Working with Custom Samples

Motif’s Sample Lab turns raw audio files into playable musical sources — trimmed loops, sliced hits, drum kits, and pitched instruments.

Import Flow

Use buildImportedAsset(filename, durationMs, src) to create an AudioAsset from a file:

Filename inference: inferSourceType(name) detects source type from the filename
Kind mapping: sourceTypeToKind(sourceType) maps source types to asset kinds
ID generation: filenameToId(filename) creates a clean, URL-safe ID

Imported assets get imported: true in their metadata.

Trim and Loop Editing

applyTrim(asset, startMs, endMs) sets the playback region non-destructively. applyLoopPoints(asset, loopStartMs, loopEndMs) defines the loop region within an asset — useful for sustain loops in melodic samples.

Slicing

Even slicing: sliceEvenly(assetId, startMs, endMs, count) divides a region into equal parts
Onset-based: sliceAtOnsets(assetId, onsets, totalEndMs) slices at specific time points

Building Kits

kitFromSlices(id, name, slices, basePitch) builds a kit by mapping slices to ascending MIDI pitches. Each kit slot maps a MIDI pitch to a sample slice.

Building Sample Instruments

createSampleInstrument(id, name, assetId, rootNote, pitchMin, pitchMax) creates a pitched instrument from a single audio source. The engine pitch-shifts the sample for each note.

Common Workflows

Drum Kit from a Loop

Import a drum loop as an audio asset
Open in Sample Lab, slice evenly or at onsets
Build a kit from slices with kitFromSlices
Use the kit in clips — each slot is a playable MIDI note

Melodic Instrument from a Single Sample

Import a tonal sample, trim to the clean sustain region
Set loop points if needed
Create a sample instrument with the correct root note
Use in clips — the engine pitch-shifts for each note

Texture from Field Recordings

Import a long ambient recording, slice into interesting sections
Build a kit — each slice becomes a triggerable texture
Use in a scene as an ambient layer triggered by game state