This is a bug in CinGG, see bugtrack entry 586. Fixed in the code 20210928.

In your /usr/share/ I only see documents, icons, images but I can wrong.

Compare: fary54(Debian11) vs me(UbuntuStudio_16.04)
/usr/lib/x86_64-linux-gnu/calf/ === /usr/lib/calf/
/usr/lib/x86_64-linux-gnu/calf/calf.la === /usr/lib/calf/calf.la
/usr/lib/x86_64-linux-gnu/calf/calf.so === /usr/lib/calf/calf.so
/usr/lib/x86_64-linux-gnu/calf/calf.a === /usr/lib/calf/calf.a

/usr/lib/lv2/ === /usr/lib/lv2/
/usr/lib/lv2/calf.lv2 === /usr/lib/lv2/calf.lv2
/usr/lib/lv2/calf.lv2/calf.so (link?) === /usr/lib/lv2/calf.lv2/calf.so (link
to /usr/lib/calf/calf.so)
/usr/lib/lv2/calf.lv2/calflv2gui.so === /usr/lib/lv2/calf.lv2/calflv2gui.so

Could you tell me if /usr/lib/lv2/calf.lv2/calf.so is a link file? If so, where is it pointing?

Could you see how many files there are inside /usr/lib/lv2/calf.lv2/ directory? In my system there are 57 files: two of them are calf.so (link) and calflv2gui.so, the others are .ttl files.

I would try a test using my workflow, adapting it to your paths /usr/lib/x86_64-linux-gnu/calf/ and /usr/lib/lv2/. (It may be that you have already tried)

I think to be on a dead line due to my poor knowledge of Linux. Sorry.

"If installed in your system, could you search where calf folder is in your system, please? (I think @phylsmith2004 can help for that because she is a Linux Expert."

You will find attached a txt file detailing the directories and files on my system related to calf.

I think the main directories are :

• /usr/share/calf
• /usr/lib/lv2/calf.lv2

"Could you do a test with L2_abGate effect if this effect is present in your system, please?"

Sorry, I don't have this filter installed on my system.

I remain at your disposal if you need more information.

If installed in your system, could you search where calf folder is in your system, please? (I think @phylsmith2004 can help for that because she is a Linux Expert.

I tried another test on my system and changing my workflow a bit. The idea is only to see the lv2 effects, without calf effects.
From "/home/user/plugins_lv2-calf_for_Cin/lv2/" folder I deleted the "calf.lv2" folder and from "/home/user/plugins_lv2-calf_for_Cin/" I deleted the "calf" folder.
So, in "/home/user/plugins_lv2-calf_for_Cin/" directory I only see "lv2" folder.
Inside "lv2" directory there is the abGate.lv2 folder. If CinelerraGG will see this effect it will be in Resources->Audio Effect and its name is L2_abGate.
Now, in CinelerraGG, I can see the lv2 effects but not calf effects (because I deleted them). That is right.

Could you do a test with L2_abGate effect if this effect is present in your system, please?
Remember of press the "Reload plugin index" button in the Preferences window (Interface tab) and restart CinelerraGG.

I apologise for not replying earlier but I was unable to post anything on the forum.
I hope this time it will be the right one.

First of all, thank you very much for your help and for your precise tutorial.

Information from my system:
- Debian 11
- Ardour 6

Directory:
/usr/lib/lv2 - no problem
/usr/lib/calf - does not exist on my system

I have read your tutorial carefully but my file system seems to be different.
If I take your points one by one.

0 - no problem
1 - no problem
2 - In my case, the calf directory in the "/usr/lib/" directory does not exist. So I can't copy it.
3 - no problem
4 - no problem
5 - no problem
6 - no problem

When restarting Cinelerra, no feedback from the terminal informing me that the Calf plugin is loaded.
In the resources window, I can see the Calf directory and its subdirectories. But no filters in them...

I had never used lv2 and Calf in CinelerraGG because it didn't work on my system on my first attempt. Keep in mind that my Linux knowledge is very very low, so excuse me for my low technical talk.
I have done some tests here and, after using my workaround, I can use a few of them in CinelerraGG with their GUI (not all). May be this workaround is wrong from an Linux Expert point of view.
I don't know if it works for other Linux distributions (Debian based).

Information about my system:
- UbuntuStudio_16.04-LTS_64bit
- Ardour 4.6.0 "Evening Star"

The paths where I found "lv2" and "calf" are:
/usr/lib/lv2
/usr/lib/calf

Inside /usr/lib/lv2/ directory there are a lot of plugins (directories) and one of them is "calf.lv2". In /usr/lib/lv2/calf.lv2/ directory I see some ".ttl" files, the "calflv2gui.so" file, and the "calf.so" link to "dot dot slash calf/calf.so". I think that last one points to "/usr/lib/calf", so it must go up two directories using "dot dot slash" twice.

