1080P/24 FPS confusion????

[D.J.KRIME]

Every where you read about the optimum output of a HD disc being at 1080P/24FPS but how does this work as PAL operates at 25FPS and NTSC at 30FPS?

Now I understand the importance of 24FPS being that on a 35mm Negative in the cinema this is the rate at which it is displayed but a film at your local Odeon is not displayed in either PAL or NTSC as these formats do not apply until the film enters the HOME CINEMA DOMAIN. So how can you get a 24FPS image from either PAL or NTSC without actually loseing information?

Also by saying that to enjoy HD video fully you need a display that can display 1080p/24 then does that mean that to us with mear HD ready sets if we wish to watch either BLU-RAY or HD-DVD then will will have a jerky image on panning shots? And if so how comes as this does not occur with dvd at either 25 or 30 FPS?

 

[Anonymous]

I have to say, some sets are good enough that you dont need the ability to accept a 24fps input.

Some people dont pick up on it as easily though

 

[D.J.KRIME]

It's not a TV's ability to show 1080p/24 that gets me its just that neither PAL or NTSC have a native frame rate of 24FPS so how is this 24FPS achieved? is it achieved by looseing 1FPS on PAL and 6FPS on NTSC then adjusting the screens refresh rate to give a "TRUE" 24FPS image? so is it not the imformation stored on a HD disc that is stored at 24FPS? or 1080/25 PAL and 1080/30 NTSC? or the HD player and screen that make the 24FPS image buy looseing the extra frames?

 

[D.J.KRIME]

Whats wrong is this question too technical for anyone to answer???

 

[Anonymous]

Sorry for not replying earlier. Right: the whole 24fps issue is only relevant because of the way video is encoded on to HD DVD and Blu-ray. Previously with DVD (and other video formats, plus any broadcast content) films had been converted from their original speed (which is, of course, 24fps) into whichever speed was appropriate to suit local market conditions.

So, 24fps film was converted to 30fps video to enable a 60Hz (twice 30fps) NTSC colour signal: this involved repeating a set number of frames of video in order to create six new frames from the 24fps original. The same 24fps content was slightly speeded up to create a 25fps/50Hz PAL image, meaning that PAL versions of feature films actually run slightly shorter than the Hollywood originals.

So don't worry: PAL and NTSC versions of movies don't contain information that you 'lose' in a 24fps output: rather, at least in the case of NTSC, they contain information that was never actually there in the first place.

Incidentally, this same 'telecine' process could also, should the studio concerned be sufficiently misguided, lead to reformatting of video (say, turning a 2.35:1 Cinemascope movie into a 1.85:1 letterbox DVD, as happened to movies like Enigma).

However, BD and HD DVD are quite different. Here, the video is encoded at its 'native' rate, 24fps. In theory, that's great, because it means what you're seeing on the screen is exactly the same (at least in terms of speed) as it was in the cinema. You shouldn't think in terms of PAL and NTSC video in this regard, incidentally: those are television standards, not relevant in this instance.

That said, it's unlikely that any TV display will render BD/HD DVD at that 24fps refresh rate: we're all used to 50Hz and 60Hz video speeds, as you mentioned. So, expect at least 48Hz and possibly 72Hz (twice or three times 24), depending on your TV.

But that's all assuming that your high-def disc player and display device are capable of sending/receiving video at the requisite 24fps speed. If it is, you should see no evidence of 'judder' - most obviously, a staccato feel to motion pans - or other instability. If not, your BD/HD DVD deck will insist on converting the 24fps content on each respective disc into a 50Hz or, more commonly 60Hz image, simply because many (most) older generations of TV won't recognise a 24fps signal.

Now remember: with earlier formats, the telecine process was done by the mastering studio, with no time constraints: the resulting converted video could then be 'dubbed' down on to the DVD disc before sale. With a BD or HD DVD player, the same job is being done by the player (clearly, not as powerful as a mastering studio) in real time. You can see why the whole process is fraught with potential pitfalls, and why juddering motion plagued earlier BD/HD DVD players. Happily, things are changing now.

Finally: if you've got a 'mere' HD-Ready set, you might not need to worry. Many will have video processing capable of accepting 1080p content at 24pfs, even if their native resolution doesn't allow for every pixel to be displayed 'dot for dot'. Panasonic's Viera range and Pioneer's Kuro line-up are good examples. Both will handle 24fps/1080p, even if both have to scale the video down to meet their respective HD-Ready resolutions.

 

[D.J.KRIME]

So if the disc is encoded at a native 1080p/24FPS does that mean that on my SamsungPS50Q97HDX which will not accept a1080p/24FPS signal that I will end up with juddery camera pans when watching a HD disc? I have a HD-DVD player for my XBOX 360 which I have used at both 720p and 1080i but put the screen judder down to the fact it was on the 360 and not a propper HD player as such.

If this is the case I will be sticking with good old DVD as this screen judder would drive me mad!

