FA-77851 / Subtitle cue timing / Open access

SRT timestamp parsing: minute and second range · case 01

A malformed timestamp such as 00:60:00,000 is accepted and silently becomes one hour.

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

ROOT CAUSE

The sexagesimal range check uses a strict > 60 bound, admitting the value 60 itself.

VERIFIED REPAIR

Reject minutes or seconds equal to or above 60.

Unsuccessful approach: Fixing only the minute bound still lets a seconds field of exactly 60 roll into the next minute.

Case contract

Parse an SRT timestamp HH:MM:SS,mmm to integer milliseconds. Hours have 2 or more digits, minutes and seconds are below 60, the fraction has 1 to 3 digits and is right-padded (",5" means 500 ms), "." is accepted as the separator, surrounding whitespace (including a CR from CRLF files) is ignored; invalid text returns None.

Why this case matters

Subtitle timing defects shift, hide or overlap captions that viewers depend on for comprehension and accessibility.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(s):
    s=s.strip()
    parts=s.replace('.',',').split(',')
    if len(parts)!=2: return None
    hms,frac=parts
    fields=hms.split(':')
    if len(fields)!=3: return None
    if not all(p.isdigit() for p in fields) or not frac.isdigit(): return None
    if len(frac)>3: return None
    h,mi,se=int(fields[0]),int(fields[1]),int(fields[2])
    if mi>60 or se>60: return None
    ms=int(frac.ljust(3,'0'))
    return h*3600000+mi*60000+se*1000+ms
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: minute and second range', ['00:60:00,000'], None), ('regression variant: minute and second range', ['10:60:60,07 '], None), ('partial repair probe: minute and second range', ['00:00:60,07'], None), ('partial repair variant: minute and second range', ['02:00:60,12\r'], None), ('boundary control', ['00:00:00,000'], 0), ('boundary control', ['00:59:59,999\r'], 3599999), ('normal control', ['00:00:01,5'], 1500), ('normal control', ['100:00:00,000'], 360000000), ('normal control', ['00:61:00;5 \r'], None)], [('regression: minute and second range', ['123:60:59,5'], None), ('regression variant: minute and second range', ['00:00:60,07'], None), ('partial repair probe: minute and second range', [' 02:30:60.500 '], None), ('partial repair variant: minute and second range', ['01:05:60,999 '], None), ('boundary control', ['00:00:01,5'], 1500), ('boundary control', ['100:00:00,000'], 360000000), ('normal control', [' 10:60:42;50\r'], None), ('normal control', ['99:00:59,001 \r'], 356459001), ('normal control', ['00:00:60.1234 '], None)], [('regression: minute and second range', [' 00:30:60,500'], None), ('regression variant: minute and second range', [' 99:60:00.000'], None), ('partial repair probe: minute and second range', ['99:30:60.000'], None), ('partial repair variant: minute and second range', ['99:30:60,001 '], None), ('boundary control', ['01:02:03.004'], 3723004), ('boundary control', ['00:00:00,000'], 0), ('normal control', [' 10:00:61.001\r'], None), ('normal control', ['99:30:00,'], None), ('normal control', [' 00:61:42,000'], None)], [('regression: minute and second range', [' 00:00:60,12 '], None), ('regression variant: minute and second range', ['99:60:59,12 \r'], None), ('partial repair probe: minute and second range', [' 10:30:60,5\r'], None), ('partial repair variant: minute and second range', ['00:59:60,07 '], None), ('boundary control', ['00:59:59,999\r'], 3599999), ('boundary control', ['00:00:01,5'], 1500), ('normal control', [' 10:05:00.000'], 36300000), ('normal control', [' 00:05:00.5 '], 300500), ('normal control', ['123:05:01,001\t'], 443101001)], [('regression: minute and second range', ['123:60:42,999'], None), ('regression variant: minute and second range', ['100:60:60,999 '], None), ('partial repair probe: minute and second range', ['123:00:60.07\t'], None), ('partial repair variant: minute and second range', ['100:05:60,001\t'], None), ('boundary control', ['100:00:00,000'], 360000000), ('boundary control', ['01:02:03.004'], 3723004), ('normal control', ['123:00:61,001 \r'], None), ('normal control', ['100:59:42.001\r'], 363582001), ('normal control', [' 10:30:61;001 '], None)]]
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 fixture	Actual	Expected	Outcome
regression: minute and second range	`3600000`	`None`	Failed
regression variant: minute and second range	`39660070`	`None`	Failed
partial repair probe: minute and second range	`60070`	`None`	Failed
partial repair variant: minute and second range	`7260120`	`None`	Failed
boundary control	`0`	`0`	Passed
boundary control	`3599999`	`3599999`	Passed
normal control	`1500`	`1500`	Passed
normal control	`360000000`	`360000000`	Passed
normal control	`None`	`None`	Passed

