كشف البداية في الصوت

An onset is the start of an acoustic event, such as a drum attack or string pluck. Classic methods compute an onset detection function (ODF) that rises when the signal changes. Spectral flux compares short-time Fourier transform magnitude frames and sums positive energy increases. Peak picking with a local threshold selects candidate onset times. When onsets are used as slice points, backtracking can move a detected time to a preceding local minimum of an energy signal. Percussive sounds with sharp attacks can be easier to detect than gradual swells. Neural models can learn onset cues from examples, but superiority over hand-designed ODFs is not universal; results depend on the training and test sets. A published inter-dataset study found that a model pretrained on one dataset failed to transfer to another, underscoring the need to evaluate each intended domain.