Demystifying Dolby Vision - Profile Levels, Dolby Vision levels, MEL & FEL

So what is Dolby Vision and what’s the hype compared to HDR10?

In a nutshell, Dolby Vision (DV) is a form of HDR hybrid which derives its HDR layer from HDR10 (open source). By adding a separate layer “underneath” the HDR10 (base layer), DV is born. There are some technical differences that make DV reign supreme over its HDR10 counterpart. Let’s see:

Dolby Vision
Bit-Depth: 12-bit
HDR10
Bit-Depth: 10-bit

Dolby Vision
Colorimetry: P3^ up to Rec 2020
HDR10
Colorimetry: P3^ up to Rec 2020

‘^’ - For many player-led decoding of DV layer (LLDV), the colorimetry is utilizing ICpCt (or IPT) colorimetry within the BT2100 boundary. It is close to the DCI-P3 colorimetry that most of us come to know. The most well-known will be streamers like Apple TV 4K, nVidia Shield TV 2019, Roku Ultra 2020, and players like Oppo 203 (which you have a choice between Player or TV-led) and of course for the media front, we have the models that runs the RealTek (RTL1619DR) chipsets like Zidoo Z9X.

Dolby Vision
Mastering Luminance: Usually up to 4,000 nits although it can go up as high as 10,000nits (no display capable of doing that at the moment, let alone the content)
HDR10
Mastering Luminance: Usually between 200 nits and 1,000 nits (Depending on the types of TV or Projector display in use. For instance, to achieve a brighter image quality for more brilliant HDR imagery, LCD panel with FLAD and multiple zones will be the best compared to its OLED counterpart which will not get as bright but win over Contrast what makes the picture pops)

Another important difference between DV and HDR10 is that DV contains “dynamic” metadata as opposed to “static” metadata from HDR10. The TL;DR version of it is that dynamic metadata allows scene-by-scene real-time analysis by the display (OLED/LCD TV) or source (bluray player) to determine what is the peak white and black for each scene in a movie and then adjust the settings of the display accordingly to provide the best PQ in terms of colors and contrast. HDR10, on the other hand, receives “static” metadata which tells the display to work within the parameters of the movie authored in the studio. Since it is not “dynamic”, it will utilize one set of number (brightness or luminance) to determine the relative brightness of the “entire” movie based on the PQ Curve (ST2084 standards).


Image source derived from: The HDR video ecosystem tracker - FlatpanelsHD - courtesy of member Yoeri G

The confusing state of Dolby Vision…

So far, I have touched on the basics of DV and its benefits over HDR10. Now let’s talk a little bit more in-depth of DV itself. Recall I mentioned LLDV (Low Latency Dolby Vision), this is in fact a variant of DV. As you can see, DV, unlike HDR10 is not FREE, TV and 4K UHD players manufacturers have to pay royalty fees to Dolby before it can decode the DV layer of the content (e.g. 4K UHD bluray disc). But Dolby knew their ultimate specs like having content authored in 10,000 nits and up to 12-bit bit-depth etc will never be realized any time soon. Compounding the issue is the limitation in hardware processor present in most TV, 4K UHD bluray player and media streaming devices. Sony OELD TV produced in the 2016 (like A1 and X1) will not have the ability to run full 4K/60fps content because it is only capable of decoding up to 4K/30fps.

Dolby likes to complicate matters, just like that way it complicates Dolby Atmos when it first rolled out circa 2013 - 2014. They provided a white paper on this and requires manufacturers of Atmos-enabled speakers to conform to certain requirements like HPF to crossover at 180Hz before it can be certified as a true Dolby-Atmos enabled speakers :P. I guess history repeats itself with the Dolby Vision standards. The problem with Dolby Vision is the complexity of the way Dolby roll out its DV implementation. Believe it or not, there are at least 6 known profile levels. Within a given profile, the maximum level a base layer (BL) or enhancement layer (EL) is restricted by the Profile. If you have used MakeMKV s/w to make back-up copies of your precious bluray or 4K UHD bluray titles, you should be familiar with terms like Profile H.265 Main10 4.1/5.1 etc.

Now let us break down what are some of the Profiles that Dolby has had dished out over the years.

First is the single-layer (Profile 5 & 8) that most LLDV-based sources will prefer - e.g. Netflix, Apple TV+, Disney Plus. Besides streaming devices that utilize this type of DV implementation are the media players such as Zidoo Z9X and nVidia Shield TV 2019 that comes with DV decoding capability (LLDV). Now there has been rumors that the new Xbox Series X/S console will also utilize LLDV (Player-led) as the preferred form of DV instead of the unadulterated version. If this is true, then the built-in 4K UHD bluray drive may not be able to read the dual-layer (usually Profile 7) containing the DV for TV to process and decode.

If we look carefully at the table, you can see the maximum Base Layer (BL) supporting the HDR10 layer to be at 10-bit H.265 (HEVC) and supports Profile of 4.2 up to 6.2 while the Enhancement Layer (EL) supports anything between 4.1 to 5.1. Within the EL, there are Full EL and Minimum EL.

