FAILURE MAP
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FA-78331 / Subtitle cue timing / Open access

Subtitle conform to an edit cut list: merged cut extent · case 01

A cut nested inside a larger cut shortens the removed range.

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

ROOT CAUSE

Merging overwrites the end with the later cut end even when it is smaller.

VERIFIED REPAIR

Keep the larger of the two ends when merging.

Unsuccessful approach: Adding the second cut length double counts the overlapping part.

Case contract

Cuts [a,b) are removed from the programme (they may overlap or be unsorted and are merged first). A time after a cut shifts left by the removed length; a time inside a cut maps to the cut point. Cues [start,end,text] are mapped and dropped when the mapped end is not after the mapped start.

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(cues, cuts):
    merged=[]
    for a,b in sorted(cuts):
        if merged and a<=merged[-1][1]:
            merged[-1][1]=b
        else:
            merged.append([a,b])
    def mapt(t):
        shift=0
        for a,b in merged:
            if t>=b:
                shift+=b-a
            elif t>a:
                return a-shift
        return t-shift
    out=[]
    for s,e,txt in cues:
        ns,ne=mapt(s),mapt(e)
        if ne>ns:
            out.append([ns,ne,txt])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: merged cut extent', [[[3200, 5200, 'c0'], [1200, 1300, 'c1']], [[500, 2000], [2000, 2100], [1500, 1600]]], [[1600, 3600, 'c0']]), ('regression variant: merged cut extent', [[[0, 300, 'c0'], [0, 100, 'c1'], [4000, 6000, 'c2'], [4000, 4100, 'c3']], [[1000, 1100], [0, 1500], [3000, 3500]]], [[2000, 4000, 'c2'], [2000, 2100, 'c3']]), ('partial repair probe: merged cut extent', [[[2500, 4500, 'c0'], [4000, 6000, 'c1'], [900, 2900, 'c2'], [200, 2200, 'c3']], [[500, 600], [500, 1000]]], [[2000, 4000, 'c0'], [3500, 5500, 'c1'], [500, 2400, 'c2'], [200, 1700, 'c3']]), ('partial repair variant: merged cut extent', [[[900, 1000, 'c0'], [600, 2600, 'c1'], [4000, 4100, 'c2'], [900, 2900, 'c3']], [[1000, 1500], [2000, 2100], [2000, 2500]]], [[900, 1000, 'c0'], [600, 1600, 'c1'], [3000, 3100, 'c2'], [900, 1900, 'c3']]), ('boundary control', [[[1200, 1800, 'a']], [[1000, 1500]]], [[1000, 1300, 'a']]), ('boundary control', [[[3000, 3500, 'a']], [[0, 500], [1000, 2000]]], [[1500, 2000, 'a']]), ('normal control', [[[1100, 1400, 'a']], [[1000, 1500]]], []), ('normal control', [[[600, 2600, 'c0'], [2500, 3300, 'c1'], [0, 2000, 'c2']], [[1000, 1100]]], [[600, 2500, 'c0'], [2400, 3200, 'c1'], [0, 1900, 'c2']]), ('normal control', [[[0, 800, 'c0'], [4000, 4300, 'c1'], [0, 800, 'c2']], [[3000, 3100], [3000, 4500], [0, 1500]]], [])], [('regression: merged cut extent', [[[1600, 2400, 'c0'], [4000, 4300, 'c1'], [1200, 3200, 'c2'], [2500, 2800, 'c3']], [[1000, 1500], [500, 