Elixir, MIDI and LiveView

(Paris.Ex meetup)

Transcript

1. Elixir, MIDI & LiveView
2. @thibaut_barrere Consultant Ruby / Elixir / Ansible Kiba ETL / Kiba Pro Remote 100% (Charente Maritime)
3. Elixir => Code-Centric Digital Audio Workstation? infiniwip (tm)
4. Previous episode https://github.com/thbar/demo-elixir-reloading-music Code.eval_file("music.exs")
5. MIDI
6. Note On {0x90 + channel, note, velocity} Note Off {0x80 + channel, note, release_velocity}
7. Keyboard / Piano / Synthetizers photo by Clavia
8. MIDI controllers photo by Novation
9. Virtual Instruments (on computer)
10. Virtual Instruments (on iOS) photo by Korg
11. Lightning = Inter-Device Audio & MIDI (IDAM) photo by Apple
12. Elixir Code / DRY Refactoring Music Augmented Human (theory, scales) Soft realtime
13. brew install portmidi
15. # Start a process for MIDI event queue {:ok, pid} = PortMidi.open(:output, "Kontakt Virtual Input") note = 48 # C-4 velocity = 127 # Send "NOTE ON" PortMidi.write(pid, {0x90, note, velocity}) # Send "NOTE OFF" PortMidi.write(pid, {0x80, note})
17. Computer: Note 60 Human: WTF????
18. Translation def note_number_to_latin_name(midi_note, middle_c \\ @default_middle_c) do remap_note(midi_note, @latin_names, middle_c) end defp remap_note(midi_note, names, middle_c) do offset = get_base_offset(middle_c) octave = div(midi_note + offset, 12) octave_note = rem(midi_note + offset, 12) octave_note = names |> Enum.at(octave_note) "#{octave_note}#{octave}" end defp get_base_offset("C4"), do: -12
19. DocTests ❤ ## Examples iex> MusicRef.note_number_to_latin_name(60) "Do4" iex> MusicRef.note_number_to_latin_name(78) "Fa#5"
20. Phoenix LiveView <div> <p> Time is <%= @time %> </p> </div> HTML? ✔
21. Phoenix LiveView <svg> <%= for note <- notes do %> <rect x="..." y="0" width="10" height="20" fill="<%= note.color %>"> <% end %> </svg> SVG? ✔
22. Phoenix LiveView <svg> <g> # white notes </g> <g> # black notes </g> </svg>
25. def note_on({channel, note, velocity}, device, portmidi \\ PortMidi) do Phoenix.PubSub.broadcast(Widgets.PubSub, "notes", {:note_on, note}) :ok = portmidi.write(device, {0x90 + channel, note, velocity}) end
27. Code & Demo