FA-78246 / Subtitle cue timing / Open access

Pop-on caption buffer timing: display erase target · case 01

Captions stay on screen after an erase-displayed-memory command.

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

ROOT CAUSE

EDM clears the non-displayed buffer instead of the displayed one.

VERIFIED REPAIR

EDM must clear the displayed memory after emitting it.

Unsuccessful approach: Resetting the timestamp without clearing the display emits the same caption again later.

Case contract

Commands [frame,cmd] at integer fps (time = frame*1000//fps). TEXT:x appends x to the non-displayed memory; ENM erases non-displayed memory; EOC swaps displayed and non-displayed memories; EDM erases displayed memory. Whenever non-empty displayed text is replaced (EOC) or erased (EDM), emit [shown_since_ms, now_ms, text].

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(events, fps):
    shown=''
    hidden=''
    since=None
    out=[]
    for frame,cmd in events:
        t=frame*1000//fps
        if cmd.startswith('TEXT:'):
            hidden+=cmd[5:]
        elif cmd=='ENM':
            hidden=''
        elif cmd=='EOC':
            if shown:
                out.append([since,t,shown])
            shown,hidden=hidden,shown
            since=t
        elif cmd=='EDM':
            if shown: out.append([since,t,shown])
            hidden=''
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: display erase target', [[[30, 'TEXT:Bye'], [37, 'EOC'], [52, 'EDM'], [52, 'ENM'], [67, 'EDM']], 30], [[1233, 1733, 'Bye']]), ('regression variant: display erase target', [[[30, 'TEXT:Hi'], [75, 'TEXT:Hi'], [120, 'EOC'], [135, 'TEXT:Hi'], [164, 'EDM'], [193, 'TEXT:Hi'], [238, 'EOC'], [267, 'EOC']], 25], [[4800, 6560, 'HiHi'], [9520, 10680, 'HiHi']]), ('partial repair probe: display erase target', [[[30, 'TEXT:Hi'], [75, 'EOC'], [90, 'EDM'], [90, 'EDM'], [135, 'TEXT:Hi'], [136, 'EDM'], [136, 'TEXT:Hi']], 29], [[2586, 3103, 'Hi']]), ('partial repair variant: display erase target', [[[3, 'TEXT:Bye'], [18, 'EOC'], [33, 'TEXT:Hi'], [33, 'EDM'], [33, 'TEXT:Hi'], [62, 'ENM'], [63, 'EOC'], [92, 'TEXT: there']], 29], [[620, 1137, 'Bye']]), ('boundary control', [[[0, 'TEXT:Hi'], [30, 'EOC'], [60, 'EDM']], 30], [[1000, 2000, 'Hi']]), ('boundary control', [[[0, 'TEXT:A'], [10, 'EOC'], [20, 'TEXT:B'], [40, 'EOC'], [50, 'EOC']], 25], [[400, 1600, 'A'], [1600, 2000, 'B']]), ('normal control', [[[0, 'EOC'], [5, 'EDM']], 30], []), ('normal control', [[[30, 'EOC'], [30, 'TEXT:Hi'], [37, 'ENM']], 24], []), ('normal control', [[[0, 'EOC'], [30, 'TEXT:Bye'], [31, 'EOC'], [46, 'EOC'], [91, 'TEXT:Hi'], [92, 'TEXT: there'], [99, 'EDM'], [129, 'ENM']], 30], [[1033, 1533, 'Bye']])], [('regression: display erase target', [[[0, 'TEXT:Bye'], [7, 'EOC'], [14, 'EDM'], [43, 'ENM'], [88, 'EDM'], [95, 'EOC'], [95, 'EOC'], [125, 'TEXT:Bye']], 24], [[291, 583, 'Bye']]), ('regression variant: display erase target', [[[30, 