SemantiFX JUCE plugin

The plugin exposes a fixed pool of two slots for each catalogue type: EQ, distortion, compressor, and reverb. The saved chain state property stores an ordered comma-separated subset of those slots, such as eq-1,reverb-1. Hosts see every slot's parameters at construction time, including its bypass parameter. Chain structure is saved state, and solo is a transient UI control rather than a host parameter.

Build and run on macOS

Build all formats and run the tests with:

JUCE is fetched at tag 8.0.8. Release artifacts use a separate build directory with -DCMAKE_BUILD_TYPE=Release.

Slot parameters and chain editing

Each slot has the generated catalogue parameters and a continuous bypass parameter. IDs are derived from the generated table, for example eq1_low_shelf_gain_db, distortion2_drive_db, and reverb1_mix. The host parameters also include global outputGain, mix, and bypass.

The card rack shows the saved effect chain from left to right. Select a card to edit it, use its bypass or solo toggle for transient auditioning, and remove or drag cards to change the chain. Left and right arrows reorder the focused card. Delete or Backspace removes it. Enter or Space selects it. The trailing + card lists catalogue types that still have a free slot.

EQ keeps its interactive response graph. Other effect types show one rotary control per generated parameter, with its catalogue display name and unit. An empty chain passes audio through and shows Press Shape sound, or + to add an effect.

Shape sound and optimize chain

1. Press Listen 10s while audio is passing through the plugin.
2. Enter a target prompt.
3. Shape sound asks the worker to assemble a chain, applies that chain, and then starts optimization from the current slot values. A no-change assembly clears the chain and stops with Prompt asks for no change; chain cleared.
4. Optimize chain runs parameter optimization on the current non-empty chain.

During a run, Stop keeps the latest audible values and Revert restores the composition, parameter values, and bypasses captured before the first start. Escape performs Revert. Every progress snapshot containing parameters is applied on the message thread, so the current candidate is audible while the worker runs. A final analysis_result is applied as the current configuration.

Changing the chain structure restarts analysis immediately. Releasing a knob on an active slot schedules one restart after 300 ms, so a group of knob edits becomes one request. Bypass and solo changes do not restart analysis. A restart keeps the original pre-run snapshot, and stale worker results are discarded by request ID.

Import accepts a successful analysis_result JSON for the current chain and validates its order, instances, effects, names, units, and finite values before applying it.

Linux full build

On a Linux box with the X11/ALSA/FreeType dev packages installed (libasound2-dev, libfreetype-dev, libfontconfig1-dev, the libx*-dev set, libglu1-mesa-dev, mesa-common-dev, libcurl4-openssl-dev, libjack-jackd2-dev) plus xvfb, the full plugin builds and validates with one command:

This configures plugin/build-linux (RelWithDebInfo, reusing the JUCE checkout at SEMANTIFX_JUCE_DIR or /tmp/juce-8.0.8 when present), builds every target, runs the whole ctest suite, and validates the VST3 with pluginval (strictness SEMANTIFX_PLUGINVAL_STRICTNESS, default 10) when the SEMANTIFX_PLUGINVAL binary exists. The equivalent manual steps are:

Linux: DSP-only checks

Linux does not need the JUCE GUI or audio modules for the reusable catalogue DSP. Run:

This builds and runs the JUCE-free math, capture, effect parity, and slot-pool tests. The full plugin and processor tests must be built on macOS, where the JUCE GUI and audio dependencies are available, or on Linux via scripts/check-plugin-linux (see "Linux full build" above).

scripts/check-plugin-syntax goes one step further on Linux: it clones the pinned JUCE tag into plugin/build-juce-src (or uses SEMANTIFX_JUCE_DIR) and runs a header-only syntax compile of every plugin source and test with warnings on. It catches type, signature, and include mistakes in the JUCE code without building JUCE; for linking and runtime behaviour use the macOS build or scripts/check-plugin-linux.

Offline render tool

plugin/tools/render.cpp builds the semantifx_render target in both the full and DSP-only configurations. It renders a WAV file through a serial chain of the exact catalogue DSP the plugin uses, for listening tests and diagnostics:

Effects apply in the order given; parameters not listed stay at their generated defaults. Accepts mono and stereo input as 16/24-bit PCM or 32-bit float WAV, writes 32-bit float WAV out at the input sample rate (default block 512), and prints input/output peak and RMS dBFS to stdout. Unknown effect types, unknown parameter names, and out-of-range values are rejected. inference/diagnostics/render_gallery.py (via scripts/render-gallery) renders the full preset gallery with this tool.

The plugin uses JUCE's dsp::Convolution for reverb in real time. Generated impulse responses are built by the message-thread timer, not by the audio callback. The direct convolver remains available for parity tests and offline DSP checks.