CMF 1.1 specification

The Common Model Format (CMF) is an executable annotation-operator contract. A conforming invocation combines a CMF package, declared input bindings, and active parameter values to transform source data into schema-typed annotations.

The specification fixes execution. It does not assert that the packaged model or its outputs are clinically valid.

Package contract

A CMF package is a directory or zip archive ending in .cmf. It contains:

• config.json, the machine-readable operator declaration;
• labels.json, the declared label metadata;
• the runtime entry point declared by runtime.entry;
• every weight, lookup, or other artifact required by that entry point.

config.json declares:

Component	Required content
Identity	cmf_version, model name, and package version
Runtime	supported runtime type and packaged entry point
Inputs	input names, modalities, channels, sampling rates, and shapes where fixed
Outputs	output names, types, labels, and shapes where fixed
Execution	whole-signal or windowed mode and its temporal semantics
Decision	threshold and, for windowed outputs, interval reconstruction settings
Parameters	names, types, defaults, and permitted values of exposed model parameters
Mapping	output name to annotation lane and label
Requirements	external runtime dependencies not bundled with the package

The invocation record supplies the concrete source and channel bindings, active parameter values, and any permitted output-mapping overrides. A stochastic runtime must expose and fix its random seed as a declared parameter; otherwise it is not deterministic under this conformance definition.

Windowed execution

A CMF 1.1 windowed declaration requires:

{
  "mode": "windowed",
  "window_size_ms": 3000,
  "stride_ms": 500,
  "window_anchor": "start",
  "terminal_window": "drop",
  "threshold": 0.9,
  "postprocessing": {
    "merge_gap_ms": 0,
    "min_duration_ms": 0
  }
}

CMF 1.1 currently defines one canonical schedule:

1. The first complete window begins at the first sample in the selected execution range.
2. Subsequent windows advance by stride_ms after conversion to the bound input's sampling grid.
3. Each result is timestamped at its window start.
4. A terminal partial window is dropped and is never padded implicitly.
5. Multiple bound inputs must resolve to the same window-start timeline.

Probability and classification reconstruction

For a mapped windowed probability or classification output:

1. A decision is positive when its value is greater than or equal to threshold.
2. A positive decision covers the complete half-open input window [start, start + window_size_ms).
3. Overlapping or touching positive windows are unioned.
4. Separate reconstructed intervals are bridged when their gap is less than or equal to merge_gap_ms.
5. Intervals shorter than min_duration_ms are removed after union and bridging.
6. Annotation confidence is the mean of the positive decision values contributing to the interval; bridged negative decisions do not contribute.
7. The declared output mapping assigns the resulting interval to its annotation lane and label.

Whole-signal interval and point outputs are emitted by the packaged runtime and mapped directly after bounds validation.

Backward compatibility

CMF 1.0 windowed packages remain loadable with these defaults:

• window_anchor = "start";
• terminal_window = "drop";
• merge_gap_ms = 0;
• min_duration_ms = 0.

CMF 1.1 windowed packages must declare these values explicitly. Negative merge gaps or minimum durations are invalid.

Sufficiency and conformance

For deterministic runtimes, a complete package plus identical bindings, parameter values, source data, coordinate registration, and execution range is sufficient to determine:

• the window timeline;
• model inputs and raw outputs;
• threshold decisions;
• reconstructed interval or point annotations;
• their lane, label, confidence, and provenance source.

Two conforming runners disagree if these canonical outputs differ beyond the numerical tolerance declared for the evaluation. Such a disagreement falsifies either runner conformance or the completeness of this specification.