600], [0, 1000]]], [[100, 900, 'c0'], [2500, 2800, 'c1'], [0, 1700, 'c2'], [1000, 1300, 'c3']]), ('regression variant: merged cut extent', [[[3200, 3300, 'c0']], [[500, 600], [0, 1500], [0, 100]]], [[1700, 1800, 'c0']]), ('partial repair probe: merged cut extent', [[[2500, 4500, 'c0'], [4000, 6000, 'c1'], [900, 2900, 'c2'], [200, 2200, 'c3']], [[500, 600], [500, 1000]]], [[2000, 4000, 'c0'], [3500, 5500, 'c1'], [500, 2400, 'c2'], [200, 1700, 'c3']]), ('partial repair variant: merged cut extent', [[[4000, 4300, 'c0'], [3200, 3500, 'c1']], [[1000, 2500], [1500, 2500], [1500, 2000]]], [[2500, 2800, 'c0'], [1700, 2000, 'c1']]), ('boundary control', [[[3000, 3500, 'a']], [[0, 500], [1000, 2000]]], [[1500, 2000, 'a']]), ('boundary control', [[[1100, 1400, 'a']], [[1000, 1500]]], []), ('normal control', [[[3200, 3300, 'c0'], [1200, 2000, 'c1'], [0, 2000, 'c2'], [3200, 3300, 'c3']], [[1000, 1500]]], [[2700, 2800, 'c0'], [1000, 1500, 'c1'], [0, 1500, 'c2'], [2700, 2800, 'c3']]), ('normal control', [[[900, 1700, 'c0'], [2500, 3300, 'c1'], [1200, 2000, 'c2']], [[1000, 2500]]], [[900, 1000, 'c0'], [1000, 1800, 'c1']]), ('normal control', [[[0, 2000, 'c0'], [0, 300, 'c1']], []], [[0, 2000, 'c0'], [0, 300, 'c1']])], [('regression: merged cut extent', [[[600, 1400, 'c0'], [1200, 3200, 'c1']], [[0, 1500], [500, 1500], [1000, 1100]]], [[0, 1700, 'c1']]), ('regression variant: merged cut extent', [[[600, 700, 'c0'], [3200, 5200, 'c1']], [[500, 2000], [1000, 1500], [2000, 3000]]], [[700, 2700, 'c1']]), ('partial repair probe: merged cut extent', [[[1600, 1900, 'c0'], [2500, 3300, 'c1'], [1600, 1900, 'c2'], [4000, 6000, 'c3']], [[500, 2000], [0, 1000]]], [[500, 1300, 'c1'], [2000, 4000, 'c3']]), ('partial repair variant: merged cut extent', [[[4000, 4300, 'c0'], [3200, 3500, 'c1']], [[1000, 2500], [1500, 2500], [1500, 2000]]], [[2500, 2800, 'c0'], [1700, 2000, 'c1']]), ('boundary control', [[[1100, 1400, 'a']], [[1000, 1500]]], []), ('boundary control', [[[1200, 1800, 'a']], [[1000, 1500]]], [[1000, 1300, 'a']]), ('normal control', [[[900, 1200, 'c0'], [2500, 3300, 'c1']], [[2000, 2500]]], [[900, 1200, 'c0'], [2000, 2800, 'c1']]), ('normal control', [[[2500, 2800, 'c0'], [600, 1400, 'c1']], []], [[2500, 2800, 'c0'], [600, 1400, 'c1']]), ('normal control', [[[0, 800, 'c0'], [200, 1000, 'c1'], [600, 1400, 'c2'], [1600, 3600, 'c3']], [[0, 100]]], [[0, 700, 'c0'], [100, 900, 'c1'], [500, 1300, 'c2'], [1500, 3500, 'c3']])], [('regression: merged cut extent', [[[600, 900, 'c0'], [600, 900, 'c1']], [[2000, 2500], [0, 1500], [500, 600]]], []), ('regression variant: merged cut extent', [[[200, 500, 'c0'], [2500, 2800, 'c1'], [600, 700, 'c2']], [[500, 2000], [1500, 1600]]], [[200, 500, 'c0'], [1000, 1300, 'c1']]), ('partial repair probe: merged cut extent', [[[1200, 2000, 'c0'], [4000, 4300, 'c1'], [200, 2200, 'c2'], [3200, 4000, 'c3']], [[1000, 2000], [0, 1500], [1500, 