FA-49561 / PCM sample encoding / Open access

Au pcm payload limit: remainder return · case 01

Partial trailing bytes are reported as the complete audio prefix.

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

ROOT CAUSE

Partial trailing bytes are reported as the complete audio prefix.

VERIFIED REPAIR

Use the stated conversion contract at remainder return.

Unsuccessful approach: Discarding partial bytes hides malformed PCM termination.

Case contract

Locate a bounded AU-like PCM byte body at an absolute data offset; -1 alone means unknown size, and incomplete frame bytes are returned separately.

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(buffers, offset, declared, frame_bytes):
    out=[]
    for blob in buffers:
        body=blob[min(offset,len(blob)):]
        body=body if declared==-1 else body[:max(0,declared)]
        complete=(len(body)//frame_bytes)*frame_bytes
        out.append([body[:complete],body[:complete]])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('oracle 1', solve(*([[9, 9, 1, 2, 3, 4, 5]], 2, -1, 2)), [[[1, 2, 3, 4], [5]]])
check('oracle 2', solve(*([[0, 1, 2, 3, 4]], 1, 3, 2)), [[[1, 2], [3]]])
check('oracle 3', solve(*([[0, 1, 2]], 1, 0, 1)), [[[], []]])
check('oracle 4', solve(*([[]], 4, -1, 2)), [[[], []]])
check('oracle 5', solve(*([], 2, 4, 2)), [])
check('oracle 6', solve(*([[9, 1, 2, 3, 4]], 1, 8, 3)), [[[1, 2, 3], [4]]])
check('oracle 7', solve(*([[9, 1, 2, 3]], 1, 2, 2)), [[[1, 2], []]])
if N == 1: check('variant packet 1', solve(*[[[9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5]], 2, -1, 2]), [[[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]]])
if N == 2: check('variant packet 2', solve(*[[[9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5]], 2, -1, 2]), [[[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]]])
if N == 3: check('variant packet 3', solve(*[[[9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5]], 2, -1, 2]), [[[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]]])
if N == 4: check('variant packet 4', solve(*[[[9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5]], 2, -1, 2]), [[[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]]])
if N == 5: check('variant packet 5', solve(*[[[9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5]], 2, -1, 2]), [[[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]]])
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], [1, 2, 3, 4]]]`	`[[[1, 2, 3, 4], [5]]]`	Failed
oracle 2	`[[[1, 2], [1, 2]]]`	`[[[1, 2], [3]]]`	Failed
oracle 3	`[[[], []]]`	`[[[], []]]`	Passed
oracle 4	`[[[], []]]`	`[[[], []]]`	Passed
oracle 5	`[]`	`[]`	Passed
oracle 6	`[[[1, 2, 3], [1, 2, 3]]]`	`[[[1, 2, 3], [4]]]`	Failed
oracle 7	`[[[1, 2], [1, 2]]]`	`[[[1, 2], []]]`	Failed
variant packet 1	`[[[1, 2, 3, 4], [1, 2, 3, 4]], [[1, 2, 3, 4], [1, 2, 3, 4]]]`	`[[[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]]]`	Failed

