FAILURE MAP
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FA-50056 / PCM sample encoding / Open access

Pcm channel status block: block boundary · case 01

A complete status block is emitted one subframe early.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

A complete status block is emitted one subframe early.

VERIFIED REPAIR

Use the stated conversion contract at block boundary.

Unsuccessful approach: Waiting for an extra subframe shifts all following block boundaries.

Case contract

Group stipulated audio subframes into fixed-size channel-status blocks, preserving PCM samples and one status bit; a new start marks prior partial data incomplete.

Why this case matters

Offline PCM interchange uses these exact bounded packet and sample representation decisions.

1 / The failure

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

N = 1
observations = []
def solve(subframes, block_length):
    blocks=[]
    current=[]
    for start,audio,status in subframes:
        if start:
            if current:
                blocks.append([current,False])
            current=[]
        current.append([audio,status&1])
        if len(current)==block_length-1:
            blocks.append([current,True])
            current=[]
    return [blocks,current]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('oracle 1', solve(*([[True, 1, 3], [False, 2, 0], [False, 3, 1]], 3)), [[[[[1, 1], [2, 0], [3, 1]], True]], []])
check('oracle 2', solve(*([[True, 1, 0], [True, 2, 1], [False, 3, 2]], 3)), [[[[[1, 0]], False]], [[2, 1], [3, 0]]])
check('oracle 3', solve(*([[False, 1, 1], [False, 2, 0], [False, 3, 1], [False, 4, 0]], 2)), [[[[[1, 1], [2, 0]], True], [[[3, 1], [4, 0]], True]], []])
check('oracle 4', solve(*([], 3)), [[], []])
check('oracle 5', solve(*([[True, 1, 1]], 1)), [[[[[1, 1]], True]], []])
check('oracle 6', solve(*([[False, 1, 2]], 3)), [[], [[1, 0]]])
check('oracle 7', solve(*([[True, 1, 0], [False, 2, 1], [True, 3, 0]], 2)), [[[[[1, 0], [2, 1]], True]], [[3, 0]]])
if N == 1: check('variant packet 1', solve(*[[[True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1]], 3]), [[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []])
if N == 2: check('variant packet 2', solve(*[[[True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1]], 3]), [[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []])
if N == 3: check('variant packet 3', solve(*[[[True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1]], 3]), [[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []])
if N == 4: check('variant packet 4', solve(*[[[True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1]], 3]), [[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []])
if N == 5: check('variant packet 5', solve(*[[[True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1]], 3]), [[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []])
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
oracle 1[[[[[1, 1], [2, 0]], True]], [[3, 1]]][[[[[1, 1], [2, 0], [3, 1]], True]], []]Failed
oracle 2[[[[[1, 0]], False], [[[2, 1], [3, 0]], True]], []][[[[[1, 0]], False]], [[2, 1], [3, 0]]]Failed
oracle 3[[[[[1, 1]], True], [[[2, 0]], True], [[[3, 1]], True], [[[4, 0]], True]], []][[[[[1, 1], [2, 0]], True], [[[3, 1], [4, 0]], True]], []]Failed
oracle 4[[], []][[], []]Passed
oracle 5[[], [[1, 1]]][[[[[1, 1]], True]], []]Failed
oracle 6[[], [[1, 0]]][[], [[1, 0]]]Passed
oracle 7[[[[[1, 0]], True], [[[2, 1]], True], [[[3, 0]], True]], []][[[[[1, 0], [2, 1]], True]], [[3, 0]]]Failed
variant packet 1[[[[[1, 1], [2, 0]], True], [[[3, 1]], False], [[[1, 1], [2, 0]], True]], [[3, 1]]][[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []]Failed