'TEXT:Hi'], [75, 'EOC'], [90, 'EDM'], [90, 'EDM'], [135, 'TEXT:Hi'], [136, 'EDM'], [136, 'TEXT:Hi']], 29], [[2586, 3103, 'Hi']]), ('partial repair probe: display erase target', [[[0, 'TEXT: there'], [1, 'EOC'], [31, 'EDM'], [38, 'EOC'], [45, 'TEXT: there'], [46, 'ENM'], [76, 'TEXT: there']], 29], [[34, 1068, ' there']]), ('partial repair variant: display erase target', [[[3, 'EOC'], [10, 'ENM'], [40, 'TEXT: there'], [55, 'EOC'], [85, 'TEXT:Hi'], [115, 'EOC'], [160, 'EDM'], [167, 'EOC']], 29], [[1896, 3965, ' there'], [3965, 5517, 'Hi']]), ('boundary control', [[[0, 'TEXT:A'], [10, 'EOC'], [20, 'TEXT:B'], [40, 'EOC'], [50, 'EOC']], 25], [[400, 1600, 'A'], [1600, 2000, 'B']]), ('boundary control', [[[0, 'EOC'], [5, 'EDM']], 30], []), ('normal control', [[[30, 'TEXT: there'], [30, 'EOC'], [59, 'ENM']], 30], []), ('normal control', [[[0, 'EDM'], [7, 'TEXT: there'], [37, 'TEXT: there']], 29], []), ('normal control', [[[0, 'ENM'], [0, 'EOC'], [30, 'TEXT:Hi']], 24], [])], [('regression: display erase target', [[[30, 'TEXT:Hi'], [30, 'EDM'], [75, 'EOC'], [120, 'EDM']], 24], [[3125, 5000, 'Hi']]), ('regression variant: display erase target', [[[0, 'TEXT: there'], [1, 'EOC'], [31, 'EDM'], [38, 'EOC'], [45, 'TEXT: there'], [46, 'ENM'], [76, 'TEXT: there']], 29], [[34, 1068, ' there']]), ('partial repair probe: display erase target', [[[30, 'TEXT:Hi'], [45, 'TEXT:Hi'], [75, 'EDM'], [76, 'TEXT: there'], [83, 'EOC'], [128, 'EDM'], [143, 'EOC']], 25], [[3320, 5120, 'HiHi there']]), ('partial repair variant: display erase target', [[[0, 'TEXT: there'], [0, 'TEXT: there'], [7, 'TEXT: there'], [37, 'EOC'], [67, 'TEXT:Hi'], [67, 'TEXT:Hi'], [97, 'EDM'], [112, 'EOC']], 29], [[1275, 3344, ' there there there']]), ('boundary control', [[[0, 'EOC'], [5, 'EDM']], 30], []), ('boundary control', [[[0, 'TEXT:Hi'], [30, 'EOC'], [60, 'EDM']], 30], [[1000, 2000, 'Hi']]), ('normal control', [[[0, 'TEXT:Bye'], [1, 'EDM'], [31, 'TEXT: there'], [61, 'ENM'], [68, 'EOC'], [98, 'EOC'], [113, 'TEXT:Bye']], 25], []), ('normal control', [[[3, 'TEXT: there'], [32, 'TEXT: there'], [33, 'TEXT: there'], [48, 'EOC'], [78, 'EOC'], [123, 'TEXT: there']], 25], [[1920, 3120, ' there there there']]), ('normal control', [[[3, 'EDM'], [18, 'EOC'], [63, 'TEXT:Bye'], [63, 'ENM'], [108, 'TEXT:Bye'], [123, 'ENM'], [138, 'TEXT: there']], 25], [])], [('regression: display erase target', [[[30, 'TEXT:Bye'], [31, 'ENM'], [76, 'EOC'], [106, 'TEXT:Hi'], [107, 'EDM'], [137, 'EOC'], [166, 'EDM'], [167, 'TEXT: there']], 24], [[5708, 6916, 'Hi']]), ('regression variant: display erase target', [[[0, 'TEXT: there'], [29, 'TEXT:Bye'], [44, 'EDM'], [73, 'EOC'], [118, 'EOC'], [163, 'TEXT: there'], [192, 'ENM']], 25], [[2920, 4720, ' thereBye']]), ('partial repair probe: display erase target', [[[30, 'TEXT:Hi'], [45, 'TEXT:Hi'], [75, 'EDM'], [76, 'TEXT: there'], [83, 'EOC'], [128, 'EDM'], [143, 'EOC']], 25], [[3320, 5120, 'HiHi there']]), ('partial