SHA-256 / 609fa955e3c202685581ffd850695e820df1274bb137ee2e4dfd343f115250fe

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(buffers, offset, declared, frame_bytes):
    out=[]
    for blob in buffers:
        body=blob[min(offset,len(blob)):]
        body=body if declared==-1 else body[:max(0,declared)]
        complete=(len(body)//frame_bytes)*frame_bytes
        out.append([body[:complete],[]])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('oracle 1', solve(*([[9, 9, 1, 2, 3, 4, 5]], 2, -1, 2)), [[[1, 2, 3, 4], [5]]])
check('oracle 2', solve(*([[0, 1, 2, 3, 4]], 1, 3, 2)), [[[1, 2], [3]]])
check('oracle 3', solve(*([[0, 1, 2]], 1, 0, 1)), [[[], []]])
check('oracle 4', solve(*([[]], 4, -1, 2)), [[[], []]])
check('oracle 5', solve(*([], 2, 4, 2)), [])
check('oracle 6', solve(*([[9, 1, 2, 3, 4]], 1, 8, 3)), [[[1, 2, 3], [4]]])
check('oracle 7', solve(*([[9, 1, 2, 3]], 1, 2, 2)), [[[1, 2], []]])
if N == 1: check('variant packet 1', solve(*[[[9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5]], 2, -1, 2]), [[[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]]])
if N == 2: check('variant packet 2', solve(*[[[9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5]], 2, -1, 2]), [[[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]]])
if N == 3: check('variant packet 3', solve(*[[[9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5]], 2, -1, 2]), [[[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]]])
if N == 4: check('variant packet 4', solve(*[[[9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5]], 2, -1, 2]), [[[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]]])
if N == 5: check('variant packet 5', solve(*[[[9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5]], 2, -1, 2]), [[[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]]])
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], []]]`	`[[[1, 2, 3, 4], [5]]]`	Failed
oracle 2	`[[[1, 2], []]]`	`[[[1, 2], [3]]]`	Failed
oracle 3	`[[[], []]]`	`[[[], []]]`	Passed
oracle 4	`[[[], []]]`	`[[[], []]]`	Passed
oracle 5	`[]`	`[]`	Passed
oracle 6	`[[[1, 2, 3], []]]`	`[[[1, 2, 3], [4]]]`	Failed
oracle 7	`[[[1, 2], []]]`	`[[[1, 2], []]]`	Passed
variant packet 1	`[[[1, 2, 3, 4], []], [[1, 2, 3, 4], []]]`	`[[[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]]]`	Failed

SHA-256 / 57d93dd3df7e3b77571ff24573bb16c78d4fd92567954385126eb5c1f7af5ae5

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(buffers, offset, declared, frame_bytes):
    out=[]
    for blob in buffers:
        body=blob[min(offset,len(blob)):]
        body=body if declared==-1 else body[:max(0,declared)]
        complete=(len(body)//frame_bytes)*frame_bytes
        out.append([body[:complete],body[complete:]])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('oracle 1', solve(*([[9, 9, 1, 2, 3, 4, 5]], 2, -1, 2)), [[[1, 2, 3, 4], [5]]])
check('oracle 2', solve(*([[0, 1, 2, 3, 4]], 1, 3, 2)), [[[1, 2], [3]]])
check('oracle 3', solve(*([[0, 1, 2]], 1, 0, 1)), [[[], []]])
check('oracle 4', solve(*([[]], 4, -1, 2)), [[[], []]])
check('oracle 5', solve(*([], 2, 4, 2)), [])
check('oracle 6', solve(*([[9, 1, 2, 3, 4]], 1, 8, 3)), [[[1, 2, 3], [4]]])
check('oracle 7', solve(*([[9, 1, 2, 3]], 1, 2, 2)), [[[1, 2], []]])
if N == 1: check('variant packet 1', solve(*[[[9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5]], 2, -1, 2]), [[[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]]])
if N == 2: check('variant packet 2', solve(*[[[9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5]], 2, -1, 2]), [[[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]]])
if N == 3: check('variant packet 3', solve(*[[[9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5]], 2, -1, 2]), [[[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]]])
if N == 4: check('variant packet 4', solve(*[[[9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5]], 2, -1, 2]), [[[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]]])
if N == 5: check('variant packet 5', solve(*[[[9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5], [9, 9, 1, 2, 3, 4, 5]], 2, -1, 2]), [[[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]]])
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], [5]]]`	`[[[1, 2, 3, 4], [5]]]`	Passed
oracle 2	`[[[1, 2], [3]]]`	`[[[1, 2], [3]]]`	Passed
oracle 3	`[[[], []]]`	`[[[], []]]`	Passed
oracle 4	`[[[], []]]`	`[[[], []]]`	Passed
oracle 5	`[]`	`[]`	Passed
oracle 6	`[[[1, 2, 3], [4]]]`	`[[[1, 2, 3], [4]]]`	Passed
oracle 7	`[[[1, 2], []]]`	`[[[1, 2], []]]`	Passed
variant packet 1	`[[[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]]]`	`[[[1, 2, 3, 4], [5]], [[1, 2, 3, 4], [5]]]`	Passed

SHA-256 / 0fb99f5b04c89acbe750d6feae85b0a236640b195410e6893b751858ed4eb861

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 2026-09-29T14:45:01.157790+00:00.

Case digest / 47b06bd88625dfc1cab85e58243ce375abfbc0aa9b179ef05c21c56dc2a79b16