In essence, the EL is a 10-bit video bitstream that carries the residual between the source and the BL and the “dynamic” metadata for DV. An enhancement layer that carries a residual signal is = 0 (zero), that is, the decoder does not need to process the residual signal, is called minimum enhancement layer (MEL). If the residual signal is > 0, it is called full enhancement layer (FEL).

An example of a typical MKV file encoded with a DV stream:

DISC INFO:
Disc Title: Gladiator.2000.MULTI.COMPLETE.UHD.BLURAY-EXTREME
Disc Size: 92,459,896,796 bytes
Protection: AACS2
BD-Java: Yes
Extras: Ultra HD
BDInfo: 0.5.8.7 (compatible layout created by DVDFab 10.0.8.4)

PLAYLIST REPORT:
Name: 00041.MPLS
Length: 2:50:56.495 (h:m:s.ms)
Size: 79,038,529,536 bytes
Total Bitrate: 61.65 Mbps

VIDEO:
Codec / Bitrate / Resolution / Frame-rate / Aspect Ratio / DV Profile / Chromacity / Bit-Depth / Colorspace

Base Layer: MPEG-H HEVC Video / 43319 kbps / 2160p / 23.976 fps / 16:9 / Main 10 Profile 5.1 High / 4:2:0 / 10 bits / HDR / BT.2020

Enhancement Layer: MPEG-H HEVC Video / 6826 kbps / 1080p / 23.976 fps / 16:9 / Main 10 Profile 5.1 High / 4:2:0 / 10 bits / Dolby Vision / BT.2020

Yes, another interesting bit in the way MKV encodes its DV stream or EL is the resolution is defaulted to 1080p resolution while the BL (HDR10) preserves the 4K (2160p) resolution. This is because, for Profile 7, the maximum EL codec level is maxed out at 5.1. For a Main 10 Profile 5.1 High, the maximum bitrate is up to 40 Mbps and 130 Mbps. These bitrates is controlled by the various Dolby Vision Levels (DVLs). Again we use Gladiator 4K UHD 1:1 rip as an example, we knew the disc contained an EL because it has a DV layer (at Profile 7) which is encoded at Main 10 Profile 5.1 High. Look at the 5th column (first table titled, “Constraints on codec level”), you will see Dolby Vision Level (maximum) is “09”. If we cross-reference it to the DVL table (see table below), you will see that at DVL = 09, the maximum resolution is set at 3840 x 2160p @60fps. The maximum bitrate for a Profile 5.1 High Tier ranged between 40 Mbps and 130 Mbps.

Which is superior? Full unadulterated Dolby Vision or Low Latency Dolby Vision?

The answer depends. If you have a fully-compliant OLED or LCD based display like a TV, it will be good for TV to do all the DV processing instead of the source (4K UHD bluray player) because the display is almost always performed consistently across the board when it comes to image upscaling and resolving individuals pixels. There is a reason why you are paying so much for a FLAD QLED/OLED TV for a reason - i.e. the ability to scale the whitest whites and the blackest blacks with accuracy and finesse.

For Projector users, it is a Hobson’s choice. LLDV is the way to go if we wanted to get “dynamic” metadata working on our display. We need an EDID manager like the Lumagen Radiance Pro Video Processor which is uber-expensive or the more affordable HD Fury Vertex 2 or Diva to “spoof” the display EDID to sources like the Apple TV 4K or even Zidoo Z9X that a DV-capable display has been detected, please process the EL of the media file within the source and send the processed signal to the display, which in this case, the Projector.

In short, a player-led (LLDV) device will have limitations in terms of processing power. The side effects include unsightly “banding effects” and less punchy colors or uneven luminance levels which may cause the overall image to be too dark or too bright if the source like media players or streaming devices fail to decode the various type of DV Profiles and its accompanying DVLs properly. As the name (LLDV) implies, “low latency” requires less computational powers which equates to less than ideal PQ.

To date, Oppo 203 is the only 4K UHD player that I know of that allows both formats of DV (full DV and LLDV) to co-exist in one single solution. So for those who are still holding on to one, you should keep it until 4K streaming becomes a mainstay and we see the demise of physical media. Seems like Dolby is not going to rest on its laurels when it comes to making things even more complex for the implementation of DV. It is now looking at a new DV variant styled, “Dolby Vision IQ” which seeks to utilize the light sensors inside a TV, to dynamically adjust the HDR picture based on the content and ambient light conditions in a viewing area.

Now that you know more about Dolby Vision and its quirks, you can decide for yourself if it is worth the hype.

Resource: https://www.dolby.com/us/en/technologies/dolby-vision/dolby-vision-for-creative-professionals/dolby-vision-uhd-bluray-authoring-workflow.pdf

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For those who are still confused with the DV Profile layer - i.e. single vs dual layer. Just remember the following are single-layer profiles while the rest not listed here are dual-layer.