repair variant: display erase target', [[[0, 'TEXT:Bye'], [45, 'EDM'], [74, 'EOC'], [119, 'TEXT:Hi'], [120, 'EDM'], [135, 'EOC'], [165, 'TEXT: there'], [194, 'TEXT: there']], 29], [[2551, 4137, 'Bye']]), ('boundary control', [[[0, 'TEXT:Hi'], [30, 'EOC'], [60, 'EDM']], 30], [[1000, 2000, 'Hi']]), ('boundary control', [[[0, 'TEXT:A'], [10, 'EOC'], [20, 'TEXT:B'], [40, 'EOC'], [50, 'EOC']], 25], [[400, 1600, 'A'], [1600, 2000, 'B']]), ('normal control', [[[30, 'TEXT:Bye'], [59, 'EOC'], [66, 'TEXT:Bye'], [111, 'EOC']], 24], [[2458, 4625, 'Bye']]), ('normal control', [[[3, 'TEXT:Hi'], [10, 'TEXT:Bye']], 30], []), ('normal control', [[[3, 'EOC'], [18, 'EOC'], [19, 'EOC']], 25], [])], [('regression: display erase target', [[[3, 'EOC'], [3, 'TEXT: there'], [4, 'TEXT: there'], [34, 'EDM'], [64, 'EOC'], [71, 'EOC'], [78, 'TEXT: there'], [78, 'TEXT: there']], 30], [[2133, 2366, ' there there']]), ('regression variant: display erase target', [[[30, 'TEXT:Hi'], [45, 'TEXT:Hi'], [75, 'EDM'], [76, 'TEXT: there'], [83, 'EOC'], [128, 'EDM'], [143, 'EOC']], 25], [[3320, 5120, 'HiHi there']]), ('partial repair probe: display erase target', [[[3, 'TEXT:Hi'], [18, 'TEXT: there'], [33, 'TEXT:Bye'], [62, 'EOC'], [91, 'EDM'], [120, 'EOC'], [149, 'EOC'], [150, 'TEXT:Bye']], 25], [[2480, 3640, 'Hi thereBye']]), ('partial repair variant: display erase target', [[[0, 'TEXT:Bye'], [30, 'EOC'], [30, 'EDM'], [45, 'EOC'], [60, 'TEXT: there'], [89, 'EDM'], [119, 'EDM'], [126, 'TEXT:Bye']], 24], [[1250, 1250, 'Bye']]), ('boundary control', [[[0, 'TEXT:A'], [10, 'EOC'], [20, 'TEXT:B'], [40, 'EOC'], [50, 'EOC']], 25], [[400, 1600, 'A'], [1600, 2000, 'B']]), ('boundary control', [[[0, 'EOC'], [5, 'EDM']], 30], []), ('normal control', [[[30, 'EDM'], [60, 'TEXT: there'], [67, 'EOC'], [112, 'EOC']], 24], [[2791, 4666, ' there']]), ('normal control', [[[3, 'EDM'], [33, 'TEXT:Bye'], [63, 'TEXT:Hi'], [108, 'EOC'], [109, 'TEXT:Hi']], 30], []), ('normal control', [[[30, 'ENM'], [31, 'TEXT: there'], [60, 'EDM'], [89, 'ENM'], [96, 'EDM'], [111, 'EOC']], 30], [])]]
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: display erase target	`[[1233, 1733, 'Bye'], [1233, 2233, 'Bye']]`	`[[1233, 1733, 'Bye']]`	Failed
regression variant: display erase target	`[[4800, 6560, 'HiHi'], [4800, 9520, 'HiHi'], [9520, 10680, 'Hi']]`	`[[4800, 6560, 'HiHi'], [9520, 10680, 'HiHi']]`	Failed
partial repair probe: display erase target	`[[2586, 3103, 'Hi'], [2586, 3103, 'Hi'], [2586, 4689, 'Hi']]`	`[[2586, 3103, 'Hi']]`	Failed
partial repair variant: display erase target	`[[620, 1137, 'Bye'], [620, 2172, 'Bye']]`	`[[620, 1137, 'Bye']]`	Failed
boundary control	`[[1000, 2000, 'Hi']]`	`[[1000, 2000, 'Hi']]`	Passed
boundary control	`[[400, 1600, 'A'], [1600, 2000, 'B']]`	`[[400, 1600, 'A'], [1600, 2000, 'B']]`	Passed
normal control	`[]`	`[]`	Passed
normal control	`[]`	`[]`	Passed
normal control	`[[1033, 1533, 'Bye']]`	`[[1033, 1533, 'Bye']]`	Passed

