203 lines
11 KiB
Markdown
203 lines
11 KiB
Markdown
# xtc — a lightweight, modular DAW
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`xtc` is a new, energyXT-inspired digital audio workstation project. It is not a clone and contains no energyXT source code or assets.
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## Design decisions
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- **Modular engine first:** sequencer, instruments, effects, mixers and I/O are nodes in one processing graph.
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- **C core:** project model, graph, DSP and audio engine are implemented in C.
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- **FLTK/C++ GUI:** C++ is confined to the graphical interface and calls the core through a C API.
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- **Linux first:** keep backend-specific details behind an interface.
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- **Small increments:** build and test each milestone before adding features.
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## Current status
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This repository is a starter scaffold, not a production DAW. It currently provides:
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- a small C library/API;
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- a mono graph model with port validation, cycle rejection and topological ordering;
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- compiled offline plans with preallocated buffers, sine oscillator, audio source, gain, meter and output nodes;
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- C tests for deterministic rendering, routing, validation and lifecycle;
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- an optional JACK-compatible backend with mono input and mono/stereo output with start/stop, routing and status;
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- safe control/audio plan handoff and concurrent replacement tests;
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- an optional FLTK shell with engine controls, view switching and backend status;
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- a modular graph editor with transactional edits and live plan adoption status;
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- versioned project save/load and a timeline for tracks and clips;
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- sample-counted transport, selection, move/trim, timeline zoom and scrolling;
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- WAV import/graph playback, bounded recording and missing-asset relinking;
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- MIDI clips, a sine instrument, JACK MIDI input and a basic piano roll;
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- stereo track/bus gain/pan/mute/solo, dBFS peak meters and gain/pan automation lanes;
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- bounded undo/redo with keyboard shortcuts;
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- configurable boundary fades, gain ramps and graceful GUI playback transitions;
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- native C processors, deterministic source packaging and staged install/uninstall;
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- architecture, format, GUI, roadmap, and decision documents.
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The JACK backend has passed software-loopback testing; physical-device playback
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and capture are unverified. MIDI recording remains deferred. Bounded LADSPA
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hosting supports the compatible mono processors documented in
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[PLUGIN_HOSTING.md](docs/PLUGIN_HOSTING.md).
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## Build
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Requirements: a C compiler, a C++ compiler, GNU Make, and `pkg-config`. FLTK is optional for the core and tests.
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```sh
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make
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make test
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```
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`make` also builds `build/xtc-check`, a headless core startup/shutdown
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check. Use `make debug` for a separate debug build and test run. See
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[docs/BUILD.md](docs/BUILD.md) for the inspected toolchain and baseline limits.
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Build the optional FLTK GUI if FLTK is installed:
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```sh
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make gui
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```
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Run the GUI:
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```sh
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./build/xtc
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```
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See [the minimal music-making workflow](docs/WORKFLOW.md) for creating, saving,
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reopening and playing a project.
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The GUI opens JACK and offers Play/Pause/Stop/To start/Reconnect, backend status and view
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switching. The initial empty graph is silent. Modular Graph supports adding,
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moving and deleting oscillator/audio/instrument/gain/meter/output nodes and connecting ports.
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Import WAV (Ctrl+I) creates playable clips; Add region creates silent placeholders.
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Record captures JACK input to a chosen WAV; Stop finalizes and adds the take.
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Save the project after recording. External asset paths must remain available;
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select a missing clip and use File/Relink selected audio to repair it.
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Add MIDI clip on an existing track, then open Piano roll (or Ctrl+5 for the selected track) to draw notes.
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Connect a MIDI source to the JACK `midi_in` port for live playing; Panic/F9
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silences held notes. See [MIDI workflow and limits](docs/MIDI.md).
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See [audio workflow and limits](docs/AUDIO_FILES.md) and the
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[sample editor workflows](docs/AUDIO_EDITOR.md).
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Mixer (Ctrl+2) selects a track for gain/pan/mute/solo and automation editing.
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Ctrl+Z undoes; Ctrl+Shift+Z or Ctrl+Y redoes up to 32 edits.
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The GUI now exposes left `output` and `output_right` JACK ports; route both
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explicitly for stereo. See [mixer workflow and limits](docs/MIXER.md).
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Use Add track/Add region, drag regions or their edges, and Zoom +/-; scrollbars pan.
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Ctrl+N/O/S creates, opens or saves a project; Save As chooses another path.
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Arrangement edits stop playback; graph edits remain live.
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The ruler seeks while stopped. Stop pauses; Reconnect and project load reset position. F5 starts, F8 stops, Space toggles, F6 reconnects, and Ctrl+1/2/3
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switches views. Ctrl+Q closes the client and window. No physical ports are
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connected automatically. In Modular Graph, drag output to input to connect;
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select a node or wire and press Delete to remove it. Invalid edits leave the
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active graph intact; queued changes are labeled until the engine adopts them.
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See [GUI documentation](docs/GUI.md).
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For Linux installation, routing and CLI options see [LINUX.md](docs/LINUX.md);
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for native effects/instruments see [NATIVE_API.md](docs/NATIVE_API.md).
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`make release`, `make dist`, `make test-install` and `make test-release` provide
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release preparation; see [RELEASING.md](docs/RELEASING.md) for exact guarantees.
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With JACK development files and an existing JACK-compatible server, run the
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isolated software-loopback test with `make test-jack` and the record/reopen/play
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acceptance test with `make test-jack-audio` and MIDI acceptance with
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`make test-jack-midi`. It connects only test
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clients. See [engine documentation](docs/AUDIO_ENGINE.md) for configuration,
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routing, ownership and recovery.