2500]]], [[1500, 1800, 'c1'], [700, 1500, 'c3']]), ('partial repair variant: merged cut extent', [[[1600, 3600, 'c0'], [2500, 4500, 'c1']], [[1000, 2000], [1500, 2000]]], [[1000, 2600, 'c0'], [1500, 3500, 'c1']]), ('boundary control', [[[1200, 1800, 'a']], [[1000, 1500]]], [[1000, 1300, 'a']]), ('boundary control', [[[3000, 3500, 'a']], [[0, 500], [1000, 2000]]], [[1500, 2000, 'a']]), ('normal control', [[[4000, 6000, 'c0'], [200, 1000, 'c1']], [[0, 500], [500, 600]]], [[3400, 5400, 'c0'], [0, 400, 'c1']]), ('normal control', [[[2500, 3300, 'c0']], []], [[2500, 3300, 'c0']]), ('normal control', [[[4000, 6000, 'c0'], [1600, 1700, 'c1']], [[500, 2000]]], [[2500, 4500, 'c0']])], [('regression: merged cut extent', [[[1600, 3600, 'c0'], [900, 2900, 'c1'], [4000, 6000, 'c2'], [900, 1200, 'c3']], [[1000, 1100], [500, 1500]]], [[600, 2600, 'c0'], [500, 1900, 'c1'], [3000, 5000, 'c2']]), ('regression variant: merged cut extent', [[[200, 2200, 'c0']], [[1000, 1100], [500, 2000]]], [[200, 700, 'c0']]), ('partial repair probe: merged cut extent', [[[2500, 3300, 'c0'], [200, 500, 'c1']], [[1500, 1600], [0, 1000], [1500, 3000]]], [[500, 800, 'c0']]), ('partial repair variant: merged cut extent', [[[1200, 1500, 'c0'], [3200, 4000, 'c1']], [[0, 1000], [0, 100]]], [[200, 500, 'c0'], [2200, 3000, 'c1']]), ('boundary control', [[[3000, 3500, 'a']], [[0, 500], [1000, 2000]]], [[1500, 2000, 'a']]), ('boundary control', [[[1100, 1400, 'a']], [[1000, 1500]]], []), ('normal control', [[[600, 2600, 'c0'], [200, 2200, 'c1'], [4000, 4300, 'c2']], []], [[600, 2600, 'c0'], [200, 2200, 'c1'], [4000, 4300, 'c2']]), ('normal control', [[[2500, 3300, 'c0'], [600, 1400, 'c1'], [1600, 3600, 'c2'], [600, 700, 'c3']], [[3000, 3500], [2000, 3000], [1000, 2000]]], [[600, 1000, 'c1'], [1000, 1100, 'c2'], [600, 700, 'c3']]), ('normal control', [[[900, 2900, 'c0'], [3200, 3500, 'c1'], [2500, 2800, 'c2']], [[1500, 3000], [3000, 4000]]], [[900, 1500, 'c0']])]]
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: merged cut extent[[2000, 4000, 'c0']][[1600, 3600, 'c0']]Failed
regression variant: merged cut extent[[2400, 4400, 'c2'], [2400, 2500, 'c3']][[2000, 4000, 'c2'], [2000, 2100, 'c3']]Failed
partial repair probe: merged cut extent[[2000, 4000, 'c0'], [3500, 5500, 'c1'], [500, 2400, 'c2'], [200, 1700, 'c3']][[2000, 4000, 'c0'], [3500, 5500, 'c1'], [500, 2400, 'c2'], [200, 1700, 'c3']]Passed
partial repair variant: merged cut extent[[900, 1000, 'c0'], [600, 1600, 'c1'], [3000, 3100, 'c2'], [900, 1900, 'c3']][[900, 1000, 'c0'], [600, 1600, 'c1'], [3000, 3100, 'c2'], [900, 1900, 'c3']]Passed
boundary control[[1000, 1300, 'a']][[1000, 1300, 'a']]Passed
boundary control[[1500, 2000, 'a']][[1500, 2000, 'a']]Passed
normal control[][]Passed
normal control[[600, 2500, 'c0'], [2400, 3200, 'c1'], [0, 1900, 'c2']][[600, 2500, 'c0'], [2400, 3200, 'c1'], [0, 1900, 'c2']]Passed
normal control[][]Passed

