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Elixir, MIDI & LiveView

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@thibaut_barrere Consultant Ruby / Elixir / Ansible Kiba ETL / Kiba Pro Remote 100% (Charente Maritime)

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Elixir => Code-Centric Digital Audio Workstation? infiniwip (tm)

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Previous episode https://github.com/thbar/demo-elixir-reloading-music Code.eval_file("music.exs")

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MIDI

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Note On {0x90 + channel, note, velocity} Note Off {0x80 + channel, note, release_velocity}

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Keyboard / Piano / Synthetizers photo by Clavia

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MIDI controllers photo by Novation

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Virtual Instruments (on computer)

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Virtual Instruments (on iOS) photo by Korg

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Lightning = Inter-Device Audio & MIDI (IDAM) photo by Apple

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Elixir Code / DRY Refactoring Music Augmented Human (theory, scales) Soft realtime

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brew install portmidi

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# 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})

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Computer: Note 60 Human: WTF????

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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

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DocTests ❤ ## Examples iex> MusicRef.note_number_to_latin_name(60) "Do4" iex> MusicRef.note_number_to_latin_name(78) "Fa#5"

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Phoenix LiveView

Time is <%= @time %>

HTML? ✔

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Phoenix LiveView SVG? ✔

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Phoenix LiveView

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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

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Code & Demo