Some Music Libraries for Kotlin (with some .NET -> Kotlin migration stories)

10 min. KotlinConf LT at Kotlin Foundation booth

Transcript

1. Some Music Libraries for Kotlin with some .NET -> Kotlin migration stories atsushieno
2. Some Music Libraries for Kotlin Dotnet Users Migration Path (DUMP) to Kotlin atsushieno
3. ktmidi Versatile MIDI processing library Provides access to MIDI 1.0 and/or UMP (MIDI 2.0) devices Can create virtual devices (not doable in javax.sound.midi) Supports MIDI 2.0 UMP (a handful of libraries do) and MIDI-CI sessions (only JUCE in C++ and ktmidi in Kotlin do)
4. MIDI? Is it still popular? MIDI 2.0: 2020 2023 updates - 7 bits => 32 bits - 16 channels => 16 channels x 16 groups - bidirectional like HTTP/3 Not for composition outputs, but it is used everywhere. - MIDI keyboards - within many cross-platform instrument plugins (implementation details) - in many audio plugin APIs: AudioUnit, CLAP (MIDI2 since around 2022)
5. Managed language for DAWs? Yes, Java is used
6. platform MIDI access: there are many backends • ALSA • WinMM ◦ Windows MIDI Services in the future • CoreMIDI • rtmidi, libremidi, portmidi... • Android MIDI API (android.media.midi) • Web MIDI API
7. surviving native interop hell (did I ...?) managed-midi (~2018) • P/Invoke (winmm, alsa, portmidi, rtmidi) • Managed API ◦ UWP ◦ xamarin-macios ◦ xamarin-android simple-ish overall (no WebMIDI atm) Someday we get some universal solution w/ cinterop...? 🥹 • Kotlin/JVM ◦ LibreMidiAccess (LibreMidi) - panama ◦ AlsaMidiAccess - javacpp ◦ AndroidMidiAccess ◦ JvmMidiAccess (javax.sound.midi) • Kotlin/Native ◦ CoreMidiAccess (cinterop) ◦ RtMidiNativeAccess (cinterop) • Kotlin/JS ◦ JzzMidiAccess - Jazz-Soft/JZZ (npm) • Kotlin/Wasm ◦ WebMidiAccess - (webmidi)
8. Text to Music files I had a compiler tool for my own language (variant of Music Macro Language) text => MIDI 2.0 song => DAW project file (using Tracktion_Engine OSS)
9. Text to Music files Text to MIDI - antlr-kotlin to parse its syntax (in C# it was jay) - generates standard MIDI file (SMF), or SMF2-alike - embeddable to any Kotlin app MIDI to some XML-based DAW project files - ended up building my own .NET XML API ports (XmlReader, XmlWriter, XLinq) - XmlSerializer... no reflection in Kotlin, so codegen w/ KSP
10. make it compile from VSCodium extension The compiler package is up on npm using npm-publish
11. compose-audio-controls maybe the coolest one mine 🤣
12. ImageStripKnob Pick any image strip from 2400+ knobs from KnobGallery (based on image strip)
13. ImageStripKnob Compact yet mobile-friendly - sizes: align with Android UI Accessibility Guidelines - drag to move your finger away horizontally without value changes - adjust value vertically - hold to switch to fine-tuning mode No value change Value change
14. DiatonicKeyboard Aligns with Android Accessibility Guideline drag to naturally play next note, or pitch bend horizontally or vertically (per-note)
15. Demo, if time permits
16. Repos https://github.com/atsushieno/ktmidi/ - MIDI library https://github.com/atsushieno/mugene-ng - text to MIDI compiler https://github.com/atsushieno/augene-ng - ... to DAW XML project compiler https://github.com/atsushieno/missing-dot - .NET XML API ports https://github.com/atsushieno/compose-audio-controls/ - audio controls in KMP https://github.com/atsushieno/kmdsp/ - visual MIDI player in KMP