  • Profile 5 single layer with Dolby Vision-only support
  • Profile 8.1 single layer with HDR10 + Dolby Vision compatibility
  • Profile 8.2 single layer with SDR compatibility

For MKV media encoded by MakeMKV, most of the clips conforming to the single-layer DV Profile will work well with LLDV-based sources like Zidoo Z9X. The issue lies with dual-layer which contains both the base layer (BL) and the enhancement layer (EL). The EL portion with Full layer (or FEL) can be problematic for most LLDV sources. Hence, most encoding will be done at single-layer DV Profile as far as possible.

The most common type of dual-layer DV Profile is Profile 7 with either MEL or FEL. If it is FEL, then it might pose a challenge for LLDV source to playback properly. The issue is most of us prefer to do a 1:1 rip, This method of 1:1 ripping is the easiest as it retains all content in its entirety with the disc structure intact. It has been tested that Profile 7 with MEL is less problematic. An investment in HD Fury Vertex 2 (EDID manager) may help to resolve all these complicated issues with various EDIDs working to be compatible with the various DV Profiles. The Vertex 2 primary role is to spoof EDID to the LLDV-based sources to get the best PQ that a display can throw out. So if your TV or your sources are having a hard time getting a 4K HDR/DV encoded MKV files to work, you may wish to consider investing in a Vertex 2.

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This was very helpful, but I’m looking for info on Profile 8.4 and don’t see it listed. Dolby’s own site is full of marketing fluff and short on specifics.

I understand that 8.4 uses HLG rather than PQ, and also that the iPhone 12 Pro shoots video in Profile 8.4.

Yes that’s right. iPhone 12 Pro HDR is utilizing this Profile format. I’ve read that HLG no need to do post color grading which makes it suitable for point and shoot devices like iPhone. Expect more mobile phone manufacturers to follow Apple’s footsteps.

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Hello Desray, I enjoyed your article. It’s one of very few that delves into the different profiles of Dolby Vision, which I think is very useful. I was a tad disappointed though that you used a graphic that I made without any attribution. Would it be possible to add that after all, perhaps even with a link to the article you found it in? That would be much appreciated. Thanks.

My apologies…may I know which image you are referring to? I will add a source link to your site for sure :slight_smile: Usually I trawled the internet for reliable sources on a topic that interest me and then rehash or whenever possible summarize using my own words after doing some rumination work and fact-checking.

BTW welcome to the forum…looking forward to your posting especially on the 4K HDR, MKV profiles. :slight_smile:

Thanks desray. This post is super informative. So good.

Thanks!

Sure, it’s the one with the PQ10, HDR10 and four ST-2094 flavors. (All the other images are extracts from Dolby materials, I think)

You probably found it here:

Here’s a newer one that includes HLG, though I’m not sure if that connects better to your story:

or here

if you want my very latest take that includes Dolby Vision profile 8.4 I’d suggest using this one:

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Lastly, here’s an overview of all I’ve published lately, a lot of which is about HDR:

Cheers - Yoeri

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Thanks Yoeri for sharing. I will definitely take a look at those articles.

Cheers.

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Hello Desray,

I happen to read your very insightful article -

Demystifying Dolby Vision - Profile Levels, Dolby Vision levels, MEL & FEL

No one has simplified this subject all this while, so many thanks for your effort. Lovely article.

I do have a query -

If DV profile 5 (LLDV) is always only single layer (i.e. BL), and the ‘dynamic metadata’ is available always only on the EL then doesn’t that mean there is no dynamic metadata on the single-layer BL Profile 5 to process in the first place.

Please enlighten me in layman’s terms on this. Many thanks.

---------------------------------------------------------------------------------------------------
*Best Regards *
Jay Nihalani
Founder & CEO

Yes Jay, you are right, there is no Dynamic metadata to process for Profile 5 single-layer in this case. That is why we have LLDV. Recalled that I’ve mentioned 2 types of Dolby Vision - i.e. Full unadulterated Dolby Vision (DV) vs Low Latency Dolby Vision (LLDV). The key similarity between a single-layer (BL+RPU) and a dual-layer (BL+RPU+EL) is that the BL+RPU will always have HDR10 at 10-bit using HEVC H.265. So long there is a HDR10 BL, the display can still output DV in the form of LLDV as long as we can trick the EDID of the display into believing that. This is accomplished by using Vertex 2 or Diva from HD Fury which your company is carrying. The difference here is of course, the sources (e.g. bluray player, media player like Zidoo Z9X or even streaming devices like nVidia Shield Pro 2019 or Apple TV) will do all the “heavy-lifting” of the dynamic scene-by-scene as compared to the hardware-based Dolby Vision (DV) at the display level. Clearly, the latter will always perform much more efficient than a source-based DV (LLDV).

Hope that clears up your doubt?

TV-Led (Dolby Vision at the display end) vs the Player-Led (LLDV Dolby Vision at the source end)…and I totally agreed. Sadly for Projector users like us, only choice for DV is the variant called LLDV. Let Vincent explain…

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