FAILURE MAP
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FA-78701 / Broadcast timecode arithmetic / Open access

Frame-rate descriptor parsing: suffix separator · case 01

Descriptors like 59.94-DF are rejected as unknown rates.

Verified by executionVariant 1 · 9 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Only spaces are removed between the rate and the suffix.

THE FAILURE

Only spaces are removed between the rate and the suffix.

Unsuccessful approach: Stripping whitespace still leaves the hyphen attached to the rate.

Case contract

Parse a rate descriptor: a known rate (23.976, 23.98, 24, 25, 29.97, 30, 50, 59.94, 60; redundant trailing decimal zeros allowed) with an optional case-insensitive DF/NDF suffix, optionally separated by a space or hyphen; surrounding whitespace ignored. Drop frame is only valid for 29.97 and 59.94. Return [num,den,drop] or None.

Why this case matters

Timecode arithmetic errors misplace edits, commercial breaks and captions against the broadcast clock.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(s):
    t=s.strip().upper()
    drop=t.endswith('DF') and not t.endswith('NDF')
    base=t[:-3] if t.endswith('NDF') else t[:-2] if t.endswith('DF') else t
    base=base.rstrip(' ')
    if '.' in base:
        base=base.rstrip('0').rstrip('.')
    table={'23.976':(24000,1001),'23.98':(24000,1001),'24':(24,1),'25':(25,1),'29.97':(30000,1001),'30':(30,1),'50':(50,1),'59.94':(60000,1001),'60':(60,1)}
    if base not in table:
        return None
    num,den=table[base]
    if drop and den!=1001 or drop and num==24000:
        return None
    return [num,den,drop]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: suffix separator', ['59.94-df'], [60000, 1001, True]), ('regression variant: suffix separator', ['29.97-NDF'], [30000, 1001, False]), ('partial repair probe: suffix separator', [' 24-NDF '], [24, 1, False]), ('partial repair variant: suffix separator', ['59.94-DF'], [60000, 1001, True]), ('boundary control', ['29.97DF'], [30000, 1001, True]), ('boundary control', ['23.976'], [24000, 1001, False]), ('normal control', ['29.97 NDF'], [30000, 1001, False]), ('normal control', ['30.0'], [30, 1, False]), ('normal control', [' 23.98df '], None)], [('regression: suffix separator', [' 23.98-NDF '], [24000, 1001, False]), ('regression variant: suffix separator', [' 29.97-DF '], [30000, 1001, True]), ('partial repair probe: suffix separator', [' 59.94-DF '], [60000, 1001, True]), ('partial repair variant: suffix separator', ['29.970-NDF'], [30000, 1001, False]), ('boundary control', ['29.97 NDF'], [30000, 1001, False]), ('boundary control', ['30.0'], [30, 1, False]), ('normal control', ['60-DF'], None), ('normal control', [' 29.97NDF '], [30000, 1001, False]), ('normal control', [' 29.97 '], [30000, 1001, False])], [('regression: suffix separator', [' 24-NDF '], [24, 1, False]), ('regression variant: suffix separator', ['25-NDF'], [25, 1, False]), ('partial repair probe: suffix separator', [' 60-NDF '], [60, 1, False]), ('partial repair variant: suffix separator', ['60-NDF'], [60, 1, False]), ('boundary control', ['30DF'], None), ('boundary control', ['29.97DF'], [30000, 1001, True]), ('normal control', ['30'], [30, 1, False]), ('normal control', ['59.94 ndf'], [60000, 1001, False]), ('normal control', [' 60 '], [60, 1, False])], [('regression: suffix separator', [' 59.94-DF '], [60000, 1001, True]), ('regression variant: suffix separator', [' 59.94-NDF '], [60000, 1001, False]), ('partial repair probe: suffix separator', ['29.97-NDF'], [30000, 1001, False]), ('partial repair variant: suffix separator', ['25.00-NDF'], [25, 1, False]), ('boundary control', ['23.976'], [24000, 1001, False]), ('boundary control', ['29.97 NDF'], [30000, 1001, False]), ('normal control', ['30 ndf'], [30, 1, False]), ('normal control', ['30NDF'], [30, 1, False]), ('normal control', ['30.0 ndf'], [30, 1, False])], [('regression: suffix separator', [' 60-NDF '], [60, 1, False]), ('regression variant: suffix separator', ['59.94-DF'], [60000, 1001, True]), ('partial repair probe: suffix separator', [' 29.97-DF '], [30000, 1001, True]), ('partial repair variant: suffix separator', ['24-NDF'], [24, 1, False]), ('boundary control', ['30.0'], [30, 1, False]), ('boundary control', ['30DF'], None), ('normal control', [' 23.976 DF '], None), ('normal control', [' 50 '], [50, 1, False]), ('normal control', [' 29.97df '], [30000, 1001, True])]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
regression: suffix separatorNone[60000, 1001, True]Failed
regression variant: suffix separatorNone[30000, 1001, False]Failed
partial repair probe: suffix separatorNone[24, 1, False]Failed
partial repair variant: suffix separatorNone[60000, 1001, True]Failed
boundary control[30000, 1001, True][30000, 1001, True]Passed
boundary control[24000, 1001, False][24000, 1001, False]Passed
normal control[30000, 1001, False][30000, 1001, False]Passed
normal control[30, 1, False][30, 1, False]Passed
normal controlNoneNonePassed

