theallelectricsmartgrid

MIDI I/O Scheduling

This page documents input/output MIDI transport and scheduling used by the UI/controller stack.

Input handling (MidiInputHandler)

Defined in JUCE/SmartGridOne/Source/MidiHandlers.hpp.

• Opens JUCE input device by identifier.
• Converts incoming 3-byte MIDI messages into SmartGrid::BasicMidi with microsecond timestamps.
• Carries route ID (m_routeId) so downstream routing is explicit.
• Persists device name and supports reconnect (AttemptConnect) from saved config.

Integrations subclass SendMessage(BasicMidi) to forward into their MessageInBus.

Output handling (MidiOutputHandler)

Also in MidiHandlers.hpp.

• Opens JUCE output device with thread-safe SpinLock.
• Stores controller shape (m_shape) and route ID.
• Requires concrete Reset() and Process() implementations.
• Supports:
  • immediate message send (SendMessageNow),
  • block send (sendBlockOfMessages) for buffered paths.
• Persists output endpoint + shape in JSON.

MidiSender realtime dispatcher

Defined in JUCE/SmartGridOne/Source/MidiSender.hpp.

Key structure:

• JUCE realtime thread (startRealtimeThread) with tight scheduling params.
• queue: CircularQueue<BasicMidi, 16384>.
• route table: MidiOutputHandler* m_outputHandlers[16].

Core behaviors:

• AllocateRoute(handler) assigns route IDs and binds handlers.
• SendMessage(msg, routeId) enqueues timestamped output.
• HandleMessage() peeks queue head and sends only when target wall-clock time is reached:
  • targetTimeMs = msgTimestampMs + x_latencyMs.
• Shutdown() enables controlled draining behavior.

Transport clock forwarding

ProcessMessagesOut(MessageOutBuffer&, timestamp) converts sequencer transport events to MIDI real-time messages on m_clockRouteId:

• clock
• start
• stop

This decouples transport timing from controller rendering traffic.

Why this architecture

• Avoids blocking audio/control threads on OS MIDI I/O.
• Maintains explicit per-integration route separation.
• Enables predictable timing with a single centralized output scheduler.

Related

• Controller Integrations
• Message Routing and Smart Buses

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