SUMMARY When the Audio Spectrum Filter is applied to the On Master effects list with a low Window Size, the spectrum visualization appears in the timeline preview, but does not appear in the video when the project is rendered. I don't know where the exact threshold lies, but I found that 256 was low enough to trigger the bug and 512 was high enough not to. STEPS TO REPRODUCE 1. Add an audio track to the timeline 2. Add an instance of Audio Spectrum Filter to the On Master effects list 3. Change the Window Size parameter to a low value (ex: 256) 4. Render the project OBSERVED RESULT The spectrum visualization is not present in the rendered video. EXPECTED RESULT The spectrum visualization is present in the rendered video. SOFTWARE/OS VERSIONS Windows: 10 Pro 22H2 19045.6332 macOS: (available in the Info Center app, or by running `kinfo` in a terminal window) Linux/KDE Plasma: KDE Plasma Version: KDE Frameworks Version: Qt Version: ADDITIONAL INFORMATION https://www.reddit.com/r/kdenlive/comments/1niq80b/help_audio_spectrum_filter_disappears_in_rendered/