FAILURE MAP
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FA-49521 / PCM sample encoding / Open access

Caf pcm packet table: remainder exclusion · case 01

Trailing encoder remainder samples leak into presentation.

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

ROOT CAUSE

Trailing encoder remainder samples leak into presentation.

THE FAILURE

Trailing encoder remainder samples leak into presentation.

Unsuccessful approach: Removing an additional sample truncates valid final PCM.

Case contract

Present a PCM packet table after globally removing declared priming and remainder sample counts; retain raw cumulative sample offsets for each packet.

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, priming, remainder):
    all_samples=[]
    packet_starts=[]
    for samples in packets:
        packet_starts.append(len(all_samples))
        all_samples.extend(samples)
    start=min(max(priming,0),len(all_samples))
    end=len(all_samples)
    return [all_samples[start:end],packet_starts,start,end]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('oracle 1', solve(*([[1, 2], [3, 4, 5]], 1, 1)), [[2, 3, 4], [0, 2], 1, 4])
check('oracle 2', solve(*([[1], [2, 3], [4]], 3, 0)), [[4], [0, 1, 3], 3, 4])
check('oracle 3', solve(*([[1, 2, 3, 4]], 2, 0)), [[3, 4], [0], 2, 4])
check('oracle 4', solve(*([], 2, 1)), [[], [], 0, 0])
check('oracle 5', solve(*([[1, 2], [3]], -1, -1)), [[1, 2, 3], [0, 2], 0, 3])
check('oracle 6', solve(*([[1, 2, 3], [4, 5]], 1, 2)), [[2, 3], [0, 3], 1, 3])
check('oracle 7', solve(*([[], [7], []], 0, 0)), [[7], [0, 0, 1], 0, 1])
if N == 1: check('variant packet 1', solve(*[[[1, 2], [3, 4, 5], [1, 2], [3, 4, 5]], 1, 1]), [[2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7], 1, 9])
if N == 2: check('variant packet 2', solve(*[[[1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5]], 1, 1]), [[2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7, 10, 12], 1, 14])
if N == 3: check('variant packet 3', solve(*[[[1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5]], 1, 1]), [[2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7, 10, 12, 15, 17], 1, 19])
if N == 4: check('variant packet 4', solve(*[[[1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5]], 1, 1]), [[2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7, 10, 12, 15, 17, 20, 22], 1, 24])
if N == 5: check('variant packet 5', solve(*[[[1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5]], 1, 1]), [[2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7, 10, 12, 15, 17, 20, 22, 25, 27], 1, 29])
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, 3, 4, 5], [0, 2], 1, 5][[2, 3, 4], [0, 2], 1, 4]Failed
oracle 2[[4], [0, 1, 3], 3, 4][[4], [0, 1, 3], 3, 4]Passed
oracle 3[[3, 4], [0], 2, 4][[3, 4], [0], 2, 4]Passed
oracle 4[[], [], 0, 0][[], [], 0, 0]Passed
oracle 5[[1, 2, 3], [0, 2], 0, 3][[1, 2, 3], [0, 2], 0, 3]Passed
oracle 6[[2, 3, 4, 5], [0, 3], 1, 5][[2, 3], [0, 3], 1, 3]Failed
oracle 7[[7], [0, 0, 1], 0, 1][[7], [0, 0, 1], 0, 1]Passed
variant packet 1[[2, 3, 4, 5, 1, 2, 3, 4, 5], [0, 2, 5, 7], 1, 10][[2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7], 1, 9]Failed

SHA-256 / ea98753ede87f9d8d322bde0ce7eafc3c31fe73a575e560ce97dd8af7a40700a

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(packets, priming, remainder):
    all_samples=[]
    packet_starts=[]
    for samples in packets:
        packet_starts.append(len(all_samples))
        all_samples.extend(samples)
    start=min(max(priming,0),len(all_samples))
    end=max(start,len(all_samples)-max(remainder,0)-1)
    return [all_samples[start:end],packet_starts,start,end]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('oracle 1', solve(*([[1, 2], [3, 4, 5]], 1, 1)), [[2, 3, 4], [0, 2], 1, 4])
check('oracle 2', solve(*([[1], [2, 3], [4]], 3, 0)), [[4], [0, 1, 3], 3, 4])
check('oracle 3', solve(*([[1, 2, 3, 4]], 2, 0)), [[3, 4], [0], 2, 4])
check('oracle 4', solve(*([], 2, 1)), [[], [], 0, 0])
check('oracle 5', solve(*([[1, 2], [3]], -1, -1)), [[1, 2, 3], [0, 2], 0, 3])
check('oracle 6', solve(*([[1, 2, 3], [4, 5]], 1, 2)), [[2, 3], [0, 3], 1, 3])
check('oracle 7', solve(*([[], [7], []], 0, 0)), [[7], [0, 0, 1], 0, 1])
if N == 1: check('variant packet 1', solve(*[[[1, 2], [3, 4, 5], [1, 2], [3, 4, 5]], 1, 1]), [[2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7], 1, 9])
if N == 2: check('variant packet 2', solve(*[[[1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5]], 1, 1]), [[2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7, 10, 12], 1, 14])
if N == 3: check('variant packet 3', solve(*[[[1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5]], 1, 1]), [[2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7, 10, 12, 15, 17], 1, 19])
if N == 4: check('variant packet 4', solve(*[[[1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5]], 1, 1]), [[2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7, 10, 12, 15, 17, 20, 22], 1, 24])
if N == 5: check('variant packet 5', solve(*[[[1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5], [1, 2], [3, 4, 5]], 1, 1]), [[2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7, 10, 12, 15, 17, 20, 22, 25, 27], 1, 29])
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, 3], [0, 2], 1, 3][[2, 3, 4], [0, 2], 1, 4]Failed
oracle 2[[], [0, 1, 3], 3, 3][[4], [0, 1, 3], 3, 4]Failed
oracle 3[[3], [0], 2, 3][[3, 4], [0], 2, 4]Failed
oracle 4[[], [], 0, 0][[], [], 0, 0]Passed
oracle 5[[1, 2], [0, 2], 0, 2][[1, 2, 3], [0, 2], 0, 3]Failed
oracle 6[[2], [0, 3], 1, 2][[2, 3], [0, 3], 1, 3]Failed
oracle 7[[], [0, 0, 1], 0, 0][[7], [0, 0, 1], 0, 1]Failed
variant packet 1[[2, 3, 4, 5, 1, 2, 3], [0, 2, 5, 7], 1, 8][[2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7], 1, 9]Failed

SHA-256 / 63583160ea60b8bc7d55e3e8a4b7b587658a1502efa5cdda8e111c929384983b

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 2026-09-29T14:45:00.948068+00:00.

Case digest / 747c77ca5fc0cec8ccc2b9e109fb4ad73335f0c3d9473cd2e0892edec75ccc0d