SHA-256 / 2019e4e645acc96a77ff3e26a9881ff5e03b33c0dcac0002650ef3c31b2d3d85

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(events, fps):
    shown=''
    hidden=''
    since=None
    out=[]
    for frame,cmd in events:
        t=frame*1000//fps
        if cmd.startswith('TEXT:'):
            hidden+=cmd[5:]
        elif cmd=='ENM':
            hidden=''
        elif cmd=='EOC':
            if shown:
                out.append([since,t,shown])
            shown,hidden=hidden,shown
            since=t
        elif cmd=='EDM':
            if shown: out.append([since,t,shown])
            since=t
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: display erase target', [[[30, 'TEXT:Bye'], [37, 'EOC'], [52, 'EDM'], [52, 'ENM'], [67, 'EDM']], 30], [[1233, 1733, 'Bye']]), ('regression variant: display erase target', [[[30, 'TEXT:Hi'], [75, 'TEXT:Hi'], [120, 'EOC'], [135, 'TEXT:Hi'], [164, 'EDM'], [193, 'TEXT:Hi'], [238, 'EOC'], [267, 'EOC']], 25], [[4800, 6560, 'HiHi'], [9520, 10680, 'HiHi']]), ('partial repair probe: display erase target', [[[30, 'TEXT:Hi'], [75, 'EOC'], [90, 'EDM'], [90, 'EDM'], [135, 'TEXT:Hi'], [136, 'EDM'], [136, 'TEXT:Hi']], 29], [[2586, 3103, 'Hi']]), ('partial repair variant: display erase target', [[[3, 'TEXT:Bye'], [18, 'EOC'], [33, 'TEXT:Hi'], [33, 'EDM'], [33, 'TEXT:Hi'], [62, 'ENM'], [63, 'EOC'], [92, 'TEXT: there']], 29], [[620, 1137, 'Bye']]), ('boundary control', [[[0, 'TEXT:Hi'], [30, 'EOC'], [60, 'EDM']], 30], [[1000, 2000, 'Hi']]), ('boundary control', [[[0, 'TEXT:A'], [10, 'EOC'], [20, 'TEXT:B'], [40, 'EOC'], [50, 'EOC']], 25], [[400, 1600, 'A'], [1600, 2000, 'B']]), ('normal control', [[[0, 'EOC'], [5, 'EDM']], 30], []), ('normal control', [[[30, 'EOC'], [30, 'TEXT:Hi'], [37, 'ENM']], 24], []), ('normal control', [[[0, 'EOC'], [30, 'TEXT:Bye'], [31, 'EOC'], [46, 'EOC'], [91, 'TEXT:Hi'], [92, 'TEXT: there'], [99, 'EDM'], [129, 'ENM']], 30], [[1033, 1533, 'Bye']])], [('regression: display erase target', [[[0, 'TEXT:Bye'], [7, 'EOC'], [14, 'EDM'], [43, 'ENM'], [88, 'EDM'], [95, 'EOC'], [95, 'EOC'], [125, 'TEXT:Bye']], 24], [[291, 583, 'Bye']]), ('regression variant: display erase target', [[[30, 'TEXT:Hi'], [75, 'EOC'], [90, 'EDM'], [90, 'EDM'], [135, 'TEXT:Hi'], [136, 'EDM'], [136, 'TEXT:Hi']], 29], [[2586, 3103, 'Hi']]), ('partial repair probe: display erase target', [[[0, 'TEXT: there'], [1, 'EOC'], [31, 'EDM'], [38, 'EOC'], [45, 'TEXT: there'], [46, 'ENM'], [76, 'TEXT: there']], 29], [[34, 1068, ' there']]), ('partial repair variant: display erase target', [[[3, 'EOC'], [10, 'ENM'], [40, 'TEXT: there'], [55, 'EOC'], [85, 'TEXT:Hi'], [115, 'EOC'], [160, 'EDM'], [167, 'EOC']], 29], [[1896, 3965, ' there'], [3965, 5517, 'Hi']]), ('boundary control', [[[0, 'TEXT:A'], [10, 'EOC'], [20, 'TEXT:B'], [40, 'EOC'], [50, 'EOC']], 25], [[400, 1600, 'A'], [1600, 2000, 'B']]), ('boundary control', [[[0, 'EOC'], [5, 'EDM']], 30], []), ('normal control', [[[30, 'TEXT: there'], [30, 'EOC'], [59, 'ENM']], 30], []), ('normal control', [[[0, 'EDM'], [7, 'TEXT: there'], [37, 'TEXT: there']], 29], []), ('normal control', [[[0, 'ENM'], [0, 'EOC'], [30, 'TEXT:Hi']], 24], [])], [('regression: display erase target', [[[30, 'TEXT:Hi'], [30, 'EDM'], [75, 'EOC'], [120, 'EDM']], 24], [[3125, 5000, 'Hi']]), ('regression variant: display erase target', [[[0, 'TEXT: there'], [1, 'EOC'], [31, 'EDM'], [38, 'EOC'], [45, 'TEXT: there'], [46, 'ENM'], [76, 'TEXT: there']], 29], [[34, 1068, ' there']]), ('partial repair probe: display erase target', [[[30, 'TEXT:Hi'], [45, 'TEXT:Hi'], [75, 'EDM'], [76, 'TEXT: there'], [83, 'EOC'], [128, 'EDM'], [143, 'EOC']], 25], [[3320, 5120, 'HiHi there']]), ('partial repair variant: display erase target', [[[0, 'TEXT: there'], [0, 'TEXT: there'], [7, 'TEXT: there'], [37, 'EOC'], [67, 'TEXT:Hi'], [67, 'TEXT:Hi'], [97, 'EDM'], [112, 'EOC']], 29], [[1275, 3344, ' there there there']]), ('boundary control', [[[0, 'EOC'], [5, 'EDM']], 30], []), ('boundary control', [[[0, 'TEXT:Hi'], [30, 'EOC'], [60, 'EDM']], 