Author Topic: question about 24p capable and non 24p capable.  (Read 2233 times)

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Offline horng

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question about 24p capable and non 24p capable.
« on: Oct 13, 2008 at 12:28 PM »
i see there is non 24p capable tv like the 32lx80 and 32pc5rv, and wonder what is the big different when watching blu-ray movies with some tv which 24p capable?! ???

will it be critical downside for 32lx80 or 32pc5rv when come to that?

any comment? ;)

Offline streetsmart

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Re: question about 24p capable and non 24p capable.
« Reply #1 on: Oct 13, 2008 at 01:36 PM »
In theory, 24p provides smoother motion. You can see this in slow pans. When it is not 24p (usually 60p), there can be a slight stutter in the motion.

You can also see this in wagon wheels (cowboy movies). At certain speeds, the spokes of the wheels seem to go backwards. That's because of the wrong timing.

But in truth, it is a very slight improvement which you can notice only in a few scenes. You actually have to look for it. Many people will not notice the difference.
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Offline horng

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Re: question about 24p capable and non 24p capable.
« Reply #2 on: Oct 13, 2008 at 01:47 PM »
thanks for the info!!! :D

Offline Niknok

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Re: question about 24p capable and non 24p capable.
« Reply #3 on: Oct 13, 2008 at 04:35 PM »
In theory, 24p provides smoother motion. You can see this in slow pans. When it is not 24p (usually 60p), there can be a slight stutter in the motion.

You can also see this in wagon wheels (cowboy movies). At certain speeds, the spokes of the wheels seem to go backwards. That's because of the wrong timing.

But in truth, it is a very slight improvement which you can notice only in a few scenes. You actually have to look for it. Many people will not notice the difference.

hi cmiiw...i think p in 24p means progressive, so if its not 24p, its usually 30i (NTSC interlaced) or 25i (PAL interlaced).  if you have a 24p material (DVD, HDDVD, Bluray), a 24p player and a 24p HDTV,  then you are viewing the native picture, the way it was filmed, no interlacing conversions happened.

24p should then be better than any interlaced signal even though 30i seems to be a higher frame rate (30 frames / 60 fields)

i think there is no 60p yet. 


Offline streetsmart

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Re: question about 24p capable and non 24p capable.
« Reply #4 on: Oct 13, 2008 at 05:33 PM »
hi cmiiw...i think p in 24p means progressive, so if its not 24p, its usually 30i (NTSC interlaced) or 25i (PAL interlaced).  if you have a 24p material (DVD, HDDVD, Bluray), a 24p player and a 24p HDTV,  then you are viewing the native picture, the way it was filmed, no interlacing conversions happened.

24p should then be better than any interlaced signal even though 30i seems to be a higher frame rate (30 frames / 60 fields)

i think there is no 60p yet. 



Yes, "p" means progressive, but the discussion here is focused on frame-rate, not deinterlacing which is a totally different problem.

1080/24p is most commonly converted to 1080/60p through a frame-rate conversion technology.

Since 60 frames per second is not a multiple of 24 frames per second, you will have a slight stutter on motion, which can only be detected in certain types of scenes. I have seen this in action (24p vs 60p) and if you look for it very closely, you can see the difference between 24p and 60p - it is smoother. But as I said, most people wouldn't even notice.
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Offline Niknok

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Re: question about 24p capable and non 24p capable.
« Reply #5 on: Oct 13, 2008 at 06:40 PM »
Yes, "p" means progressive, but the discussion here is focused on frame-rate, not deinterlacing which is a totally different problem.

1080/24p is most commonly converted to 1080/60p through a frame-rate conversion technology.

Since 60 frames per second is not a multiple of 24 frames per second, you will have a slight stutter on motion, which can only be detected in certain types of scenes. I have seen this in action (24p vs 60p) and if you look for it very closely, you can see the difference between 24p and 60p - it is smoother. But as I said, most people wouldn't even notice.

oops...sorry i guess i totally misread the question.  i thought the 24p vs  non-24p question was in reference to a non-progressive signal which to me is interlaced.  anyway, i stand corrected, thanks...

Offline koykoy

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Re: question about 24p capable and non 24p capable.
« Reply #6 on: Nov 06, 2008 at 11:41 AM »
I see that the 24p applies only to 1080/24p

does that mean if you dont have a 1080 material, the 24p becomes irrelevant?

Offline cnn

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Re: question about 24p capable and non 24p capable.
« Reply #7 on: Nov 06, 2008 at 02:38 PM »
I see that the 24p applies only to 1080/24p

does that mean if you dont have a 1080 material, the 24p becomes irrelevant?

I guess this would be logical...

