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# 3D questions/clarification - Page 4

Quote:
Originally Posted by Lee Stewart

2205P frames @ 24 FPS X5 = 120 2205P/sec - frames are in storage memory/buffer (not necessarily all 120 frames)

Display then splits the 2205P frame into L 1080P and R 1080P frames and displays them sequentially; L, R, L, R 60 times a second each. Each frame has the same on screen time.

You're saying that 120 frames are converted to 60 frames each second. This means that you are dropping 60 frames. Since 60 frames is not evenly divisible by 24, then you will get uneven judder. Each 24Hz frame will not have the same on screen time.

It's very simple and has been solved before. To get from 24Hz per eye to 60Hz per eye you need to do 3:2 frame rate conversion. The same thing that happens on all 60Hz fixed rate displays.

Edit: You could also do motion compensated frame interpolation to get from 24 to 60Hz. Some TVs do this to smooth motion artifacts now. But you would need to do it independently for each eye.

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Quote:
Originally Posted by HokeySmoke

You're saying that 120 frames are converted to 60 frames each second. This means that you are dropping 60 frames. Since 60 frames is not evenly divisible by 24, then you will get uneven judder. Each 24Hz frame will not have the same on screen time.

It's very simple and has been solved before. To get from 24Hz per eye to 60Hz per eye you need to do 3:2 frame rate conversion. The same thing that happens on all 60Hz fixed rate displays.

Edit: You could also do motion compensated frame interpolation to get from 24 to 60Hz. Some TVs do this to smooth motion artifacts now. But you would need to do it independently for each eye.

It is 120 FPS total, displayed @ 60 FPS PER EYE

No dropping of frames

Remember we have 3 different frames here:

1920x2205 (contains 1080 L and 1080 R in Over/Under config)

1920x1080 L

1920x1080 R

Quote:

2205P frames @ 24 FPS X5 = 120 2205P/sec - frames are in storage memory/buffer (not necessarily all 120 frames)

Display then splits the 2205P frame into L 1080P and R 1080P frames and displays them sequentially; L, R, L, R 60 times a second each. Each frame has the same on screen time.
Lee, I'll try one more time.

Your 5x multiplier creates 120 left eye and right eye frames. That is, 240 frames total. Then, somehow we must display all of these frames in 120 frames per second. How?
Quote:
Originally Posted by HokeySmoke

Lee, I'll try one more time.

Your 5x multiplier creates 120 left eye and right eye frames. That is, 240 frames total. Then, somehow we must display all of these frames in 120 frames per second. How?

After the 5X multipler we have 120 L frames and 120 R frames = 240 total

We need 60 frames per eye per second for a total of 120/sec

We have 120 frames too many - 60 of each L & R frame

We can "throw away" 60 of each L & R frames giving us the proper math - every other frame could be discarded

How's that?
Quote:
Originally Posted by Lee Stewart

After the 5X multipler we have 120 L frames and 120 R frames = 240 total

We need 60 frames per eye per second for a total of 120/sec

We have 120 frames too many - 60 of each L & R frame

We can "throw away" 60 of each L & R frames giving us the proper math - every other frame could be discarded

How's that?

That's great. But as I posted before, 60 is not divisible by 24. That's why you will get uneven judder. What you did when you threw away those 60 frames is you cut your multiplier by half, to 2.5. Obviously you cannot display a half frame. Therefore you must persist with the previous one, causing a temporal delay.
Quote:
Originally Posted by HokeySmoke

Lee, I'll try one more time.

Your 5x multiplier creates 120 left eye and right eye frames. That is, 240 frames total. Then, somehow we must display all of these frames in 120 frames per second. How?

He seems to be saying that 120 L frames + 120 R frames = 120 Over/Under frames, and we get 120 Over/Under frames per second. I have no opinion whether that's right, but it seems clear enough.
That's right Greg, but 120Hz 3D only shows 60 frames per second. It's only 120Hz so that each eye can see a different view of a 60Hz image. So 120 over/under (frame packed) frames are twice too many for a 120Hz system.
OK . . .

I just finished sending Panasonic an Email:

Thank you for being so helpful in my last request for information on your DMP-BDT350 [T20100227006LS010Z68359]

I have another question that relates to the BDT350 and your new VT25 3DTV's

It is to my understanding that the data for 3D Bluray will be stored in large "block" frames that are 1920x2205 with 45 vertical active blanking between the two 1920x1080 frames. Here is a picture:

http://hdguru.com/3d-hdtv-and-hdmi-explained/1336/

The VT25's will have a total refresh rate of 120Hz with 60Hz per eye.

The BDT350 will be ouputing film content at 24 frames/sec

Question:

How will the VT25 deal with the output of the BDT350 with 3D content and not use the 2:3 pulldown which would introduce Frame Judder in the images? 24 doesn't go into 60 evenly.

Thanks again for your time and consideration.
I understand that the 120Hz Plasma TVs will accept the 24fps Blu_ray Block frames and will use 5:5 pulldown to convert the 24fps block frames to 120fps block frames therefor eliminating Judder caused by all frames not being refreshed the same number of times. Then the Plasms dislpays will split the block frames in to 2 60fps steames which are not free of variable frame rate Judder,
Quote:
Originally Posted by HokeySmoke

That's great. But as I posted before, 60 is not divisible by 24. That's why you will get uneven judder. What you did when you threw away those 60 frames is you cut your multiplier by half, to 2.5. Obviously you cannot display a half frame. Therefore you must persist with the previous one, causing a temporal delay.

