Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

MacinJosh

macrumors 6502a
Jan 29, 2006
676
55
Finland
You're right that a 60Hz display will get no benefit from 24Hz output, but it doesn't have to be 120Hz -- any multiple of 24 will do. Eg Pioneer plasmas have done 72Hz forever and in PAL regions there are quite a few 96Hz ones.

iTunes store content is mostly 23.976fps in my experience so 24Hz output would have made sense IMO. Most recent video SOCs have 1080p24 capability so there's a chance it might be enabled in a firmware update but because the ATV is basically an iPhone in a box, it might not have the same capabilities.

Interesting. I've been out in the boonies so I'm not quite up to speed on current tech. I thought the TV would have to have a common multiple for both 24p and 30p. How would a 72hz display it? Can it switch to 60hz like most PAL sets can switch between 50 and 60?
 

Ballis

macrumors 6502a
May 27, 2008
961
915
Oslo, Norway
They include frame interpolation to reduce smearing on crappy LCD panels. Native 48fps is another story but so far ~100% of movies have been shot at 24fps and the answer isn't frame interpolation, it's displaying the material as it was shot.
"Smearing"?! I believe its called motion blur, and black frame insertion is whats used to reduce that. Frame Interpolation, what Sony lables MotionFlow and Samsung lables Smooth Motion, is indeed whats used to get, well, Smooth motion. Don't speak out of your ass if you have no idea what you're talking about.
 

peterjcat

macrumors 6502
Jun 14, 2010
457
1
"Smearing"?! I believe its called motion blur, and black frame insertion is whats used to reduce that. Frame Interpolation, what Sony lables MotionFlow and Samsung lables Smooth Motion, is indeed whats used to get, well, Smooth motion. Don't speak out of your ass if you have no idea what you're talking about.

The problem is motion blur, or smearing. The solutions are either to insert a black or dimmed frame or to insert an interpolated frame. Having used frame interpolation to solve the smearing problem, manufacturers decided to turn it into a marketable feature by arguing that it's good to smooth out motion by inventing intermediate frames. Many people disagree.

The point, anyway, is that 24fps material is better played at an even multiple of 24Hz, because even though 24fps isn't a very high framerate and can lead to judder, at least it's a uniform judder, whereas if you pull it down to 60Hz you also get a 3:2 cadence that many people find irritating.
 

jkozlow3

macrumors 6502a
Jul 16, 2008
973
658
You realize that most modern TVs don't process 24p properly either?

Mine does.

So does mine, but most don't.

Key word here being *properly*. Just because a TV plays back a 24p signal at a multiple of 24 (i.e. 72, 96, 120, etc) doesn't mean it doesn't do it without introducing artifacts or other unwanted effects.

Your displays may very well playback 24p *properly*, but I agree that most do not.
 

heliocentric

Guest
Original poster
Nov 26, 2008
385
0
Wirelessly posted

I'm 100% sure mine plays back 24p properly at 24hz. It looks great when playing back blurays.

I think we need to focus on the atv not individual tvs though...

I'm disappointed it doesn't do 24p, I always thought they would bring it in when they released an apple tv capable of 1080p. It seems very short sighted, hopefully a software update in the future will add it.
 

Irishman

macrumors 68040
Nov 2, 2006
3,392
843
Key word here being *properly*. Just because a TV plays back a 24p signal at a multiple of 24 (i.e. 72, 96, 120, etc) doesn't mean it doesn't do it without introducing artifacts or other unwanted effects.

Your displays may very well playback 24p *properly*, but I agree that most do not.

For the record, Pioneer 9G KURO Pro-111FD.
 

tctony

macrumors 6502a
Jun 15, 2009
684
0
My reaction to this thread: :confused:

Did Apple really release a 1080p product that is incompatible with most 1080p videos?

Forgive me if this is incorrect. I am not really up to speed with tech specs of TVs and movies and such.
 

Irishman

macrumors 68040
Nov 2, 2006
3,392
843
My reaction to this thread: :confused:

Did Apple really release a 1080p product that is incompatible with most 1080p videos?

Forgive me if this is incorrect. I am not really up to speed with tech specs of TVs and movies and such.

No, they didn't. The videophiles among us are having a healthy discussion about minutia, as we always end up doing. :)
 

steve-p

macrumors 68000
Oct 14, 2008
1,740
42
Newbury, UK
In fact the 1080p 50/60 playback will be good enough for the vast majority so I don't think we can be too critical. Just like the fixed 48KHz audio output won't worry most people, even though it does bother me that my lossless audio is no longer bit perfect into the DAC because ATV converts it from the original sample rate. That's one thing ATV1 did better.
 

heliocentric

Guest
Original poster
Nov 26, 2008
385
0
Wirelessly posted

tctony said:
No, they didn't. The videophiles among us are having a healthy discussion about minutia, as we always end up doing. :)

Haha. It happens. Could you possibly explain in layman's terms to me?

