LMMS Progress Report: August 2025

Welcome back to our monthly series of LMMS Progress Reports!

If you missed last month's report, you can find it here.

Nightly News

August was a fairly quiet month for development. In total 9 PRs were merged.

  • VST crash fixes (#7976, #7987)
    By far the most significant pair of PRs merged last month were fixes for certain 64-bit Windows VSTs on our Windows and Linux builds. Prior to this, 64-bit Synth1 and other VSTs would crash after playing a couple notes. Thanks to Fastigium for the hard work of troubleshooting and fixing the issue, and tresf for polishing up the PR for Linux and successfully submitting and merging a patch for Winebuild upstream. While these fixes are significant, an issue remains with VSTs in our Windows MSVC builds which is being tracked here.

Other changes:

  • Refactor Global Spacebar Play (#7926)
  • Fix crash01, cello01, and e-organ01 sample lengths (#7948)
  • PianoRoll: fix getKey and remove dead code (#8008)
  • Audio buffer view improvements (#8016)
  • Fix a segfault if JACK libs are missing (#8026)
  • Fix several problems (#8032)
  • OpulenZ: Fix compilation error (#8040)

In progress

In the past month, 10 new PRs were opened, of which 3 have already been merged. The following is a list of both new and old PRs which were worked on in the past month.

Nearing completion

  • FIFO thread removal (#7568)

  • SlewDistortion effect (#7641)
    LostRobotMusic's new distortion plugin has undergone some rounds of review and testing which caught a couple floating-point exception bugs, and now it is nearly ready to merge.

  • Pitch Bending Directly in the Piano Roll (#7759)
    This PR needs a code review, but is in good shape as far as testing goes.

  • Better loop handles + prevent negative loops (#8015)
    This new PR by allejok96 makes adjusting the loop range more intuitive while also fixing a bug that allowed invalid loops.

In the works

  • Multi-channel plugins (#7459)
    messmerd improved how audio ports are initialized and activated, and is working on fixing the auto-quit feature for effects in the new multi-channel world.

  • Add ability to drag files to and from external applications (#7849)
    Code reviews are continuing on, and more testing is needed.

  • Fix audio resampling functionality (#7858)
    sakertooth recently added a bip buffer class (a type of circular buffer) in hopes of simplifying how the resampler is used.

  • Fix knob linking / refactor linking (#7883)
    allejok96 contributed some simplifications to the linking functions, and the PR is again ready for review.

  • Oscilloscope Effect (#7937)
    regulus79 has been busy implementing changes suggested by code reviewers.

  • MPE output support (#8034)
    This is an exciting new feature from regulus79, finally adding MIDI Polyphonic Expression (MPE) support to LMMS. This enables per-note pitch bending for VSTs that support it, and could be extended in the future to LV2 and CLAP plugins.

  • Add support for multiple tracks/channels to MidiExport (#8048)
    This was a stale 5-year-old feature branch by EmoonX which messmerd recently resuscitated. It allows exporting projects to MIDI with each track on a different MIDI channel, and also integrates nicely with Sf2 Player for drum mapping.

  • While there is no PR yet, LobotRobotMusic is also working on a new frequency shifter plugin. Stay tuned!

Other PRs

These PRs were also created or worked on during August.

  • Improved Waveshaper / Spline-based graph replacement (#4367)
  • Refactor to move positionChanged signal to Timeline (#7454)
  • Improve search behavior in the file browser (#7679)
  • Make playhead red when recording (#7847)
  • Fix the sidebar bookmarks getting reset when opening a file dialog (#8019)
  • Fix assertion error, floating point exception plus some other cleanup (#8025)
  • Optimize cloning steps in Pattern Clips (#8042)
  • Temporary fix for Mallets UI (#8044)
  • Change Freeboy's tooltips (#8045)

Goals for September

We're continuing to work towards the goal of releasing a new alpha version. The VST crashes fixed by #7976 and #7987 were the most significant to-do item from the 1.3-alpha.2 milestone issues, so we're glad to finally have that completed.

We will be concentrating on the rest of the milestone issues this month so we can release the new alpha as soon as possible.

New contributors

  • SameExpert fixed an OpulenZ compilation error in #8040.

Closing thoughts

Thanks for reading! We have a lot of work ahead of us, but if you'd like to contribute to LMMS's development, it could go faster. Whether you're a developer or a tester, it all helps!

If you have any questions or suggestions, please let us know below or on our Discord.

Have a great September!