Apple TV 4K doesn't support 24Hz output (Correction - it does now)

Discussion in 'Apple TV and Home Theater' started by ActionableMango, Sep 14, 2017.

  1. WilliamG macrumors G3

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    #301
    Apologies, I meant the opposite! So yes, it’s outputting 24p when it should be outputting 24hz for some media. Oy... Apple, jeez...
     
  2. Mac 128 macrumors 603

    Mac 128

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    #302
    Thanks for confirming. That's the conclusion I was left with, but not sure. I suppose I could force the frame rate manually until they update ...
     
  3. 500kilohertz macrumors newbie

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    #303
    Are there any news for this issue? Did 11.3 fix the fps problem?
     
  4. Rigby macrumors 601

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    #304
    tvOS 11.3 now supports automatic framerate switching on the (non-4K) ATV4, if that's what you're asking. It works fine.
     
  5. Krevnik, Apr 5, 2018
    Last edited: Apr 5, 2018

    Krevnik macrumors 68040

    Krevnik

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    #306
    The problem is that HDMI doesn't actually support true 24Hz, only 23.97Hz. It doesn't support true 60Hz either, hilariously enough. 24Hz/60Hz is just shorthand for the NTSC definitions of 23.97 and 29.97 frames per second (*2 to get the field rate of 29.97 = 59.94Hz).

    There isn't much of a fix here, to be honest. Apple has a choice of a couple different hacks here, with their own problems:
    1) Display the 24fps content as if it was 23.97fps. This would cause audio/video desync if the audio was not similarly altered, which is tricky.
    2) Display the 24fps content at 24fps, but output at 23.97Hz over HDMI. This causes the frame drops you see when two frames at @23.97 just happen to lie on either side of a single frame's time position and span. This is what Apple does on the Apple TV.

    They could potentially do some frame blending to address the problems and at least avoid the frame drops, at the cost of some detail. Much like what you see when PAL TV programs are brought over to the US, trying to convert 25fps to ~30fps.
     
  6. WilliamG macrumors G3

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    #307
    What do you mean HDMI doesn’t support 24hz? It absolutely does. Whether the Apple TV supports 24hz is another question.
     
  7. ActionableMango thread starter macrumors G3

    ActionableMango

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    #308
    That's odd--I've read many times that Plex is ONLY able to use the native video player on devices, which is why they cannot add additional decoding support beyond what exists in the native player.
     
  8. WilliamG macrumors G3

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    #309
    I had it confirmed by one of the Plex devs that it is using the native video player on iPad.
     
  9. pedromvu macrumors newbie

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    Jun 2, 2018
    #310
    So I just found out of this limitation, it's only a minority of content that is in 24.00 instead of 23.976, unfortunately once you get one of those, the frame skips are very bothersome.

    Please send feedback here, to see if Apple listens:

    https://www.apple.com/feedback/appletv.html
     
  10. Bpmd macrumors newbie

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    Nov 28, 2015
    #311
    Done. And thank you, it's been driving me nuts trying to figure out why I was still getting frame skips on 24Hz content.
     
  11. WilliamG macrumors G3

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    #312
    Bumping this thread to say I'm MASSIVELY disappointed in the Apple TV 4K. Had some friends over today to watch "The Idol" (2016) movie, and the frame skipping is all over the place because the movie is a 24.000hz movie, and with Frame-rate matching enabled on the Apple TV it's playing it at 24p (23.976hz). The frame-rate is a mess.

    Just embarrassing. How on earth does Apple even LET you rent/buy movies that don't display properly on their devices?!
     
  12. kiranmk2 macrumors 6502a

    kiranmk2

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    Oct 4, 2008
    #313
    I'm guessing a new Apple TV 4K will be coming this year sporting HDMI 2.1 with Variable Refresh Rate support (can output any frame rate), Quick Media Syncing (no blank screens when changing resolution/refresh rate) and Auto-Low Latency to automatically switch TVs into game mode. Probably an A12X chip too to give 'XBox One S' power. Of course, most of these features will only work with compatible TVs and I'm not aware of any TV that supports VRR, QMD and ALL (some 2018 Samsungs do VRR and ALL I believe).
     