30], [[1000, 2000, 'Hi']]), ('normal control', [[[0, 'TEXT:Bye'], [1, 'EDM'], [31, 'TEXT: there'], [61, 'ENM'], [68, 'EOC'], [98, 'EOC'], [113, 'TEXT:Bye']], 25], []), ('normal control', [[[3, 'TEXT: there'], [32, 'TEXT: there'], [33, 'TEXT: there'], [48, 'EOC'], [78, 'EOC'], [123, 'TEXT: there']], 25], [[1920, 3120, ' there there there']]), ('normal control', [[[3, 'EDM'], [18, 'EOC'], [63, 'TEXT:Bye'], [63, 'ENM'], [108, 'TEXT:Bye'], [123, 'ENM'], [138, 'TEXT: there']], 25], [])], [('regression: display erase target', [[[30, 'TEXT:Bye'], [31, 'ENM'], [76, 'EOC'], [106, 'TEXT:Hi'], [107, 'EDM'], [137, 'EOC'], [166, 'EDM'], [167, 'TEXT: there']], 24], [[5708, 6916, 'Hi']]), ('regression variant: display erase target', [[[0, 'TEXT: there'], [29, 'TEXT:Bye'], [44, 'EDM'], [73, 'EOC'], [118, 'EOC'], [163, 'TEXT: there'], [192, 'ENM']], 25], [[2920, 4720, ' thereBye']]), ('partial repair probe: display erase target', [[[30, 'TEXT:Hi'], [45, 'TEXT:Hi'], [75, 'EDM'], [76, 'TEXT: there'], [83, 'EOC'], [128, 'EDM'], [143, 'EOC']], 25], [[3320, 5120, 'HiHi there']]), ('partial repair variant: display erase target', [[[0, 'TEXT:Bye'], [45, 'EDM'], [74, 'EOC'], [119, 'TEXT:Hi'], [120, 'EDM'], [135, 'EOC'], [165, 'TEXT: there'], [194, 'TEXT: there']], 29], [[2551, 4137, 'Bye']]), ('boundary control', [[[0, 'TEXT:Hi'], [30, 'EOC'], [60, 'EDM']], 30], [[1000, 2000, 'Hi']]), ('boundary control', [[[0, 'TEXT:A'], [10, 'EOC'], [20, 'TEXT:B'], [40, 'EOC'], [50, 'EOC']], 25], [[400, 1600, 'A'], [1600, 2000, 'B']]), ('normal control', [[[30, 'TEXT:Bye'], [59, 'EOC'], [66, 'TEXT:Bye'], [111, 'EOC']], 24], [[2458, 4625, 'Bye']]), ('normal control', [[[3, 'TEXT:Hi'], [10, 'TEXT:Bye']], 30], []), ('normal control', [[[3, 'EOC'], [18, 'EOC'], [19, 'EOC']], 25], [])], [('regression: display erase target', [[[3, 'EOC'], [3, 'TEXT: there'], [4, 'TEXT: there'], [34, 'EDM'], [64, 'EOC'], [71, 'EOC'], [78, 'TEXT: there'], [78, 'TEXT: there']], 30], [[2133, 2366, ' there there']]), ('regression variant: display erase target', [[[30, 'TEXT:Hi'], [45, 'TEXT:Hi'], [75, 'EDM'], [76, 'TEXT: there'], [83, 'EOC'], [128, 'EDM'], [143, 'EOC']], 25], [[3320, 5120, 'HiHi there']]), ('partial repair probe: display erase target', [[[3, 'TEXT:Hi'], [18, 'TEXT: there'], [33, 'TEXT:Bye'], [62, 'EOC'], [91, 'EDM'], [120, 'EOC'], [149, 'EOC'], [150, 'TEXT:Bye']], 25], [[2480, 3640, 'Hi thereBye']]), ('partial repair variant: display erase target', [[[0, 'TEXT:Bye'], [30, 'EOC'], [30, 'EDM'], [45, 'EOC'], [60, 'TEXT: there'], [89, 'EDM'], [119, 'EDM'], [126, 'TEXT:Bye']], 24], [[1250, 1250, 'Bye']]), ('boundary control', [[[0, 'TEXT:A'], [10, 'EOC'], [20, 'TEXT:B'], [40, 'EOC'], [50, 'EOC']], 25], [[400, 1600, 'A'], [1600, 2000, 'B']]), ('boundary control', [[[0, 'EOC'], [5, 'EDM']], 30], []), ('normal control', [[[30, 'EDM'], [60, 'TEXT: there'], [67, 'EOC'], [112, 'EOC']], 24], [[2791, 4666, ' there']]), ('normal control', [[[3, 'EDM'], [33, 'TEXT:Bye'], [63, 'TEXT:Hi'], [108, 'EOC'], [109, 'TEXT:Hi']], 30], []), ('normal control', [[[30, 'ENM'], [31, 'TEXT: there'], [60, 'EDM'], [89, 'ENM'], [96, 'EDM'], [111, 'EOC']], 30], [])]]
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: display erase target	`[[1233, 1733, 'Bye'], [1733, 2233, 'Bye']]`	`[[1233, 1733, 'Bye']]`	Failed
regression variant: display erase target	`[[4800, 6560, 'HiHi'], [6560, 9520, 'HiHi'], [9520, 10680, 'HiHi']]`	`[[4800, 6560, 'HiHi'], [9520, 10680, 'HiHi']]`	Failed
partial repair probe: display erase target	`[[2586, 3103, 'Hi'], [3103, 3103, 'Hi'], [3103, 4689, 'Hi']]`	`[[2586, 3103, 'Hi']]`	Failed
partial repair variant: display erase target	`[[620, 1137, 'Bye'], [1137, 2172, 'Bye']]`	`[[620, 1137, 'Bye']]`	Failed
boundary control	`[[1000, 2000, 'Hi']]`	`[[1000, 2000, 'Hi']]`	Passed
boundary control	`[[400, 1600, 'A'], [1600, 2000, 'B']]`	`[[400, 1600, 'A'], [1600, 2000, 'B']]`	Passed
normal control	`[]`	`[]`	Passed
normal control	`[]`	`[]`	Passed
normal control	`[[1033, 1533, 'Bye']]`	`[[1033, 1533, 'Bye']]`	Passed

