CODEWITHSUNDEEP
colorscairomanim
Bachir Messaouri
Bachir Messaouri

Reputation: 784

Manim / Cairo : color discrepancies

I have some discrepancies in terms of brightness, saturation and hue when using a jpg picture in Manim.

I have a picture which color profile/space is Adobe RGB. I create it, edit it and save it that way. All of my apps previewing the picture are more, or less consistent with the original (enough to be acceptable). Including a movie export test from After effects. Even the image previewer of VS Code shows the image correctly. But when I render it with Manim, it's no good. Way too bright, oversaturated with a slight shift in hue and as if it was downgraded in terms of quality (some subtle but weird color artifacts are showing). You can tell something is off.

Granted, the picture I try to use is an abstract background with subtle gradients of color and light but still. The overall difference and loss in quality are sufficiently there not to be acceptable. I know that managing color spaces and profiles is a bit tricky and is an art in and on itself but the problem here is that the image is consistent everywhere so far but in Manim's rendered MP4 file.

The only thing I've seen in the doc related to color spaces is this parameter "image_mode". I tried to set it both to RGB and RGBA (only two options available) in the Manim script but it doesn't change anything.

I suspect it's a feature that is more related to the renderer (Cairo) or the MP4 export parameters than Manim itself or maybe it downgrades jpg to gif/png before it renders the picture in Mp4 ? I don't know and I don't know what to do with that anyway since I don't know how to parameter any of this within Manim itself. I can't see any parameters that allow to edit any of this in the doc. Maybe a plugin could add some functionalities or something ?

Any help would be appreciated.

PS: the picture is 4k and I render it in 4k in Manim, so it should be a pixel to pixel match.

Here is my Manim script:

from manim import *

class Graph(Scene):

    def construct(self):

        bg = ImageMobject("media/background/13.jpg")
    
        self.add(bg)
        self.wait()

And here are the relevant parts of my manim.cfg

[CLI]
write_to_movie = True
format = mp4
save_last_frame = False
write_all = False
save_pngs = False
save_as_gif = False
preview = False
background_color = #212021
background_opacity = 1
renderer = cairo
use_webgl_renderer = False
webgl_renderer_path = 
use_opengl_renderer = False
enable_gui = False
gui_location = 0,0
fullscreen = False
window_size = default
window_monitor = 0
force_window = False
use_projection_fill_shaders = False
use_projection_stroke_shaders = False
movie_file_extension = .mp4
frame_rate = 60
frame_size = 3664,1980
pixel_height = 1980
pixel_width = 3664
max_files_cached = 100
flush_cache = True
disable_caching = True
disable_caching_warning = False
enable_wireframe = False
dry_run = False
tex_template = 
plugins =

Upvotes: 1

Views: 260

Answers (1)

Uli Schlachter
Uli Schlachter

Reputation: 9867

TL;DR: Some random pointers, but no answer to the question.

I have no clue about manim, so I just went searching for "JPEG" in its source code. That brought me to https://github.com/3b1b/manim/blob/3c7a38660af41478e1561073a5319b23fb6b7787/docs/source/documentation/custom_config.rst#L59 which says

The directory for storing raster images to be used in the code (including .jpg, .jpeg, .png and .gif), which will be read by ImageMobject.

Okay, what's ImageMobject? Another search found the place where it loads images and apparently this just uses the Python library PIL to call PIL.Image.open: https://github.com/3b1b/manim/blob/669182944da040c227ccfd018250ee2bbc49649d/manimlib/mobject/types/image_mobject.py#L31

Okay, so does this support color profiles? I don't know. What does this question even mean? You are loading some color image that contains a color profile and it ends up being part of a movie... Should the movie now use that color profile?

Another random pointer that I found is PIL/Pillow decode icc profile information but that didn't really help. All I can say is: The manim code that I found doesn't do anything fancy with color profiles.

Upvotes: 1

Related Questions