Improve HDR —> SDR tonemapping

[SpykeSIK]

Hello,
I’m testing latest Apple TV 128Gb with infuse as replacement to my android device. I really like Infuse interface and it is true that it is fast and intuitive, but i have some problem with the most important thing for the player - picture quality.

I noticed that HDR to SDR tone mapping looks really bad in comparison to other competitors. It has significant loss of details and some problem with color gradation in red, yellow and green colors. Also it has some strange saturation bugs.

I did many comparison screenshots through my capture card to show the difference between my current player and Apple TV with latest version of infuse.

I’m a new user and can’t upload screen to my topic. First pic is always Apple TV and second the other player.

Here’s comparison screens

As you can see there is something definitely not right with red, yellow and green color gradation.

I can live without bitstream audio and other stuff, but quality of video playback is the main feature of any media player. And current implementation of tone mapping definitely needs some rework.

[AlexxxDee]

Hello.
I confirm the existence of these problems. I own an Apple TV 4K of all three generations. I have seen the problems indicated by the author on all of them.
As far as I understand, players with VS10 support do tonemapping correctly, without these problems.

When disabling VS10 algorithms, problems are present on all media players. This means that the problem is software-based and is solved with the help of software.

If infuse fails to fix this problem, I suggest considering the possibility of introducing VS10 algorithms into infuse.
Or, try sending a ticket to Apple from the FireCore developers to solve this problem.
@james, please pay due attention to this topic. Thanks.

[ARM697]

Infuse HDR to SDR tone mapping needs some improvement.

[SpykeSIK]

More examples:

[Natty]

What player are you comparing InFuse to?

I would not expect InFuse to do dynamic tone mapping or frame by frame (or even scene by scene) analysis…though that would be very cool!

But I would expect InFuse to follow the PQ EOTF up to 100 nits in the original signal, to track the SDR section of the signal accurately, kind of like the Panasonic disk players do.

[SpykeSIK]

@Natty

What player are you comparing InFuse to?

It’s a Zidoo Z9X Pro, which has much slower SOC than Apple TV. 2 days ago i received new Dune 8k+ and it has exactly the same tone mapping with VS10 as Zidoo. No difference at all. So problem with tone mapping of infuse is not hardware, but software side.

[blipoids]

What is this HDR to SDR tonemapping in Infuse? Is this something you can turn on? What are the uses of it?

[SpykeSIK]

It’s useful If you have projector, 1080p SDR TV or 4K TV with bad internal tone mapping.

[Natty]

True. It is particularly useful for projectors. Even those that claim to support HDR typically a better tone mapping solution is to convert to SDR in the player.

Of course, the conversion between REC2020 and REC709 color space may be much of the issue that we are seeing here.

[Natty]

@SpykeSIK

Zidoo Z9X Pro

Thanks for the tip.

[SpykeSIK]

Dolby Vision/HDR10 to SDR tonemapping is still very bad.

[james]

This is not something we are seeing here, but to get a better idea of whether this is an issue with Infuse or something that is affecting all output from the Apple TV you may consider comparing picture you see in Infuse to what you see when playing the same videos through the Computers app.

If you are seeing a difference there, it may be helpful to learn a bit more about the content type you are playing, the video settings on the Apple TV, and the type of hardware the Apple TV is connected to.

You may also try adjusting the ‘HDMI Output’ and ‘Chroma’ options found in the Apple TV > Settings > Video and Audio menu to see if this provides an improvement (or change) in what you are seeing.

[Natty]

I infer the OP was comparing this not with other AppleTV playback options but with OTHER tone mapping solutions in the market, based on the screen shots they have linked to.

@james

This is not something we are seeing here, but to get a better idea of whether this is an issue with Infuse or something that is affecting all output from the Apple TV you may consider comparing picture you see in Infuse to what you see when playing the same videos through the Computers app.

If you are seeing a difference there, it may be helpful to learn a bit more about the content type you are playing, the video settings on the Apple TV, and the type of hardware the Apple TV is connected to.

You may also try adjusting the ‘HDMI Output’ and ‘Chroma’ options found in the Apple TV > Settings > Video and Audio menu to see if this provides an improvement (or change) in what you are seeing.

[james]

I understand that, but there are many variables at play here and all of these can have an impact on the result you see on the TV.

• Video type
• Apple TV app (EG Infuse vs Computers)
• Apple TV settings
• HDMI cable
• Other intermediate device(s) and settings (EG AVR receiver)
• TV model and capabilities
• TV HDMI input settings
• TV picure settings

This gets even more complicated when you introduce another 3rd party device and attempt to compare playback to that, so I am trying to gather more info on which of these variables may be affecting the appearance of these videos and which (if any) can be improved.

[Axl2021]

James hello.
Under the same conditions, the same video files are played on two media players. One Apple TV 4K + infuse, the second Zidoo/Dune + VS10.
If VS 10 is disabled in the Zidoo/Dune media player, then tonemapping works the same way as in Apple TV 4K + infuse.
The question is whether you can fix the tonemapping in infuse and/or add VS 10 algorithms to infuse, as they did in the Zidoo/Dune media players.

[james]

Renamed and moved to suggestions.

[Natty]

Makes sense to call this a suggestion for new functionality.

Since the op was posting about HDR to SDR conversion, and the examples given reflect systems that allow user adjustment of that process, I am curious whether this is something that has been explored already?

[Natty]

An intrepid user over at AVS has done some detailed analysis of how the Apple TV converts HDR to SDR (and DV to SDR).

Since they used Infuse to do the analysis, I figure it may be appropriate to share here?

This is not an indictment of Infuse, since IIRC Infuse simply uses the toolkit Apple provides for this? On the other hand, this topic is about offering different tone mapping of HDR to SDR than what currently exists in Infuse, so IF Infuse were to offer custom or bespoke tone mapping to SDR gamma and the option of keeping REC2020 color or mapping to 709 color, this data might be useful?

https://www.avsforum.com/posts/63404359/

Blockquote
First HDR10, then DV Profile 5. The digital capture analysis is done using RGB High output from an ATV4K Gen3. [the rest of this post is a quote as well but I don’t know how to indicate that here]

For HDR10, here’s the tone curve for 1000-nit content, leveling out at 973 nits:

Looking at ~17,000 colors outside of the BT709 subspace of BT2020, there’s clipping to the BT709 gamut:

Sampling some of those, there’s no attempt to maintain hue:

The white lines start at a source color and end at the corresponding output color (colored dot).

Given the tone mapping, for color accuracy I’m ignoring any luminance errors and calculating dEITP without factoring in luminance differences. Using ~19,000 colors within the BT709 subspace, average dEITP is 4.3, std dev 3.5, max 28.2.

Here are colors with dEITP <= 1:

Here are colors with dEITP > 1 and <= 3:

Here are colors with dEITP > 3:

Overall, the colors are oversaturated. Here’s an example slice at a lower luminance:

But there are marked changes for the worse along the blue-magenta-red edges at higher luminances:

---

They also did a similar analysis for Dolby Vision conversion to SDR by the Apple kit, but I’ll pause quoting their analysis for now. (The link to it is at the start of this post.)

[chronomac]

Any update on this? I started watching HDR-to-SDR tonemapped movies on my Sony XW5000ES projector and noticed that Infuse is not capturing information in highlights properly and it’s pushing red and orange a bit too.

[SpykeSIK]

I think infuse team is easier to use the Dolby SDK (Dolby VS10) for that purpose. Their latest SDK is much better with Dolby Vision to SDR tonemapping. We’re still waiting for a good news.