What's the actual error message when you do the import? If there's no graphical error, try launching it from the terminal and check the messages in the terminal when you try to import the video.
There is no KDEnlive community yet but
And maybe in the future
run mediainfo on the video and send it. Im not sure if flatpak has a codecs package but you may need that.
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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).
Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.
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