SHA-256 / 0bb64910707fbd64c942e046d47ebd6ed71374a89d8e4f5d02eb30694841f483

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(cues, cuts):
    merged=[]
    for a,b in sorted(cuts):
        if merged and a<=merged[-1][1]:
            merged[-1][1]=merged[-1][1]+b-a
        else:
            merged.append([a,b])
    def mapt(t):
        shift=0
        for a,b in merged:
            if t>=b:
                shift+=b-a
            elif t>a:
                return a-shift
        return t-shift
    out=[]
    for s,e,txt in cues:
        ns,ne=mapt(s),mapt(e)
        if ne>ns:
            out.append([ns,ne,txt])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: merged cut extent', [[[3200, 5200, 'c0'], [1200, 1300, 'c1']], [[500, 2000], [2000, 2100], [1500, 1600]]], [[1600, 3600, 'c0']]), ('regression variant: merged cut extent', [[[0, 300, 'c0'], [0, 100, 'c1'], [4000, 6000, 'c2'], [4000, 4100, 'c3']], [[1000, 1100], [0, 1500], [3000, 3500]]], [[2000, 4000, 'c2'], [2000, 2100, 'c3']]), ('partial repair probe: merged cut extent', [[[2500, 4500, 'c0'], [4000, 6000, 'c1'], [900, 2900, 'c2'], [200, 2200, 'c3']], [[500, 600], [500, 1000]]], [[2000, 4000, 'c0'], [3500, 5500, 'c1'], [500, 2400, 'c2'], [200, 1700, 'c3']]), ('partial repair variant: merged cut extent', [[[900, 1000, 'c0'], [600, 2600, 'c1'], [4000, 4100, 'c2'], [900, 2900, 'c3']], [[1000, 1500], [2000, 2100], [2000, 2500]]], [[900, 1000, 'c0'], [600, 1600, 'c1'], [3000, 3100, 'c2'], [900, 1900, 'c3']]), ('boundary control', [[[1200, 1800, 'a']], [[1000, 1500]]], [[1000, 1300, 'a']]), ('boundary control', [[[3000, 3500, 'a']], [[0, 500], [1000, 2000]]], [[1500, 2000, 'a']]), ('normal control', [[[1100, 1400, 'a']], [[1000, 1500]]], []), ('normal control', [[[600, 2600, 'c0'], [2500, 3300, 'c1'], [0, 2000, 'c2']], [[1000, 1100]]], [[600, 2500, 'c0'], [2400, 3200, 'c1'], [0, 1900, 'c2']]), ('normal control', [[[0, 800, 'c0'], [4000, 4300, 'c1'], [0, 800, 'c2']], [[3000, 3100], [3000, 4500], [0, 1500]]], [])], [('regression: merged cut extent', [[[1600, 2400, 'c0'], [4000, 4300, 'c1'], [1200, 3200, 'c2'], [2500, 2800, 'c3']], [[1000, 1500], [500, 600], [0, 1000]]], [[100, 900, 'c0'], [2500, 2800, 'c1'], [0, 1700, 'c2'], [1000, 1300, 'c3']]), ('regression variant: merged cut extent', [[[3200, 3300, 'c0']], [[500, 600], [0, 1500], [0, 100]]], [[1700, 1800, 'c0']]), ('partial repair probe: merged cut extent', [[[2500, 4500, 'c0'], [4000, 6000, 'c1'], [900, 2900, 'c2'], [200, 2200, 'c3']], [[500, 600], [500, 1000]]], [[2000, 4000, 'c0'], [3500, 5500, 'c1'], [500, 2400, 'c2'], [200, 1700, 'c3']]), ('partial repair variant: merged cut extent', [[[4000, 4300, 'c0'], [3200, 3500, 'c1']], [[1000, 2500], [1500, 2500], [1500, 2000]]], [[2500, 2800, 'c0'], [1700, 2000, 'c1']]), ('boundary control', [[[3000, 3500, 'a']], [[0, 500], [1000, 2000]]], [[1500, 2000, 'a']]), ('boundary control', [[[1100, 1400, 'a']], [[1000, 1500]]], []), ('normal control', [[[3200, 3300, 'c0'], [1200, 2000, 'c1'], [0, 2000, 'c2'], [3200, 3300, 'c3']], [[1000, 1500]]], [[2700, 2800, 'c0'], [1000, 1500, 'c1'], [0, 1500, 'c2'], [2700, 2800, 'c3']]), ('normal control', [[[900, 1700, 'c0'], [2500, 3300, 'c1'], [1200, 2000, 'c2']], [[1000, 2500]]], [[900, 1000, 'c0'], [1000, 1800, 'c1']]), ('normal control', [[[0, 2000, 'c0'], [0, 300, 'c1']], []], [[0, 2000, 'c0'], [0, 300, 'c1']])], [('regression: merged cut extent', [[[600, 1400, 'c0'], [1200, 3200, 'c1']], [[0, 1500], [500, 1500], [1000, 1100]]], [[0, 1700, 'c1']]), ('regression variant: merged cut extent', [[[600, 700, 'c0'], [3200, 5200, 'c1']], [[500, 2000], [1000, 1500], [2000, 3000]]], [[700, 2700, 'c1']]), ('partial repair probe: merged cut extent', [[[1600, 1900, 'c0'], [2500, 3300, 'c1'], [1600, 1900, 'c2'], [4000, 6000, 'c3']], [[500, 2000], [0, 1000]]], [[500, 1300, 'c1'], [2000, 4000, 'c3']]), ('partial repair variant: merged cut extent', [[[4000, 4300, 'c0'], [3200, 3500, 'c1']], [[1000, 2500], [1500, 2500], [1500, 