Terje, to fix the below plugin errors, you will have to modify cinelerra-5.1/ffmpeg/plugin.opts for your specific ffmpeg version since it will be different from everyone else when using your O/S version. Since you have successfully completed the build, you can just modify cinelerra-5.1/bin/ffmpeg/plugin.opts instead. This file is a blacklist and it is self-explanatory when you look at the last few lines of the file. Just add # lines for each of the error plugins. For example, add: #lv2 and #sofalizer, etc.

You can just ignore these errors, BUT sooner or later you will get a plugin error that will prevent CinGG from executing.

build plugin index for: /home/cinelerra/cinelerra-5.1/bin/plugins
PluginFFilter::new_ffilter(lv2)
err: Operation not permitted
[sofalizer_205 @ 0x3f0f2940] Valid SOFA filename must be set.
PluginFFilter::new_ffilter(sofalizer)
err: Invalid argument
PluginFFilter::new_ffilter(blend_vulkan)
err: Input/output error
PluginFFilter::new_ffilter(libplacebo)
err: Operation not permitted
PluginFFilter::new_ffilter(overlay_qsv)
err: Input/output error
PluginFFilter::new_ffilter(overlay_vulkan)
err: Input/output error
PluginFFilter::new_ffilter(xfade_vulkan)
err: Input/output error
PluginFFilter::new_ffilter(hstack_qsv)
err: Operation not permitted
PluginFFilter::new_ffilter(vstack_qsv)
err: Operation not permitted
PluginFFilter::new_ffilter(xstack_qsv)
err: Operation not permitted