Created attachment 160506 [details] Project with the issue SUMMARY When the timeline has text (dynamic text, title clip) the rendering fails (presumably) with QGuiApplication::font(): no QGuiApplication instance and no application font set. STEPS TO REPRODUCE 1. Create a title clip with some text 2. Add the title clip to the timeline 3. Make a preview render including the title clip OBSERVED RESULT Preview render fails when it gets to a part with the text EXPECTED RESULT Preview render succeeds SOFTWARE/OS VERSIONS Linux: 6.4.3-arch1-2 KDE Frameworks Version: 5.108.0 Qt Version: 5.15.10 MLT Version: 7.16.0-2 ADDITIONAL INFORMATION This issue doesn't happen when making a full render. I think the issue is upstream in MLT but I'm not certain. I'm not sure about the error message because "Show details" button works only sometimes for me. It could be an issue on my end due to possibly incorrect installation of fonts, but i didn't find any useful information online. I have attached a minimal project that reproduces the issue.
I can confirm that for appimage 23.04.2 and 23.08 beta, as well as for installed 23.04.3 (via kdenlive-stable ppa). Error message says: ``[swscaler @ 0x7f7ab48d8740] deprecated pixel format used, make sure you did set range correctly``. It doesn't matter which font is used or which preview render profile is defined.
Fixed now with this commit: https://invent.kde.org/multimedia/kdenlive/-/commit/3c93355a75dedc18700fd84003f7f54e44152c91 I will release a 23.08 beta2 appimage before next week so you can check.
(In reply to Jean-Baptiste Mardelle from comment #2) > Fixed now with this commit: > https://invent.kde.org/multimedia/kdenlive/-/commit/ > 3c93355a75dedc18700fd84003f7f54e44152c91 > I will release a 23.08 beta2 appimage before next week so you can check. Sorry about the delay. Just updated to 23.08.0 and preview renders seem to work fine. Thanks a lot!