A chance to talk to FlatpanelsHD's reviewers.
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By Rasmus Larsen
JMGNYC wrote:tvOS beta 11.2 was release today which feature automatic switching for both native frame rate and dynamic range so if you enable that SDR/HDR/DV conversion problems become a thing of the past. It's really great news IMO.
It's great news indeed. We've also published a new article on tvOS 11.2. However, it is worth pointing out that this is not true adaptive frame rate. When switching frame rate it can cause a short blackout or flicker, depending on the TV.

http://www.flatpanelshd.com/news.php?su ... 1509422850

HDMI 2.1 is the first step towards adaptive/dynamic frame rate, and I think this is where Apple is heading. The timing is curious considering that Microsoft recently commented that the HDMI 2.1 spec is expected to be finalized in November 2017 (Xbox One X will get HDMI 2.1's Game Mode VVR via a firmware update).
By Kuschelmonschter
I still doubt that adaptive refresh rate is the solution to the video problem. I don't mind the short dropout. What hurts is a GUI running at 24fps.

I still believe that a constant refresh rate + decent frame rate conversion of the content is the solution.
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By Rasmus Larsen
But tvOS (and Android TV etc.) is a full TV platform. Besides long-form video, it also encompasses short-form video, apps, various UIs, games etc. Dropouts are poison if you experience them regurlarly when browing the user interface.

Some day adaptive frame rate will also support frame rate control in fields, or windows. Because it all happens in real-time, it is within grasp. To do that the timing controllers will need to become more advanced. Another way forward would be to utilize the advantages of HFR, allowing 24p content to be output via HDMI in for example x5 = 120Hz. That way the native frame rate of the content would still be respected and the UI would be super smooth.
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By Rasmus Larsen
Apple has released tvOS 11.2 that enables Apple TV 4K to automatically match its output to the native frame rate and dynamic range (SDR / HDR10 / Dolby Vision) of the content. See the added paragraphs in the ’Picture quality’ section. As such, tvOS 11.2 solves the issues that kept us from giving Apple TV 4K our Highly Recommended Award.
By MrRoboto
From my measurements it seems that 11.3 has serious problem with YCbCr. Can you make a quick test?
As you can see from my screenshots readings from Ted's patterns and ATV RGB High are correct, YCbCr is off.
ATV 4K + Mobile Forge - YCbCr
ATV 4K + Mobile Forge - YCbCr
YCBCR.png (344.21 KiB) Viewed 10815 times
ATV 4K + Mobile Forge - RGB High
ATV 4K + Mobile Forge - RGB High
RGB_HIGH.png (335.6 KiB) Viewed 10815 times
B7 Internal Player + Ted's Patterns
B7 Internal Player + Ted's Patterns
TED.png (335.31 KiB) Viewed 10815 times
By gjlaws

From my understanding:
  • Apple TV is streaming only and you cannot download 4k movies to it
    A connection of 25Mbps is recommended
    Only HD movies can be downloaded to Mac/iOS devices for streaming over a LAN
Therefore '4k' is streaming only.

My situation:
  • I am in a low internet bandwidth area (8-10Mbps).
    I have a LG 55" OLED with Dolby Vision
    I sit 7' from the tv therefore 4k resolution is less critical for me - https://www.rtings.com/tv/reviews/by-si ... lationship
    However I am interested in the benefits of Dolby Vision.
Does anyone know whether Dolby Vision can be enabled but resolution set to 1080p?

It's not mentioned in the review but from the screenshots it looks like '1080p Dolby Vision' is an option in 'Format'.

From my understanding the bandwidth requirement for DV is small as it is metadata.

This would then stream smoothly without buffering, but still give benefits of DV, and allow the LG to upscale. Given my viewing distance I would prefer high quality 1080p than either compressed 2160p or buffering/stuttering.

Before seeing these screen shots in 'Format' I had understood HDR/DV to only be available when viewing '4k' (2160p).

Separately I understand that Netflix offer 'HDR' (DV?) at 1080p - https://help.netflix.com/en/node/42384

User avatar
By Torben Rasmussen
DV works in every resolution/quality just like in Netflix. Bandwidth for DV is nothing on top of the video stream. Looking at Netflix for instance the bandwidth didn't increase when changing from a 4K to a 4K HDR stream.
By gjlaws
Thanks Torben, that's great, I think I'll buy one then.
As Dolby Vision movies via iTunes at £4.99/5.99 (UK) currently even at 1080p seem a pretty good deal.
If it's a movie I really care about I'll get it on 4k blu ray.

One last question, if I let the Apple tv determine format based on the TV (4k/DV), would it bump down to 1080p automatically due to bandwidth (8-10Mbps) or would it try to stream 4k and buffer?

If the latter I assume my best option is to manually set format to 1080p DV even though the tv can display 4k?

(Also if you can help with my login, as I signed up via twitter and now can't add my email address)
User avatar
By Torben Rasmussen
You will get a warning in iTunes if your bandwidth is insufficient for 4K and it will bump down just like Netflix. You seldom see buffering on Netflix as the stream will simply change to a lower bandwidth version and so will iTunes.

You can also just set resolution to 1080p. don’t go for DV as it will covert all content to Dv - use SDR and use “match content”. If you use 1080p res you will not get any benefit of 4K anywhere inside the interface. I would set the resolution to 4K SDR 60 Hz and activate match content for both dynamic range and frame rate.

Send me a PM with the email you would like to add and I’ll change it for you.
By gjlaws
Torben Rasmussen wrote: I would set the resolution to 4K SDR 60 Hz and activate match content for both dynamic range and frame rate.
Great, thanks again! :)
By wentworth
I don't understand your sentence 'If you are ready to say goodbye to the built-in tuner in your TV ...'
As far as I know, AppleTV does not have a tv tuner, does it?
So how can you achive that?
It would be a very good idea taking into account that Android for TV is a nightmare.