FAILURE MAP
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FA-78206 / Subtitle cue timing / Open access

Timed-text time expression evaluation: clock frame bound · case 01

A frame field equal to the frame rate is accepted and rolls into the next second.

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

ROOT CAUSE

The frame field bound allows the frame rate itself.

VERIFIED REPAIR

Reject frame fields at or above the frame rate.

Unsuccessful approach: A fixed limit of 60 ignores the declared frame rate.

Case contract

Evaluate a timed-text time expression to integer ms, rounded half up. Offset form <number><metric> with metric h, m, s, ms, f (frames at frame_rate) or t (ticks at tick_rate). Clock form HH:MM:SS with optional .fraction (any digits) or :FF frames (FF < frame_rate). Minutes/seconds above 59 or malformed text give 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
import math
import re
from fractions import Fraction
N = 1
observations = []
def solve(expr, frame_rate, tick_rate):
    m=re.fullmatch(r'(\d+(?:\.\d+)?)(h|ms|m|s|f|t)',expr)
    if m:
        v=Fraction(m.group(1))
        unit=m.group(2)
        scale={'h':3600000,'m':60000,'s':1000,'ms':1}
        if unit in scale:
            x=v*scale[unit]
        elif unit=='f':
            x=v*1000/frame_rate
        else:
            x=v*1000/tick_rate
        return math.floor(x+Fraction(1,2))
    m=re.fullmatch(r'(\d{2,}):(\d{2}):(\d{2})(?:\.(\d+)|:(\d{2,}))?',expr)
    if not m:
        return None
    h,mi,se,frac,fr=m.groups()
    if int(mi)>59 or int(se)>59:
        return None
    x=Fraction(int(h)*3600+int(mi)*60+int(se))*1000
    if frac:
        x+=Fraction('0.'+frac)*1000
    if fr:
        if int(fr)>frame_rate:
            return None
        x+=Fraction(int(fr)*1000,frame_rate)
    return (x*2+1)//2
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: clock frame bound', ['00:00:00:25', 25, 1000], None), ('regression variant: clock frame bound', ['100:59:05:30', 30, 1000], None), ('partial repair probe: clock frame bound', ['10:30:00:25', 16, 10000000], None), ('partial repair variant: clock frame bound', ['100:30:00:29', 25, 90000], None), ('boundary control', ['10t', 25, 1000], 10), ('boundary control', ['00:00:01.0005', 25, 1000], 1001), ('normal control', ['3f', 16, 1000], 188), ('normal control', ['10:59:59:15', 40, 1000], 39599375), ('normal control', ['01:60:59:30', 50, 10000000], None)], [('regression: clock frame bound', ['100:59:05:30', 30, 