Source: https://guthlabs.ai/docs/instruments/latency-buffer-size-calculator/mechanism/

instrument mechanism / verified-clean

# Latency / Buffer Size Calculator mechanism

The inspectable method record for Latency / Buffer Size Calculator, kept separate from implementation and qualification.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Model scope

The arithmetic is valid only under the explicit 0 ms I/O-overhead assumption. The instrument cannot be verified as fully specified until the overhead estimate and round-trip toggle behavior are defined. The honest label correctly indicates that driver and DAC hardware latency add-ons are excluded, but it should also disclose that the I/O overhead term is either omitted or an explicitly defined estimate.

- The base formula bufferSize/sampleRate*1000 is correct for the duration of one buffer, assuming bufferSize is in samples and sampleRate is in samples per second (Hz).

- Multiplying by 2 is a reasonable simplified estimate for input-plus-output buffer latency, but it is not universally the complete round-trip latency formula because interface, driver, conversion, and scheduling delays may differ.

- The phrase '+ I/O overhead estimate' is incomplete: no overhead value, input, default, or calculation method is specified, so the stated formula cannot produce a unique output.

- The round-trip toggle semantics are not explicitly defined for whether the I/O overhead estimate is applied in one-way mode, round-trip mode, or both.

## Units and conventions

- bufferSize is a non-negative number of samples per buffer.

- sampleRate is a positive number of samples per second, expressed in Hz.

- 1000 converts seconds to milliseconds.

- The test calculations assume the unspecified I/O overhead estimate is 0 ms; this assumption must be made explicit before implementation.

- A round-trip estimate is modeled as two buffer durations: 2*bufferSize/sampleRate*1000.

## Inspectable vector

One of 4 source-bound review vectors:

````
{
  "inputs": {
    "bufferSize": 256,
    "sampleRate": 48000,
    "roundTrip": true
  },
  "expected_outputs": {
    "latencyMs": 10.666666667
  },
  "working": "One buffer: 256 / 48000 s = 0.005333333333 s. Convert: 0.005333333333 * 1000 = 5.333333333 ms. Round trip: 5.333333333 * 2 = 10.666666667 ms. I/O overhead assumed: 0 ms. Total = 10.666666667 ms."
}
````

## Failure boundary

**BREAK_CLAIMED** · SELF_FLAGGED

A sample rate of zero causes an undefined division and must be rejected. Additionally, the specification provides no numeric I/O overhead estimate, so exact total latency is underdetermined unless the implementation documents or supplies H; the outputs above therefore include the computable base latency and express the total as base plus H.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/latency-buffer-size-calculator/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/latency-buffer-size-calculator/implementation/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/latency-buffer-size-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`

- `BOUNDARY_HAZARD_CATALOG.json`