Offline barrister

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Re: question about 24p capable and non 24p capable.
« Reply #8 on: Nov 06, 2008 at 04:19 PM »
The faster the frame rate, the smoother the motion.  But if that is true, why would a lower 24 fps (frames per second) rate be smoother than a 30 fps rate?

The only way to understand 24p is to start with the history of frame rate standards.

The standard frame rate for film started at 16 fps during the silent movie era.  The standard changed to 24 fps sometime during the dawn of the sound films in the mid 1920's.  Since then, the standard frame rate for film has always been 24 fps.

As for TV, NTSC television engineering standards were adopted on May 2, 1941, with 30 frames per second or 60 fields per second with interlaced scanning.  The NTSC standard remains at 30 fps (or more accurately 29.97 fps), or 60 interlaced frames per second until today.

The frame rate difference between film's 24 fps and TV's 30 fps (60 interlaced fps) used to be irrelevant, since nobody at the time even dreamed that film would someday have to be be converted to NTSC standard for home video viewing.  Thus, nobody thought that compatibility between film and broadcast standards was at all necessary.

With the invention of home video, frame rate incompatibility between film and TV becomes a problem.  Now, the 24 fps standard has to be converted to the NTSC standard of 30 fps (60 interlaced) and/or the PAL standard of 25 fps (50 interlaced).

Due to the incompatible rates, film to video ("Telecine") conversion needs a corresponding frame rate conversion called "pulldown", a very complicated process that inevitably causes motion artifacts (http://en.wikipedia.org/wiki/Telecine).

To eliminate telecine motion artifacts, the remedy is to maintain film's original 24 fps rate on the video, so that both the film source and its video conversion have perfectly matching frame rates.  That's where the 24p (24 progressive frames per second) spec for home video comes in. 

And that's why a 24 fps rate on home video is smoother -- because it eliminates the 2:3 pulldown that causes motion judder.  This is possible with a Blu-ray player and TV that support 24p (24 progressive frames per second), usually referred to these days as "1080/24p" (1080 progressive resolution at 24 progressive fps). 

« Last Edit: Nov 07, 2008 at 01:00 PM by barrister »

Offline Carlo777

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Re: question about 24p capable and non 24p capable.
« Reply #9 on: Nov 08, 2008 at 12:06 AM »
The faster the frame rate, the smoother the motion.  But if that is true, why would a lower 24 fps (frames per second) rate be smoother than a 30 fps rate?

The only way to understand 24p is to start with the history of frame rate standards.

The standard frame rate for film started at 16 fps during the silent movie era.  The standard changed to 24 fps sometime during the dawn of the sound films in the mid 1920's.  Since then, the standard frame rate for film has always been 24 fps.

As for TV, NTSC television engineering standards were adopted on May 2, 1941, with 30 frames per second or 60 fields per second with interlaced scanning.  The NTSC standard remains at 30 fps (or more accurately 29.97 fps), or 60 interlaced frames per second until today.

The frame rate difference between film's 24 fps and TV's 30 fps (60 interlaced fps) used to be irrelevant, since nobody at the time even dreamed that film would someday have to be be converted to NTSC standard for home video viewing.  Thus, nobody thought that compatibility between film and broadcast standards was at all necessary.

With the invention of home video, frame rate incompatibility between film and TV becomes a problem.  Now, the 24 fps standard has to be converted to the NTSC standard of 30 fps (60 interlaced) and/or the PAL standard of 25 fps (50 interlaced).

Due to the incompatible rates, film to video ("Telecine") conversion needs a corresponding frame rate conversion called "pulldown", a very complicated process that inevitably causes motion artifacts (http://en.wikipedia.org/wiki/Telecine).

To eliminate telecine motion artifacts, the remedy is to maintain film's original 24 fps rate on the video, so that both the film source and its video conversion have perfectly matching frame rates.  That's where the 24p (24 progressive frames per second) spec for home video comes in. 

And that's why a 24 fps rate on home video is smoother -- because it eliminates the 2:3 pulldown that causes motion judder.  This is possible with a Blu-ray player and TV that support 24p (24 progressive frames per second), usually referred to these days as "1080/24p" (1080 progressive resolution at 24 progressive fps). 



Sir is this "pulldown" the same as the one found in the Panny PX500 Plasma?

Progressive Cinema Scan (3/2 Pulldown)
Progressive Cinema Scan (3/2 Pulldown) achieves exceptionally faithful movie reproduction through a sophisticated analog-to-digital conversion. Movies on film are converted to NTSC interlaced video (480i) for television by a process known as telecine conversion, in which the 24 frame-per-second film is converted to video at 60 fields per second. The fields are then paired to create 30-frame-per-second 480i video. Some of the frames will contain dissimilar pairs of fields derived from two different frames of the original film, which causes artifacts. Panasonic's Progressive Cinema Scan circuitry converts 480i video to 480p while restoring the original frames of the film for a more authentic movie reproduction. This widescreen TV features a width-to-height ratio similar to movie theater screens, providing a theater-like experience at home. View HDTV broadcasts and widescreen DVDs the way they were meant to be seen.


