FA-11201 / Streaming segment lifecycle / Open access

Segment explicit gap skips download · case 01

A declared missing segment is repeatedly downloaded instead of represented as a playback gap.

Verified by executionVariant 1 · 4 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

A declared missing segment is repeatedly downloaded instead of represented as a playback gap.

THE FAILURE

A declared missing segment is repeatedly downloaded instead of represented as a playback gap.

Unsuccessful approach: Keeping only gaps reverses the available-segment selection.

Case contract

Convert manifest [segment-ID,gap flag] entries to required downloads; explicitly missing gap segments are skipped without suppressing neighboring media.

Why this case matters

A deterministic local media controller stage; metadata and downloaded data are supplied explicitly. No external player, service or codec is required.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(segments):
    return [identity for identity,gap in segments]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*([['a', False], ['b', True], ['c', False]],)),['a', 'c'])
check('fixture 2',solve(*([['a', True]],)),[])
check('fixture 3',solve(*([],)),[])
check('fixture 4',solve(*([['a', False]],)),['a'])
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
fixture 1	`['a', 'b', 'c']`	`['a', 'c']`	Failed
fixture 2	`['a']`	`[]`	Failed
fixture 3	`[]`	`[]`	Passed
fixture 4	`['a']`	`['a']`	Passed

SHA-256 / 4ea197e76a4557bd9a5d05a76102b2208974ec4854ba08aca853da1215f9555a

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(segments):
    return [identity for identity,gap in segments if gap]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*([['a', False], ['b', True], ['c', False]],)),['a', 'c'])
check('fixture 2',solve(*([['a', True]],)),[])
check('fixture 3',solve(*([],)),[])
check('fixture 4',solve(*([['a', False]],)),['a'])
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
fixture 1	`['b']`	`['a', 'c']`	Failed
fixture 2	`['a']`	`[]`	Failed
fixture 3	`[]`	`[]`	Passed
fixture 4	`[]`	`['a']`	Failed

SHA-256 / 909ec17f3c65bcedad116cac6fa1d8aa34ea3fd3d9af8f78f1196777c4138028

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 4 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

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 2026-09-29T14:38:45.855214+00:00.

Case digest / a6dfbf2df214e2263dcde6ad10ed50e82ba1f2b14c5777a8115122b2c5ea6242