Natron renders fail in Kubuntu 24.04

Software Natron
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1

Hello everybody! :slightly_smiling_face:
I’m kind of new to Natron and I’m mainly using it to add G’MIC filters to videos. While using Ubuntu I managed to do some successful renders. But since I switched to Kubuntu the renders always fail. Sometimes I get error messages, but most of the times I don’t. I tried all sort of combinations of render settings, codecs and file types, but the final result is always the same. The most successful try was outputting EXR files: I got 59 exr files in 50 minutes. After which the render failed :sweat_smile:
I don’t know what to do, maybe someone here could give me an advice?

TECHNICAL DATA
OS: Kubuntu 24.04
Natron version: 2.5, snap version installed with Discover (Software Center)
Processor: AMD Ryzen 7 5700G
GPU: NVIDIA GeForce RTX 3050/PCIe/SSE2 with 8 GiB of RAM
System Memory: 62,6 GiB of RAM
Original video: MKV file, AVC codec with Progressive High@L4 profile, video bitrate of 9000 kb/s, 23,98 fps, resolution of 1440×1080, color YUV 4:2:0 8 bits, duration of 25min 38sec, file size of 1.79 GiB.
Filter applied in Natron: Pencil Portrait from G’MIC, with standard settings.
Most succesful render settings: EXR files (Output Components = I unticked the Alpha Channel, File Colorspace = linear/Linear, Frame range = Manual, 500 frames; I left unchanged the rest).
Most common error message received: Read1 error: FFmpeg Reader Failed to flush the decoder of remaining frames: End of file

Thanks in advance for your help!
lymphor

2

Try converting the MKV file to an image sequence, and importing the image sequence in Natron instead of the MKV file.
Natron doesn’t like compressed video files, and generally you should use image sequences for compositing.
You can use FFMPEG CLI or something like Shutter Encoder to do the conversion.
Outputting as image sequence also gives you the freedom to “resume” a failed render from the last successful frame instead of restarting all the way from the first frame. So if you are getting 59 successful EXRs, I would delete the 59th one for safety and set the start frame to 59, then save project and restart Natron. Then when the render is run the next time, it will start from 59 instead of 1.
I should also point out that not all the GMIC effects work properly in Natron, so that could be the issue.