  13. brentsg macrumors 68040

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    #314
    Maybe it's display dependent, or I'm not watching enough movies. I've never experienced this.
     
  14. WilliamG macrumors G3

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    #315
    You'd not notice it on many movies if you just watch mainstream ones, - not foreign film.
     
  15. bluraycinema macrumors newbie

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    #316
    Isn't HDMI 2.1 backwards compatible?

    Samsung are supporting their 8K tv customers in upgrading their Connect Box to HDMI 2.1.
     
  16. BODYBUILDERPAUL, Jan 1, 2019
    Last edited: Jan 1, 2019

    BODYBUILDERPAUL macrumors 65816

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    #317
    What TV are you using buddy? I have the LG B7 OLED and before that Panasonic EX700 which was a crappy LCD and yet never ever experienced what you are describing. Sounds more like the films fault rather than the Apple TV. Do let us know your TV brand.
    Are you using the Belkin HDMI cable?
    I used that along with Match in the settings and i'll be honest, it's outstanding. It's the only electrical item that doesn't give me stress :) I seriously cannot fault it.

    What I cannot get my head around though it why computers do not adjust to frame rates in video like the iPad Pro does with Pro Motion? Films look juddery on my MacBook (I noticed judder instantly) and whilst I was in the Apple Store in Covent Garden, they had the new animated Apple advert playing on the iMac, iMac Pro and new Mac Mini with LG Display and guess what... EVERY single one of these computers could not play the video properly - the panning was a complete mess of judders. I seriously could not believe it on a £5000 computer. How does Apple not notice or care about this? Surely a £5000 computer should have Pro Motion as standard? Same with MacBook Pro. It's bizarre as a 1970s TV had no picture judder on panning etc. Sometimes I do feel as though we are taking two steps forward and one step backwards with tech. (hence why I try to live my life with as few tech products as possible - less is more and less is less disappointment!).
     
  17. WilliamG macrumors G3

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    #318
    The iPad Pros with ProMotion are amazing for watching movies. Best tablets on the planet.

    I’m using two displays: a JVC DLA-RS540 projector and a C7 OLED. Both displays play the same using the two Apple TV 4Ks I have.

    24p movies have no issue. 24hz movies have issues.
    --- Post Merged, Jan 1, 2019 ---
    Just spend the $4 on renting The Idol (2016) - it’s a good movie anyway. Then you’ll see the issues.
     
  18. BODYBUILDERPAUL, Jan 1, 2019
    Last edited: Jan 1, 2019

    BODYBUILDERPAUL macrumors 65816

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    #319
    I agree about the iPad Pro. The way that they are calibrated - just incredible - same with the iPhone X and SE and my old 4S at the time.

    The C7 is incredible. Probably the best of the best.

    Do you think that it could be an iTunes error? Or the transfer? I'm asking as I bought 'Notting Hill' from iTunes and very sadly, there was a very slight lip sync problem with it. It drove me nuts and in the end I asked Apple for a full refund. It was even more noticeable when watching on my iPhone and MacBook up close. I was so disappointed as i'm in the stage of replacing the very last of old DVDs from years ago and that was a film that I wanted. The picture quality of it from iTunes in HD was awesome, Just a shame the sound was out. Also a shame that people at Apple are obviously not checking these films once they have been compressed etc ready for iTunes as they would notice these faults instantly. Very surprised that Apple have no quality control on this - very un-Apple in my opinion and experience.

    PS Just seen the trailer and it looks brilliant! I LOVE Foreign film, independent film AND releases from StudioCanal. Plus I have friends from that region - I know that it will be excellent!
     
  19. WilliamG macrumors G3

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    #320
    I had someone over on AVS test the file. It's encoded at 23.976hz, which I'm nigh certain the source is NOT, so someone at Apple screwed up. This is just a bad encode.