1000], None), ('regression variant: clock frame bound', ['10:00:00:25', 25, 3], None), ('partial repair probe: clock frame bound', ['100:30:05:30', 16, 10000000], None), ('partial repair variant: clock frame bound', ['10:30:05:25', 24, 3], None), ('boundary control', ['3f', 16, 1000], 188), ('boundary control', ['10t', 25, 1000], 10), ('normal control', ['0ms', 16, 90000], 0), ('normal control', ['2t', 30, 3], 667), ('normal control', ['0.001t', 24, 1000], 0)], [('regression: clock frame bound', ['10:00:00:25', 25, 3], None), ('regression variant: clock frame bound', ['00:30:59:30', 30, 3], None), ('partial repair probe: clock frame bound', ['01:30:05:25', 16, 90000], None), ('partial repair variant: clock frame bound', ['01:59:59:24', 16, 3], None), ('boundary control', ['00:00:01:15', 16, 1000], 1938), ('boundary control', ['3f', 16, 1000], 188), ('normal control', ['0f', 24, 90000], 0), ('normal control', ['15t', 30, 3], 5000), ('normal control', ['01:60:05:12', 16, 10000000], None)], [('regression: clock frame bound', ['00:30:59:30', 30, 3], None), ('regression variant: clock frame bound', ['01:59:05:24', 24, 3], None), ('partial repair probe: clock frame bound', ['10:00:00:30', 25, 1000], None), ('partial repair variant: clock frame bound', ['01:00:59:29', 25, 10000000], None), ('boundary control', ['00:00:01.0005', 25, 1000], 1001), ('boundary control', ['00:00:01:15', 16, 1000], 1938), ('normal control', ['0t', 24, 3], 0), ('normal control', ['17s', 25, 1000], 17000), ('normal control', ['100:59:59:03', 50, 3], 363599060)], [('regression: clock frame bound', ['01:59:05:24', 24, 3], None), ('regression variant: clock frame bound', ['00:00:00:25', 25, 1000], None), ('partial repair probe: clock frame bound', ['00:59:59:30', 24, 3], None), ('partial repair variant: clock frame bound', ['00:59:05:30', 24, 3], None), ('boundary control', ['10t', 25, 1000], 10), ('boundary control', ['00:00:01.0005', 25, 1000], 1001), ('normal control', ['2ms', 40, 90000], 2), ('normal control', ['17h', 24, 10000000], 61200000), ('normal control', ['00:59:00:03', 24, 1000], 3540125)]]
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: clock frame bound1000NoneFailed
regression variant: clock frame bound363546000NoneFailed
partial repair probe: clock frame boundNoneNonePassed
partial repair variant: clock frame boundNoneNonePassed
boundary control1010Passed
boundary control10011001Passed
normal control188188Passed
normal control3959937539599375Passed
normal controlNoneNonePassed

