pre-echo is a human-made category of audible pre-artifacts in audio coding, defined by the temporal spreading of quantization noise or coding error before a transient event. It is carved by parameters including pre-echo duration in milliseconds, transient rise time, coding window length, and bit-rate, and it persists through psychoacoustic models, codec standards such as MPEG Layer III and AAC, engineering test signals, and literature on temporal masking. [formal: prae-echo | substrate: mind | horizon: a moment | explicit: yes | epoch: 0.11]
Accepted ontology entry
pre-echo
pre-echo is a human-made category of audible pre-artifacts in audio coding, defined by the temporal spreading of quantization noise or coding error before a transient event. It is carved by parameters including pre-echo duration in millise…
Definition
Why it is in scope
A human-made audio artifact describing audible artifacts preceding transients in lossy audio compression, built to persist in psychoacoustic literature, codec specifications, and audio engineering practice.
Names and aliases
- pre-echoen · CANONICAL
Relations from this entry
- cmsthfps6014z13a4dzw2hmvcDERIVED_FROM →
Pre-echo as a categorized artifact was identified and formalized within psychoacoustics research on temporal masking and codec perception; the concept inherits its perceptual framing from psychoacoustics.
- cmstf97xx014613a4pbllmi2dDERIVED_FROM →
Pre-echo was derived from temporal masking research. Which came first? Temporal masking is a more fundamental psychoacoustic phenomenon that was identified earlier; pre-echo as a codec artifact was recognized within that framework. Direction: pre-echo DERIVED_FROM temporal-masking.
- cmsp6zgox04bkjlssq1q4peafDEPENDS_ON →
Pre-echo IS the temporal spreading of quantization error across the codec's finite analysis window — the artifact's own accepted definition carves it by 'coding window length', and the canonical fix (short-window/granule switching) is precisely a change of windowing. Removal test: remove windowing (no finite analysis window to carry error across) and quantization error cannot spread before the transient — pre-echo stops existing as a phenomenon. Pinned sense: windowing as the technique of tapering a segment by a window function before transform, per its accepted definition.
- cmsnet9gh03q31q131146onk3DEPENDS_ON →
Pre-echo IS the temporal spreading of quantization error across finite analysis windows. Remove quantization entirely — no discrete amplitude levels, no quantization error — and pre-echo has no mechanism and cannot exist. The accepted definition of pre-echo carves it by reference to 'quantization error' and 'coding window length.' Removal test passes: X (pre-echo) stops existing without Y (quantization).
- transform-codingDERIVED_FROM →
Pre-echo as a named artifact concept derives from transform coding — it was identified and characterized within the context of transform-coded audio where block-based transforms and windowing cause quantization error to spread temporally. Remove transform coding and the concept of pre-echo as described here has no referent.
Relations to this entry
No accepted relations in this direction.
Record identity
- Created
- Aug 16, 2026, 9:59 AM UTC
- Content hash
- f41fc22f22abe940b34b22ae2fdc8d7abbd3383849f7be38212affe0c5a8a6ed