DNG Sequence Blurry at High Resolution

[Tim Fraser]

It appears that after converting my NEF files from my V1, Adobe DNG converter inserts a thumbnail into the DNG file. The thumbnail has been verified as 256×171 by a colorist in California, hence why the footage resolve shows is this measly res.

Although Davinci Resolve has been said by their support people not to support a directory of seqential DNG files, Resolve does actually play the clip, perform grading, even outputs the results “deliver”, however they are unfortunately correct in saying to me on blackmagic forum that Resolve defaults to the lowest resolution image in each DNG file when dealing with sequential DNG images.

My conclusion, is that if we find a way to convert from NEF to DNG file without having the thumbnail embedded, or find a utility to remove the thumbnail after conversion, then we could have our cake and eat it!

Tim

[Tim Fraser]

see previous post also!

I wondered about the structure of DNG files and if I could potentially alter the embedded recorded res size of the thumbnail (to say 4500 x 4500) it might trick Resolve into seeing the thumbnail res as larger than the V1 raw res of 3872 x 2592, then the raw res would be the smallest, so Resolve might use that raw image instead.

I could use a hex editor directly on the binary DNG file, but would need to find out which part of the file the thumbnail res info might reside, and if the thumbnail res info exists in addition to the actual pixel data of the thumbnail.

I have located a hex editor that records macros and performs batch operations so in theory would do a whole directory of images in one go Hoping to make progress but would appreciate any help in making sense of DNG file binary strucure!!

[Daniel Lama]

I did it!!!
converted to dng in lightroom, but before i did it i went to preferences and disabled the creation of jpg thumbnails. I imported the sequence into davinci and it recognized as a cinema dng file 4928×3264 px.

[Tim Fraser]

Well done! I didn’t know Lightroom has that feature.

Now I believe Resolve 10 beta lite (newly available) allows for higher resolution delivery (output) than 1080p, so you may now be able to output higher res for web.

While I believe even Vimeo Pro only allows 1080p, I think youtube allows far more, and while you have to put up with their compression. The resolution will likely shine though.

If you put up any high res footage, please share it with us.

In the intervening time since the last posts, I heard news that Resolve has been updated to handle sequential DNG’s and should handle those in the same folder as a movie clip. I never got this to work myself as yet, but now for those without Lightroom or those wishing to use free products, using Adobe free Raw2Dng converter should prepare clips for Resolve. The only workflow I managed was via sequential tiff’s into Resolve, using Nikon ViewNX.

If only Nikon V1 allowed 6-7 seconds of raw 🙂

Tim