SHA-256 / 530861df00828f628d4751d317d37d9f4516b872ed65efe7670e2f097703d1a8

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
import re
from fractions import Fraction
N = 1
observations = []
def solve(expr, frame_rate, tick_rate):
    m=re.fullmatch(r'(\d+(?:\.\d+)?)(h|ms|m|s|f|t)',expr)
    if m:
        v=Fraction(m.group(1))
        unit=m.group(2)
        scale={'h':3600000,'m':60000,'s':1000,'ms':1}
        if unit in scale:
            x=v*scale[unit]
        elif unit=='f':
            x=v*1000/frame_rate
        else:
            x=v*1000/tick_rate
        return math.floor(x+Fraction(1,2))
    m=re.fullmatch(r'(\d{2,}):(\d{2}):(\d{2})(?:\.(\d+)|:(\d{2,}))?',expr)
    if not m:
        return None
    h,mi,se,frac,fr=m.groups()
    if int(mi)>59 or int(se)>59:
        return None
    x=Fraction(int(h)*3600+int(mi)*60+int(se))*1000
    if frac:
        x+=Fraction('0.'+frac)*1000
    if fr:
        if int(fr)>=60:
            return None
        x+=Fraction(int(fr)*1000,frame_rate)
    return (x*2+1)//2
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: clock frame bound', ['00:00:00:25', 25, 1000], None), ('regression variant: clock frame bound', ['100:59:05:30', 30, 1000], None), ('partial repair probe: clock frame bound', ['10:30:00:25', 16, 10000000], None), ('partial repair variant: clock frame bound', ['100:30:00:29', 25, 90000], None), ('boundary control', ['10t', 25, 1000], 10), ('boundary control', ['00:00:01.0005', 25, 1000], 1001), ('normal control', ['3f', 16, 1000], 188), ('normal control', ['10:59:59:15', 40, 1000], 39599375), ('normal control', ['01:60:59:30', 50, 10000000], None)], [('regression: clock frame bound', ['100:59:05:30', 30, 1000], None), ('regression variant: clock frame bound', ['10:00:00:25', 25, 3], None), ('partial repair probe: clock frame bound', ['100:30:05:30', 16, 10000000], None), ('partial repair variant: clock frame bound', ['10:30:05:25', 24, 3], None), ('boundary control', ['3f', 16, 1000], 188), ('boundary control', ['10t', 25, 1000], 10), ('normal control', ['0ms', 16, 90000], 0), ('normal control', ['2t', 30, 3], 667), ('normal control', ['0.001t', 24, 1000], 0)], [('regression: clock frame bound', ['10:00:00:25', 25, 3], None), ('regression variant: clock frame bound', ['00:30:59:30', 30, 3], None), ('partial repair probe: clock frame bound', ['01:30:05:25', 16, 90000], None), ('partial repair variant: clock frame bound', ['01:59:59:24', 16, 3], None), ('boundary control', ['00:00:01:15', 16, 1000], 1938), ('boundary control', ['3f', 16, 1000], 188), ('normal control', ['0f', 24, 90000], 0), ('normal control', ['15t', 30, 3], 5000), ('normal control', ['01:60:05:12', 16, 10000000], None)], [('regression: clock frame bound', ['00:30:59:30', 30, 3], None), ('regression variant: clock frame bound', ['01:59:05:24', 24, 3], None), ('partial repair probe: clock frame bound', ['10:00:00:30', 25, 1000], None), ('partial repair variant: clock frame bound', ['01:00:59:29', 25, 10000000], None), ('boundary control', ['00:00:01.0005', 25, 1000], 1001), ('boundary control', ['00:00:01:15', 16, 1000], 1938), ('normal control', ['0t', 24, 3], 0), ('normal control', ['17s', 25, 1000], 17000), ('normal control', ['100:59:59:03', 50, 3], 363599060)], [('regression: clock frame bound', ['01:59:05:24', 24, 3], None), ('regression variant: clock frame bound', ['00:00:00:25', 25, 1000], None), ('partial repair probe: clock frame bound', ['00:59:59:30', 24, 3], None), ('partial repair variant: clock frame bound', ['00:59:05:30', 24, 3], None), ('boundary control', ['10t', 25, 1000], 10), ('boundary control', ['00:00:01.0005', 25, 1000], 1001), ('normal control', ['2ms', 40, 90000], 2), ('normal control', ['17h', 24, 10000000], 61200000), ('normal control', ['00:59:00:03', 24, 1000], 3540125)]]
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: clock frame bound1000NoneFailed
regression variant: clock frame bound363546000NoneFailed
partial repair probe: clock frame bound37801563NoneFailed
partial repair variant: clock frame bound361801160NoneFailed
boundary control1010Passed
boundary control10011001Passed
normal control188188Passed
normal control3959937539599375Passed
normal controlNoneNonePassed

