Originally Posted by Jamie E
Boy my head hurts after reading through this thread, but I've "drawn" my own experimental frame display diagrams and come to the same conclusion as you, 8:13. There is really no way around some kind of pulldown alteration of a 24p source being shown to two eyes when using a 120Hz TV. For each frame, one eye is going to have to get three flashes while the other gets two, or the display of the frames themselves will have to be staggered as you drew them. Either way I can't imagine it'll be very pretty.
All I know for sure right now is that before I personally take the plunge into 3D, I want to wait for a 480Hz TV, that is guaranteed to be able to accept and display 2D and 3D recorded at 48p and 60p (that's probably inevitable for the future). Of course it will also have to be able to show all combinations of 24p, 30p, 48p, 60i, and 60p in 2D and 3D with no pulldown judder. 480Hz should make that perfectly doable since it's evenly divisible by all combos.
24p 2d = 20 flashes per frame.
24p 3d = 10 flashes per eye per frame.
30p 2d = 16 flashes per frame.
30p 3d = 8 flashes per eye per frame.
48p 2d = 10 flashes per frame.
48p 3d = 5 flashes per eye per frame.
60p 2d = 8 flashes per frame.
60p 3d = 4 flashes per eye per frame.
After doing the math, I definitely argue that 480Hz is a better "grail" than 240Hz.
I made some calculations from the 3D thread in this forum I made and here are the results below. This is without 3:2 pulldown.Section f
24p........................ = 23.97600 FPS.. = 41.708375 Milliseconds Time between frames
NTSC's....................... 29.97......... = 33.3667 Milliseconds Time between frames
48p........................ = 47.95200 FPS.. = 20.8541875 Milliseconds Time between frames
NTSC's....................... 59.94 FPS..... = 16.68335 Milliseconds Time between frames
1000 / 23.97600 = 41.708375
1000 / 29.97 = 33.3667
1000 / 47.95200 = 20.8541875
1000 / 59.94 = 16.68335
There's 1000 milliseconds in a second.
MS / FPS = MS: 1000 ms / FPS = Time between frames
"The REAL D system uses triple flash to provide the best motion rendition possible. Use of triple flash puts the refresh rate above the normal flicker fusion threshold for humans, providing smoother motion. The triple flash approach also makes the left and right eye images to appear closer in time, giving significantly less motion induced parallax errors and therefore more comfortable motion rendition."http://www.edcf.net/edcf_docs/real-d.pdfFlicker fusion threshold
"If the frame rate falls below the flicker fusion threshold for the given viewing conditions, flicker will be apparent to the observer, and movements of objects on the film will appear jerky. For the purposes of presenting moving images, the human flicker fusion threshold is usually taken as 16 hertz (Hz)."LINK
MS / HZ = MS: 1000 / 16 = 62.5
• What does this mean?
1000ms / fps = ms > 1000ms / 16hz = 62.5ms = fps:ms faster than 62.5ms: No flicker
1000ms / fps = ms < 1000ms / 16hz = 62.5ms = fps:ms slower than 62.5ms: flicker
• In Actual practice though, for 3D, the Hz to use is the one Real D uses: "triple flash", as this is standard in digital cinema = 72Hz 2D (71.928fps) per eye.
1000ms / fps = ms > or = 1000ms / 72hz
1000ms / fps = ms > or = 1000ms / 72hz = 13.8888889ms = fps:ms faster than or equal too 13.8888889ms: if equal too it's decent quality 3D(but can be better).
On a 240Hz monitor, 60p video using 2:2 pulldown making it 120p video
1 000ms / 119.88fps = 8.34167501ms
8.34167501ms is faster than 13.8888889ms so there should be no flicker when using a 240hz monitor and 60p tv in stereoscopic 3D.
This is from post #2.