Well basically people are making their own bluray rips to play on atv. Most blurays films are encoded at 24 frames per second. The atv has to options for output which are 50hz or 60hz but no 24hz. This means the 24p content is not shown correctly on your hdtv (assuming your tv outputs 24p of course). Side affects are stuttering and juddering which ate mostly noticeable on panning shots.
 

Segaboy

macrumors newbie
Mar 6, 2012
3
0
I believe nothing will be done...

Howdy...

I believe there will NOT be a FW update to support 24p output on the ATV due to the fact that Apple wants you to pull content from the online iTunes store.

A 'few' people that go through the trouble to rip a BD or DVD are not the core audience or target audience for a product that Apple continues to consider a 'hobby'. :cool:

Don't get me wrong, I am a devoted videophile. I own a mess of LD's, D-VHS, D-Theater, DVD, HD-DVD, and Blu-ray content. I am trained in the deadly arts of ISF Calibration and know what a correct video signal looks like. :D

I just don't see this in the ATV future...Jailbreak...well that is a different story.
 

kiranmk2

macrumors 68000
Oct 4, 2008
1,534
1,987
Howdy...

I believe there will NOT be a FW update to support 24p output on the ATV due to the fact that Apple wants you to pull content from the online iTunes store.

A 'few' people that go through the trouble to rip a BD or DVD are not the core audience or target audience for a product that Apple continues to consider a 'hobby'. :cool:

Don't get me wrong, I am a devoted videophile. I own a mess of LD's, D-VHS, D-Theater, DVD, HD-DVD, and Blu-ray content. I am trained in the deadly arts of ISF Calibration and know what a correct video signal looks like. :D

I just don't see this in the ATV future...Jailbreak...well that is a different story.

But isn't HD from the iTunes store encoded at 24 fps?
 

MacinJosh

macrumors 6502a
Jan 29, 2006
676
55
Finland
anyone know if its possible to convert your 24p bluray rips to 25 or 30 to avoid this problem?

One possible way is to *conform* 24p to 25p. Not convert. That means speeding it up a bit. I understand that movie studios do this for the PAL market resulting in a slightly shorter movie duration. They also change the pitch of the audio.

Converting to 30fps results in the same result you see on your TV as a pull down needs to be performed.
 

spacepower7

macrumors 68000
May 6, 2004
1,509
1
Mine does.

Cool what HDTV do you have?

----------

Key word here being *properly*. Just because a TV plays back a 24p signal at a multiple of 24 (i.e. 72, 96, 120, etc) doesn't mean it doesn't do it without introducing artifacts or other unwanted effects.

Your displays may very well playback 24p *properly*, but I agree that most do not.

So true, especially when you consider that the AppleTV is $99 and most true 24p HDTVs are multiple of thousands of dollars.

----------

Wirelessly posted



Well basically people are making their own bluray rips to play on atv. Most blurays films are encoded at 24 frames per second. The atv has to options for output which are 50hz or 60hz but no 24hz. This means the 24p content is not shown correctly on your hdtv (assuming your tv outputs 24p of course). Side affects are stuttering and juddering which ate mostly noticeable on panning shots.

Most HDTVs don't play 24hz, except the expensive ones like you have. It's kind of hard to complain about that feature lacking on a $99 box. I think my wdtv only does 50/60 hz.

----------

still not a viable purchase if you want to play bluray rips then :(

Although I guess it would be ok for dvd rips...

It's viable if you don't have a $2000 HDTV that plays 24p. Most people don't have a 24p HDTV, so they won't notice the difference you are pointing out. Their blu-ray rips will still look decent.

----------

What commercial content out there on dvd or bluray is 60 frames per second? Its either 24, 25 or 30 isnt it?

and to output 30 frames it should be set to 60hz, in the uk everything is 25 frames (50hz)...

anyway here is a picture that shows the 24p at 60hz problem -

Image

I really thought once we hit 1080p on the atv they would of allowed true 24p...

Wait you don't even know that that your blu-ray is not really 24p and your complaining.

----------

It shouldn't have anything to do with bluray though.

I wonder is it possible to convert a 24p file to 25 or 30 to make it compatible?

Yes it is possible to convert but you might as well let the hardware do it for you.
 

heliocentric

Guest
Original poster
Nov 26, 2008
385
0
A £100 bluray player I had did 24p so why cant I expect this to do it? I know its totally up to Apple though on wether they include the feature or not , I just can't see the benefits of not including it.