SHA-256 / c0e447669f73a4e43fd3b0fa9d512a5b6a338f88c1e178b51a6a0b7ca1927df6

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(subframes, block_length):
    blocks=[]
    current=[]
    for start,audio,status in subframes:
        if start:
            if current:
                blocks.append([current,False])
            current=[]
        current.append([audio,status&1])
        if len(current)>block_length:
            blocks.append([current,True])
            current=[]
    return [blocks,current]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('oracle 1', solve(*([[True, 1, 3], [False, 2, 0], [False, 3, 1]], 3)), [[[[[1, 1], [2, 0], [3, 1]], True]], []])
check('oracle 2', solve(*([[True, 1, 0], [True, 2, 1], [False, 3, 2]], 3)), [[[[[1, 0]], False]], [[2, 1], [3, 0]]])
check('oracle 3', solve(*([[False, 1, 1], [False, 2, 0], [False, 3, 1], [False, 4, 0]], 2)), [[[[[1, 1], [2, 0]], True], [[[3, 1], [4, 0]], True]], []])
check('oracle 4', solve(*([], 3)), [[], []])
check('oracle 5', solve(*([[True, 1, 1]], 1)), [[[[[1, 1]], True]], []])
check('oracle 6', solve(*([[False, 1, 2]], 3)), [[], [[1, 0]]])
check('oracle 7', solve(*([[True, 1, 0], [False, 2, 1], [True, 3, 0]], 2)), [[[[[1, 0], [2, 1]], True]], [[3, 0]]])
if N == 1: check('variant packet 1', solve(*[[[True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1]], 3]), [[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []])
if N == 2: check('variant packet 2', solve(*[[[True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1]], 3]), [[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []])
if N == 3: check('variant packet 3', solve(*[[[True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1]], 3]), [[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []])
if N == 4: check('variant packet 4', solve(*[[[True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1]], 3]), [[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []])
if N == 5: check('variant packet 5', solve(*[[[True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1]], 3]), [[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []])
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
oracle 1[[], [[1, 1], [2, 0], [3, 1]]][[[[[1, 1], [2, 0], [3, 1]], True]], []]Failed
oracle 2[[[[[1, 0]], False]], [[2, 1], [3, 0]]][[[[[1, 0]], False]], [[2, 1], [3, 0]]]Passed
oracle 3[[[[[1, 1], [2, 0], [3, 1]], True]], [[4, 0]]][[[[[1, 1], [2, 0]], True], [[[3, 1], [4, 0]], True]], []]Failed
oracle 4[[], []][[], []]Passed
oracle 5[[], [[1, 1]]][[[[[1, 1]], True]], []]Failed
oracle 6[[], [[1, 0]]][[], [[1, 0]]]Passed
oracle 7[[[[[1, 0], [2, 1]], False]], [[3, 0]]][[[[[1, 0], [2, 1]], True]], [[3, 0]]]Failed
variant packet 1[[[[[1, 1], [2, 0], [3, 1]], False]], [[1, 1], [2, 0], [3, 1]]][[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []]Failed

SHA-256 / 756d2445ddf3212e5ebd54f74913e89a7340b472a2f599da650e1aa92fde3e55

3 / The verified repair

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

N = 1
observations = []
def solve(subframes, block_length):
    blocks=[]
    current=[]
    for start,audio,status in subframes:
        if start:
            if current:
                blocks.append([current,False])
            current=[]
        current.append([audio,status&1])
        if len(current)==block_length:
            blocks.append([current,True])
            current=[]
    return [blocks,current]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('oracle 1', solve(*([[True, 1, 3], [False, 2, 0], [False, 3, 1]], 3)), [[[[[1, 1], [2, 0], [3, 1]], True]], []])
check('oracle 2', solve(*([[True, 1, 0], [True, 2, 1], [False, 3, 2]], 3)), [[[[[1, 0]], False]], [[2, 1], [3, 0]]])
check('oracle 3', solve(*([[False, 1, 1], [False, 2, 0], [False, 3, 1], [False, 4, 0]], 2)), [[[[[1, 1], [2, 0]], True], [[[3, 1], [4, 0]], True]], []])
check('oracle 4', solve(*([], 3)), [[], []])
check('oracle 5', solve(*([[True, 1, 1]], 1)), [[[[[1, 1]], True]], []])
check('oracle 6', solve(*([[False, 1, 2]], 3)), [[], [[1, 0]]])
check('oracle 7', solve(*([[True, 1, 0], [False, 2, 1], [True, 3, 0]], 2)), [[[[[1, 0], [2, 1]], True]], [[3, 0]]])
if N == 1: check('variant packet 1', solve(*[[[True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1]], 3]), [[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []])
if N == 2: check('variant packet 2', solve(*[[[True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1]], 3]), [[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []])
if N == 3: check('variant packet 3', solve(*[[[True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1]], 3]), [[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []])
if N == 4: check('variant packet 4', solve(*[[[True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1]], 3]), [[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []])
if N == 5: check('variant packet 5', solve(*[[[True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1], [True, 1, 3], [False, 2, 0], [False, 3, 1]], 3]), [[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []])
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
oracle 1[[[[[1, 1], [2, 0], [3, 1]], True]], []][[[[[1, 1], [2, 0], [3, 1]], True]], []]Passed
oracle 2[[[[[1, 0]], False]], [[2, 1], [3, 0]]][[[[[1, 0]], False]], [[2, 1], [3, 0]]]Passed
oracle 3[[[[[1, 1], [2, 0]], True], [[[3, 1], [4, 0]], True]], []][[[[[1, 1], [2, 0]], True], [[[3, 1], [4, 0]], True]], []]Passed
oracle 4[[], []][[], []]Passed
oracle 5[[[[[1, 1]], True]], []][[[[[1, 1]], True]], []]Passed
oracle 6[[], [[1, 0]]][[], [[1, 0]]]Passed
oracle 7[[[[[1, 0], [2, 1]], True]], [[3, 0]]][[[[[1, 0], [2, 1]], True]], [[3, 0]]]Passed
variant packet 1[[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []][[[[[1, 1], [2, 0], [3, 1]], True], [[[1, 1], [2, 0], [3, 1]], True]], []]Passed

SHA-256 / c41b704bd8b43b25e554e943106b5f09fd1afc04f10dd4761e5e27b1e1318b8d

Verification & scope

Stipulated finite model; no claim of hardware timing or full file-format conformance. 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 2026-09-29T14:45:05.631314+00:00.

Case digest / 8cd231adebd0c46e0ec602ba60c19f8c4569124cc0db938fc7ec28e6ab467c73