SHA-256 / c8ece343b4d586875e9902ad440f7abaf3c21f3157315aa544e9f19547126631

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(events, fps):
    shown=''
    hidden=''
    since=None
    out=[]
    for frame,cmd in events:
        t=frame*1000//fps
        if cmd.startswith('TEXT:'):
            hidden+=cmd[5:]
        elif cmd=='ENM':
            hidden=''
        elif cmd=='EOC':
            if shown:
                out.append([since,t,shown])
            shown,hidden=hidden,shown
            since=t
        elif cmd=='EDM':
            if shown: out.append([since,t,shown])
            shown=''
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: display erase target', [[[30, 'TEXT:Bye'], [37, 'EOC'], [52, 'EDM'], [52, 'ENM'], [67, 'EDM']], 30], [[1233, 1733, 'Bye']]), ('regression variant: display erase target', [[[30, 'TEXT:Hi'], [75, 'TEXT:Hi'], [120, 'EOC'], [135, 'TEXT:Hi'], [164, 'EDM'], [193, 'TEXT:Hi'], [238, 'EOC'], [267, 'EOC']], 25], [[4800, 6560, 'HiHi'], [9520, 10680, 'HiHi']]), ('partial repair probe: display erase target', [[[30, 'TEXT:Hi'], [75, 'EOC'], [90, 'EDM'], [90, 'EDM'], [135, 'TEXT:Hi'], [136, 'EDM'], [136, 'TEXT:Hi']], 29], [[2586, 3103, 'Hi']]), ('partial repair variant: display erase target', [[[3, 'TEXT:Bye'], [18, 'EOC'], [33, 'TEXT:Hi'], [33, 'EDM'], [33, 'TEXT:Hi'], [62, 'ENM'], [63, 'EOC'], [92, 'TEXT: there']], 29], [[620, 1137, 'Bye']]), ('boundary control', [[[0, 'TEXT:Hi'], [30, 'EOC'], [60, 'EDM']], 30], [[1000, 2000, 'Hi']]), ('boundary control', [[[0, 'TEXT:A'], [10, 'EOC'], [20, 'TEXT:B'], [40, 'EOC'], [50, 'EOC']], 25], [[400, 1600, 'A'], [1600, 2000, 'B']]), ('normal control', [[[0, 'EOC'], [5, 'EDM']], 30], []), ('normal control', [[[30, 'EOC'], [30, 'TEXT:Hi'], [37, 'ENM']], 24], []), ('normal control', [[[0, 'EOC'], [30, 'TEXT:Bye'], [31, 'EOC'], [46, 'EOC'], [91, 'TEXT:Hi'], [92, 'TEXT: there'], [99, 'EDM'], [129, 'ENM']], 30], [[1033, 1533, 'Bye']])], [('regression: display erase target', [[[0, 'TEXT:Bye'], [7, 'EOC'], [14, 'EDM'], [43, 'ENM'], [88, 'EDM'], [95, 'EOC'], [95, 'EOC'], [125, 'TEXT:Bye']], 24], [[291, 583, 'Bye']]), ('regression variant: display erase target', [[[30, 'TEXT:Hi'], [75, 'EOC'], [90, 'EDM'], [90, 'EDM'], [135, 'TEXT:Hi'], [136, 'EDM'], [136, 'TEXT:Hi']], 29], [[2586, 3103, 'Hi']]), ('partial repair probe: display erase target', [[[0, 'TEXT: there'], [1, 'EOC'], [31, 'EDM'], [38, 'EOC'], [45, 'TEXT: there'], [46, 'ENM'], [76, 'TEXT: there']], 29], [[34, 1068, ' there']]), ('partial repair variant: display erase target', [[[3, 'EOC'], [10, 'ENM'], [40, 'TEXT: there'], [55, 'EOC'], [85, 'TEXT:Hi'], [115, 'EOC'], [160, 'EDM'], [167, 'EOC']], 29], [[1896, 3965, ' there'], [3965, 5517, 'Hi']]), ('boundary