The Preamble

The preamble is the Rosetta Stone of a .life file.

It must contain sufficient information for a reader with no prior knowledge of LIFE to understand the structure of what follows. It is the first section of every .life file and must appear before the codec and events.

Required fields

Field	Type	Description
format	string	Always "LIFE". Identifies the file type.
version	string	Specification version. Currently "1.0".
created	string	ISO 8601 date of creation.
scaling	object	The mathematical bridge between source and target spectra.
reference	object	The anchor frequency for all ratio calculations.
spectrum	object	The target electromagnetic range.

The scaling object

The scaling object must explain not just the value used but the reasoning behind it. A .life file is designed to be interpretable without external documentation - the file must explain itself.

Field	Type	Description
method	string	"octave_halving" in v1.0
constant	string	Human-readable expression - "2^40"
value	integer	Numeric value - 1099511627776
rational	string	Plain language explanation. Required.

The reference object

Field	Type	Description
frequency_hz	float	Reference frequency. Conventionally 440.0 (concert A4).
ratio	string	Always "1:1".
description	string	Human-readable description.

The spectrum object

Field	Type	Description
min_nm	integer	Minimum wavelength in nanometres.
max_nm	integer	Maximum wavelength in nanometres.
description	string	Human-readable description.

Example

"preamble": {
  "format":  "LIFE",
  "version": "1.0",
  "created": "2026-05-05",
  "scaling": {
    "method":   "octave_halving",
    "constant": "2^40",
    "value":    1099511627776,
    "rational": "40 octaves separate the audible and visible spectra.
                 Dividing any acoustic frequency by 2^40 maps it into
                 the electromagnetic range while preserving all harmonic
                 relationships. This constant is physically derived,
                 not conventionally assigned."
  },
  "reference": {
    "frequency_hz": 440.0,
    "ratio":        "1:1",
    "description":  "Concert pitch A4."
  },
  "spectrum": {
    "min_nm":      380,
    "max_nm":      700,
    "description": "Visible light, violet to red."
  }
}