    That movie also had some lip sync issues, and lip sync issues make me crazy. It's part of the reason I love ripping my own media, because I have full control via my remote to adjust sync + or - WHILE the movie is playing, without anyone even noticing, using a proper media player. The Apple TV 4K is simply not good enough as a Plex player etc etc. No buffer control, no sync control etc etc, no transport key shortcuts. It'll do in a pinch, but since dedicated players (that can do 24hz and DTS-HD MA, too) are so cheap these days, there's no reason to use the Apple TV 4K for anything other than a HomeKit hub and for Netflix/Prime etc.

    Which is what I do.
     
  20. brentsg, Jan 1, 2019
    Last edited: Jan 1, 2019

    brentsg macrumors 68040

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    #321
    Now you've totally lost me. You were dogging the Apple TV 4K in the post I originally replied to.

    Now you're saying it's just a bad encode. A bad encode is a bad encode on any device.

    And Plex is an app. So you don't like a bad encode and you don't like an app. No doubt that it's a deal breaker if your go-to app sucks on a particular device, but it's a different discussion.

    Also, what do you consider to be a "dedicated player"?
     
  21. WilliamG macrumors G3

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    #322
    I'm a bit confused. Yes, the movie issue I had is a bad encode. That's a separate issue from 24hz movies not playing correctly.

    But the Apple TV does not support 24hz playback. That's the issue here, and I've NO idea why the thread title has been updated to say it does. It supports 24p playback, NOT 24hz playback. 24p is 23.976hz (which the Apple TV 4K supports). 24hz is 24.000hz playback, which the Apple TV does NOT support.

    And this is why using the words 24p and 24hz interchangeably is a bad, bad idea.

    You can follow the thread over at AVS if you want more info:

    https://www.avsforum.com/forum/39-n...2-apple-tv-4k-lacks-support-24-000-video.html
     
  22. BODYBUILDERPAUL, Jan 1, 2019
    Last edited: Jan 2, 2019

    BODYBUILDERPAUL macrumors 65816

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    #323
    Definitely worth reporting to Apple if it's a bad encode. Apple prides themselves on being the best. It's clear that QC is slipping at iTunes.

    On the plus side, considering that the film does not seem to be available on disc etc we should be thankful that Apple are offering it on iTunes. I would love the 1982 film 'Summer Lovers' to be on iTunes. Instead, I had to buy a USA import of the disc at £21. It took 10 days to arrive and was a horrible 4:3 Pan and Scan copy. I was thank full that someone posted a BluRay limited edition rip onto YouTube. The difference seeing it in widescreen was beautiful plus the colour coding was in a different league. So much of the film had been lost in the pan and scan PLUS I cannot watch a film in a 4:3 ratio. It's hideous! I would of happily put up with some judder in order to see a Widescreen HD version as opposed to that overpriced DVD.
     
  23. andrewstirling macrumors 6502

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    May 19, 2015
    #324
    Guys let’s not confuse the issue. The following has been established and is not really up for debate as it is entirely reproducible.

    1. The Apple TV can properly output the VAST majority of film content which is encoded at 23.976Hz at its native frame rate.
    2. There are a small number of films on iTunes which are encoded at 24hz and the Apple TV still outputs these at 23.976Hz which results in frame skipping.
    3. This is not tv or calibration dependent although ironically if you have your TV set up incorrectly then it may mask the problem. For example, if you do not use ‘match frame rate’ on the Apple TV then everything will be chucked out at 60hz anyway (or whatever you have your dashboard set to). Also, some TVs require an additional menu setting to handle native video frame rates. For example on my oled, to get true film cadence I need to have ‘real cinema’ enabled. If I don’t have this enabled then pretty much everything will look wrong but some people adjust to this and prefer it.

    One thing requiring further testing (which I can’t be bothered to do) is to check if this is player dependent. On the U.K. avforums i saw someone say that they experienced frame skipping when watching ‘prisoners’ via the movies or tv option on the Apple TV. However, he also stated that downloading it and playing it via the computer app fixed the frame skipping
     
  24. vaskokvas macrumors newbie

    Joined:
    Sep 26, 2013
    #325
    Apple TV 4K doesn't support 24Hz output (Correction - it does now)

    Lie. It does not. 24.000 fps is not supported and plays with stuttering. Only 23.976 fps plays OK. So Apple simply lies putting 24 fps in Format Menu.
     

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