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Information and older arcticles from my original website.
Animated Frames Per Second
OK, I thought everybody already knew this, but just in case...
The number of FRAMES PER SECOND depends upon HOW YOU DEFINE A FRAME:
- If you define a FRAME by the number of times a television set refreshes the screen, even a STILL PICTURE plays at 30FPS because ALL NTSC (US standard) televisions do so.
- If you define a FRAME by the number of passes the electron gun in a TV set makes a complete scan from the top of the screen to the bottom, even a STILL PICTURE plays at 60FPS because ALL NTSC televisions do so.
- If you define a FRAME as being the individual sprites that define each independent point of movement for a particular character on screen, then you are only talking about the frame rate for that CHARACTER. NOT the entire SCREEN.
- If you define a FRAME as being one full screen of video data generated by the system CPU and Video processors, THEN you are giving an ACTUAL measurement of the power of a system unit.
However, there are other factors that go into the definition of a frame:
- How many pixels wide is the screen?
- How many pixels high is the screen?
- How many colors are being used on-screen?
- How much of the screen is generated from scratch each and every frame rather than being reused?
All of those factors must be considered when asking the question:
How many frames are being played back per second?
For instance, in order to display 30 seconds of animation at 800x600 pixels, 512 colors and 30 frames per second, you would need to move 9 bits of data for each pixel generated. That's 4,320,000 bits (9x800x600) or 540,000 bytes per frame (527 kb). 16,200,000 bytes (15,820 kb) per second. 486,000,000 bytes (474,609 kb) in 30 seconds.
That's a LOT of information (463 Megabytes!) to be moving around - especially if it has to be generated on the fly. Remember, that example assumes only a palette of 512 colors. The more colors you add, the more memory is needed.
With a 24-bit display, which can show any of 16,777,216 different hues, the numbers are astronomical. Each pixel on-screen is formed by three components called registers, they are: RED, GREEN and BLUE. Each register can have a different intensity level depending upon the value it holds. Since each register in a 24-bit display has 8 bits of information to define it, there are 256 possible values for each register. When you want to determine the number of colors, just multiply 256Rx256Gx256B to yield 16,777,216 total possible colors.
So, to display 30 seconds of animation in 800x600 resolution, using 24-bit graphics at 60FPS you need:
- 24 bits per pixel x (800x600 pixels) = 11,520,000 bits per frame
- 11,520,000 bits divided by 8 yields 1,440,000 bytes per frame (1406.25 kb)
- 1406.25 kb per frame x 60 frames per second = 84,375 kb per second.
- 84,375 kb per second x 30 seconds = 2,531,250 kb generated and displayed in 30 seconds
I DO NOT BELIEVE THAT ANY HOME SYSTEM IS CAPABLE OF GENERATING GRAPHICS OF THIS QUALITY ON THE FLY - IF AT ALL. Let me know if I am wrong.
The simple fact of the matter is that in order to achieve 60FPS one must make shortcuts - reducing graphic quality by using a lower pixel count, reducing the size of the color palette or finding a reasonable compromise between the two.
DON'T be led astray by questionable statistics. Just because a system can DISPLAY 16,777,216 colors, 800x600 graphics or 60FPS:
does not mean it is always displaying graphics in that mode does not mean all those colors can be on-screen simultaneously does not mean it can do all of that AT THE SAME TIME
Unta Glebin Gloutin Globin,
Red Ronin, The Cybernetic Samurai
PS: If that level of graphic quality can be achieved on any home system, AutoDesk should release AutoCAD for it. I'd buy it in a hot second.
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(AKA Red Ronin, The Cybernetic Samurai)
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