5 ms·

>But again, our visual systems do not have the ability to distinguish between individual events separated by 1/60th of a second. We just can't do it, and trying

>But again, our visual systems do not have the ability to distinguish between individual events separated by 1/60th of a second. We just can't do it, and trying to animate at that speed is purely wasted effort. And yet, there's a very clear perceivable difference between a game running at 30hz and 60hz. How does that work?

ajross 17y ago
I don't buy it. Until someone shows me a real study (or even a demo where I can verify the frame rate and see the effect for myself), I'm not going to believe this "effect" exists. Almost certainly, you're not seeing a 30Hz game. You're seeing a game running at 30Hz typically and being annoyed by a handful of frames that take longer than ~100ms. It's the outliers that are doing it, not the frame rate.
- DarkShikari 17y ago
  Then watch a 60fps video. Then decimate it to 30fps, and watch that. Or will you claim that there are "outliers" in a constant framerate video, too? The visual difference is so significant that television broadcasters have kept interlacing solely for the greater temporal resolution, despite the tens of billions of dollars in inefficiencies that the legacy technology creates.
  - ajross 17y ago
    If the decimation does anything but average frames, then it's a lossy process and of course there will be detectable differences. And if it does average frames, it's susceptible to the aliasing issues I mentioned above (lighning flashes become gray blurs, etc...) The question was if there's a single game (or video) you can point me to that (1) has a solid 30Hz frame rate and (2) looks perceptibly "not smooth" for some obvious definition thereof.
    - DarkShikari 17y ago
      Sure. Here, I'll give an example that doesn't even rely on high motion, flashing, or other such tricks: a simple video game clip. This particular game engine has its display locked to 60fps: the in-game time between two frames is absolutely constant, so even if your computer is too slow to display in realtime, it will simply output frames slower. As a result, the FRAPS'd capture of the game is a perfect smooth 60fps no matter what. Additionally, it doesn't have any single-frame effects that would be visually aliased (e.g. lightning), nor does it have any sort of motion blur. http://mirror05.x264.nl/Dark/testfps1.mkv http://mirror05.x264.nl/Dark/testfps1.mkv http://mirror05.x264.nl/Dark/testfps2.mkv http://mirror05.x264.nl/Dark/testfps2.mkv Don't look at the filesizes (obviously, 60fps will be larger), and don't go checking the file info or whatever. Just play them in your favorite media player. I'm pretty sure you'll be able to tell which is 60fps.
      - ajross 17y ago
        Uh... then why is there a frame rate counter in the bottom right of the screen giving variable numbers between 40-70? :) I agree that the smaller file looks jumpier. But it's still reporting the same frame rates as the bigger file, which leads me to believe the jumps are an artifact of translation somewhere. Certainly nothing seems to be "locked".
        DarkShikari 17y ago
        Uh... then why is there a frame rate counter in the bottom right of the screen giving variable numbers between 40-70? :) Because that's the rate of the frames being displayed during capture. Again, the in-game time between two frames is the same, so if it captures at 50fps, that just means the game runs at 50/60=5/6 times normal speed. It's similar to how you can capture a 1000fps recording in Counterstrike: the game doesn't actually have to run at 1000fps, it just slows down the game accordingly. I agree that the smaller file looks jumpier. But it's still reporting the same frame rates as the bigger file, which leads me to believe the jumps are an artifact of translation somewhere. Certainly nothing seems to be "locked". It sounds like your media player is broken, because ffmpeg gives 60fps for the higher framerate file and 30fps for the lower one.
- rufo 17y ago
  There is a significant difference between a locked-at-30fps game and a locked-at-60fps game. Heck, I've seen 60fps video on a PC and you could instantly tell that it was uncannily smooth compared to regular 30fps video. Many high-end filmmakers have been pushing for higher framerate movies as well - Roger Ebert has been a big proponent of this due to demos he's seen (preferring it over 3D), and James Cameron was pushing for Avatar to be filmed at 60fps. One of the most interesting examples of 30fps vs. 60fps. was the PC port of the original Halo. It has the option to unlock the framerate from 30fps and render as fast as possible, unlike the locked-at-30 Xbox original. However, all the animations were 30hz - if you disabled the framerate lock, the gameworld would run perfectly smooth (moving, physics, etc.), but all of the animations stayed at 30hz, appearing choppy and disconcerting. (I believe there are demos of Halo 1 for PC and Mac, should you have a computer capable of running it - since it's many years old it should be OK on anything with a reasonable graphics card, though you may need to turn the graphics settings all the way down to see the effects.) Many games will be fine at 30FPS, as long as they maintain that framerate - but for very fast action games, the extra frames do make a noticeable difference in feel and responsiveness.
lutorm 17y ago
As the article said, you see chopping because the images are sharp. Imagine if your eye only worked at 10fps. You'd still see the difference between 30 and 60 because moving objects would chop even after averaging over 3 or 6 frames. It's just that the difference between the frames would be smaller at higher fps, so eventually they are too close to notice and you effectively get motion blur. If the game rendered at 30fps but with motion blurring to account for 1/30s of motion, and at 60fps to account for 1/60s of motion, I predict it would be very difficult to tell the difference.

ajross 17y ago

I don't buy it. Until someone shows me a real study (or even a demo where I can verify the frame rate and see the effect for myself), I'm not going to believe this "effect" exists. Almost certainly, you're not seeing a 30Hz game. You're seeing a game running at 30Hz typically and being annoyed by a handful of frames that take longer than ~100ms. It's the outliers that are doing it, not the frame rate.

