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24 fps playback feature - please explain

GeauxCajuns82
10-15-2009, 01:21 PM
I've heard a lot of talk about this feature but I'm having trouble grasping the idea. If all blueray videos are shot at 24 frames per second but your TV is only capable of showing video at 60 frames per second, how does it fill in the remaining 36 frames? Can someone explain this phenomenon?

I'm stuck between a Panasonic Plasma G10 or S1 and am trying to determine if I really need this feature. Yes I plan on watching a lot of blue ray movies but I can't see how it would be that much better. Currently the only blue ray I've seen is on a Samsung LCD LN52A650 and the 120hz was usually turned off (so 60hz). Motion wise, is this basically the kind of picture I can expect if I choose not to go with 24fps playback feature?

Forgot to mention, I've been remodeling my living room for the last 6 months and when I started the demolition I got rid of the 10 year old, 300 lb mammoth, Hitachi 50" projection TV (Had to pull off the front trim just to get it to fit through a 32" door) so I've had no TV in the room for 6 month. And just about anything is a step up from the old Hitachi.

Loves2Watch
10-15-2009, 01:36 PM
I've heard a lot of talk about this feature but I'm having trouble grasping the idea. If all blueray videos are shot at 24 frames per second but your TV is only capable of showing video at 60 frames per second, how does it fill in the remaining 36 frames? Can someone explain this phenomenon? It does this using 2:3 pulldown. See here for further explanation - http://www.hometheaterblog.com/hometheater/2004/12/what-is-pulldown-and-if-its-so-great-why-would-you-want-to-remove-it/

I'm stuck between a Panasonic Plasma G10 or S1 and am trying to determine if I really need this feature. Yes I plan on watching a lot of blue ray movies but I can't see how it would be that much better. Currently the only blue ray I've seen is on a Samsung LCD LN52A650 and the 120hz was usually turned off (so 60hz). You can't turn 120 Hz on and off it either is 120Hz or it isn't. Motion wise, is this basically the kind of picture I can expect if I choose not to go with 24fps playback feature?

Forgot to mention, I've been remodeling my living room for the last 6 months and when I started the demolition I got rid of the 10 year old, 300 lb mammoth, Hitachi 50" projection TV (Had to pull off the front trim just to get it to fit through a 32" door) so I've had no TV in the room for 6 month. And just about anything is a step up from the old Hitachi.

Either plasma would look very good and if you haven't noticed any difference in movies played on your current system using 2:3 pulldown I doubt it would make much difference to you now, especially with a Panasonic plasma TV as they do the pulldown correctly. The choice is yours.

Hope this helps. Link - http://www.hometheaterblog.com/hometheater/2004/12/what-is-pulldown-and-if-its-so-great-why-would-you-want-to-remove-it/

GeauxCajuns82
10-15-2009, 03:20 PM
Thanks Loves2Watch, very insightful article. However, I still have a few questions:

1) Do all blueray players automatically convert the 24fps data on the disc to 60 fps (3:2 pulldown) for the video output regardless of the receiving device's capability? If so, then are we basically just going in one big circle from 24 to 60 back to 24? Blue ray converts to 60, TV converts back to 24...

2) If I get a TV WITHOUT this 24 fps playback feature, what will I see on my screen? Will it be a 60 fps video with interlaced scan? (Figure 2 in the article?)

3) If I get a TV WITH this 24fps playback feature, will I actually see 24 FULL frames in one second? No 3:2, no interlacing? So basically when I hit pause I will see a nice, clean frame-worthy picture? (Figure 3 in the article?)

4) Where did the 60 fps come from in the first place? If all film is shot in 24 fps than why do we need 60? Or would 24fps look really funny if it was interlaced at its original rate? Is this basically a technology that was introduced ahead of its time compared to film technology? In other words, will cameras in the near future be shooting film in 60 fps?

Lee Stewart
10-15-2009, 05:05 PM
Thanks Loves2Watch, very insightful article. However, I still have a few questions:

1) Do all blueray players automatically convert the 24fps data on the disc to 60 fps (3:2 pulldown) for the video output regardless of the receiving device's capability? If so, then are we basically just going in one big circle from 24 to 60 back to 24? Blue ray converts to 60, TV converts back to 24...

There exists an option output called 24P that will send the native signal from a BD (24P) to the HDTV. From there, the HDTV deals with it. If not selected, then the 24P is converted to 60P by the player and sent to the HDTV.

2) If I get a TV WITHOUT this 24 fps playback feature, what will I see on my screen? Will it be a 60 fps video with interlaced scan? (Figure 2 in the article?)

You will see 60P converted from 24P by the 3:2 pulldown method

3) If I get a TV WITH this 24fps playback feature, will I actually see 24 FULL frames in one second? No 3:2, no interlacing? So basically when I hit pause I will see a nice, clean frame-worthy picture? (Figure 3 in the article?)

No - 24P is too slow - you would see massive flicker in the image. The HDTV will apply a multiplyer like 3X or 5X (showing each frame 3 times or 5X very quickly - 72Hz or 120Hz. At the theater they show 24 frames per second as 48 frames a second so there is no flicker.