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Clean generated files:
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```sh
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make clean
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```
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## Suggested first agent task
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Read `AGENT.md` and `docs/ARCHITECTURE.md`. Inspect the existing implementation, run `make test`, and report gaps before adding the next feature. Do not jump directly to plugin hosting or a full sequencer.
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## License
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The project is scaffolded under the MIT License; see `LICENSE`. Review the licenses of any future dependencies before distribution.
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Audio timing, transitions, latency limits and listening previews are described
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in [docs/AUDIO_QUALITY.md](docs/AUDIO_QUALITY.md). Human listening acceptance
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of the transitions remains pending.
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The engine adds no-clobber recording/recovery, parameterized native C processors,
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and trusted in-process LADSPA hosting with persisted identity/control values.
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See [RECOVERY.md](docs/RECOVERY.md), [NATIVE_API.md](docs/NATIVE_API.md) and
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[PLUGIN_HOSTING.md](docs/PLUGIN_HOSTING.md) for commands and limits.
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For everyday use see [USER_MANUAL.md](docs/USER_MANUAL.md),
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[KNOWN_LIMITATIONS.md](docs/KNOWN_LIMITATIONS.md) and
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[MAINTENANCE.md](docs/MAINTENANCE.md). `xtc-check --diagnose` reports build features;
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`make test-package` checks a local system-linked Linux binary archive.
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Effect automation/controllers, editing commands, v7 project-folder media paths,
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performance baselines and release/installation checks are also supported.
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Non-destructive audio splitting, clip gain/fades and cached timeline waveforms
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are supported, with undo and v8 persistence (reading v1–v7). See
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[AUDIO_FILES.md](docs/AUDIO_FILES.md#non-destructive-clip-editing).
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`make test-audio-editing` checks source preservation and exact boundary output.
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Time stretching and independent pitch shifting remain deferred.
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Signal-flow graph layout, routing diagnostics, direction/role indicators and
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atomic unity-gain insertion into a wire are supported. See
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[ROUTING.md](docs/ROUTING.md); `make test-routing` verifies the C routing contract.
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One-level mix buses, routing, coherent track/bus peaks and master clipping
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indicators are supported, persisted in v9 (reading v1–v8). See [MIXER.md](docs/MIXER.md).
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LADSPA descriptor browsing, an identity/parameter editor with reset,
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transactional replacement and insertion into graph wires are supported. See
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[PLUGIN_HOSTING.md](docs/PLUGIN_HOSTING.md) for compatibility and lifecycle limits.
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Common parameter targets, Linear/Hold mixer automation and saved per-channel
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live MIDI CC bindings are supported. Project v10 reads v1–v9. See
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[CONTROL.md](docs/CONTROL.md) for timing, precedence and qualification limits.
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Undo storage is reserved before edits/publication, completed takes are grouped,
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surviving editor selections are preserved and context menus/focus feedback are
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improved. See [EDITING.md](docs/EDITING.md) for the workflow audit and failure
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boundaries.
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Project troubleshooting: `xtc-check --validate PROJECT.xtc` reports metadata
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errors with the expected record and syntax line. `xtc-check --inspect PROJECT.xtc`
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lists resolved media/module paths and plugin identities without executing plugins
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or starting JACK. Exit codes: 0 = valid metadata and available files, 2 = missing
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or unreadable references, 1 = metadata/I/O error. File availability does not
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certify WAV contents or plugin compatibility. See [PROJECT_FORMAT.md](docs/PROJECT_FORMAT.md)
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for the compatibility and relocation policy.
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**File → Load plugin** supports LADSPA plus an initial Linux
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CLAP/VST2/VST3 effect subset. Select the actual module binary (`.clap` or `.so`,
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including a VST3 bundle's inner binary). Modern effects require one mono input
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and output, float32 and zero latency; they use default configuration. Instruments,
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modern parameter editing/automation, opaque state and custom editors are not
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implemented. Projects now save v11 and read v1–v11. See PLUGIN_HOSTING.md for the
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full contract and test/qualification limits.
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A compact sequencer Create menu, optional track inspector and per-track modular
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effect chains are supported. Open **View → Track inserts** (or Ctrl+5 for the selected track) to add,
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search, reorder, bypass, inspect and mix mono LADSPA/VST2/VST3/CLAP effects or
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internal devices. Chains support undo, presets, audio/MIDI rendering and export.
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Projects save format 17 and read formats 1–17. See
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[track insert workflows and limits](docs/TRACK_INSERTS.md) and the
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[screenshot gallery](screenshots/README.md).
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Direct selected-track inserts, effect duplication, chain copy/
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paste, A/B snapshots, three internal effect templates, bulk rack actions, insert
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peak meters, tap tempo, audio crossfades and MIDI chord strumming are supported. See
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[creative workflows and limits](docs/CREATIVE_WORKFLOWS.md).
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MIDI devices and defaults are configurable in **Preferences → midi**, including
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JACK/PipeWire input/output choices, channel filtering and optional thru. Use
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**File → Import MIDI** or **Export selected clip as MIDI** to exchange note clips.
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Application preferences load from **`~/.xtc.conf`** at startup and save on Apply
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and clean exit. See [configuration and MIDI workflows](docs/MIDI_WORKFLOWS.md)
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for file support, routing and persistence details.
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[Steinberg SDK integration (Phase 106)](docs/STEINBERG.md) adds conventional Linux
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VST3 bundle loading, transport context, official-SDK gain/synth examples and
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validator checks. Run `make VST3_SDK_ROOT=/path/to/vst3sdk test-steinberg-sdk`
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for optional SDK qualification. A Windows ASIO device diagnostic is provided;
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a native ASIO playback/capture backend remains planned.
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