blurred more than normal, but it will still be a usable image.


BTW, I hope you are not evaluating motion blur based on that horrid 3dfx quake demo. Many next-gen game engines on XB360 and PS3 will be using motion blur, so look for it there to make a better evaluation (e.g. Project Offset, Project Gotham Racing 3)

 

[see colon]

current console titles already use motion blur to make games appear to run smoother than they actaulay are. unreal chanpoinship on the xbox, re4 on the GC, and pretty much any ps2 GTA game use it to great success.

 

[Mate Kovacs]

We're not talking about ATI's "temporal" AA, but real temporal AA.

What I meant by "Multisampling Temporal AA" is what zeckensack described in this post.

You can approximate it pretty nicely by producing multiple scene snapshots at multiple points in time that are spread out across the time interval of the whole frame.

What I wanted to say is MTAA can be useful, because rendering 250FPS with vsync off on a 85Hz monitor instead of averaging additional frames to produce 85FPS with vsync on is pointless. But rendering 25FPS with averaging additional frames on a 85Hz monitor instead of just rendering 85FPS is pointless too.

 

[Reverend]

BTW, I hope you are not evaluating motion blur based on that horrid 3dfx quake demo.

Yeah, it looked ridiculous, but it was Good Marketing!

Wonder how you got hold of that demo?

 

[Bolloxoid]

3dfx hyped this gimmick.

What 3dfx did was indeed a gimmick. They made the image of a moving object persist on a location it had previously been in, effectively creating a trail.

This is not temporal antialiasing at all.

 

[Laa-Yosh]

Current motion blur implementations are AFAIK only image processing effects. Each pixel gets a motion vector based 2D blur and that's it.

'Real' 3D motion blur is very very slow in most offline renderers. The almost only exeption, PRMan, manages to go quite fast through 1. (patented) stochastic sampling and 2. serious quality degrading on motion blurred objects, which will not get noticed though.

 

[Blazkowicz]

My opinion is, don't bother with seriously expensive motion blur stuff, just render in the 100fps and it looks good enough (for LCD users, you knew you were buying a slow display, don't you? )

 

[Thelacky]

My opinion is, don't bother with seriously expensive motion blur stuff, just render in the 100fps and it looks good enough (for LCD users, you knew you were buying a slow display, don't you? )

I do not mind as long as FPS are locked at one frequency and Vsync is on. I would take 60Hz rock solid FPS over a high FPS but jumps around alot. I dont like variable FPS because i can see the jerking effect when ever the FPS changes.

Walk sideways in a FirstPersonShooter with FPS locked solid at 60Hz. Then walk sideways in a FirstPersonShooter with ever changing FPS (100-60hz)

Real motion blur would be a nice feature to add to the hardware in future, to help give you that silky smooth feel