CinemaDNG workflow for Blackmagic or Sigma FP cameras in Darktable

/dev/sdb1 2.2T 655G 1.4T 32% /storage

It should work, unless samples are getting real large :slight_smile:

Should be fixed, it now gives error that the sample already exists.

@andabata thank you!

@jedsmith now, could you please contribute the (new, full) entire sample set for that camera please? :slight_smile:

Trying to upload SDIM4591_6k_14bit.DNG from my google drive link to raw.pixls.us, I now get a more informative error message (thank you for fixing that!):

The file either already exists, the CC0/modified checkboxes weren’t checked, or you forgot to choose a file. Please go back and try again.

I assume that error message is showing because another sample from the Sigma fp already exists, so I can’t upload a duplicate. The existing file is here I believe: SDIM0094.DNG

I’m guessing you’ve uploaded SDIM4591.DNG? Thank you!

Oh nice, it looks like it went through despite the error message!

Hello again, I’ve made some test shots in CinemaDNG 3:1 and 1:1 from a Blackmagic Micro Cinema Camera (BMMCC) and struggling to upload them to the raw pixls database.

EDIT: Looks like they might have uploaded. I can’t see them in the database and the compressed (3:1) file didn’t get any comments or anything filled in.

They have to be approved before they show up, I believe.

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I only see one pending upload for Micro Cinema Camera, CAM1_2000-01-01_1659_C0002_000100.dng, so i guess they didn’t upload after all?

I’ve also just uploaded a 3:1 compressed DNG that I took yesterday. It looks like it went through.

@independent Ok, i guess i’ve found that upload too, verified both uploads, thank you for contributing the samples!

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Reading this: Cinema Raw : Shooting and Color Grading with the Ikonoskop, Digital Bolex, and Blackmagic Cinema Cameras by Kurt Lancaster.

There’s a pretty interesting quote in it from the early days of BMPCC.

Because the Pocket camera records to an SD card, filmmaker Marco Solorio of OneRiver media wanted to know more about how Blackmagic Design could create a raw camera in such a small package. He interviewed Grant Petty, founder and CEO of Blackmagic Design at the industry trade show, NAB, in Las Vegas, April 2013. Petty explained how they were able to get raw CinemaDNG onto an SD card at 24 frames per second, but ran into issues at 30 fps. They really wanted to do raw, so they went back to the CinemaDNG spec sheet. They discovered that not only was there uncompressed raw that they put into their 2.5K Cinema camera, but there were two compression types for 12-bit raw CinemaDNG. Petty explains:
There’s a lossless compression (which is about 2.5:1 to 1.5:1—that’s not very much compression—it’s mathematically clean, It’s perfect). And then there’s a slightly lossy version, which is like a variation of jpg—it’s visually lossless; it’s very clean—and of course you’re still getting 12 bit raw, so it’s awesome. … So we’ve decided to Implement those standards. Blackmagic Design had actually developed their own 3:1 compression codec, but they decided to stick with the open standard of CinemaDNG. The Pocket Cinema Camera (BMPC) contains the CinemaDNG lossless compression, while they added the “slightly lossy” DNG codec to their 4K camera in order to keep the data rate down. Petty claims that, “[m]ost people are going to find that you cannot tell the difference” between the compressed CinemaDNG and the uncompressed. Furthermore, Blackmagic is also developing a QuickTime wrapper for the CinemaDNG format. “What we want to do,” Petty says to Solorio, “is to save the DNG into the QuickTime movie. That would potentially let us decode and read the files. We’ll make it a QuickTime movie, but it’s actually CinemaDNG inside—so that would be much more readable by Final Cut Pro and other applications like Premiere Pro.”

Thing is, there is no such thing in the CinemaDNG spec sheet as far as 12-bit JPEG extensions, nor in the original DNG spec sheet.

It’s a proprietary Blackmagic thing in the description near the bottom of CinemaDNG - Wikipedia

Of course the interesting thing is that now DNG 1.7 supports JPEG XL, which I think is going to be the killer app for JXL.

The DNG spec allows only for lossless JPEG when it comes to raw, at any bit depth (and is what is likely to be implemented at some point). The lossy (3:1, 4:1) 12-bit JPEG for raw was never in the spec indeed.

Yup. Lossy mandated 8-bit JPEG until 1.7 with the advent of JXL.

Of course it’s best described as “pseudo-raw” since it’s demosaiced but not color-converted, which also happens to be a solid way to work around RED’s pesky patent.

FWIW Blackmagic removed CinemaDNG from cameras they could move on to BRAW. It’s not currently supported by them AFAIK (except in Resolve). I think that the BMPCC4K had an even more compressed version of CinemaDNG before the switchover to BRAW in firmware 6.1 (I think).

I just corrected my post and left out some unnecessary commentry

Does anyone have access to a camera that produces that new raw format?
It would be rather awesome if someone could contribute the appropriate sample set.

This is what I found about BRAW:

Blackmagic RAW is defined as an Open Standard because it is cross-platform and open for anybody to include in their products/develop with using our free SDK. You can find all the information on Blackmagic RAW including drivers, manuals, the SDK and the player at our developer website: (/developer/product/camera)

In my post above I meant to say the CinemaDNG format was what they abandoned. However, there are still many older cinema cameras that shoot in CinemaDNG and several contempary cameras. Many people love CinemaDNG :smiling_face_with_three_hearts:.

From what it sounds like, a tricky thing as well, is there are differences between Sigma FPs CinemaDNG files and their stills DNGs. So, the Sigma FP DNGs can be read by Darktable and not the CinemaDNGs it produces.

Is there a chance CinemaDNGs (CDNGs) can be supported by Darktable? Would even having a toggle based system (tickbox, only loading CDNGs for instance) to separate all the noise the CDNGs create when trying to figure out what DNGs belong to what camera?

Again, this a wide term. What do you mean specifically? We have established there are (at least?) three kinds of “CinemaDNGs”:

  1. Uncompressed, as written by Sigma fp (i.e. not different to any regular DNG/TIFF) - already supported

  2. Lossless compressed, as written by Blackmagic, Magick Lantern FW on Canon cams, recently DJI drones and possibly others - it looks like this is becoming a more realistic goal thanks to recent efforts by @LebedevRI

  3. Lossy 3:1/4:1, as hacked by Blackmagic - although the tech is there (libjpeg-turbo 3.x now has support for 12b), it might take a while to put all together because it is an ugly hack breaking the DNG spec, which probably means ugly workarounds in darktable/RawSpeed (not impossible, but would need a strong motivation to do, if @LebedevRI is at all willing to consider it)