SHA-256 / 11a09d9cd248dc289157ba5e0d20d22c8c60b0bb7cb3b91d00ec8256e0959cc3

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(s):
    s=s.strip()
    parts=s.replace('.',',').split(',')
    if len(parts)!=2: return None
    hms,frac=parts
    fields=hms.split(':')
    if len(fields)!=3: return None
    if not all(p.isdigit() for p in fields) or not frac.isdigit(): return None
    if len(frac)>3: return None
    h,mi,se=int(fields[0]),int(fields[1]),int(fields[2])
    if mi>=60 or se>60: return None
    ms=int(frac.ljust(3,'0'))
    return h*3600000+mi*60000+se*1000+ms
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: minute and second range', ['00:60:00,000'], None), ('regression variant: minute and second range', ['10:60:60,07 '], None), ('partial repair probe: minute and second range', ['00:00:60,07'], None), ('partial repair variant: minute and second range', ['02:00:60,12\r'], None), ('boundary control', ['00:00:00,000'], 0), ('boundary control', ['00:59:59,999\r'], 3599999), ('normal control', ['00:00:01,5'], 1500), ('normal control', ['100:00:00,000'], 360000000), ('normal control', ['00:61:00;5 \r'], None)], [('regression: minute and second range', ['123:60:59,5'], None), ('regression variant: minute and second range', ['00:00:60,07'], None), ('partial repair probe: minute and second range', [' 02:30:60.500 '], None), ('partial repair variant: minute and second range', ['01:05:60,999 '], None), ('boundary control', ['00:00:01,5'], 1500), ('boundary control', ['100:00:00,000'], 360000000), ('normal control', [' 10:60:42;50\r'], None), ('normal control', ['99:00:59,001 \r'], 356459001), ('normal control', ['00:00:60.1234 '], None)], [('regression: minute and second range', [' 00:30:60,500'], None), ('regression variant: minute and second range', [' 99:60:00.000'], None), ('partial repair probe: minute and second range', ['99:30:60.000'], None), ('partial repair variant: minute and second range', ['99:30:60,001 '], None), ('boundary control', ['01:02:03.004'], 3723004), ('boundary control', ['00:00:00,000'], 0), ('normal control', [' 10:00:61.001\r'], None), ('normal control', ['99:30:00,'], None), ('normal control', [' 00:61:42,000'], None)], [('regression: minute and second range', [' 00:00:60,12 '], None), ('regression variant: minute and second range', ['99:60:59,12 \r'], None), ('partial repair probe: minute and second range', [' 10:30:60,5\r'], None), ('partial repair variant: minute and second range', ['00:59:60,07 '], None), ('boundary control', ['00:59:59,999\r'], 3599999), ('boundary control', ['00:00:01,5'], 1500), ('normal control', [' 10:05:00.000'], 36300000), ('normal control', [' 00:05:00.5 '], 300500), ('normal control', ['123:05:01,001\t'], 443101001)], [('regression: minute and second range', ['123:60:42,999'], None), ('regression variant: minute and second range', ['100:60:60,999 '], None), ('partial repair probe: minute and second range', ['123:00:60.07\t'], None), ('partial repair variant: minute and second range', ['100:05:60,001\t'], None), ('boundary control', ['100:00:00,000'], 360000000), ('boundary control', ['01:02:03.004'], 3723004), ('normal control', ['123:00:61,001 \r'], None), ('normal control', ['100:59:42.001\r'], 363582001), ('normal control', [' 10:30:61;001 '], None)]]
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 fixture	Actual	Expected	Outcome
regression: minute and second range	`None`	`None`	Passed
regression variant: minute and second range	`None`	`None`	Passed
partial repair probe: minute and second range	`60070`	`None`	Failed
partial repair variant: minute and second range	`7260120`	`None`	Failed
boundary control	`0`	`0`	Passed
boundary control	`3599999`	`3599999`	Passed
normal control	`1500`	`1500`	Passed
normal control	`360000000`	`360000000`	Passed
normal control	`None`	`None`	Passed