My workaround.
0. Make a backup of your ".bcast5" folder (inside "/home/user/" directory).
1. Create a new folder in "/home/user/" named "plugins_lv2-calf_for_Cin" without double quote.
2. Copy and Paste "calf" folder from "/usr/lib/" to "/home/user/plugins_lv2-calf_for_Cin/".
3. Create a new "lv2" folder inside "/home/user/plugins_lv2-calf_for_Cin/".
4. Copy and Paste a few of folders (I started with 14 folders) from "/usr/lib/lv2/" to "/home/user/plugins_lv2-calf_for_Cin/lv2/". Among those folders you MUST copy "calf.lv2" folder, it is important for the "calf" directory.
5. Run CinelerraGG.
6. In CinelerraGG, change the "Default LV_PATH:", that you find in menu-> Settings-> Preferences...-> Interface tab, with "$HOME/plugins_lv2-calf_for_Cin/lv2" (without double quote), and press the Apply button. Cinelerra will restart.

In terminal you can see all the LOADs for the plugins.
You may need to press the "Reload plugin index" button in the Preferences window (Interface tab) to see all the plugins.
You should find those plugins in the Resources window->Audio Effects.

Then you can copy other folders from "/usr/lib/lv2/" to "/home/user/plugins_lv2-calf_for_Cin/lv2/" (see #4 point). If CinelerraGG doesn't start you can delete a specific folder (Effect) from "/home/user/plugins_lv2-calf_for_Cin/lv2/".

On my system it works fine with cinelerra-5.1-ub16.04-20201031.x86_64static and CinGG-x86_64-older_distros.AppImage.
I hope it works for you too. Let me know. Thanks!

As you asked me, I just reloaded the index via Settings → Preferences → Interface tab → Reload plugins index and click on OK which performs a restart.

But no changes, no LV2 plugins are loaded and no feedback from the terminal.

Personally, I am disappointed that I did not find the plugin to be problematic.

But hey, I take it with philosophy and it at least allowed me:

• to solve my launch problem.
• to have succeeded for the first time in a single-user build compilation, even if it was not useful to us.

It is indeed a good idea, if we cannot go further, to add a note in the manual.

I remain at your disposal if you need more information.

Anyway, a big thank you for your help.

I think we have gone as far with this problem as necessary and my best option is to warn  users in the next Release Notes to check their LV2 path in Cinelerra if problems on startup when system or application upgrades take place. 

Now I am just guessing, but I think that installing Ardour may have set up some kind of LV2_PATH that interfered with whatever you had for the original LV2 Path in your Cinelerra_rc file.   So I think it is too late to work on the original problem.

In your original forum post, it shows the name of each LV2 plugin as they are being loaded with each LOAD statement so some how that was the first time for the LV2 load.  However, in order to save time on startup, Cinelerra does not automatically reload the plugins once loaded so in order to see terminal messages and force a reload you would have to do:

Settings → Preferences → Interface tab → Reload plugin index and click on OK which does a restart.

Question: If the appimage does not return any useful information, wouldn't it be more productive for everyone if I compiled cinelerraGG myself. This would give you the name of the filter that is causing the problem.

You would still not get the name of the filter causing the problem because you would still not be automatically reloading the plugins.

If so, having never done it:
- Is it accessible at my level?
- if I compile using your guide (file:///tmp/.mount_CinGG-fGvuDb/usr/bin/doc/CinelerraGG_Manual/single_user_build.html#1027) could this cause problems for my production cinelerraGG?

Yes, I am certain you could do this but the first time, it takes quite a bit of work and going back and forth is quite time-consuming and if you have problems, I am not sure I can be much help.  Once you got it down, it is easy.  But I do not believe there would be any gain in addressing the original forum post problem.

If you compile using the single user build and you put it in a specific directory, it does not interfere with production.

I get the list of LV2 plugins via lv2ls.

Then in Settings->Preferences, Interface tab, I changed the default value of LV2 to:
http://calf.sourceforge.net/plugins/Analyzer

I validate and cinelerraGG restarts.

Cinelerra Infinity - built: Jul 31 2021 09:18:57
git://git.cinelerra-gg.org/goodguy/cinelerra.git
(c) 2006-2019 Heroine Virtual Ltd. by Adam Williams
2007-2020 mods for Cinelerra-GG by W.P.Morrow aka goodguy
Cinelerra is free software, covered by the GNU General Public License,
and you are welcome to change it and/or distribute copies of it under
certain conditions. There is absolutely no warranty for Cinelerra.

init plugin index: /tmp/.mount_CinGG-fGvuDb/usr/bin/plugins
init lv2 index:
init ladspa index: /tmp/.mount_CinGG-fGvuDb/usr/bin/ladspa

The terminal does not tell me that it has loaded the LV2 plugin
plugin and I can't find any trace of this plugin in the resources window.

However, in the Cinelerra_rc file, the plugin has been added and no error return from cinelerraGG. (see attachment)

I tried with several other plugins and always got the same result.

Question: If the appimage does not return any useful information, wouldn't it be more productive for everyone if I compiled cinelerraGG myself. This would give you the name of the filter that is causing the problem. If so, having never done it:
- Is it accessible at my level?
- if I compile using your guide (file:///tmp/.mount_CinGG-fGvuDb/usr/bin/doc/CinelerraGG_Manual/single_user_build.html#1027) could this cause problems for my production cinelerraGG?