DarkShikari 17y ago
Then watch a 60fps video. Then decimate it to 30fps, and watch that. Or will you claim that there are "outliers" in a constant framerate video, too? The visual difference is so significant that television broadcasters have kept interlacing solely for the greater temporal resolution, despite the tens of billions of dollars in inefficiencies that the legacy technology creates.
- ajross 17y ago
  If the decimation does anything but average frames, then it's a lossy process and of course there will be detectable differences. And if it does average frames, it's susceptible to the aliasing issues I mentioned above (lighning flashes become gray blurs, etc...) The question was if there's a single game (or video) you can point me to that (1) has a solid 30Hz frame rate and (2) looks perceptibly "not smooth" for some obvious definition thereof.
  - DarkShikari 17y ago
    Sure. Here, I'll give an example that doesn't even rely on high motion, flashing, or other such tricks: a simple video game clip. This particular game engine has its display locked to 60fps: the in-game time between two frames is absolutely constant, so even if your computer is too slow to display in realtime, it will simply output frames slower. As a result, the FRAPS'd capture of the game is a perfect smooth 60fps no matter what. Additionally, it doesn't have any single-frame effects that would be visually aliased (e.g. lightning), nor does it have any sort of motion blur. http://mirror05.x264.nl/Dark/testfps1.mkv http://mirror05.x264.nl/Dark/testfps1.mkv http://mirror05.x264.nl/Dark/testfps2.mkv http://mirror05.x264.nl/Dark/testfps2.mkv Don't look at the filesizes (obviously, 60fps will be larger), and don't go checking the file info or whatever. Just play them in your favorite media player. I'm pretty sure you'll be able to tell which is 60fps.
    - ajross 17y ago
      Uh... then why is there a frame rate counter in the bottom right of the screen giving variable numbers between 40-70? :) I agree that the smaller file looks jumpier. But it's still reporting the same frame rates as the bigger file, which leads me to believe the jumps are an artifact of translation somewhere. Certainly nothing seems to be "locked".
      - DarkShikari 17y ago
        Uh... then why is there a frame rate counter in the bottom right of the screen giving variable numbers between 40-70? :) Because that's the rate of the frames being displayed during capture. Again, the in-game time between two frames is the same, so if it captures at 50fps, that just means the game runs at 50/60=5/6 times normal speed. It's similar to how you can capture a 1000fps recording in Counterstrike: the game doesn't actually have to run at 1000fps, it just slows down the game accordingly. I agree that the smaller file looks jumpier. But it's still reporting the same frame rates as the bigger file, which leads me to believe the jumps are an artifact of translation somewhere. Certainly nothing seems to be "locked". It sounds like your media player is broken, because ffmpeg gives 60fps for the higher framerate file and 30fps for the lower one.
rufo 17y ago
There is a significant difference between a locked-at-30fps game and a locked-at-60fps game. Heck, I've seen 60fps video on a PC and you could instantly tell that it was uncannily smooth compared to regular 30fps video. Many high-end filmmakers have been pushing for higher framerate movies as well - Roger Ebert has been a big proponent of this due to demos he's seen (preferring it over 3D), and James Cameron was pushing for Avatar to be filmed at 60fps. One of the most interesting examples of 30fps vs. 60fps. was the PC port of the original Halo. It has the option to unlock the framerate from 30fps and render as fast as possible, unlike the locked-at-30 Xbox original. However, all the animations were 30hz - if you disabled the framerate lock, the gameworld would run perfectly smooth (moving, physics, etc.), but all of the animations stayed at 30hz, appearing choppy and disconcerting. (I believe there are demos of Halo 1 for PC and Mac, should you have a computer capable of running it - since it's many years old it should be OK on anything with a reasonable graphics card, though you may need to turn the graphics settings all the way down to see the effects.) Many games will be fine at 30FPS, as long as they maintain that framerate - but for very fast action games, the extra frames do make a noticeable difference in feel and responsiveness.

lutorm 17y ago

As the article said, you see chopping because the images are sharp. Imagine if your eye only worked at 10fps. You'd still see the difference between 30 and 60 because moving objects would chop even after averaging over 3 or 6 frames. It's just that the difference between the frames would be smaller at higher fps, so eventually they are too close to notice and you effectively get motion blur. If the game rendered at 30fps but with motion blurring to account for 1/30s of motion, and at 60fps to account for 1/60s of motion, I predict it would be very difficult to tell the difference.