With the 5X multiplier, many times it make "the film look" more like "the video look"

4) Where did the 60 fps come from in the first place? If all film is shot in 24 fps than why do we need 60? Or would 24fps look really funny if it was interlaced at its original rate? Is this basically a technology that was introduced ahead of its time compared to film technology? In other words, will cameras in the near future be shooting film in 60 fps?

It came from our electrical system (USA) which is 120V/ 60Hz.

There is talk that yes in the future, they may increase the frame rate from 24 to either 30, 48 or 60. But it won't be done using 35mm film cameras. They will use Digital Movie Cameras like my Avatar which is the Panavision Genesis

Loves2Watch
10-15-2009, 06:11 PM
I will also add that the Panasonic plasma G10/G15 has the option to play 24p at 48Hz, the S1 does not offer that option and can only do the 2:3 pulldown.

Lee Stewart
10-15-2009, 08:15 PM
I will also add that the Panasonic plasma G10/G15 has the option to play 24p at 48Hz, the S1 does not offer that option and can only do the 2:3 pulldown.

I have heard complaints that it isn't fast enough (48Hz) and filcker is detected.

Loves2Watch
10-15-2009, 09:26 PM
I have heard complaints that it isn't fast enough (48Hz) and filcker is detected.

There is a firmware update that is supposed to resolve that issue. If a theater can display it at 48fps with no problem I would think a TV would be able to do the same.

Lee Stewart
10-15-2009, 09:31 PM
There is a firmware update that is supposed to resolve that issue. If a theater can display it at 48fps with no problem I would think a TV would be able to do the same.

But film is analog. You are seeing 48 real frames/sec. While with BD you are seeing 48 compressed frames/sec. Plus the dynamic range is greater with film than it is with video.

OBTW BD is not 24P. It is really 23.976HZ. Just like it really isn't 60 Hz. It's 59.94 Hz.

Loves2Watch
10-15-2009, 10:14 PM
But film is analog. You are seeing 48 real frames/sec. While with BD you are seeing 48 compressed frames/sec. Plus the dynamic range is greater with film than it is with video.

OBTW BD is not 24P. It is really 23.976HZ. Just like it really isn't 60 Hz. It's 59.94 Hz.

In any case it does work.

Lee Stewart
10-15-2009, 10:45 PM
In any case it does work.

All it does is remove the need for the pulldown, but it doesn't do anything for smoothing out camera pans.

Loves2Watch
10-15-2009, 11:10 PM
All it does is remove the need for the pulldown, but it doesn't do anything for smoothing out camera pans.

It seems you like to argue just for the sake of arguing...

Techlord
10-15-2009, 11:15 PM
There exists an option output called 24P that will send the native signal from a BD (24P) to the HDTV. From there, the HDTV deals with it. If not selected, then the 24P is converted to 60P by the player and sent to the HDTV.



You will see 60P converted from 24P by the 3:2 pulldown method



No - 24P is too slow - you would see massive flicker in the image. The HDTV will apply a multiplyer like 3X or 5X (showing each frame 3 times or 5X very quickly - 72Hz or 120Hz. At the theater they show 24 frames per second as 48 frames a second so there is no flicker.

With the 5X multiplier, many times it make "the film look" more like "the video look"



It came from our electrical system (USA) which is 120V/ 60Hz.

There is talk that yes in the future, they may increase the frame rate from 24 to either 30, 48 or 60. But it won't be done using 35mm film cameras. They will use Digital Movie Cameras like my Avatar which is the Panavision Genesis

Wow, I'm learning some new things I didn't quite understand! Lee what does the 3 and the 2 represent? Also in the future if movie studios do decide to make a move towards Digital Movie Cameras won't everything have a video look to it?

Techlord
10-15-2009, 11:22 PM
But film is analog. You are seeing 48 real frames/sec. While with BD you are seeing 48 compressed frames/sec. Plus the dynamic range is greater with film than it is with video.

OBTW BD is not 24P. It is really 23.976HZ. Just like it really isn't 60 Hz. It's 59.94 Hz.

When I built my brother's computer a year ago I set everything up for stock clocks at 2.4GHz, but the software shows 2399MHz. My overclocked computer shows 3199MHz when set to 3.2GHz. :lol:

Loves2Watch
10-16-2009, 12:18 AM
Wow, I'm learning some new things I didn't quite understand! Lee what does the 3 and the 2 represent? Also in the future if movie studios do decide to make a move towards Digital Movie Cameras won't everything have a video look to it?

It's actually 2:3 pulldown and it represents 2 frames then 3 and so on...See here - http://www.zerocut.com/tech/pulldown.html and here - http://www.moviola.com/pulldown

Techlord
10-16-2009, 08:35 PM
It's actually 2:3 pulldown and it represents 2 frames then 3 and so on...See here - http://www.zerocut.com/tech/pulldown.html and here - http://www.moviola.com/pulldown

I feel like I'm learning geometry when I haven't even mastered multiplication, what is a field? They expect you to know what a field is before they lay it out for you!

Lee Stewart
10-16-2009, 08:42 PM
I feel like I'm learning geometry when I haven't even mastered multiplication, what is a field? They expect you to know what a field is before they lay it out for you!