control', [[[0, 'TEXT:A'], [10, 'EOC'], [20, 'TEXT:B'], [40, 'EOC'], [50, 'EOC']], 25], [[400, 1600, 'A'], [1600, 2000, 'B']]), ('boundary control', [[[0, 'EOC'], [5, 'EDM']], 30], []), ('normal control', [[[30, 'TEXT: there'], [30, 'EOC'], [59, 'ENM']], 30], []), ('normal control', [[[0, 'EDM'], [7, 'TEXT: there'], [37, 'TEXT: there']], 29], []), ('normal control', [[[0, 'ENM'], [0, 'EOC'], [30, 'TEXT:Hi']], 24], [])], [('regression: display erase target', [[[30, 'TEXT:Hi'], [30, 'EDM'], [75, 'EOC'], [120, 'EDM']], 24], [[3125, 5000, 'Hi']]), ('regression variant: display erase target', [[[0, 'TEXT: there'], [1, 'EOC'], [31, 'EDM'], [38, 'EOC'], [45, 'TEXT: there'], [46, 'ENM'], [76, 'TEXT: there']], 29], [[34, 1068, ' there']]), ('partial repair probe: display erase target', [[[30, 'TEXT:Hi'], [45, 'TEXT:Hi'], [75, 'EDM'], [76, 'TEXT: there'], [83, 'EOC'], [128, 'EDM'], [143, 'EOC']], 25], [[3320, 5120, 'HiHi there']]), ('partial repair variant: display erase target', [[[0, 'TEXT: there'], [0, 'TEXT: there'], [7, 'TEXT: there'], [37, 'EOC'], [67, 'TEXT:Hi'], [67, 'TEXT:Hi'], [97, 'EDM'], [112, 'EOC']], 29], [[1275, 3344, ' there there there']]), ('boundary control', [[[0, 'EOC'], [5, 'EDM']], 30], []), ('boundary control', [[[0, 'TEXT:Hi'], [30, 'EOC'], [60, 'EDM']], 30], [[1000, 2000, 'Hi']]), ('normal control', [[[0, 'TEXT:Bye'], [1, 'EDM'], [31, 'TEXT: there'], [61, 'ENM'], [68, 'EOC'], [98, 'EOC'], [113, 'TEXT:Bye']], 25], []), ('normal control', [[[3, 'TEXT: there'], [32, 'TEXT: there'], [33, 'TEXT: there'], [48, 'EOC'], [78, 'EOC'], [123, 'TEXT: there']], 25], [[1920, 3120, ' there there there']]), ('normal control', [[[3, 'EDM'], [18, 'EOC'], [63, 'TEXT:Bye'], [63, 'ENM'], [108, 'TEXT:Bye'], [123, 'ENM'], [138, 'TEXT: there']], 25], [])], [('regression: display erase target', [[[30, 'TEXT:Bye'], [31, 'ENM'], [76, 'EOC'], [106, 'TEXT:Hi'], [107, 'EDM'], [137, 'EOC'], [166, 'EDM'], [167, 'TEXT: there']], 24], [[5708, 6916, 'Hi']]), ('regression variant: display erase target', [[[0, 'TEXT: there'], [29, 'TEXT:Bye'], [44, 'EDM'], [73, 'EOC'], [118, 'EOC'], [163, 'TEXT: there'], [192, 'ENM']], 25], [[2920, 4720, ' thereBye']]), ('partial repair probe: display erase target', [[[30, 'TEXT:Hi'], [45, 'TEXT:Hi'], [75, 'EDM'], [76, 'TEXT: there'], [83, 'EOC'], [128, 'EDM'], [143, 'EOC']], 25], [[3320, 5120, 'HiHi there']]), ('partial repair variant: display erase target', [[[0, 'TEXT:Bye'], [45, 'EDM'], [74, 'EOC'], [119, 'TEXT:Hi'], [120, 'EDM'], [135, 'EOC'], [165, 'TEXT: there'], [194, 'TEXT: there']], 29], [[2551, 4137, 'Bye']]), ('boundary control', [[[0, 'TEXT:Hi'], [30, 'EOC'], [60, 'EDM']], 30], [[1000, 2000, 'Hi']]), ('boundary control', [[[0, 'TEXT:A'], [10, 'EOC'], [20, 