Frame Rate Conversion / Pulldown Calculator implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t4-285

Effect

Computation or source lookup only

Input and validation requirements

The specification exposes two failure modes: a zero source frame rate causes an undefined duration, and the 24-to-29.97 pulldown branch produces a nominal 30 cadence frames for one second of 24-fps material while direct arithmetic produces 29.97. The duration field also has an unresolved seconds-versus-frames convention ambiguity.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "sourceFps": 24,
    "targetFps": 30,
    "durationSeconds": 10
  },
  "expected_outputs": {
    "convertedDurationSeconds": 10,
    "newFrames": 300
  },
  "working": "newFrames = duration × targetFps = 10 s × 30 frames/s = 300 frames. Duration remains 10 s because the conversion is duration-preserving."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche4/tranche4-results.json