Jalv 1.4.2

jalv 1.4.2 has been released. Jalv is a simple but fully featured LV2 host for Jack which exposes plugin ports to Jack, essentially making any LV2 plugin function as a Jack application. For more information, see http://drobilla.net/software/jalv.


  • Fix crash when running "jalv" with bad command line arguments
  • Fix potential crash with UIs and debug printing
  • Fix parameter changes with Qt UI
  • Nicer printing of atom messages with -d
  • Add command-line option to control UI update frequency
  • Support rsz:minimumSize for atom and event ports
  • Fix default setting for non-sequential enumeration ports (patch from Robin Gareus)
  • Work around Gtk bug for labels on sliders (patch from Robin Gareus)
  • Upgrade to waf 1.7.11

Suil 0.6.14

suil 0.6.14 has been released. Suil is a library for loading and wrapping LV2 plugin UIs. For more information, see http://drobilla.net/software/suil.


  • Print system error message if module fails to load
  • Lower dependency from Gtk 2.24 introduced in 0.6.12
  • Add support for new LV2 idle interface
  • Support resizing for X11 in Gtk (patch from Robin Gareus)
  • Upgrade to waf 1.7.11

Ingen as LV2 in Ardour

I found some time today to make Ingen's support for running as an LV2 more solid. I have posted about this before, but it now works at RT appropriate buffer sizes, and several other bugs have been fixed. Here's the obligatory contrived screenshot:

Ingen in Ardour

People are sometimes confused about how Ingen works as an LV2 (I need to write proper documentation One of These Days): you don't load an "Ingen" plugin so much (it wouldn't do anything), as you save an Ingen graph as an LV2 plugin. The idea is that Ingen is a tool for visually building plugins. Since LV2 does not support dynamically adding ports, it's easiest to do your building as a Jack app, so the basic work flow is something like:

  1. Run Ingen as a Jack app: ingen -eg
  2. Build a graph, adding ports, plugins, etc.
  3. Save the graph to somewhere in your LV2_PATH, e.g. ~/.lv2 (which happens to be the default directory of the save dialog for this reason).
  4. Voila, your graph should now show up in any LV2 host (its URI will simply be its local filesystem path, unless you explicitly set a stable one). You can check with lv2ls.

There is no export or compilation involved, Ingen's native format is LV2 compatible (graphs are always saved in the same format). If you saved a graph elsewhere you can simply copy it to ~/.lv2 to use it as a plugin, though for now you may have to create or fix the symlink to the engine binary manually to do this.

Note that you can edit the graph while it's running as an LV2 plugin, including adding new nodes and connections, you just can't add top-level ports because the host doesn't know about them. There is still some work to be done polishing this up to be ready for prime-time, but for the brave, it's more or less good to go.

Jalv 1.4.0

jalv 1.4.0 has been released. Jalv is a simple but fully featured LV2 host for Jack which exposes plugin ports to Jack, essentially making any LV2 plugin function as a Jack application. For more information, see http://drobilla.net/software/jalv.


  • Send time information to plugin when Jack tempo changes
  • Group controls under headings if port group information is available
  • Add spinbuttons for precisely setting control values
  • Use a more efficient dense layout for controls
  • Make URI map thread-safe, fixing occasional crashes for plugins with UIs
  • Add menu bar and pass parent widget in Qt version for true UI embedding
  • Support state:loadDefaultState
  • Update to waf 1.7.8 and autowaf r90

Suil 0.6.12

suil 0.6.12 has been released. Suil is a library for loading and wrapping LV2 plugin UIs. For more information, see http://drobilla.net/software/suil.


  • Fix key events for X11 in Gtk without using a troublesome event filter
  • Fix crash when a broken UI returns a NULL descriptor
  • Fix compilation on BSD

Lilv 0.16.0

lilv 0.16.0 has been released. Lilv is a C library to make the use of LV2 plugins as simple as possible for applications. For more information, see http://drobilla.net/software/lilv.


  • Add lilv_world_ask() for easily checking if a statement exists
  • Add lilv_world_get() and lilv_port_get() for easily getting one value
  • Add lilv_nodes_merge()
  • Make lilv_plugin_get_port_by_designation() return a const pointer
  • Require a URI for lilv_state_to_string() and fail gracefully otherwise
  • Fail gracefully when lilv_state_new_from_string() is called on NULL
  • Make state loading functions fall back to lv2:default for port values, so a plugin description can be loaded as default state
  • Ignore state ports with no value instead of printing an error
  • Support atom:supports in lilv_port_supports_event()
  • Add va_list variant of lilv_plugin_get_num_ports_of_class()
  • Fix several plugin functions that failed to load data if called first
  • Correctly depend on serd at build time (fix compilation in odd cases)
  • Disable timestamps in HTML documentation for reproducible build
  • lilvmm.hpp: Support varargs for Plugin::get_num_ports_of_class()
  • lilvmm.hpp: Add several missing methods
  • Update to waf 1.7.8 and autowaf r90 (install docs to versioned directory)

Sratom 0.4.2

sratom 0.4.2 has been released. Sratom is a library for serialising LV2 atoms to/from RDF, particularly the Turtle syntax. For more information, see http://drobilla.net/software/sratom.


