FA-49516 / PCM sample encoding / Open access

Caf pcm packet table: priming global · case 01

Encoder priming samples remain audible at the start.

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

ROOT CAUSE

Encoder priming samples remain audible at the start.

VERIFIED REPAIR

Use the stated conversion contract at priming global.

Unsuccessful approach: Clamping a sample count against packet count trims the wrong duration.

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=0
    end=max(start,len(all_samples)-max(remainder,0))
    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 fixture	Actual	Expected	Outcome
oracle 1	`[[1, 2, 3, 4], [0, 2], 0, 4]`	`[[2, 3, 4], [0, 2], 1, 4]`	Failed
oracle 2	`[[1, 2, 3, 4], [0, 1, 3], 0, 4]`	`[[4], [0, 1, 3], 3, 4]`	Failed
oracle 3	`[[1, 2, 3, 4], [0], 0, 4]`	`[[3, 4], [0], 2, 4]`	Failed
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	`[[1, 2, 3], [0, 3], 0, 3]`	`[[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	`[[1, 2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7], 0, 9]`	`[[2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7], 1, 9]`	Failed

SHA-256 / 8bc2a311dd8b43b8a4295af666b25d8ea1bd87984c32f9af745fe8ff0d7c8279

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(packets))
    end=max(start,len(all_samples)-max(remainder,0))
    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 fixture	Actual	Expected	Outcome
oracle 1	`[[2, 3, 4], [0, 2], 1, 4]`	`[[2, 3, 4], [0, 2], 1, 4]`	Passed
oracle 2	`[[4], [0, 1, 3], 3, 4]`	`[[4], [0, 1, 3], 3, 4]`	Passed
oracle 3	`[[2, 3, 4], [0], 1, 4]`	`[[3, 4], [0], 2, 4]`	Failed
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], [0, 3], 1, 3]`	`[[2, 3], [0, 3], 1, 3]`	Passed
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], [0, 2, 5, 7], 1, 9]`	`[[2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7], 1, 9]`	Passed

SHA-256 / c4c2d5460738f343e9c7fddc745a03b04ea9252b15d04da4546876a90631fff9

3 / The verified repair

Exit 0

"""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))
    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 fixture	Actual	Expected	Outcome
oracle 1	`[[2, 3, 4], [0, 2], 1, 4]`	`[[2, 3, 4], [0, 2], 1, 4]`	Passed
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], [0, 3], 1, 3]`	`[[2, 3], [0, 3], 1, 3]`	Passed
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], [0, 2, 5, 7], 1, 9]`	`[[2, 3, 4, 5, 1, 2, 3, 4], [0, 2, 5, 7], 1, 9]`	Passed

SHA-256 / 154ccc99c8e9b8b75066d1c13da7552fbb25232a78e2eaf47fbede1239051d1e

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 2026-09-29T14:45:00.651652+00:00.

Case digest / d3e66c24ff43108bc626e7095ed0a09ea11cbb1d0e9c853e9c11ec2be7ae18a2