What's The Deal with Refresh Rates on TV's?

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  ReverseBias on 06/11/2019 - 18:28

  Don't quote me on it, but for most Hisense models the real refresh rate of the panel is half the "smooth motion" rate.

  If that holds for this TV it's only 50Hz native refresh panel and will show stutter when fed a 24 fps signal from blu-ray unless you leave the motion interpolation on, in which case it will look awful in the ways motion interpolation does instead.

  • 

    OzBerghainer on 06/11/2019 - 18:33

    i suspected that, so at 50hz that means i'll get a max of 50fps no matter the content?

    • 

      p1 ama on 06/11/2019 - 20:14

      No content in Australia that is not 24 fps or 50 fps.

      • 

        ReverseBias on 07/11/2019 - 01:40

        Unless you have a game console, or watch YouTube, or any one of the streaming services that might deliver NTSC-native content…

        • 

          p1 ama on 07/11/2019 - 02:19

          @ReverseBias: True, keep forgetting that we're more Americanised these days, perhaps add the 30/60 into the mix too.

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  OzBerghainer on 06/11/2019 - 19:54

  It's odd, and I think retailers don't quite understand either… specs on some sites like Bing Lee show 100 Hz: https://www.binglee.com.au/hisense-55r6-55-uhd-smart-led-tv and others show 50hz. I think truly though it is 50hz.

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  p1 ama on 06/11/2019 - 20:14

  +1

  They are TVs, not monitors. If you're watching a movie, 24 fps, sports on TV, 50 fps. That's all you need to know for a TV. Whatever the box says doesn't matter, it could be 2123098120938 Hz, if there's only 24 frames every second, then it can only display 24 distinct pictures every second.

  • 

    Kangal on 06/11/2019 - 22:32

    Not entirely true.
    High-end TV's with much higher refresh rates actually create synthetic frames by the unit, so they're able to increase the fps in an effort to smooth out the objects (less juddering and ghosting). You can notice this when watching tennis (big uniform green/blue background, with a light/white ball). The image may be encoded in 24 fps, and it might be poor on a cheap 50Hz TV. Playback thee same thing on a pricey 240Hz TV and the experience isn't the same. Just look out for the fake refresh rates, they don't measure them in gtg (grey-to-grey).

    I think the higher refresh rate units are mostly overblown, but you will get a better experience on a midrange TV ($1,100 ?) with 120Hz. If you want a premium experience, you'd need to step up to a PC Monitor… or get a TV with HDMI 2.1 and support for ActiveSync/Vsync/FreeSync2. The current Xbox One X supports it, so do Gaming PCs/HTPCs, few laptops, and potentially the 2020 PS5 and Xbox V.

    • 

      p1 ama on 07/11/2019 - 01:00

      High-end TV's with much higher refresh rates actually create synthetic frames by the unit, so they're able to increase the fps in an effort to smooth out the objects (less juddering and ghosting).

      How exactly do they do this when the source is still 50 fps? Unless they're doing some fancy magic to "fill in" the ball when it literally isn't there?

      • 

        ReverseBias on 07/11/2019 - 01:33

        How exactly do they do this when the source is still 50 fps? Unless they're doing some fancy magic to "fill in" the ball when it literally isn't there?

        They are, and it has exactly the problems you would imagine it has - the intermediate frames generated don't make any semantic sense, so everything just sort of…squishes around. This video is old and it's not QUITE this bad anymore but it gets the idea across: https://www.youtube.com/watch?v=B_dE6HPIAJM

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        OzBerghainer on 07/11/2019 - 01:47

        From videos I have seen that’s quite literally what they do, fill in- through various technologies varying by brand. That’s where there’s settings in the menu to turn off auto motion or something similiar which may add a blur or if you want to watch a 24fps movie as it is supposed to be watched

        • 

          Kangal on 07/11/2019 - 12:47

          +1

          @OzBerghainer: Here's an updated demo/video about the topic:
          https://www.youtube.com/watch?v=AUipoxcYtas#t=1m31s

          TV's that are 120Hz (or more), and have HDMI 2.0 (or newer), supporting HEVC (h.265), with faster on-board processors (Quadcore ?), and are sourced from Japan or Korea (particularly after 2015). These are the units that can do Interpolation properly. Here, it doesn't suck that much.

          The units from China, Germany, and USA, may be using the older algorithms or using worse hardware. Here, it sucks, you might as well turn it off.

          I'd be weary of that Hisense unit, and won't spend much money on it, unless the reviews are positive. But reviews must be from independent/third-party and reputable sources. Hope for the best, assume the worst.

      • 

        Beanvee on 07/11/2019 - 11:43

        Yes they use interpolation to create their own between frames, and in my experience interpolation always sucks.

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  ReverseBias on 07/11/2019 - 01:42

  The thing is, most "50Hz" panels aren't just 50Hz panels, and most 100Hz panels aren't just 100Hz.
  Because the same models are sold in multiple territories they're nearly always 50/60Hz panels and perfectly capable of displaying 60Hz when that's what the source provides. This is fortunate, because a lot of streaming content is 60Hz.

  This is the reason why "100Hz" panels are better for 24fps sources like most blu-ray films - they're nearly always 100/120Hz panels. 100Hz still isn't a nice multiple of 24 so judder would be inevitable…show 1 input frame for 4 panel refreshes 5 frames in 6, then every 6th frame for 5 panel refreshes. Ugh. Fortunately 24/120 = 5, so you get nice judder-free motion on panels that are actually capable of switching to 120Hz refresh.

  Note that this doesn't work down at 50/60Hz, which is why 50/60Hz panels should be avoided for any serious film viewing.

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  Bluberry on 07/11/2019 - 02:18

  -1

  Fake news

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  DarthAntz on 07/11/2019 - 13:06

  This August I upgraded my tv to the Samsung Q70R 55 inch. I bought it because i wanted the 120hz. Rtings.com and a few youtube reviews is what convinced me to get it over other brands. I use it as a monitor with my PC, all media comes through it. IMO after a few months of using it, some games (Nier Automata, Gears of war 4) look awesome with the higher frame rates, but that is less than 10% of what I'm using the TV for. I would get full value out of 120hz TV if 100% of the things i used it for utilized the 120hz.
  The clear motion, motion plus, judder, smooth motion, HDR is all super confusing after all these months. We watched the lion king and there were scenes that looked horrible, and it took about 30 minutes of back and forth between menus and researching to make it smoother, and its still not a consistent result. I tinkered with VLC also. All of that Jargon is marketing and requires a lot of mucking around on the users end. With 144hz monitor i had 5 years ago, i didnt have this problem with needing to experiment with settings, and its a shame a modern TV has settings that hinder functionality.
  The big plus of the TV is the panel. In comparison to the previous TV, the definition and clarity has been the big upgrade here. Overall I'm satisfied, but I was a sucker for 120hz. I will still get good value out of it, but if I had the opportunity to purchase again, I would have bought a 32inch 144hz monitor for much cheaper and put it on an monitor arm, to use it for that 10%. Wife loves the TV.
  To answer your question, TV manufacturers dont tell you the Hz because theyre selling you a TV with prescribed marketing jargon that represents quality (HDR logos, Dolby). What you think is a quality feature differs from the marketing technique at the current time to get you to buy a TV. 120hz will be very mainstream next year or the year after, and then it will be considered 'the current marketing value'. You're an early subscriber.