SHA-256 / 626775f21d6d62c87f339e90fd69185a431739ace0318f828bcd7e38b685d8da

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(s):
    t=s.strip().upper()
    drop=t.endswith('DF') and not t.endswith('NDF')
    base=t[:-3] if t.endswith('NDF') else t[:-2] if t.endswith('DF') else t
    base=base.strip()
    if '.' in base:
        base=base.rstrip('0').rstrip('.')
    table={'23.976':(24000,1001),'23.98':(24000,1001),'24':(24,1),'25':(25,1),'29.97':(30000,1001),'30':(30,1),'50':(50,1),'59.94':(60000,1001),'60':(60,1)}
    if base not in table:
        return None
    num,den=table[base]
    if drop and den!=1001 or drop and num==24000:
        return None
    return [num,den,drop]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: suffix separator', ['59.94-df'], [60000, 1001, True]), ('regression variant: suffix separator', ['29.97-NDF'], [30000, 1001, False]), ('partial repair probe: suffix separator', [' 24-NDF '], [24, 1, False]), ('partial repair variant: suffix separator', ['59.94-DF'], [60000, 1001, True]), ('boundary control', ['29.97DF'], [30000, 1001, True]), ('boundary control', ['23.976'], [24000, 1001, False]), ('normal control', ['29.97 NDF'], [30000, 1001, False]), ('normal control', ['30.0'], [30, 1, False]), ('normal control', [' 23.98df '], None)], [('regression: suffix separator', [' 23.98-NDF '], [24000, 1001, False]), ('regression variant: suffix separator', [' 29.97-DF '], [30000, 1001, True]), ('partial repair probe: suffix separator', [' 59.94-DF '], [60000, 1001, True]), ('partial repair variant: suffix separator', ['29.970-NDF'], [30000, 1001, False]), ('boundary control', ['29.97 NDF'], [30000, 1001, False]), ('boundary control', ['30.0'], [30, 1, False]), ('normal control', ['60-DF'], None), ('normal control', [' 29.97NDF '], [30000, 1001, False]), ('normal control', [' 29.97 '], [30000, 1001, False])], [('regression: suffix separator', [' 24-NDF '], [24, 1, False]), ('regression variant: suffix separator', ['25-NDF'], [25, 1, False]), ('partial repair probe: suffix separator', [' 60-NDF '], [60, 1, False]), ('partial repair variant: suffix separator', ['60-NDF'], [60, 1, False]), ('boundary control', ['30DF'], None), ('boundary control', ['29.97DF'], [30000, 1001, True]), ('normal control', ['30'], [30, 1, False]), ('normal control', ['59.94 ndf'], [60000, 1001, False]), ('normal control', [' 60 '], [60, 1, False])], [('regression: suffix separator', [' 59.94-DF '], [60000, 1001, True]), ('regression variant: suffix separator', [' 59.94-NDF '], [60000, 1001, False]), ('partial repair probe: suffix separator', ['29.97-NDF'], [30000, 1001, False]), ('partial repair variant: suffix separator', ['25.00-NDF'], [25, 1, False]), ('boundary control', ['23.976'], [24000, 1001, False]), ('boundary control', ['29.97 NDF'], [30000, 1001, False]), ('normal control', ['30 ndf'], [30, 1, False]), ('normal control', ['30NDF'], [30, 1, False]), ('normal control', ['30.0 ndf'], [30, 1, False])], [('regression: suffix separator', [' 60-NDF '], [60, 1, False]), ('regression variant: suffix separator', ['59.94-DF'], [60000, 1001, True]), ('partial repair probe: suffix separator', [' 29.97-DF '], [30000, 1001, True]), ('partial repair variant: suffix separator', ['24-NDF'], [24, 1, False]), ('boundary control', ['30.0'], [30, 1, False]), ('boundary control', ['30DF'], None), ('normal control', [' 23.976 DF '], None), ('normal control', [' 50 '], [50, 1, False]), ('normal control', [' 29.97df '], [30000, 1001, True])]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
regression: suffix separatorNone[60000, 1001, True]Failed
regression variant: suffix separatorNone[30000, 1001, False]Failed
partial repair probe: suffix separatorNone[24, 1, False]Failed
partial repair variant: suffix separatorNone[60000, 1001, True]Failed
boundary control[30000, 1001, True][30000, 1001, True]Passed
boundary control[24000, 1001, False][24000, 1001, False]Passed
normal control[30000, 1001, False][30000, 1001, False]Passed
normal control[30, 1, False][30, 1, False]Passed
normal controlNoneNonePassed

SHA-256 / 66a43add39700c9b0ca258f111d2df82ee4834f50be233cfb97e9a4ea894ccf4

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 9 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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Verification & scope

A deterministic bounded teaching model with a stipulated toy contract; it does not claim conformance to SMPTE or any broadcast standard. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:49:37.927257+00:00.

Case digest / b78cf6dbab1ef09ab26ffcf8c120fa4cd98ffcce9cb9f1d7a97fdf9f59b4eee4