So could we safely say that the 1080p/24 tech is the advanced version of the feature stated above?

Thank you ;)
 



Offline barrister

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Re: question about 24p capable and non 24p capable.
« Reply #10 on: Nov 08, 2008 at 03:17 PM »
No, that's not how I understood it.

For purposes of clarity, let's divide the text into 3 parts:

1.  Progressive Cinema Scan (3/2 Pulldown) achieves exceptionally faithful movie reproduction through a sophisticated analog-to-digital conversion.

The first part states the name of the proprietary tech, "Progressive Cinema Scan (3/2 Pulldown)", and refers to it as an "analog to digital conversion".


2.  Movies on film are converted to NTSC interlaced video (480i) for television by a process known as telecine conversion, in which the 24 frame-per-second film is converted to video at 60 fields per second. The fields are then paired to create 30-frame-per-second 480i video. Some of the frames will contain dissimilar pairs of fields derived from two different frames of the original film, which causes artifacts.

The next part discusses the telecine process, and describes how telecine can cause artifacts as a result of the 24 fps and 30 fps difference.  Note that this part is discussing telecine only; it does not mention anything about Panny's Progressive Cinema Scan technology.



http://www.hometheaterhifi.com/volume_7_4/dvd-benchmark-part-5-progressive-10-2000.html


3.  Panasonic's Progressive Cinema Scan circuitry converts 480i video to 480p while restoring the original frames of the film for a more authentic movie reproduction. This widescreen TV features a width-to-height ratio similar to movie theater screens, providing a theater-like experience at home. View HDTV broadcasts and widescreen DVDs the way they were meant to be seen.

The last part discusses Panasonic's progressive scanning (conversion of interlaced video to progressive video), then the screen's aspect ratio.

There's nothing new about the phrase, "while restoring the original frames of the film for a more authentic movie reproduction".  That is what progressive scanning is supposed to do --- assemble pairs of interlaced fields into one progressive frame, and show it in a manner which will emulate the original 24fps speed. 

But it still won't be a 1:1 frame conversion.  There will still be 10 progressive video frames for every 4 film frames: 



http://www.hometheaterhifi.com/volume_7_4/dvd-benchmark-part-5-progressive-10-2000.html



----------------------------------------------




Clearly, Panasonic is discussing progressive scanning, not 24p technology. 

The text was written for marketing purposes.  It gives you an impression that the model has some high tech 24p capability when it does not.  Yet it was so cleverly written that after a close scrutiny, you will find that you cannot fairly accuse Panasonic of false advertising. 

I assure you, if that TV were 24p capable, they would have simply said so in no uncertain terms.  ;)   



---------------------------------------------




Sir is this "pulldown" the same as the one found in the Panny PX500 Plasma?

No, the pulldown is already there.  The Panny merely adds progressive scanning.

2:3 pulldown is performed during telecine conversion of film to video.  It is done during the encoding of the scanned film frames to video format.  http://en.wikipedia.org/wiki/Telecine#2:3_pulldown

The video encoded on the disc had already been pulled down to 30 fps during the encoding process.  Assuming that the interlaced video was converted to progressive by the DVD player, all the TV has to do is display the progressively-scanned image.

But if the DVD player merely passes an interlaced video signal to the TV, the latter converts the interlaced video to progressive before displaying it on screen.  And that's all that Progressive Cinema Scan does. 

Read that part again:   

Panasonic's Progressive Cinema Scan circuitry converts 480i video to 480p while restoring the original frames of the film for a more authentic movie reproduction.


So could we safely say that the 1080p/24 tech is the advanced version of the feature stated above?

No, not even close.  The feature in question is just a cleverly presented progressive scanning capability (the techier term is deinterlacing  ;)).

In 1080/24p tech, it is not enough that the TV is 24p capable; the disc itself must also be encoded in 24p.

« Last Edit: Nov 08, 2008 at 04:40 PM by barrister »

Offline Carlo777

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Re: question about 24p capable and non 24p capable.
« Reply #11 on: Nov 09, 2008 at 02:10 AM »
@barrister

Thanks for the info! That particular Panny model (PX500U) was the reason why I ended up preferring plasma over lcd. I've been searching in vain to find one, only to realize it's an older (G8 panel) model. Every time I see it in a friend's house, it always amazes me, the question was more like trying to dissect it's features and to understand them better.

The full features of the plasma:

http://www.vanns.com/shop/servlet/item/features/463496142