FAILURE MAP
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FA-49071 / PCM sample encoding / Open access

Pcm byte lane shuffle: repeat lanes · case 01

Repeated byte-lane entries are deduplicated despite explicit replicated-byte conversion.

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

ROOT CAUSE

Repeated byte-lane entries are deduplicated despite explicit replicated-byte conversion.

THE FAILURE

Repeated byte-lane entries are deduplicated despite explicit replicated-byte conversion.

Unsuccessful approach: Using a set also loses map order.

Case contract

Repack each fixed-size sample container using an explicit byte-lane map, retain duplicate selections and validate only declared zero-pad lanes.

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(packets, lanes, ignored):
    out=[]
    for packet in packets:
        selected=[packet[i] for i in dict.fromkeys(lanes)]
        ignored_values=[packet[i] for i in ignored]
        good=all(value==0 for value in ignored_values)
        out.append([selected,good,len(selected)])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('oracle 1', solve(*([[1, 0, 2, 0], [3, 0, 4, 5]], [2, 0], [1, 3])), [[[2, 1], True, 2], [[4, 3], False, 2]])
check('oracle 2', solve(*([[8, 9]], [1, 0, 1], [])), [[[9, 8, 9], True, 3]])
check('oracle 3', solve(*([], [], [])), [])
check('oracle 4', solve(*([[0, 1, 0]], [1], [0, 2])), [[[1], True, 1]])
check('oracle 5', solve(*([[0, 0]], [], [0, 1])), [[[], True, 0]])
check('oracle 6', solve(*([[4, 3, 2, 1]], [3, 1, 0], [2])), [[[1, 3, 4], False, 3]])
check('oracle 7', solve(*([[1]], [0], [])), [[[1], True, 1]])
if N == 1: check('variant packet 1', solve(*[[[1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5]], [2, 0], [1, 3]]), [[[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2]])
if N == 2: check('variant packet 2', solve(*[[[1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5]], [2, 0], [1, 3]]), [[[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2]])
if N == 3: check('variant packet 3', solve(*[[[1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5]], [2, 0], [1, 3]]), [[[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2]])
if N == 4: check('variant packet 4', solve(*[[[1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5]], [2, 0], [1, 3]]), [[[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2]])
if N == 5: check('variant packet 5', solve(*[[[1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5]], [2, 0], [1, 3]]), [[[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2]])
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[[[2, 1], True, 2], [[4, 3], False, 2]][[[2, 1], True, 2], [[4, 3], False, 2]]Passed
oracle 2[[[9, 8], True, 2]][[[9, 8, 9], True, 3]]Failed
oracle 3[][]Passed
oracle 4[[[1], True, 1]][[[1], True, 1]]Passed
oracle 5[[[], True, 0]][[[], True, 0]]Passed
oracle 6[[[1, 3, 4], False, 3]][[[1, 3, 4], False, 3]]Passed
oracle 7[[[1], True, 1]][[[1], True, 1]]Passed
variant packet 1[[[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2]][[[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2]]Passed

SHA-256 / 3438faebb17ec67323a2d75c3de4ec4642755f1c5435814853920e3cc10e330b

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(packets, lanes, ignored):
    out=[]
    for packet in packets:
        selected=[packet[i] for i in set(lanes)]
        ignored_values=[packet[i] for i in ignored]
        good=all(value==0 for value in ignored_values)
        out.append([selected,good,len(selected)])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('oracle 1', solve(*([[1, 0, 2, 0], [3, 0, 4, 5]], [2, 0], [1, 3])), [[[2, 1], True, 2], [[4, 3], False, 2]])
check('oracle 2', solve(*([[8, 9]], [1, 0, 1], [])), [[[9, 8, 9], True, 3]])
check('oracle 3', solve(*([], [], [])), [])
check('oracle 4', solve(*([[0, 1, 0]], [1], [0, 2])), [[[1], True, 1]])
check('oracle 5', solve(*([[0, 0]], [], [0, 1])), [[[], True, 0]])
check('oracle 6', solve(*([[4, 3, 2, 1]], [3, 1, 0], [2])), [[[1, 3, 4], False, 3]])
check('oracle 7', solve(*([[1]], [0], [])), [[[1], True, 1]])
if N == 1: check('variant packet 1', solve(*[[[1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5]], [2, 0], [1, 3]]), [[[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2]])
if N == 2: check('variant packet 2', solve(*[[[1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5]], [2, 0], [1, 3]]), [[[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2]])
if N == 3: check('variant packet 3', solve(*[[[1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5]], [2, 0], [1, 3]]), [[[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2]])
if N == 4: check('variant packet 4', solve(*[[[1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5]], [2, 0], [1, 3]]), [[[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2]])
if N == 5: check('variant packet 5', solve(*[[[1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5], [1, 0, 2, 0], [3, 0, 4, 5]], [2, 0], [1, 3]]), [[[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2]])
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, 2], True, 2], [[3, 4], False, 2]][[[2, 1], True, 2], [[4, 3], False, 2]]Failed
oracle 2[[[8, 9], True, 2]][[[9, 8, 9], True, 3]]Failed
oracle 3[][]Passed
oracle 4[[[1], True, 1]][[[1], True, 1]]Passed
oracle 5[[[], True, 0]][[[], True, 0]]Passed
oracle 6[[[4, 3, 1], False, 3]][[[1, 3, 4], False, 3]]Failed
oracle 7[[[1], True, 1]][[[1], True, 1]]Passed
variant packet 1[[[1, 2], True, 2], [[3, 4], False, 2], [[1, 2], True, 2], [[3, 4], False, 2]][[[2, 1], True, 2], [[4, 3], False, 2], [[2, 1], True, 2], [[4, 3], False, 2]]Failed

SHA-256 / 176de0011dc7ce7802895f526ade0a2eec77c97a241602c69b74e38a79f7fb3a

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 8 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

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 2026-09-29T14:44:56.612156+00:00.

Case digest / 58c5447a8d360ea2e258e6fbab66c1f639ba1774bfe0096a5665e3e6218e315c