  • Fix serialisation of nested tuples
  • Fix memory leaks
  • Use new sord API to clean up and shrink code
  • Disable timestamps in HTML documentation for reproducible build
  • Update to waf 1.7.9 and autowaf r90 (install docs to versioned directory)

Sord 0.12.0

sord 0.12.0 has been released. Sord is a lightweight C library for storing RDF statements in memory. For more information, see http://drobilla.net/software/sord.


  • Update to waf 1.7.9 and autowaf r90 (install docs to versioned directory)
  • Add sord_get() for easily getting single property values
  • sord_validate: Pass type check when range is xsd:anyURI and value is a URI
  • sord_validate: Support any subClassOf rdf:Property, not just baked-in ones
  • sordmm.hpp: Add convenient constructors for decimal and integer literals
  • sordmm.hpp: Add Node::to_serd_node()
  • sordmm.hpp: Don't automatically add RDF namespace prefix to world

Better stock LV2 plugin UIs

Today I implemented better UI generation for LV2 plugin controls in Jalv, particularly grouping controls under headings which makes a big difference. Unfortunately few plugins group their controls currently, but hopefully more host support will provide the incentive to do so.

Other improvements:

  • Added a spinbutton to slider controls for precisely setting values numerically
  • Much more efficient layout to pack more controls on the screen at once
  • Support for named scale points ("ticks") on non-enumeration ports

Here is the UI generated for Amsynth (after I added the necessary metadata):

Generic Jalv UI for Amsynth LV2

Still pretty utilitarian, but much more usable, which is the important thing. Of course, this plugin is quite large, and has a pretty good custom UI, but I happened to be polishing up its metadata anyway and the controls group nicely so I used it as my test case.

Maybe some day this code will get smarter and evolve into a library that can be used by other Gtk hosts. Better group layout is the obvious "next level" advancement, a flat linear list of controls is pretty limited. Unfortunately there's no stock Gtk container which can do text-like reflow, which would be ideal. Perhaps a simpler scheme based on a maximum reasonable width for a controller would do, where the table will expand to have more columns if the window is wide enough for several.

Most of the metadata required to generate a good UI is also useful for other purposes, for example groups make building a decent menu of many controls feasible (e.g. to add automation lanes in Ardour), and some types of host UIs like a modular patcher inherently need to generate their own "UI" of sorts.

Good metadata is not at odds with custom UIs, they each have their uses, but it is important to remove the burden of custom UIs for simple plugins with just a few controls that really don't need them. It's a waste of that most precious of all resources - developer time - to have to code UIs for a few sliders and toggles. Hopefully better host generated UIs and support for more advanced controls like file selectors free up developers to spend more time making useful plugins and less time wrestling with GUI toolkits.

It is, after all, all about the sound.

Ardour MIDI Patch, Controller, and Note Names

Ardour has supported displaying MIDI patch names loaded from a MIDINameDocument (or "midnam" file) for a while, though only patches, and even that was pretty flaky. Since this has become an itch for me and it's time for Ardour MIDI to reach release quality, I took some time to give it a serious overhaul. In this case, a picture or two is indeed worth a thousand words:

Human readable MIDI note names in Ardour 3

Human readable MIDI controller menu in Ardour

The note names are mainly useful for doing percussion. Several of the bundled midnam files have note names defined, and I have added one for General MIDI drums, which more or less corresponds to a lot of instruments, including Hydrogen.

Controller names, to my surprise, were not present in any of the existing midnam files at all. I wanted to sequence a hardware synth (the Moog Minitaur) without constantly referring to the manual and trying to remember which CC is which, so I wrote a new midnam file for the device and implemented support in Ardour. I am very disappointed to learn that there is no ability to group controllers, which really is the best way to do things, so I may embrace and extend (in a completely backwards compatible way) the format in the future to provide a better interface.

The quality of midnam files scattered around the 'net is atrocious. The MMA actually hosts a DTD for it, but most files use the wrong DOCTYPE (usually with a broken link), among other problems. I fixed and cleaned up all the bundled ones in Ardour, validated them against the DTD, and left a README in that directory about how to do so. Hopefully this, along with incentive added by these features, encourages the community to grow a nice set of quality midnam files.

So, MIDI name support in Ardour is now in pretty good shape. Now we just need to add the corresponding LV2 support...

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