SUMMARY
neofetch:

OS: KDE neon 5.27 x86_64  Kernel: 6.2.0-39-generic  Shell: bash 5.1.16  Resolution: 1920x1080, 1920x1080  DE: Plasma 5.27.10  CPU: AMD Ryzen 5 3600 (12) @ 3.950GHz  GPU: NVIDIA GeForce GTX 1660 Ti  Memory: 18739MiB / 31994MiB

Kdenlive: 23.08.4


Summary:

Kdenlive's timeline / entire UI becomes impossible to use for large projects.


Performance decreasers & possible causes:

Possible reasons for my particular project are:

- no loop function / mass clip group copy-pasted nodes

- mp3 files cannot be proxied / mass mp3 amount in project bin

- project contains 6 sequences of roughly 40min edited footage each, 1 extra main sequence that imports these sequences and adds background music using mp3s


Performance increasers:

I am barely using animations / transitions, FYI. Further, I have proxied pretty much everything in the entire project. Additionally, I have made sure to try and optimize Kdenlive settings for performance, i.e. disabling thumbnails for 90% of my editing process, modifying clips externally, disabling detrimental experimental features like GPU processing, disabling timeline autoscrolling, etc.


My workflow before the escalation:

When I say it becomes impossible to use I mean I have been editing more or less blindly ever since getting to hour 1 of my multiple hour long footage. I.e. I literally memorize the steps I am performing and perform them blindly while the UI needs usually around 30sec to 1min to catch up.


Why I made this report:

Issue #1

I have now gotten to the point where I am done editing ~5hrs of footage and would like to put it all together in a main sequence and overlay some music. You can image how long of a tedious journey I have come due to UI lagging and occasional crashes, occasional malfunctioning of the video preview etc. Precisely with the addition of a third song though Kdenlive has turned unusable. It now takes FROM A MINIMUM OF 2 UP TO 5 MINUTES to do anything at all. That includes simply clicking on a clip and loading it. Clicking on e.g. a mp3 to open context menu. Adding a keyframe to a loaded clip. Scrolling. Zooming. Clicking on any part of the UI, e.g. Help-menu.

My RAM usage is around 50-70% of 32GiB.

Issue #2

Now for the very fun part:

When I have the video preview running while doing anything else really, e.g. adding a keyframe, clicking on a clip to look at properties, trying to change master volume etc., Kdenlive hangs up entirely, does not ever stop playing the preview and RISES IN RAM USE BY 4-8% PER SECOND UNTIL THE ENTIRE SYSTEM CRASHES. I have been working on 99.7% RAM use for days and at this point I can never even look at the preview. So now I am quite literally blindly editing.


Please fix, I love Kden and I'd hate to choose another editor because of all this.

STEPS TO REPRODUCE
1. Make large Kdenlive project, length > 1hr
2. Let the preview run
3. Tab out / keep editing while the preview is running
4. Attempt stopping the preview by e.g. clicking on a timeline guide

OBSERVED RESULT
UI becomes hardly or entirely unnavigable (1-4hr project has up to 1min loading times per click, e.g. for adding a keyframe, project lengths above have up to 5 min of loading time, lowest being aounrd 2min).
Memory rises continuously until it reaches 100% cap.
App freezes completely. Becomes hardly or entirely unnavigable & unresponsive during the entire process (depending on project size).

EXPECTED RESULT
UI should continue to function at project sizes > 1hr.
RAM shouldnt be leaking uncontrollably.
RAM shouldnt be leaking just because the preview is playing. This works on pretty much all project sizes I have tried.
The preview should stop after a certain threshold to prevent this.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: KDE neon 5.27
KDE Plasma Version: Plasma 5.27.10

ADDITIONAL INFORMATION
https://www.reddit.com/r/kdenlive/comments/194qbs6/timeline_unbearably_slow_2min_per_click_vast/