SHA-256 / ac3c738bf6977c94fed71671d16dc38fe8b9e8b72266e0dc55e8cb12cdaf7b00

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json
import math
import re
from fractions import Fraction
N = 1
observations = []
def solve(expr, frame_rate, tick_rate):
    m=re.fullmatch(r'(\d+(?:\.\d+)?)(h|ms|m|s|f|t)',expr)
    if m:
        v=Fraction(m.group(1))
        unit=m.group(2)
        scale={'h':3600000,'m':60000,'s':1000,'ms':1}
        if unit in scale:
            x=v*scale[unit]
        elif unit=='f':
            x=v*1000/frame_rate
        else:
            x=v*1000/tick_rate
        return math.floor(x+Fraction(1,2))
    m=re.fullmatch(r'(\d{2,}):(\d{2}):(\d{2})(?:\.(\d+)|:(\d{2,}))?',expr)
    if not m:
        return None
    h,mi,se,frac,fr=m.groups()
    if int(mi)>59 or int(se)>59:
        return None
    x=Fraction(int(h)*3600+int(mi)*60+int(se))*1000
    if frac:
        x+=Fraction('0.'+frac)*1000
    if fr:
        if int(fr)>=frame_rate:
            return None
        x+=Fraction(int(fr)*1000,frame_rate)
    return (x*2+1)//2
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: clock frame bound', ['00:00:00:25', 25, 1000], None), ('regression variant: clock frame bound', ['100:59:05:30', 30, 1000], None), ('partial repair probe: clock frame bound', ['10:30:00:25', 16, 10000000], None), ('partial repair variant: clock frame bound', ['100:30:00:29', 25, 90000], None), ('boundary control', ['10t', 25, 1000], 10), ('boundary control', ['00:00:01.0005', 25, 1000], 1001), ('normal control', ['3f', 16, 1000], 188), ('normal control', ['10:59:59:15', 40, 1000], 39599375), ('normal control', ['01:60:59:30', 50, 10000000], None)], [('regression: clock frame bound', ['100:59:05:30', 30, 1000], None), ('regression variant: clock frame bound', ['10:00:00:25', 25, 3], None), ('partial repair probe: clock frame bound', ['100:30:05:30', 16, 10000000], None), ('partial repair variant: clock frame bound', ['10:30:05:25', 24, 3], None), ('boundary control', ['3f', 16, 1000], 188), ('boundary control', ['10t', 25, 1000], 10), ('normal control', ['0ms', 16, 90000], 0), ('normal control', ['2t', 30, 3], 667), ('normal control', ['0.001t', 24, 1000], 0)], [('regression: clock frame bound', ['10:00:00:25', 25, 3], None), ('regression variant: clock frame bound', ['00:30:59:30', 30, 3], None), ('partial repair probe: clock frame bound', ['01:30:05:25', 16, 90000], None), ('partial repair variant: clock frame bound', ['01:59:59:24', 16, 3], None), ('boundary control', ['00:00:01:15', 16, 1000], 1938), ('boundary control', ['3f', 16, 1000], 188), ('normal control', ['0f', 24, 90000], 0), ('normal control', ['15t', 30, 3], 5000), ('normal control', ['01:60:05:12', 16, 10000000], None)], [('regression: clock frame bound', ['00:30:59:30', 30, 3], None), ('regression variant: clock frame bound', ['01:59:05:24', 24, 3], None), ('partial repair probe: clock frame bound', ['10:00:00:30', 25, 1000], None), ('partial repair variant: clock frame bound', ['01:00:59:29', 25, 10000000], None), ('boundary control', ['00:00:01.0005', 25, 1000], 1001), ('boundary control', ['00:00:01:15', 16, 1000], 1938), ('normal control', ['0t', 24, 3], 0), ('normal control', ['17s', 25, 1000], 17000), ('normal control', ['100:59:59:03', 50, 3], 363599060)], [('regression: clock frame bound', ['01:59:05:24', 24, 3], None), ('regression variant: clock frame bound', ['00:00:00:25', 25, 1000], None), ('partial repair probe: clock frame bound', ['00:59:59:30', 24, 3], None), ('partial repair variant: clock frame bound', ['00:59:05:30', 24, 3], None), ('boundary control', ['10t', 25, 1000], 10), ('boundary control', ['00:00:01.0005', 25, 1000], 1001), ('normal control', ['2ms', 40, 90000], 2), ('normal control', ['17h', 24, 10000000], 61200000), ('normal control', ['00:59:00:03', 24, 1000], 3540125)]]
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: clock frame boundNoneNonePassed
regression variant: clock frame boundNoneNonePassed
partial repair probe: clock frame boundNoneNonePassed
partial repair variant: clock frame boundNoneNonePassed
boundary control1010Passed
boundary control10011001Passed
normal control188188Passed
normal control3959937539599375Passed
normal controlNoneNonePassed

SHA-256 / c5e8cee3d584c5d24d39708ed9c253573852113acd0af0603306400b5cf1b7b8

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 2026-09-29T14:49:33.289709+00:00.

Case digest / e39bd84adf652647bf5e1b36f0c06654909f6476a6e94f4a96193e5de52f31a2