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Using Magic Lantern => Raw Video => Raw Video Postprocessing => Topic started by: harkr on February 10, 2021, 03:19:36 AM

Title: MLV App: MLV -> DNG completely different colors?
Post by: harkr on February 10, 2021, 03:19:36 AM
Hello there,  I've been trying to find some clue to help me solve this issue.  My searches on this forum seemed fruitless.  Would very much appreciate any help or advice!

I'm using MLV App to convert MLV files from a shoot to DNGs for color grading in Davinci. My DNGs, when exported, are coming out very blue! They look completely different from the images I'm seeing in MLV App.  In fact, it seems like no matter what changes I make to the color space in the Edit Window within MLV App, the exported DNGs always look the same: weirdly tinted blue...

This issue only seems to happen when exporting to DNG.  If I attempt to export MLV to ProRes for example, the ProRes files come out looking correct.

Here are some screenshots for reference:

Here's the image I'm seeing in MLV App:
(https://www.magiclantern.fm/forum/proxy.php?request=https%3A%2F%2Fi.imgur.com%2FfKM8NRI.png&hash=4646144aed2b5f5d27d762c9e39296bf) (https://i.imgur.com/fKM8NRI.png)

Here's what the same image looks like when I export it to DNG:
(https://www.magiclantern.fm/forum/proxy.php?request=https%3A%2F%2Fi.imgur.com%2F8qfMJKO.png&hash=a6ef229bff9743ed96a593fd51d41d3f) (https://i.imgur.com/8qfMJKO.png)

Has anyone heard of a problem like this before?  Would appreciate ANY help or ideas.  Thank you very much.
Title: Re: MLV App: MLV -> DNG completely different colors?
Post by: masc on February 11, 2021, 06:25:07 PM
You have to process RAW data. MLV is RAW and DNG is also RAW. When exporting DNG, all settings you did in MLVApp are NOT exported, becaues DNG is not processed RAW data. When processing, you have to setup all necessary parameters, like exposure, white balance, and many many other parameters depending on the software you use. With default parameters (different in all applications) you will get very different results - nothing new.
Title: Re: MLV App: MLV -> DNG completely different colors?
Post by: Levas on February 11, 2021, 08:26:51 PM
When using DNG's sequences in DaVinci Resolve, you can edit the raw parameters in the camera raw tab, it is within the 'Color' window, you have to click the camera icon on the left of the screen.
In here you set the raw paramaters like; white balance, exposure etc.
See left lower border of this screenshot:

(https://www.magiclantern.fm/forum/proxy.php?request=https%3A%2F%2Flive.staticflickr.com%2F65535%2F50932768563_9887cdca22_o.png&hash=eb03f2f7f765b47f1f075aa103c0747c)
Title: Re: MLV App: MLV -> DNG completely different colors?
Post by: harkr on February 12, 2021, 12:08:32 AM
Thank you!  Just to clarify: this issue of blue DNGs is not occurring for all of the shots I recorded, only some of them.  The rest of the shots look neutral/normal when exported as DNG through MLV App.

The reason it's troublesome is that it complicates the process of matching the look/color between shots in Davinci.  The colorist I've been working with is having trouble reconciling these inexplicably blue images with the more neutral ones.  It's like the DNGs are coming out of MLV App with some weird blue LUT applied...

Title: Re: MLV App: MLV -> DNG completely different colors?
Post by: Danne on February 12, 2021, 04:05:15 AM
The blue tint is what kelvin was set to in your camera. You probably were recording using auto white balance, AWB. This setting can't be translated into the correct raw metadata so kelvin temperature will instead be applied. Long story short. Use any white balance routine in camera but awb to get control over the dng files. Skip using AWB.

If you want to match dng metadata you can do this in post with exiftool. Grab the As Shot Neutral tag from the dng looking correct and use it to overwrite the blue looking dng files.

You can post two dng files here. One "correct" and one with blue tint and I show you what to do.

