New "JNG" container proposal (original JPEG + adjusted preview JPEG in 1 file as in DNG)

[BorisKvid]

Hello, I just converted my raws to the DNG format. Because I prefer to browse my images in XnView and not in a heavy application like Lightroom, the only reason for my move were the embedded preview JPEGs that (in DNG) can contain the adjustments I've done. My XnView is set to display the embedded 1:1 preview image, so after the conversion I can now browse 'pictures' instead of 'negatives'. Fantastic.

It would be extremely useful to have such an "adjusted-preview" feature for JPEGs as well. Unfortunately, the JPEG thumbnails can't be used for this, and if a JPEG is converted to DNG, the resulting file is approx. 7x larger than the original JPEG. The original JPG-compressed file is thrown away and replaced by a compressed TIFF in the container, making the whole idea of converting JPEGs quite absurd. My Fuji F30 unfortunately never supported RAW...

I propose to create a new image format - let's call it JNG - that would be a simple container that would contain the original JPEG and *could optionally* contain an adjusted JPEG as well. The user would then set his image browser to prefer to display the adjusted JPEG (if available) similarly to choosing between rendering actual RAWs or displaying  JPEG previews for RAW files.
As opposed to DNGs 7x size, the proposed JNG would only be max ~2x larger, wouldn't force you to convert your original JPG to a compressed TIFF, and for non-adjusted files, it would actually be the same size as the original JPEG (1x)!

What do you think?

An alternative would be to update the DNG standard to allow complete compressed JPEGs files (i.e. including metadata, for easy extraction) to act as 'raw' data in a DNG. This would be quite complex, because the spec would e.g. have to resolve the duplicate metadata issue (DNG EXIF would have to point to or carbon-copy the JPEG EXIF etc.). Creating "JNG" spec from scratch would be incomparably simpler in that regard. A guy like Phil Harvey could have it done in a day (and avoid stupidity
http://www.sno.phy.queensu.ca/~phil/exiftool/standards.html
http://www.sno.phy.queensu.ca/~phil/exiftool/commentary.html

[Schewe]

What do you think?

Great, just what the world needs...ANOTHER file format.

It would be far easier (and better in the long term) for JPEG viewers to be able to see and read the embedded .xmp image adjustment metadata and rip a fast preview...otherwise, why not just render out a new rendered file?

[NikoJorj]

The original JPG-compressed file is thrown away and replaced by a compressed TIFF in the container, making the whole idea of converting JPEGs quite absurd.

I'd think you already got the point?  
Bottom line : a jpeg image is made for viewing, not for additional treatment.
As capable as your f30 is, you may do yourself a favor treating yourself with a raw-capable camera. Christmas is coming.  

And as Jeff said, we don't want neither another image format nor another format possibility into the DNG standard (for me, I'd say the possibility of a rendered linear DNG is already confusing enough).

[EduPerez]

If I understood your post correctly, the core of the problem you are trying to solve is that your camera does not support RAW, isn't it?

[BorisKvid]

Thanks for your replies. Of course I shoot RAW now. The problem is my collection of JPEGs from up to 10 years ago with which I'd like to have a nicer workflow outside of LR. Rendering the adjustments on the fly would be good, but still slower than reading a ready rendered image. And rendering everything out as Jeff suggests would be a pain to manage. I'd have 2 files and would have to cripple the original JPG extensions so that they're not picked up by the viewer, and individually rename back files when I'd like to work on them. That's frustrating IMO.