2000]]], [[2500, 2800, 'c0'], [1700, 2000, 'c1']]), ('boundary control', [[[1100, 1400, 'a']], [[1000, 1500]]], []), ('boundary control', [[[1200, 1800, 'a']], [[1000, 1500]]], [[1000, 1300, 'a']]), ('normal control', [[[900, 1200, 'c0'], [2500, 3300, 'c1']], [[2000, 2500]]], [[900, 1200, 'c0'], [2000, 2800, 'c1']]), ('normal control', [[[2500, 2800, 'c0'], [600, 1400, 'c1']], []], [[2500, 2800, 'c0'], [600, 1400, 'c1']]), ('normal control', [[[0, 800, 'c0'], [200, 1000, 'c1'], [600, 1400, 'c2'], [1600, 3600, 'c3']], [[0, 100]]], [[0, 700, 'c0'], [100, 900, 'c1'], [500, 1300, 'c2'], [1500, 3500, 'c3']])], [('regression: merged cut extent', [[[600, 900, 'c0'], [600, 900, 'c1']], [[2000, 2500], [0, 1500], [500, 600]]], []), ('regression variant: merged cut extent', [[[200, 500, 'c0'], [2500, 2800, 'c1'], [600, 700, 'c2']], [[500, 2000], [1500, 1600]]], [[200, 500, 'c0'], [1000, 1300, 'c1']]), ('partial repair probe: merged cut extent', [[[1200, 2000, 'c0'], [4000, 4300, 'c1'], [200, 2200, 'c2'], [3200, 4000, 'c3']], [[1000, 2000], [0, 1500], [1500, 2500]]], [[1500, 1800, 'c1'], [700, 1500, 'c3']]), ('partial repair variant: merged cut extent', [[[1600, 3600, 'c0'], [2500, 4500, 'c1']], [[1000, 2000], [1500, 2000]]], [[1000, 2600, 'c0'], [1500, 3500, 'c1']]), ('boundary control', [[[1200, 1800, 'a']], [[1000, 1500]]], [[1000, 1300, 'a']]), ('boundary control', [[[3000, 3500, 'a']], [[0, 500], [1000, 2000]]], [[1500, 2000, 'a']]), ('normal control', [[[4000, 6000, 'c0'], [200, 1000, 'c1']], [[0, 500], [500, 600]]], [[3400, 5400, 'c0'], [0, 400, 'c1']]), ('normal control', [[[2500, 3300, 'c0']], []], [[2500, 3300, 'c0']]), ('normal control', [[[4000, 6000, 'c0'], [1600, 1700, 'c1']], [[500, 2000]]], [[2500, 4500, 'c0']])], [('regression: merged cut extent', [[[1600, 3600, 'c0'], [900, 2900, 'c1'], [4000, 6000, 'c2'], [900, 1200, 'c3']], [[1000, 1100], [500, 1500]]], [[600, 2600, 'c0'], [500, 1900, 'c1'], [3000, 5000, 'c2']]), ('regression variant: merged cut extent', [[[200, 2200, 'c0']], [[1000, 1100], [500, 2000]]], [[200, 700, 'c0']]), ('partial repair probe: merged cut extent', [[[2500, 3300, 'c0'], [200, 500, 'c1']], [[1500, 1600], [0, 1000], [1500, 3000]]], [[500, 800, 'c0']]), ('partial repair variant: merged cut extent', [[[1200, 1500, 'c0'], [3200, 4000, 'c1']], [[0, 1000], [0, 100]]], [[200, 500, 'c0'], [2200, 3000, 'c1']]), ('boundary control', [[[3000, 3500, 'a']], [[0, 500], [1000, 2000]]], [[1500, 2000, 'a']]), ('boundary control', [[[1100, 1400, 'a']], [[1000, 1500]]], []), ('normal control', [[[600, 2600, 'c0'], [200, 2200, 'c1'], [4000, 4300, 'c2']], []], [[600, 2600, 'c0'], [200, 2200, 'c1'], [4000, 4300, 'c2']]), ('normal control', [[[2500, 3300, 'c0'], [600, 1400, 'c1'], [1600, 3600, 'c2'], [600, 700, 'c3']], [[3000, 3500], [2000, 3000], [1000, 2000]]], [[600, 1000, 'c1'], [1000, 1100, 'c2'], [600, 700, 'c3']]), ('normal control', [[[900, 2900, 'c0'], [3200, 3500, 'c1'], [2500, 2800, 'c2']], [[1500, 3000], [3000, 4000]]], [[900, 1500, 'c0']])]]
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: merged cut extent[[1500, 3500, 'c0']][[1600, 3600, 'c0']]Failed
regression variant: merged cut extent[[1900, 3900, 'c2'], [1900, 2000, 'c3']][[2000, 4000, 'c2'], [2000, 2100, 'c3']]Failed
partial repair probe: merged cut extent[[1900, 3900, 'c0'], [3400, 5400, 'c1'], [500, 2300, 'c2'], [200, 1600, 'c3']][[2000, 4000, 'c0'], [3500, 5500, 'c1'], [500, 2400, 'c2'], [200, 1700, 'c3']]Failed
partial repair variant: merged cut extent[[900, 1000, 'c0'], [600, 1500, 'c1'], [2900, 3000, 'c2'], [900, 1800, 'c3']][[900, 1000, 'c0'], [600, 1600, 'c1'], [3000, 3100, 'c2'], [900, 1900, 'c3']]Failed
boundary control[[1000, 1300, 'a']][[1000, 1300, 'a']]Passed
boundary control[[1500, 2000, 'a']][[1500, 2000, 'a']]Passed
normal control[][]Passed
normal control[[600, 2500, 'c0'], [2400, 3200, 'c1'], [0, 1900, 'c2']][[600, 2500, 'c0'], [2400, 3200, 'c1'], [0, 1900, 'c2']]Passed
normal control[][]Passed

