Yes - it didn’t work. I reported back further up.
Let’s hope that the Win world adapts to compressed DNG format soon.
Pity. I seem to remember that it took MS a very long time to get File Explorer to, natively, display thumbnails of Canon RAW files. Prior to them finally fixing this, you had to download something from the MS Store (akin to the suggestion to try the JPEG-XL image extension). In other words, there’s hope that MS will eventually fix your problem but don’t hold your breath.
DxO support are working with me to try to resolve this.
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Yes, I wonder if DXO have also coded the internal jpg image, which programs display rather than decoding the raw , in Jpeg-XL to minimise file size?
I’ve downloaded PR6 trial, checked sample ‘High Fidelity’ DNG output from Nikon Z8 raw NEF (losslessly compressed) with exiftool. Quick and dirty investigations show that it’s purely Microsoft problem and I don’t see anything strange about DxO DNG packaging.
The main full-resolution 8256 x 5504 subfile of the PR6 ‘High Fidelity’ DNG (which is a TIFF with DNG-specific tags included) has the following key tags:
- SamplesPerPixel : 3
- BitsPerSample : 16 16 16
- Compression : JPEG XL (52546)
- PhotometricInterpretation : Linear Raw (34892)
So it’s JPEG XL compression for the main image data indeed.
The other two subfiles inside the DNG are:
- thumbnail, 258 x 172 pixels, uncompressed 8-bit RGB, 133,344 bytes
- preview image, 8256 x 5504 pixels, like the original raw, JPEG compression with PhotometricInterpretation = YCbCr, YCbCrSubSampling = YCbCr4:4:4 (1 1), 8,339,194 bytes.
To address @IanS post above, the preview image is a perfectly standard JPG file, with JFIF header, standard JPEG compression/encoding and so on. You can extract it using “exiftool -b -PreviewImage” and display it using Windows Photos app without any problems. I’m not sure why Windows Photos doesn’t display at least this preview image, when trying to display the DNG containing it and JPEG XL extension missing – the code for that is missing.
BTW, the “-JpgFromRaw” exiftool option doesn’t work, probably because it doesn’t consider linear DNG to be RAW.
Some background info: The original NEF was 61MB (45mpx, 14-bit losslessly compressed, shot at ISO 12k), while PR6.0 ‘High Fidelity’ linear raw DNG was 37MB in size, with the 8MB JPG full-resolution preview and a small thumbnail inside.
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I was using corollaries.
Put simply, DxO are using a defined standard. Every other bit of software you want to use also needs to be able to use the same standard. Adobe uses it. DxO uses it. macOS uses it. More besides use it. It is not some invention of DxO.
Microsoft Windows does not use it. It won’t until Microsoft implement it (or a third party can offer an extension of some kind).
JPEG-XL is also a standard that, apparently, Microsoft do not natively support. I would guess the extension you have installed enables JPEG-XL files but does not enable JPEG-XL compression within a DNG container.
DxO are working with me on this. It’s pretty clear to me that they think something is not quite right.
DxO are working with me on this.
Excellent information thanks for taking the time to investigate this. 
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DxO are looking at it using my files.
Yes, you are correct. Having looked further the extension, as you say, just enables working with files with the jpeg xl extension.
As Wlodek has found out the strange part is that the embedded jpg is normally encoded which is why I guess Faststone can display a thumbnail. Unless DXO have omitted a tag that Windows needs to display the embedded jpg thumbnail you have to wonder how long it will be for Microsoft to make a change? The best hope is a third party app. 
I’ve tested ‘High Fidelity DNG’ (“linear raw”) generated by PR6.0, Z8 NEF.
PL7.21 and Capture One 16.7.4 can open the DNG, PL7 with some usual limitations.
But RawTherapee 5.12, Darktable 5.4.1, and Affinity Photo 2.6.5 (non-Canva) can’t.
That’s with Microsoft JPEG XL extensions installed, if it matters.
As I keep saying, DxO are looking at this using my files. They clearly think that something is wrong and are looking for a fix.
For saying that so many people diss DxO support, I have to say that they have been fantastic so far, and this is my first time having to use them.
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It’s probably because it’s those who have problems that we hear the most.
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You are lucky, I got 1 month and a week.
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That feels very wrong
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Not sure to whom you are addressing this, but it is the very nature of forums that you get far more posts from people looking for help with the software than you do from people just there to sing its praises or to hang out. I’m not quite sure what the intention of this comment was - could you perhaps clarify?
If you were suggesting that I should not have raised my issue here, then perhaps you could explain why not.
Thanks.
Affinity Studio (V3) can’t, either, and I have reported the issue to them (asked for support to be added).
I’m just a fly on the wall and don’t mean to stick my nose where it doesn’t belong, but I’m pretty sure @Franky was referring to your comment here:
My understanding is that he’s explaining why there are so many complaints about DxO’s support in this forum, exactly to your point of:
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