 

[Anonymous]

You're right. That's why you're getting motion judder, and until we see a player with very powerful onboard video processing able to more effectively convert 24fps into either 25 or 30fps for PAL/NTSC (not a purist solution, but at least one that should help patch things up) you'll be stuck with it. Unless you change both your TV and your player for new 24fps-ready kit, of course.

 

[Anonymous]

Hmmm as I have the same screen as Krime, I'm very interested and concerned. I read this set of articles and suggest we wait for an HD player with HQV chipsets to do a decent job of handling motion. http://www.hqv.com/technology.cfm

 

[D.J.KRIME]

This almost makes a complete farse of the whole HD-DVD/BLU-RAY as being the successor to DVD then as 99% of people who have already invested in a HD ready or FULL HD set but only a select few can handle 24FPS and the Manufacturer's of the HD players are hardly likely to invest into a technolgy that converts 24fps to either 25FPS or 30FPS are they? So infact the terms HD READY and FULL HD on your tv are very missleading as it does not mean that they can handle a true full hd signal in its native form.

When I chose my current screen this whole 24FPS was not a well known factor, and to be honest from the effect it gives on a non 24fps capible screen, it has resulted in a backwards step from DVD and seriously ruins the whole movie experience for me. Yes the detail of HD is far greater than that of DVD but atleast when I watch upscaled DVD via my Denon 3930 tho not as detailed as that of HD-DVD at least it is a smoth and stable image.

 

[Anonymous]

DJ Krime - you are so right, I can see from your kit list that you have spent a significant sum on putting your home cimena together and now find out that it perhaps it doesn't do what it should and you feel ripped off.

I blame the manufacturers because they are always looking for the next marketing headline to ensure their products continue to sell. Next year no doubt you will see someone create a "24fps ready symbol" and it being on a load of new kit coming into the market place which will ensure a new round of buyers part with their hard earned cash for Plasmas, LCD, HD Players and AV Amps

 

[D.J.KRIME]

I have this afternoon just been around to a friends house to compare a BD via his PS3 on a 1080p but non 24PFS screen and the judder effect is just as bad on his set, so the problem obviously only lies in the frame rate and not the resolution.

I personally find it soo of putting it makes the film almost unwatchable, so why encode a disc into a frame rate that hardly anyone can enjoy at home? Are we the consumer constantly ment to keep upgrading our equipment?

 

[Anonymous]

I have the predecessor (PX60) to the latest Panasonic Viera set (PX70) that you rate so highly. Is my TV capable of displaying Blu-ray and HD-DVD or will I have to buy a set that can at least accept 1080P and downscale it? This is most worrying as I was looking to buy a HD player in the near future.

 

[Clare Newsome]

Panasonic's specs are - as ever - not the most forthcoming, but the PX60 is unlikely to accept native 1080p and almost certainly not 24fps. However, as an HD Ready set, it should accept a 1080i feed from an HD player happily enough - the player should detect this automatically, though you can also set up any player (including upscaling DVD players) to output at the best resolution for your set, too.

 

[Anonymous]

There will always be a trade off in quality and 'watchability' where differences exist in the encoding and displaying frequencies. Ideal scenarios are of course where these match, i.e. taking 24fps and displaying each frame 3 times (hence 72 Hz). Where problems will always occur is where there are differences in these, for example getting 24fps to display on a 50 or 60Hz system. The processing systems need to speed up or add frames to fit the refresh rates. There will always be problems with displays whilst these situations exist.

As TV is not going away in the UK and this is pretty settled on not being an easy multiple of 24 displays will always have to be able to accept a range of inputs. I just hope that now they've settled on 24fps and there's going to be no sneaky surprises further down the road.

 

[Anonymous]

Had I bought a set a few months ago I too would be feeling a little bit conned. If I bought a Blu-ray(or HD-DVD) player hoping to watch a film in 1080p at 24fps, just as nature intended, only to find my screen was not capable of swallowing such a diet, I would not be a happy bunny. I have just lept aboard so my feet are still dry but in a few months time....?

As fo 24fps. I think that will be around for a good while yet. It is more a 'look' issue rather than a technological one.

 

[bluesurf9]

I am thinking about buying a Pana th37px70 will this have the same problems as mentioned above? As I will be buying a PS3 too.

 

[Clare Newsome]

You'll be fine - the Pana works fine with the PS3, in 24fps mode (despite what the specs say). More here....

 

[Anonymous]

Hi,

Will the panasonic PZ700 be capable to read 1080p 24fps signal? Is this signal output from just a Blu Ray DVD Player?

The denon 2930 will it be capable of reading a Blu Ray DVD?

Thanks

 

[professorhat]

[quote user="norge"]
Will the panasonic PZ700 be capable to read 1080p 24fps signal?[/quote]
See Clare's previous response in this thread.

[quote user="norge"]Is this signal output from just a Blu Ray DVD Player?[/quote]

HD players output this signal i.e. Blu Ray and HD-DVD.
[quote user="norge"]The denon 2930 will it be capable of reading a Blu Ray DVD?[/quote]
No, this is a DVD player so will only play standard DVDs. A Blu-Ray disc can only be played on a Blu-Ray player and an HD-DVD disc can only be played on an HD-DVD player.