SHA-256 / 84c559ae935cf29730416bb01f51236b637bc6b1a5f76f9791d9b2092c9ee7c5

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(cues, cuts):
    merged=[]
    for a,b in sorted(cuts):
        if merged and a<=merged[-1][1]:
            merged[-1][1]=max(merged[-1][1],b)
        else:
            merged.append([a,b])
    def mapt(t):
        shift=0
        for a,b in merged:
            if t>=b:
                shift+=b-a
            elif t>a:
                return a-shift
        return t-shift
    out=[]
    for s,e,txt in cues:
        ns,ne=mapt(s),mapt(e)
        if ne>ns:
            out.append([ns,ne,txt])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: merged cut extent', [[[3200, 5200, 'c0'], [1200, 1300, 'c1']], [[500, 2000], [2000, 2100], [1500, 1600]]], [[1600, 3600, 'c0']]), ('regression variant: merged cut extent', [[[0, 300, 'c0'], [0, 100, 'c1'], [4000, 6000, 'c2'], [4000, 4100, 'c3']], [[1000, 1100], [0, 1500], [3000, 3500]]], [[2000, 4000, 'c2'], [2000, 2100, 'c3']]), ('partial repair probe: merged cut extent', [[[2500, 4500, 'c0'], [4000, 6000, 'c1'], [900, 2900, 'c2'], [200, 2200, 'c3']], [[500, 600], [500, 1000]]], [[2000, 4000, 'c0'], [3500, 5500, 'c1'], [500, 2400, 'c2'], [200, 1700, 'c3']]), ('partial repair variant: merged cut extent', [[[900, 1000, 'c0'], [600, 2600, 'c1'], [4000, 4100, 'c2'], [900, 2900, 'c3']], [[1000, 1500], [2000, 2100], [2000, 2500]]], [[900, 1000, 'c0'], [600, 1600, 'c1'], [3000, 3100, 'c2'], [900, 1900, 'c3']]), ('boundary control', [[[1200, 1800, 'a']], [[1000, 1500]]], [[1000, 1300, 'a']]), ('boundary control', [[[3000, 3500, 'a']], [[0, 500], [1000, 2000]]], [[1500, 2000, 'a']]), ('normal control', [[[1100, 1400, 'a']], [[1000, 1500]]], []), ('normal control', [[[600, 2600, 'c0'], [2500, 3300, 'c1'], [0, 2000, 'c2']], [[1000, 1100]]], [[600, 2500, 'c0'], [2400, 3200, 'c1'], [0, 1900, 'c2']]), ('normal control', [[[0, 800, 'c0'], [4000, 4300, 'c1'], [0, 800, 'c2']], [[3000, 3100], [3000, 4500], [0, 1500]]], [])], [('regression: merged cut extent', [[[1600, 2400, 'c0'], [4000, 4300, 'c1'], [1200, 3200, 'c2'], [2500, 2800, 'c3']], [[1000, 1500], [500, 600], [0, 1000]]], [[100, 900, 'c0'], [2500, 2800, 'c1'], [0, 1700, 'c2'], [1000, 1300, 'c3']]), ('regression variant: merged cut extent', [[[3200, 3300, 'c0']], [[500, 600], [0, 1500], [0, 100]]], [[1700, 1800, 'c0']]), ('partial repair probe: merged cut extent', [[[2500, 4500, 'c0'], [4000, 6000, 'c1'], [900, 2900, 'c2'], [200, 2200, 'c3']], [[500, 600], [500, 1000]]], [[2000, 4000, 'c0'], [3500, 5500, 'c1'], [500, 2400, 'c2'], [200, 1700, 'c3']]), ('partial repair variant: merged cut extent', [[[4000, 4300, 'c0'], [3200, 3500, 'c1']], [[1000, 2500], [1500, 2500], [1500, 