Chronos > Chronos User Discussion
Unbalanced colors in .dng, .mp4 files
mtrovato:
Dear all,
images look nice when viewing from the camera. However, the colors of .dng (and .mp4) files are completely unbalanced when opening them offline with editors like preview (macOs) or shotwell (centos7). After adjusting the colors images look decent. See an example here: https://anl.box.com/s/r0z9z2a5hczfgywobr0ekr3kkoa5wtfo
Is the color profile embedded in .dng and .mp4 files? If so, which software should I use to open them? I am guessing that it is a problem of software interpretation
Thanks
Best,
Marco
Nikon1:
Short on time rn, so i just leave this here, hope this helps any, else just post any left over Questions again:
https://forum.krontech.ca/index.php?topic=687.msg4734#msg4734
(LUT is for 0.7.0, meanwhile 0.7.1 is released, in which the Color was somewhat fixed/ changed/ improved, so might not work anymore/ as well, but you can easily make you own LUT with a Color-Checker)
mtrovato:
Thanks. I have no experience with DaVinci Resolve or similar softwares but I will dig into it. In any case I gather from your answer that indeed an offline correction (LUT) is needed
Meanwhile I was able to adjust the photo brightness and achieve similar results as shotwell by the simple script below
import cv2
import numpy as np
def change_brightness(img, value=30):
hsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
h, s, v = cv2.split(hsv)
v = cv2.multiply(v,value)
v[v > 255] = 255
v[v < 0] = 0
final_hsv = cv2.merge((h, s, v))
img = cv2.cvtColor(final_hsv, cv2.COLOR_HSV2BGR)
return img
img = cv2.imread('./frame_notadjusted.jpg')
img = change_brightness(img, value=5)
cv2.imwrite('ColorAdjusted_py.jpg', img)
Nikon1:
--- Quote from: mtrovato on April 14, 2022, 08:06:53 AM ---Thanks. I have no experience with DaVinci Resolve or similar softwares but I will dig into it.
Meanwhile I was able to adjust the photo brightness and achieve similar results as shotwell by the simple script below
import cv2
import numpy as np
def change_brightness(img, value=30):
hsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
h, s, v = cv2.split(hsv)
v = cv2.multiply(v,value)
v[v > 255] = 255
v[v < 0] = 0
final_hsv = cv2.merge((h, s, v))
img = cv2.cvtColor(final_hsv, cv2.COLOR_HSV2BGR)
return img
img = cv2.imread('./frame_notadjusted.jpg')
img = change_brightness(img, value=5)
cv2.imwrite('ColorAdjusted_py.jpg', img)
--- End quote ---
Can you explain whatever is happening there? I on the other Hand probably know less about code than you about Editing Software, but just from looking at it, is this basically just some kind of Color Space Conversion from HSV Color Space to RGB Color Space or something? If that seems To fix the Problem you are having, that might be a clue to what is wrong in the Color Science of the Camera? would be worth looking into at least, i guess.
Thanks however for Sharing anyways, even though i have no clue at all of what i am looking at.
mtrovato:
--- Quote from: Nikon1 on April 14, 2022, 08:13:09 AM ---
Can you explain whatever is happening there? I on the other Hand probably know less about code than you about Editing Software, but just from looking at it, is this basically just some kind of Color Space Conversion from HSV Color Space to RGB Color Space or something? If that seems To fix the Problem you are having, that might be a clue to what is wrong in the Color Science of the Camera? would be worth looking into at least, i guess.
Thanks however for Sharing anyways, even though i have no clue at all of what i am looking at.
--- End quote ---
Sure I can. Basically I am retrieving the brightness from the HSV color space of the photo, multiply by 5 (eyeballed value to get similar results if compared to shotwell output) and save the modify image. I have done something similar in DaVinci Resolve: I have reduce the brightness range in the Colors/Curves - Custom and I get nice results (see Keys.mov in the same folder)
I am bit puzzled by your answer though, as it seems that my camera may have issues. As far as I understand from this thread prior to your last answer is that LUTs are needed to correctly view .dng/.mp4 files. This is not a bug in the camera but rather a compatibility issue between the camera and the offline software (shotwell/DaVinci, etc...). Also live videos/photos appear very nice on the camera screen
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