[Ardour-Users] ambix LV2 vs ardour?

Fernando Lopez-Lezcano nando at ccrma.Stanford.EDU
Sat Feb 23 18:39:08 PST 2019

On 2/23/19 4:13 PM, Robin Gareus wrote:
> On 2/21/19 12:52 AM, Fernando Lopez-Lezcano wrote:
>> Hi all,
>> Anyone out there successfully using the Ambix (0.2.8) LV2 plugins with
>> Ardour5?
>> I am having problems loading any of the plugins into Ardour5. This
>> happens with both the Fedora ardour package and the demo install from
>> Ardour.org. The Ambix plugins do load, for example, in Qtractor, but not
>> in Ardour.
>> Ardour shows them in the plugin manager, you can select one, "Add" it
>> and then when you do an insert it a panel pops up that says "the plugin
>> xxx could not be loaded". Looking at the log I see (for example):
>> [ERROR]: LV2: Failed to instantiate plugin
>> file:///usr/lib64/lv2/ambix_converter_o1.lv2/ambix_converter_o1
>> The directory looks like this:
>> ls -l /usr/lib64/lv2/ambix_converter_o1.lv2/
>> total 5068
>> -rwxr-xr-x. 1 root root 5171056 Nov 29 20:43 ambix_converter_o1.so
>> -rw-r--r--. 1 root root    5504 Nov 29 19:50 ambix_converter_o1.ttl
>> -rw-r--r--. 1 root root     901 Nov 29 19:50 manifest.ttl
>> -rw-r--r--. 1 root root     378 Nov 29 19:50 presets.ttl
>> I built the plugins according to the build instructions, and nothing
>> weird is shappening there that I can see (the build uses a recent
>> lv2-devel package, etc). All the Ambix standalone applications that are
>> also built work just fine with jack.
> I just had a quick look. The plugin has an invalid URI, it just uses the
> plugin-name as-is.
> liblilv will prefix that with the absolute path, resulting in a
> file://URI, 

(darn, I had noticed that it was the only plugin to use file:// but 
failed to mention it)

> and when Ardour tries to instantiate the plugins this causes
> a failure. The given URI does not match the URI in the plugin's so. It
> also fails with jalv. I'm surprised that it works in qtractor, perhaps
> you were using the VST, there?

Nope, I was loading the lv2. But not very useful since qtractor is stereo.

> Could you try patching ambix like http://paste.debian.net/1069875/ (That
> patch also includes an update for zita-convolver3 new API and removes a
> call to fftw's thread-safe planner which is for a plugin-host to make.)

I'm building now, will take a while - will report back.

> That doesn't link statically, but it should work with a local Ardour
> build at least.

It should, yes. I did some analysis and comparisons of the shared 
libraries loaded by both the plugins and ardour and did not find 
anything suspicious (ie: same versions, etc - after all both are build 
in the same environment).

Thanks soooo much for looking at this!
-- Fernando

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