'TEXT:B'], [40, 'EOC'], [50, 'EOC']], 25], [[400, 1600, 'A'], [1600, 2000, 'B']]), ('normal control', [[[30, 'TEXT:Bye'], [59, 'EOC'], [66, 'TEXT:Bye'], [111, 'EOC']], 24], [[2458, 4625, 'Bye']]), ('normal control', [[[3, 'TEXT:Hi'], [10, 'TEXT:Bye']], 30], []), ('normal control', [[[3, 'EOC'], [18, 'EOC'], [19, 'EOC']], 25], [])], [('regression: display erase target', [[[3, 'EOC'], [3, 'TEXT: there'], [4, 'TEXT: there'], [34, 'EDM'], [64, 'EOC'], [71, 'EOC'], [78, 'TEXT: there'], [78, 'TEXT: there']], 30], [[2133, 2366, ' there there']]), ('regression variant: display erase target', [[[30, 'TEXT:Hi'], [45, 'TEXT:Hi'], [75, 'EDM'], [76, 'TEXT: there'], [83, 'EOC'], [128, 'EDM'], [143, 'EOC']], 25], [[3320, 5120, 'HiHi there']]), ('partial repair probe: display erase target', [[[3, 'TEXT:Hi'], [18, 'TEXT: there'], [33, 'TEXT:Bye'], [62, 'EOC'], [91, 'EDM'], [120, 'EOC'], [149, 'EOC'], [150, 'TEXT:Bye']], 25], [[2480, 3640, 'Hi thereBye']]), ('partial repair variant: display erase target', [[[0, 'TEXT:Bye'], [30, 'EOC'], [30, 'EDM'], [45, 'EOC'], [60, 'TEXT: there'], [89, 'EDM'], [119, 'EDM'], [126, 'TEXT:Bye']], 24], [[1250, 1250, 'Bye']]), ('boundary control', [[[0, 'TEXT:A'], [10, 'EOC'], [20, 'TEXT:B'], [40, 'EOC'], [50, 'EOC']], 25], [[400, 1600, 'A'], [1600, 2000, 'B']]), ('boundary control', [[[0, 'EOC'], [5, 'EDM']], 30], []), ('normal control', [[[30, 'EDM'], [60, 'TEXT: there'], [67, 'EOC'], [112, 'EOC']], 24], [[2791, 4666, ' there']]), ('normal control', [[[3, 'EDM'], [33, 'TEXT:Bye'], [63, 'TEXT:Hi'], [108, 'EOC'], [109, 'TEXT:Hi']], 30], []), ('normal control', [[[30, 'ENM'], [31, 'TEXT: there'], [60, 'EDM'], [89, 'ENM'], [96, 'EDM'], [111, 'EOC']], 30], [])]]
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: display erase target	`[[1233, 1733, 'Bye']]`	`[[1233, 1733, 'Bye']]`	Passed
regression variant: display erase target	`[[4800, 6560, 'HiHi'], [9520, 10680, 'HiHi']]`	`[[4800, 6560, 'HiHi'], [9520, 10680, 'HiHi']]`	Passed
partial repair probe: display erase target	`[[2586, 3103, 'Hi']]`	`[[2586, 3103, 'Hi']]`	Passed
partial repair variant: display erase target	`[[620, 1137, 'Bye']]`	`[[620, 1137, 'Bye']]`	Passed
boundary control	`[[1000, 2000, 'Hi']]`	`[[1000, 2000, 'Hi']]`	Passed
boundary control	`[[400, 1600, 'A'], [1600, 2000, 'B']]`	`[[400, 1600, 'A'], [1600, 2000, 'B']]`	Passed
normal control	`[]`	`[]`	Passed
normal control	`[]`	`[]`	Passed
normal control	`[[1033, 1533, 'Bye']]`	`[[1033, 1533, 'Bye']]`	Passed

SHA-256 / 31afff737318241c3bc7a05c8f29958c9f26bfac279464b54d957b9c9c0994d4

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 2026-09-29T14:49:33.382902+00:00.

Case digest / 42812270fea72be2c07f9b3d035a1fe1ff84870862a7e90d830241f64b0dd00d