Some programs do apply awb externally to your dng. This could also work. For instance this program(Mac only).
https://bitbucket.org/Dannephoto/switch_mini-git/src/master/
Title: Re: MLV App: MLV -> DNG completely different colors?
Post by: harkr on February 15, 2021, 10:08:34 PM
The blue tint is what kelvin was set to in your camera. You probably were recording using auto white balance, AWB. This setting can't be translated into the correct raw metadata so kelvin temperature will instead be applied. Long story short. Use any white balance routine in camera but awb to get control over the dng files. Skip using AWB.

If you want to match dng metadata you can do this in post with exiftool. Grab the As Shot Neutral tag from the dng looking correct and use it to overwrite the blue looking dng files.

You can post two dng files here. One "correct" and one with blue tint and I show you what to do.

Some programs do apply awb externally to your dng. This could also work. For instance this program(Mac only).
https://bitbucket.org/Dannephoto/switch_mini-git/src/master/

Very much appreciate your help, Danne!  I bet you are right about the AWB.  I tried to run switchmini but can't tell if I'm using it correctly.  When I run it, nothing seems to happen... but I could definitely be making a mistake.

Here are a couple of the DNG files.

The first one has the blue AWB issue: https://www.dropbox.com/s/3gdf2ocrgspmfbo/M20-1539_frame_1.dng?dl=0 
The second one is a more neutral look: https://www.dropbox.com/s/jgyj716rzrmmk82/M21-1521_004916.dng?dl=0 

If you have time, would truly appreciate any granular advice about how to overwrite the metadata tags. I've never used exiftool before. Thank you so much.
Title: Re: MLV App: MLV -> DNG completely different colors?
Post by: Danne on February 16, 2021, 08:13:16 AM
Try and install exiftool in terminal with
Code: [Select]
brew install exiftool

If brew isnĀ“t installed you can get it here:
https://docs.brew.sh/Installation

Finding your as shot neutral tag in terminal with:
Code: [Select]
exiftool M21-1521_004916.dng | grep 'As Shot Neutral'Gives me this:
Code: [Select]
0.4757272085 1 0.6440925123
Then add this to the blue tinted file:
Code: [Select]
exiftool "-AsShotNeutral=0.4757272085 1 0.6440925123" M20-1539_frame_1.dng -overwrite_original
Now we get this difference:
(https://www.magiclantern.fm/forum/proxy.php?request=https%3A%2F%2Fi.postimg.cc%2F1RbhRMR3%2FSka-rmavbild-2021-02-16-kl-08-08-03-png-500px.png&hash=6c97a0d37ca7c968eacef55decc41440)

After adding the corrected tag.
(https://www.magiclantern.fm/forum/proxy.php?request=https%3A%2F%2Fi.postimg.cc%2FbYZfj4h5%2FSka-rmavbild-2021-02-16-kl-08-08-12-png-500px.png&hash=2284861b3e381e550c9c63e17cc16f3f)

Finally you can use this to add the corrected tag to all dng files inside a folder:
Code: [Select]
exiftool "-AsShotNeutral=0.4757272085 1 0.6440925123" *.dng -overwrite_original

Maybe a lot to learn here but start with small steps. If you want more help around switch mini I suggest you post a screen recording of what you are doing for it not to work.

Title: Re: MLV App: MLV -> DNG completely different colors?
Post by: harkr on February 17, 2021, 05:49:17 AM
This worked!

Thank you so much for your help.
Title: Re: MLV App: MLV -> DNG completely different colors?
Post by: ljglmail on January 02, 2022, 08:15:31 AM
Hello,It is good to hear that you are satisfied with the performance of MLVApp.Many photographers use RAW format because it is a high quality file format. However, you have to process RAW data in order to get a high quality photo.

RAW data is processed by the camera itself. So, you do not need an additional software for processing RAW files.

MLVApp does not process RAW files. It processes DNG files which are converted from RAW data. When exporting DNG, all settings you did in MLVApp are NOT exported, becaues DNG is not processed RAW data.

So, if you want to export a photo in high quality, please shoot in RAW format and then process it with an external software that supports RAW format such as Adobe Lightroom or Adobe Photoshop.

We hope this information helps you.Looking forward to hearing from you again soon!