https://bugs.kde.org/show_bug.cgi?id=425012
Bug ID: 425012
Summary: Color shifting / image degradation when importing clip
or extracting frame
Product: kdenlive
Version: 20.04.3
Platform: Fedora RPMs
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: Video Display & Export
Assignee: j...@kdenlive.org
Reporter: airfullb...@hotmail.com
Target Milestone: ---
Created attachment 130635
--> https://bugs.kde.org/attachment.cgi?id=130635&action=edit
Clip
SUMMARY
When I load a clip, its colors and sharpness as shown in the Project monitor
(with force monitor size = 100%) don't match what can be seen with an external
player (e.g. mpv). The colors are dull, the edges more blurry, and there are
some artifacts which are not there in the original clip. All of those problems
also show up in the rendering.
Even more degradation occurs when a frame is extracted. The png of an extracted
frame don't perfectly match the frame itself!
STEPS TO REPRODUCE
1. To create a short static clip, I displayed a 480x300 png image on my screen
and recorded it with ffmpeg:
ffmpeg -f x11grab -s 480x300 -r 30 -i :0.0 -c:v libx264rgb -crf 0
ffmpeg.x264rgb.mkv
2. While playing this clip with mpv, I extracted a screenshot. This is the
attached file ffmpeg.x264rgb.png
3. This png image matches the original png pixel for pixel. So this can be
taken as the original image.
4. I loaded the clip ffmpeg.x264rgb.mkv in Kdenlive and setup the Project
monitor at 100% and took a screenshot of it. This is the attached file
kdenlive.project_monitor.png
5. I also used the function Extract frame to project. This is the attached file
kdenlive.frame.png
6. I took a screenshot of the extracted frame as shown in the Project monitor:
kdenlive.project_monitor.frame.png
7. I have added the extracted frame in the project (file project.kdenlive).
OBSERVED RESULT
1. There are apparent differences/degradation in all kdenlive.*.png images
compare to ffmpeg.x264rgb.png (and com to kdenlive.project_monitor.png to
kdenlive.project_monitor.frame.png. For easy comparison, I have attached a Gimp
file with four layers : comparison.xcf.bz2
2. In the project, toggling on and off the visibiliy of the extracted frame
shows that the colors are shifting.
EXPECTED RESULT
1. All 4 images should look the same.
2. The image displayed in the Project monitor should match the underlying clip
/ extracted frame
2. Adding an extracted frame should not change the colors.
SOFTWARE/OS VERSIONS
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.70.0
Qt Version: 5.14.2
ADDITIONAL INFORMATION
Project settings were automatically adjusted at the moment the clip was added.
They are
Frame size: 480 x 300 (480:300)
Frame rate: 30 fps
Pixel Aspect Ratio: 1
Color Space: ITU-R 601
Interlaced: no
Is this a problem with wrong colorspaces ? If yes, how can this be solved ?
--
You are receiving this mail because:
You are watching all bug changes.
