Skip to content
Stardust

Patch Sequencing

Walk through an ordered list of patches in a Song, advancing with a footswitch. Zero stuck notes. Instant switching.

✅ Shipped · v0.5.0

What it does

Each Song in Stardust contains an ordered list of Patches that the keyboardist advances through during the performance. Press the footswitch → next patch loads instantly with no clicks, pops, or stuck notes from the previous patch.

This is the core play experience of Stardust. See Shows, Songs, and Patches for the concept.

How advancing works

When you advance from Patch N to Patch N+1:

  1. All notes held on the outgoing patch are handled per the patch’s transition config:
    • Release naturally (default — sounds musical)
    • Cut immediately
    • Carry over to the new patch (for sustained pads)
  2. Sustain pedal is conceptually released for the outgoing patch (to prevent stuck-sustain)
  3. The new patch’s VST chain is already loaded — pre-loaded in memory
  4. A configurable transition plays — immediate / short fade / crossfade
  5. MIDI mappings swap to the new patch’s mappings instantly
  6. UI updates — patch label changes, patch list strip highlights the new active patch
  7. Patch N+2 begins pre-loading in the background so the next advance is also instant

Total perceived latency: under 20 ms for the audio swap. UI updates are 30-60 ms (imperceptible to musicians).

Pre-loading strategy

To make patch advances instant, we pre-load adjacent patches in memory:

  • Current patch is fully instantiated and processing audio
  • Next patch (N+1) is instantiated with state loaded, but muted
  • Previous patch (N-1) similarly pre-loaded for back-foot navigation
  • When you advance: just swap which patch is unmuted; the new one is ready

Memory cost: ~2-3x what a single patch would use. Worth it for instant switching.

Direct jump

In addition to next/prev advance:

  • Keyboard 1-9 — number keys jump directly to that patch in the current Song
  • Footswitch with jump action — assign specific footswitches to specific patches
  • MIDI cue — incoming MIDI message triggers a Patch jump
  • Touch the patch list strip in Live Mode — tap a patch to jump

Jumps work the same way as advance — pre-loading, voice tracking, transitions all apply.

Voice tracking (preventing stuck notes)

Stuck notes between patches are the single most common reliability complaint about live-host software. Stardust avoids them by tracking every active voice.

Every active note is recorded by (channel, note, plugin_id) in a pre-allocated buffer. On patch change:

  1. Identify all notes currently held on the outgoing patch’s plugins
  2. Send note-off for each, plus sustain-off, plus all-notes-off as belt-and-suspenders
  3. Switch to the new patch
  4. Notes physically pressed now go to the new patch’s plugins

The voice tracker is pre-allocated (no allocation in audio thread), tracks up to N voices (default 1024 — far more than any musician would ever hold), and is reset on Show load.

If something goes wrong (plugin crashes, MIDI message dropped), the panic button brute-force broadcasts all-notes-off on every channel.

See Voice Tracking.

Patch transitions

Each Patch can configure its transition style:

  • Immediate (default) — instant swap, fast and tight
  • Short fade — 50-100 ms crossfade, hides any minor mismatch
  • Long crossfade — 1-3 second blend, useful for ambient transitions where you want to merge sounds

Transitions are per-target patch (i.e., “when this patch becomes active, fade in over X ms”). The outgoing patch’s audio is faded out by the same envelope.

Sustain bridging

A configurable option per Patch: when a note is being held during a patch change, what happens?

  • Cut — notes stop immediately (snappy, predictable)
  • Release naturally (default) — notes follow their normal release envelope on the outgoing patch
  • Carry over — held notes continue sustaining on the new patch (rare, for sustained pad/string parts)

Carry-over is unusual but useful: e.g. a sustained string pad that needs to glide between sound design variations without note retrigger.

Patch list UI

In Live Mode, the patch list strip widget shows all patches in the current Song:

[Patch 1: Whistle]  [Patch 2: Bells]  [● Patch 3: Pad]  [Patch 4: Glass]
                                       ^current

Current patch highlighted, others dimmed. Tap any patch to jump. Strip auto-scrolls if there are too many to fit.

Optionally show next patch preview as a separate widget — large text saying “Up next: Patch 4 — Glass” so you know what’s coming.

See Widget Registry.

Performance characteristics

OperationTarget
Footswitch press → audio swap< 20 ms
UI update on advance< 60 ms
Plugin pre-load (background)< 500 ms per plugin
Voice tracker capacity1024 simultaneous notes (configurable)
Memory overhead~2-3x single patch (for adjacent pre-load)

Phase status

PhaseWhat’s available
v0.2Voice tracker, panic key, manual patch swap in code
v0.4Full sequencing with UI, pre-load, transitions, sustain bridging
v0.5Smarter transitions (per-instrument crossfade rules)