2000]]], [[2500, 2800, 'c0'], [1700, 2000, 'c1']]), ('boundary control', [[[3000, 3500, 'a']], [[0, 500], [1000, 2000]]], [[1500, 2000, 'a']]), ('boundary control', [[[1100, 1400, 'a']], [[1000, 1500]]], []), ('normal control', [[[3200, 3300, 'c0'], [1200, 2000, 'c1'], [0, 2000, 'c2'], [3200, 3300, 'c3']], [[1000, 1500]]], [[2700, 2800, 'c0'], [1000, 1500, 'c1'], [0, 1500, 'c2'], [2700, 2800, 'c3']]), ('normal control', [[[900, 1700, 'c0'], [2500, 3300, 'c1'], [1200, 2000, 'c2']], [[1000, 2500]]], [[900, 1000, 'c0'], [1000, 1800, 'c1']]), ('normal control', [[[0, 2000, 'c0'], [0, 300, 'c1']], []], [[0, 2000, 'c0'], [0, 300, 'c1']])], [('regression: merged cut extent', [[[600, 1400, 'c0'], [1200, 3200, 'c1']], [[0, 1500], [500, 1500], [1000, 1100]]], [[0, 1700, 'c1']]), ('regression variant: merged cut extent', [[[600, 700, 'c0'], [3200, 5200, 'c1']], [[500, 2000], [1000, 1500], [2000, 3000]]], [[700, 2700, 'c1']]), ('partial repair probe: merged cut extent', [[[1600, 1900, 'c0'], [2500, 3300, 'c1'], [1600, 1900, 'c2'], [4000, 6000, 'c3']], [[500, 2000], [0, 1000]]], [[500, 1300, 'c1'], [2000, 4000, 'c3']]), ('partial repair variant: merged cut extent', [[[4000, 4300, 'c0'], [3200, 3500, 'c1']], [[1000, 2500], [1500, 2500], [1500, 2000]]], [[2500, 2800, 'c0'], [1700, 2000, 'c1']]), ('boundary control', [[[1100, 1400, 'a']], [[1000, 1500]]], []), ('boundary control', [[[1200, 1800, 'a']], [[1000, 1500]]], [[1000, 1300, 'a']]), ('normal control', [[[900, 1200, 'c0'], [2500, 3300, 'c1']], [[2000, 2500]]], [[900, 1200, 'c0'], [2000, 2800, 'c1']]), ('normal control', [[[2500, 2800, 'c0'], [600, 1400, 'c1']], []], [[2500, 2800, 'c0'], [600, 1400, 'c1']]), ('normal control', [[[0, 800, 'c0'], [200, 1000, 'c1'], [600, 1400, 'c2'], [1600, 3600, 'c3']], [[0, 100]]], [[0, 700, 'c0'], [100, 900, 'c1'], [500, 1300, 'c2'], [1500, 3500, 'c3']])], [('regression: merged cut extent', [[[600, 900, 'c0'], [600, 900, 'c1']], [[2000, 2500], [0, 1500], [500, 600]]], []), ('regression variant: merged cut extent', [[[200, 500, 'c0'], [2500, 2800, 'c1'], [600, 700, 'c2']], [[500, 2000], [1500, 1600]]], [[200, 500, 'c0'], [1000, 1300, 'c1']]), ('partial repair probe: merged cut extent', [[[1200, 2000, 'c0'], [4000, 4300, 'c1'], [200, 2200, 'c2'], [3200, 4000, 'c3']], [[1000, 2000], [0, 1500], [1500, 2500]]], [[1500, 1800, 'c1'], [700, 1500, 'c3']]), ('partial repair variant: merged cut extent', [[[1600, 3600, 'c0'], [2500, 4500, 'c1']], [[1000, 2000], [1500, 2000]]], [[1000, 2600, 'c0'], [1500, 3500, 'c1']]), ('boundary control', [[[1200, 1800, 'a']], [[1000, 1500]]], [[1000, 1300, 'a']]), ('boundary control', [[[3000, 3500, 'a']], [[0, 500], [1000, 2000]]], [[1500, 2000, 'a']]), ('normal control', [[[4000, 