That's what I'm understanding. I'll be interested to see Panasonic's response.

Maybe it's possible that given that the dropped frames can float between the Left and Right eye, that perhaps the judder will be a tad less noticeable than standard 3-2 pulldown? In other words, the "dropped frame" might still allow one eye to see it's "half", if you will, even if the other eye gets the new frame instead. So perhaps by creatively not dropping the same frame in both eyes, the judder could be reduced?
Another technique the plasma models could be using it to create an ouput buffer using the full 2205x1080 input buffer and have the 120HZ refresh circuit to alternate using the right eye frame in it with the left eye frame to refresh the physical display since this would cause each of the 24HZ frames in the input buffer to be displayed 5 times.
And therefor since with actiive glases each eye only sees actual content 1/2 of the time so the glasess only need to sync at 60fps. This technique also eliminates the need to have 240 frames which would be requied if a separate frame buffer was being used for each eye.
Quote:
Originally Posted by DaViD Boulet

Maybe it's possible that given that the dropped frames can float between the Left and Right eye, that perhaps the judder will be a tad less noticeable than standard 3-2 pulldown? In other words, the "dropped frame" might still allow one eye to see it's "half", if you will, even if the other eye gets the new frame instead. So perhaps by creatively not dropping the same frame in both eyes, the judder could be reduced?

If your left and right eyes are out of sync then you will see depth changes during pans because the left to right difference of the images will be larger. I doubt this new artifact would be considered better than judder, but I haven't seen it myself.
Thanks guys! I understand now. I really appreciate you taking the time!!
So let me get this straight.
I have Denon 3808ci avr and a Denon dbp-1610 Blu-ray player. I also have a Panasonic Th-50px600u. Now I am looking to upgrade my TV and can't ignore this 3D craze. So if I get a 3D tv I still couldn't watch 3d?
Meaning I would have to upgrade my avr to a compliant 3d HDMI 1.4 AVR, and I would have to go and buy a new blu-ray player that is 3D.
Any chance that Denon will be alble to provide firmware upgrades to corrected this? If not I don't think I am willing to re-buy everything just to get 3d.
Am I missing something her? Sounds alot like beta players, or laser disk fads
Quote:
Originally Posted by jqwhite79

So let me get this straight.
I have Denon 3808ci avr and a Denon dbp-1610 Blu-ray player. I also have a Panasonic Th-50px600u. Now I am looking to upgrade my TV and can't ignore this 3D craze. So if I get a 3D tv I still couldn't watch 3d?
Meaning I would have to upgrade my avr to a compliant 3d HDMI 1.4 AVR, and I would have to go and buy a new blu-ray player that is 3D.
Any chance that Denon will be alble to provide firmware upgrades to corrected this? If not I don't think I am willing to re-buy everything just to get 3d.
Am I missing something her? Sounds alot like beta players, or laser disk fads

If you are willing to use your "new" 3DTV as a switcher and not just the AVR then you could buy a new Panasonic 3D BD player that offers 2 HDMI outputs - one for 3D video (to the 3DTV) and the other is HD Audio only (to the AVR)

Just use it for 3D BD's. Continue to use your Denon BD player for regular BD's

That is one solution
Quote:
Originally Posted by Lee Stewart

If you are willing to use your "new" 3DTV as a switcher and not just the AVR then you could buy a new Panasonic 3D BD player that offers 2 HDMI outputs - one for 3D video (to the 3DTV) and the other is HD Audio only (to the AVR)

Just use it for 3D BD's. Continue to use your Denon BD player for regular BD's

That is one solution

Actually, with that solution, he could use the Panny 3D BD player for regular BDs also. Retire the Denon to the bedroom.
Quote:
Originally Posted by taz291819

Actually, with that solution, he could use the Panny 3D BD player for regular BDs also. Retire the Denon to the bedroom.

True - I thought it was an expensive BD player - I just checked - it isn't
The 3808 would have trouble adding its GUI to a novel video stream but do we have any idea if it would mess up the video stream before sending it out to a PJ? The dual HDMI (one for rcvr and one for PJ) ought to allow us not to have to upgrade the receiver, so perhaps I will need a splitter for the output from my (soon to be firmware upgraded) PS3 BD to get audio through an existing 3808?
Quote:
Originally Posted by AJSJones

. . . The dual HDMI (one for rcvr and one for PJ) ought to allow us not to have to upgrade the receiver, so perhaps I will need a splitter for the output from my (soon to be firmware upgraded) PS3 BD to get audio through an existing 3808?

Actually, it will be pretty interesting to see how HDCP over HDMI handshaking will work if the plan is to allow splitting a single HDMI output from a player in order to bypass a non-3D-compliant AVR and just deliver the [3D] video to a 3D-compliant display!
There's a chance that some existing HDMI 1.3 receivers will pass the 3D video signal uncorrupted to the 1.4 display. Makes more sense to get the display and fimware updated PS3 hooked up through your current gear first to see if it works... you may not need to do anything further.
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