Bit Rate ↔ File Size for Audio Codecs (MP3/AAC/FLAC estimate) 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

t5-115

Effect

Computation or source lookup only

Input and validation requirements

An extreme but numerically representable input overflows ordinary JavaScript floating-point arithmetic and produces Infinity instead of a finite size. The convention probe also exposes materially different displayed values if decimal and binary bitrate or storage units are mixed.

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": {
    "codec": "MP3",
    "bitrate_bps": 128000,
    "duration_seconds": 180
  },
  "expected_outputs": {
    "estimated_size_bytes": 2880000,
    "estimated_size_MB_decimal": 2.88,
    "estimated_size_MiB": 2.74658203125
  },
  "working": "size = bitrate × duration ÷ 8\n= 128,000 bits/s × 180 s ÷ 8\n= 23,040,000 bits ÷ 8\n= 2,880,000 bytes\n= 2.88 MB decimal\n= 2,880,000 ÷ 1,048,576\n= 2.74658203125 MiB"
}

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-tranche5/tranche5-results.json