SHA-256 / b568922ad63f04221173b08dae00d009d9cf522fb3c3fc0968eeef0a07507dce

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(s):
    s=s.strip()
    parts=s.replace('.',',').split(',')
    if len(parts)!=2: return None
    hms,frac=parts
    fields=hms.split(':')
    if len(fields)!=3: return None
    if not all(p.isdigit() for p in fields) or not frac.isdigit(): return None
    if len(frac)>3: return None
    h,mi,se=int(fields[0]),int(fields[1]),int(fields[2])
    if mi>=60 or se>=60: return None
    ms=int(frac.ljust(3,'0'))
    return h*3600000+mi*60000+se*1000+ms
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: minute and second range', ['00:60:00,000'], None), ('regression variant: minute and second range', ['10:60:60,07 '], None), ('partial repair probe: minute and second range', ['00:00:60,07'], None), ('partial repair variant: minute and second range', ['02:00:60,12\r'], None), ('boundary control', ['00:00:00,000'], 0), ('boundary control', ['00:59:59,999\r'], 3599999), ('normal control', ['00:00:01,5'], 1500), ('normal control', ['100:00:00,000'], 360000000), ('normal control', ['00:61:00;5 \r'], None)], [('regression: minute and second range', ['123:60:59,5'], None), ('regression variant: minute and second range', ['00:00:60,07'], None), ('partial repair probe: minute and second range', [' 02:30:60.500 '], None), ('partial repair variant: minute and second range', ['01:05:60,999 '], None), ('boundary control', ['00:00:01,5'], 1500), ('boundary control', ['100:00:00,000'], 360000000), ('normal control', [' 10:60:42;50\r'], None), ('normal control', ['99:00:59,001 \r'], 356459001), ('normal control', ['00:00:60.1234 '], None)], [('regression: minute and second range', [' 00:30:60,500'], None), ('regression variant: minute and second range', [' 99:60:00.000'], None), ('partial repair probe: minute and second range', ['99:30:60.000'], None), ('partial repair variant: minute and second range', ['99:30:60,001 '], None), ('boundary control', ['01:02:03.004'], 3723004), ('boundary control', ['00:00:00,000'], 0), ('normal control', [' 10:00:61.001\r'], None), ('normal control', ['99:30:00,'], None), ('normal control', [' 00:61:42,000'], None)], [('regression: minute and second range', [' 00:00:60,12 '], None), ('regression variant: minute and second range', ['99:60:59,12 \r'], None), ('partial repair probe: minute and second range', [' 10:30:60,5\r'], None), ('partial repair variant: minute and second range', ['00:59:60,07 '], None), ('boundary control', ['00:59:59,999\r'], 3599999), ('boundary control', ['00:00:01,5'], 1500), ('normal control', [' 10:05:00.000'], 36300000), ('normal control', [' 00:05:00.5 '], 300500), ('normal control', ['123:05:01,001\t'], 443101001)], [('regression: minute and second range', ['123:60:42,999'], None), ('regression variant: minute and second range', ['100:60:60,999 '], None), ('partial repair probe: minute and second range', ['123:00:60.07\t'], None), ('partial repair variant: minute and second range', ['100:05:60,001\t'], None), ('boundary control', ['100:00:00,000'], 360000000), ('boundary control', ['01:02:03.004'], 3723004), ('normal control', ['123:00:61,001 \r'], None), ('normal control', ['100:59:42.001\r'], 363582001), ('normal control', [' 10:30:61;001 '], None)]]
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 fixture	Actual	Expected	Outcome
regression: minute and second range	`None`	`None`	Passed
regression variant: minute and second range	`None`	`None`	Passed
partial repair probe: minute and second range	`None`	`None`	Passed
partial repair variant: minute and second range	`None`	`None`	Passed
boundary control	`0`	`0`	Passed
boundary control	`3599999`	`3599999`	Passed
normal control	`1500`	`1500`	Passed
normal control	`360000000`	`360000000`	Passed
normal control	`None`	`None`	Passed

SHA-256 / b320c3ddf333d2d4b97233ac5121c4d0406a4aef4db3b9d6c696d4603f9474ab

Verification & scope

A deterministic bounded teaching model with a stipulated toy contract; it does not claim conformance to any subtitle 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 2026-09-29T14:49:29.792053+00:00.

Case digest / b43fecf033de21ccb49de3e3d87834413a65984dc5e8ea447c8df912ad167af3