Source: https://guthlabs.ai/docs/instruments/frame-rate-conversion-pulldown-calculator/implementation/

instrument implementation / implementation-contract

# Frame Rate Conversion / Pulldown Calculator implementation

A source-bound implementation contract for Frame Rate Conversion / Pulldown Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## 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

[01**Overview**](<https://guthlabs.ai/docs/instruments/frame-rate-conversion-pulldown-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/frame-rate-conversion-pulldown-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/frame-rate-conversion-pulldown-calculator/qualification/>)

## 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`