Data Rate / Storage Planner (Camera Codecs)

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Audio, Music, Photography & Color

Tranche

tranche-7

Evidence ID

t7-040

Ledger rows

1

No ledger note is attached.

Review findings

The arithmetic method is valid after explicit unit and lookup-key conventions are added. The current specification is incomplete because it claims resolution/fps-aware codec lookup and card-count output without listing resolution, fps, or card capacity as required inputs, and it does not define decimal GB versus GiB. The honest-label warning about manufacturer-published nominal rates and scene-dependent VBR is appropriate but should also mention audio/container overhead and recommend a safety margin.

Formula and scope findings

• storage = dataRate(MB/s) × duration(s) is correct only when the rate is truly in decimal MB/s; if the lookup table stores Mbps, the required conversion is dataRate(Mbps) ÷ 8.
• The advertised storage GB output requires an explicit convention: decimal GB = MB ÷ 1000, or binary GiB = MiB ÷ 1024. These are not interchangeable.
• The specification does not state the formula for cards needed. Under the stated storage-planning purpose it should be cardsNeeded = ceil(storageGB ÷ cardCapacityGB), with card capacity using the same decimal/binary convention.
• Resolution and frame rate are mentioned in the computation claim but are absent from the listed inputs and are required lookup keys for most codec-rate tables.
• A single nominal rate is not generally valid for VBR H.264 or H.265; scene complexity, encoder settings, audio, container overhead, and camera-specific implementation can change the actual rate.
• The codec preset lookup must identify the manufacturer, codec profile, resolution, frame rate, bit depth, chroma subsampling, and intra/inter-frame mode; names such as H.264 or ProRes alone are insufficient.

Unit assumptions

• The vectors use decimal megabytes and gigabytes: 1 MB = 1,000,000 bytes and 1 GB = 1,000 MB.
• When a table value is in megabits per second, conversion is Mbps ÷ 8 = MB/s.
• Duration is in seconds and must be nonnegative.
• Card capacity is treated as decimal GB and must be positive.
• Cards needed is rounded upward with the mathematical ceiling function; zero-duration input produces zero required storage and zero cards under the literal formula.
• Nominal codec rates exclude or ignore possible audio, container, metadata, filesystem, and formatting overhead unless the selected table explicitly includes them.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

A card size of exactly zero makes the cards-needed calculation undefined due to division by zero; the instrument should reject that input. The convention probe also shows materially different results if duration units are misread.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "codec_preset": "Apple ProRes 422 HQ",
    "resolution": "3840x2160",
    "fps": 30,
    "duration_s": 3600,
    "card_capacity_GB": 128
  },
  "expected_outputs": {
    "data_rate_Mbps": 707,
    "data_rate_MB_s": 88.375,
    "storage_GB": 318.15,
    "cards_needed": 3
  },
  "reference_data": {
    "codec": "Apple ProRes 422 HQ",
    "resolution": "3840x2160",
    "fps": 30,
    "nominal_data_rate_Mbps": 707,
    "source_convention": "widely tabulated standard value; Apple ProRes manufacturer nominal-rate table"
  },
  "working": "1. Convert rate: 707 Mbps ÷ 8 = 88.375 MB/s. 2. Storage: 88.375 MB/s × 3,600 s = 318,150 MB. 3. Convert to decimal GB: 318,150 MB ÷ 1,000 = 318.15 GB. 4. Cards: ceil(318.15 GB ÷ 128 GB) = ceil(2.485546875) = 3 cards."
}

Related workflows

No source-defined multi-instrument workflow membership is recorded.

Sources and evidence

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

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche7/tranche7-results.json
• BOUNDARY_HAZARD_CATALOG.json