Created attachment 186633 [details] observed result screenshot SUMMARY Unchecking the "Proxy Clip" box undoes desired duration of low Playback Speed clips in the timeline. STEPS TO REPRODUCE 1. Download project: https://drive.google.com/drive/folders/1ePmXX3tAwtdBzY_5_Ne5uhk8IL9PgasG?usp=sharing 2. Open "test before.kdenlive" 3. Right click the mp4 file in the Project Bin 4. Uncheck "Proxy Clip" OBSERVED RESULT The clips in the timeline are normal duration with slow speed instead of being longer duration due to their slower speed. Screenshot: https://drive.google.com/file/d/19hFBjMdIl44YzGwvI6zJKbdUEM7wQTRd/view?usp=drive_link EXPECTED RESULT The clips should still be at slow speed. SOFTWARE/OS VERSIONS Operating System: Kubuntu 25.10 KDE Plasma Version: 6.4.5 KDE Frameworks Version: 6.17.0 Qt Version: 6.9.2 Kernel Version: 6.17.0-6-generic (64-bit) Graphics Platform: Wayland Processors: 12 × AMD Ryzen 5 2600 Six-Core Processor Memory: 16 GiB of RAM (15.0 GiB usable) Graphics Processor: NVIDIA GeForce RTX 2080
Thanks for your detailed report. I can confirm that enabling or disabling proxy on a clip resets its duration when it has a speed change, working on a fix.
Git commit e3375afd441c1c981b922c84f45c60da43d97d2f by Jean-Baptiste Mardelle. Committed on 15/11/2025 at 15:58. Pushed by mardelle into branch 'release/25.12'. Fix proxying changing timeline duration of clips with speed change FIXED-IN: 25.12.0 M +1 -1 src/timeline2/model/timelinemodel.cpp https://invent.kde.org/multimedia/kdenlive/-/commit/e3375afd441c1c981b922c84f45c60da43d97d2f