6000, 'c0'], [200, 1000, 'c1']], [[0, 500], [500, 600]]], [[3400, 5400, 'c0'], [0, 400, 'c1']]), ('normal control', [[[2500, 3300, 'c0']], []], [[2500, 3300, 'c0']]), ('normal control', [[[4000, 6000, 'c0'], [1600, 1700, 'c1']], [[500, 2000]]], [[2500, 4500, 'c0']])], [('regression: merged cut extent', [[[1600, 3600, 'c0'], [900, 2900, 'c1'], [4000, 6000, 'c2'], [900, 1200, 'c3']], [[1000, 1100], [500, 1500]]], [[600, 2600, 'c0'], [500, 1900, 'c1'], [3000, 5000, 'c2']]), ('regression variant: merged cut extent', [[[200, 2200, 'c0']], [[1000, 1100], [500, 2000]]], [[200, 700, 'c0']]), ('partial repair probe: merged cut extent', [[[2500, 3300, 'c0'], [200, 500, 'c1']], [[1500, 1600], [0, 1000], [1500, 3000]]], [[500, 800, 'c0']]), ('partial repair variant: merged cut extent', [[[1200, 1500, 'c0'], [3200, 4000, 'c1']], [[0, 1000], [0, 100]]], [[200, 500, 'c0'], [2200, 3000, 'c1']]), ('boundary control', [[[3000, 3500, 'a']], [[0, 500], [1000, 2000]]], [[1500, 2000, 'a']]), ('boundary control', [[[1100, 1400, 'a']], [[1000, 1500]]], []), ('normal control', [[[600, 2600, 'c0'], [200, 2200, 'c1'], [4000, 4300, 'c2']], []], [[600, 2600, 'c0'], [200, 2200, 'c1'], [4000, 4300, 'c2']]), ('normal control', [[[2500, 3300, 'c0'], [600, 1400, 'c1'], [1600, 3600, 'c2'], [600, 700, 'c3']], [[3000, 3500], [2000, 3000], [1000, 2000]]], [[600, 1000, 'c1'], [1000, 1100, 'c2'], [600, 700, 'c3']]), ('normal control', [[[900, 2900, 'c0'], [3200, 3500, 'c1'], [2500, 2800, 'c2']], [[1500, 3000], [3000, 4000]]], [[900, 1500, 'c0']])]]
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: merged cut extent[[1600, 3600, 'c0']][[1600, 3600, 'c0']]Passed
regression variant: merged cut extent[[2000, 4000, 'c2'], [2000, 2100, 'c3']][[2000, 4000, 'c2'], [2000, 2100, 'c3']]Passed
partial repair probe: merged cut extent[[2000, 4000, 'c0'], [3500, 5500, 'c1'], [500, 2400, 'c2'], [200, 1700, 'c3']][[2000, 4000, 'c0'], [3500, 5500, 'c1'], [500, 2400, 'c2'], [200, 1700, 'c3']]Passed
partial repair variant: merged cut extent[[900, 1000, 'c0'], [600, 1600, 'c1'], [3000, 3100, 'c2'], [900, 1900, 'c3']][[900, 1000, 'c0'], [600, 1600, 'c1'], [3000, 3100, 'c2'], [900, 1900, 'c3']]Passed
boundary control[[1000, 1300, 'a']][[1000, 1300, 'a']]Passed
boundary control[[1500, 2000, 'a']][[1500, 2000, 'a']]Passed
normal control[][]Passed
normal control[[600, 2500, 'c0'], [2400, 3200, 'c1'], [0, 1900, 'c2']][[600, 2500, 'c0'], [2400, 3200, 'c1'], [0, 1900, 'c2']]Passed
normal control[][]Passed

SHA-256 / 4469365a61eb45a305b1244550c58f265fd6171395b89db8be2438a4c3842983

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 2026-09-29T14:49:34.127393+00:00.

Case digest / a0b215f4617ec2099cc8a2066aa214c2291ba22f33edfd4c73e9b5584c427141