5.3. Key Detection and Matching

Benchmark-Guided Modal is the default detector projection and supports Ionian, Dorian, Phrygian, Lydian, Mixolydian, and Aeolian. Benchmark Major / Minor provides a conventional two-mode view. Chroma-Driven Modal retains the earlier modal projection for comparison.

Start / end keys compares the detected second half of the source track with the first half of the destination. This is the default because a transition is directional: the outgoing part of one track meets the incoming part of another.

Whole-track key combines both analyzed halves in proportion to their duration, detects one key, and uses it at both boundaries. When whole-track matching is active, the separate start/end relationship control is not used.

With start/end matching, the relationship control can require, prefer, ignore, discourage, or require a key change within each track. Preferences are soft tie-breakers after transition quality; requirements filter newly selected tracks.