A field is half a frame. They are used in the Interlace process. 2 fields make a frame.

Techlord
10-16-2009, 11:15 PM
A field is half a frame. They are used in the Interlace process. 2 fields make a frame.

Two fields done in one pass would be progressive equaling one frame?

IGExpandingPan
10-17-2009, 01:48 AM
But film is analog. You are seeing 48 real frames/sec. While with BD you are seeing 48 compressed frames/sec. Plus the dynamic range is greater with film than it is with video.

OBTW BD is not 24P. It is really 23.976HZ. Just like it really isn't 60 Hz. It's 59.94 Hz.

TV was 60hz in the B&W days. NTSC color was a bit of a mickey mouse solution. I forget all the technical details but basically a drop from 525 lines to 455 lines, and the color subcarrier at an odd multiple worked out to be 3.58mhz.

In most of the world on pal, this was never an issue since they ditched the old B&W standard in favor of the new color one, and such 50hz was actually 50hz.

24P actually does exist as a standard, as well as 23.976. Just some gear doesn't handle 24.000P well. You get dropped frames or out of sync audio. But every once and a while you get a BD title @ 24.000P.

PFC5
10-17-2009, 03:12 PM
Two fields done in one pass would be progressive equaling one frame?

Correct! It has to be ONE pass to be progressive though.

Techlord
10-17-2009, 03:24 PM
Correct! It has to be ONE pass to be progressive though.

Interlaced scans odd then even lines, but doesn't progressive scan both fields in one pass?

Lee Stewart
10-17-2009, 07:13 PM
Interlaced scans odd then even lines, but doesn't progressive scan both fields in one pass?

60i = 60 fields per second

60P = 60 frames per second

2 fields = 1 frame.

You could say (for the sake of this discussion) that 60i = 30P

Techlord
10-18-2009, 01:29 AM
60i = 60 fields per second

60P = 60 frames per second

2 fields = 1 frame.

You could say (for the sake of this discussion) that 60i = 30P

Alright! :D

LoToMo
10-18-2009, 12:02 PM
So, (I already asked many times) the 24 frames from blu-ray player will be delivered to TV if we set the feature ON. In TV, shoud it display that frame 5 times (if I set my TV to 120Hz) or it would ake up four other similar frames (in transient). for example, I have frame 1 and 2 and 3 deilvered to my TV and my TV is 120 Hz. So, I will have 1 - 1 - 1 - 1 - 1 - 2 - 2 - 2 - 2 - 2 - 3 - 3 - 3 - 3 - 3 ... on my display, or 1.0 - 1.1 - 1.2 - 1.3 - 1.4 - 2.0 - 2.1 - 2.2 - 2.3 - 2.4 - 3.0 - 3.1 ... frames on my display? 1.0, 2.0 are original frames, and 1.1, 1.2, 1.3 .... are the one that my TV makes up to make the picture look smoother? like 120 frames per second instead of 24 frames. Please help me understand more about this .... Thanks alot!

Lee Stewart
10-18-2009, 02:14 PM
So, (I already asked many times) the 24 frames from blu-ray player will be delivered to TV if we set the feature ON. In TV, shoud it display that frame 5 times (if I set my TV to 120Hz) or it would ake up four other similar frames (in transient). for example, I have frame 1 and 2 and 3 deilvered to my TV and my TV is 120 Hz. So, I will have 1 - 1 - 1 - 1 - 1 - 2 - 2 - 2 - 2 - 2 - 3 - 3 - 3 - 3 - 3 ... on my display, or 1.0 - 1.1 - 1.2 - 1.3 - 1.4 - 2.0 - 2.1 - 2.2 - 2.3 - 2.4 - 3.0 - 3.1 ... frames on my display? 1.0, 2.0 are original frames, and 1.1, 1.2, 1.3 .... are the one that my TV makes up to make the picture look smoother? like 120 frames per second instead of 24 frames. Please help me understand more about this .... Thanks alot!

Here is a thread over at our sister site (HDD) that you will find helpful. It will take some time to go through but it should answer any further questions about 24P and 120Hz:

http://forums.highdefdigest.com/home-theater-gear/25688-displays-support-1080p-24-signal-multiplies-original-frame-rate.html

PFC5
10-19-2009, 09:26 PM
Interlaced scans odd then even lines, but doesn't progressive scan both fields in one pass?

Yes. That is why I said you were correct. ;)

Techlord
10-19-2009, 11:01 PM
Yes. That is why I said you were correct. ;)

Strange, I didn't see that post until now.

PFC5
10-20-2009, 02:10 AM
Strange, I didn't see that post until now.

You quoted it here:

http://www.highdefforum.com/950739-post20.html

You must have misunderstood the last sentence though. I wondered if i could have possibly confused things by adding it.

Techlord
10-20-2009, 02:59 PM
You quoted it here:

http://www.highdefforum.com/950739-post20.html

You must have misunderstood the last sentence though. I wondered if i could have possibly confused things by adding it.

I think it took me back to the beginning when I was already on the next step of understanding. :lol: Once I knew what a field was the fog cleared. No worries. :D