What does it matter if some cheap tvs don't do it, we aren't talking about tvs here we are talking about the ATV...

Content providers in the uk do indeed speed up 24p content to 25 for tv broadcasts and DVDs. Why would they bother doing that if it was fine to leave it as it is.
 
Last edited:

steve-p

macrumors 68000
Oct 14, 2008
1,740
42
Newbury, UK
Sadly we are probably stuck with 60 Hz encoded files becoming a de facto standard for HD electronic distribution, even though 50 works better with movies. In the same way we are stuck with the lower quality NTSC equivalent of 720x480 for SD compared to 720x576 for PAL. Incidentally, iTunes SD content is even worse. Try 640x360 for some widescreen SD material that's only a few years old, which is so poor it's a joke. I don't now how Apple dare sell that as SD. To me, that does not qualify, and you can't tell what you are going to get until you have already purchased and downloaded it.
 

Irishman

macrumors 68040
Nov 2, 2006
3,392
843
But isn't HD from the iTunes store encoded at 24 fps?

Nope. In the US store it would be 60, and in the UK, I believe 50 (please someone correct me if I'm wrong).

----------

A £100 bluray player I had did 24p so why cant I expect this to do it? I know its totally up to Apple though on wether they include the feature or not , I just can't see the benefits of not including it.

What does it matter if some cheap tvs don't do it, we aren't talking about tvs here we are talking about the ATV...

Content providers in the uk do indeed speed up 24p content to 25 for tv broadcasts and DVDs. Why would they bother doing that if it was fine to leave it as it is.

I think you're just a wee bit confused. It's the original content encoded in 24p on most of your blu-ray movies. The Blu-ray player is just designed to know how to deal with that. It also knows how to deal with other refresh rates, too.

Make sense?? So, transferring the situation over to iTunes, Netflix and the ATV, if the original content isn't encoded in 24p, it doesn't matter if Apple builds 24p support into the ATV. They don't work as well together as they would if they both spoke the same refresh rate.
 

heliocentric

Guest
Original poster
Nov 26, 2008
385
0
Yeah I know they probably haven't included 24p output because nothing in the iTunes store is encoded at that and that's fine.

But the problem is that when I play (my own) 24p bluray content on an apple tv it's a bit jumpy and skips the odd frame, but when I play it from a ps3/bluray player it's nice and smooth.

The problem is obviously because it's outputting at a refresh rate that doesn't match the content I am trying to play on it.

Is their a way to convert 24p to 25? That would be ideal for uk users, seeing as the stand refresh rate for tvs here is 50hz...
 

spacepower7

macrumors 68000
May 6, 2004
1,509
1
Sadly we are probably stuck with 60 Hz encoded files becoming a de facto standard for HD electronic distribution, even though 50 works better with movies. In the same way we are stuck with the lower quality NTSC equivalent of 720x480 for SD compared to 720x576 for PAL. Incidentally, iTunes SD content is even worse. Try 640x360 for some widescreen SD material that's only a few years old, which is so poor it's a joke. I don't now how Apple dare sell that as SD. To me, that does not qualify, and you can't tell what you are going to get until you have already purchased and downloaded it.

The 640x360 is Apple's SD because they still sell the iPhone 3GS, I haven't checked in awhile but I think it might be 640x360 anamorphic, making it 16x9 for TV shows. You can't expected Apple to sell video that doesn't playback on one of their products that they still sell, regardless of how old it is. Otherwise we would have people complaining about their device not being supported. Take a minute and think about the rationale of Apple's business decisions.
 

spacepower7

macrumors 68000
May 6, 2004
1,509
1
A £100 bluray player I had did 24p so why cant I expect this to do it? I know its totally up to Apple though on wether they include the feature or not , I just can't see the benefits of not including it.

What does it matter if some cheap tvs don't do it, we aren't talking about tvs here we are talking about the ATV...

Content providers in the uk do indeed speed up 24p content to 25 for tv broadcasts and DVDs. Why would they bother doing that if it was fine to leave it as it is.

I didn't mean to rant at you so I apologize for that.

The blu-ray discs usually have 23,98p not true 24p.

Content providers, DVD and the like traditionally provided a 25p/50i version because European tube TVs use a 50hz electrical system while USA uses a 60hz electrical signal.

It all comes down to making things compatible with the largest number of users.

----------

Bollocks. I just picked three random movies that I bought on iTunes, all are 24p.

Are you sure that the aren't 23.98? I have never hear of anything distrubuted at true 24p. Can you use mediaInfonor some of freeware to make sure
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.