FA-48936 / PCM sample encoding / Open access
Ones complement pcm: negative zero policy · case 01
A caller-requested zero canonicalization policy is ignored.
ROOT CAUSE
A caller-requested zero canonicalization policy is ignored.
VERIFIED REPAIR
Use the stated conversion contract at negative zero policy.
Unsuccessful approach: OR-ing the policy flags every code when preservation is enabled.
Case contract
Decode bounded ones-complement PCM fields; optionally preserve a per-sample negative-zero sideband while numeric zero stays JSON integer zero.
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(codes, width, preserve_negative_zero):
mask=(1<<width)-1
sign=1<<(width-1)
values=[]
negative_zero=[]
for raw in codes:
code=raw&mask
magnitude=(~code)&mask if code&sign else code
value=-magnitude if code&sign else magnitude
values.append(value)
negative_zero.append(bool(code==mask))
return [values,negative_zero]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('oracle 1', solve(*([0, 1, 7, 8, 14, 15], 4, True)), [[0, 1, 7, -7, -1, 0], [False, False, False, False, False, True]])
check('oracle 2', solve(*([15, 0, 8], 4, False)), [[0, 0, -7], [False, False, False]])
check('oracle 3', solve(*([31, 16, 17], 4, True)), [[0, 0, 1], [True, False, False]])
check('oracle 4', solve(*([], 4, True)), [[], []])
check('oracle 5', solve(*([0, 3, 4, 6, 7], 3, True)), [[0, 3, -3, -1, 0], [False, False, False, False, True]])
check('oracle 6', solve(*([255, 128, 254, 127], 8, False)), [[0, -127, -1, 127], [False, False, False, False]])
check('oracle 7', solve(*([255], 8, True)), [[0], [True]])
if N == 1: check('variant packet 1', solve(*[[0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15], 4, True]), [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True]])
if N == 2: check('variant packet 2', solve(*[[0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15], 4, True]), [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True]])
if N == 3: check('variant packet 3', solve(*[[0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15], 4, True]), [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True]])
if N == 4: check('variant packet 4', solve(*[[0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15], 4, True]), [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True]])
if N == 5: check('variant packet 5', solve(*[[0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15], 4, True]), [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, 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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| oracle 1 | [[0, 1, 7, -7, -1, 0], [False, False, False, False, False, True]] | [[0, 1, 7, -7, -1, 0], [False, False, False, False, False, True]] | Passed |
| oracle 2 | [[0, 0, -7], [True, False, False]] | [[0, 0, -7], [False, False, False]] | Failed |
| oracle 3 | [[0, 0, 1], [True, False, False]] | [[0, 0, 1], [True, False, False]] | Passed |
| oracle 4 | [[], []] | [[], []] | Passed |
| oracle 5 | [[0, 3, -3, -1, 0], [False, False, False, False, True]] | [[0, 3, -3, -1, 0], [False, False, False, False, True]] | Passed |
| oracle 6 | [[0, -127, -1, 127], [True, False, False, False]] | [[0, -127, -1, 127], [False, False, False, False]] | Failed |
| oracle 7 | [[0], [True]] | [[0], [True]] | Passed |
| variant packet 1 | [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True]] | [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True]] | Passed |
SHA-256 / 51294461203c075ad242a7993ec9d3f1be2ea669ebc86857c359c6a7fc486240
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(codes, width, preserve_negative_zero):
mask=(1<<width)-1
sign=1<<(width-1)
values=[]
negative_zero=[]
for raw in codes:
code=raw&mask
magnitude=(~code)&mask if code&sign else code
value=-magnitude if code&sign else magnitude
values.append(value)
negative_zero.append(bool(preserve_negative_zero or code==mask))
return [values,negative_zero]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('oracle 1', solve(*([0, 1, 7, 8, 14, 15], 4, True)), [[0, 1, 7, -7, -1, 0], [False, False, False, False, False, True]])
check('oracle 2', solve(*([15, 0, 8], 4, False)), [[0, 0, -7], [False, False, False]])
check('oracle 3', solve(*([31, 16, 17], 4, True)), [[0, 0, 1], [True, False, False]])
check('oracle 4', solve(*([], 4, True)), [[], []])
check('oracle 5', solve(*([0, 3, 4, 6, 7], 3, True)), [[0, 3, -3, -1, 0], [False, False, False, False, True]])
check('oracle 6', solve(*([255, 128, 254, 127], 8, False)), [[0, -127, -1, 127], [False, False, False, False]])
check('oracle 7', solve(*([255], 8, True)), [[0], [True]])
if N == 1: check('variant packet 1', solve(*[[0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15], 4, True]), [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True]])
if N == 2: check('variant packet 2', solve(*[[0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15], 4, True]), [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True]])
if N == 3: check('variant packet 3', solve(*[[0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15], 4, True]), [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True]])
if N == 4: check('variant packet 4', solve(*[[0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15], 4, True]), [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True]])
if N == 5: check('variant packet 5', solve(*[[0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15], 4, True]), [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, 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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| oracle 1 | [[0, 1, 7, -7, -1, 0], [True, True, True, True, True, True]] | [[0, 1, 7, -7, -1, 0], [False, False, False, False, False, True]] | Failed |
| oracle 2 | [[0, 0, -7], [True, False, False]] | [[0, 0, -7], [False, False, False]] | Failed |
| oracle 3 | [[0, 0, 1], [True, True, True]] | [[0, 0, 1], [True, False, False]] | Failed |
| oracle 4 | [[], []] | [[], []] | Passed |
| oracle 5 | [[0, 3, -3, -1, 0], [True, True, True, True, True]] | [[0, 3, -3, -1, 0], [False, False, False, False, True]] | Failed |
| oracle 6 | [[0, -127, -1, 127], [True, False, False, False]] | [[0, -127, -1, 127], [False, False, False, False]] | Failed |
| oracle 7 | [[0], [True]] | [[0], [True]] | Passed |
| variant packet 1 | [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [True, True, True, True, True, True, True, True, True, True, True, True]] | [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True]] | Failed |
SHA-256 / a1ad3e695fe019e61419b5c723b4f5d3ec5d4b7f97eb858ad287096e4a4114de
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(codes, width, preserve_negative_zero):
mask=(1<<width)-1
sign=1<<(width-1)
values=[]
negative_zero=[]
for raw in codes:
code=raw&mask
magnitude=(~code)&mask if code&sign else code
value=-magnitude if code&sign else magnitude
values.append(value)
negative_zero.append(bool(preserve_negative_zero and code==mask))
return [values,negative_zero]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('oracle 1', solve(*([0, 1, 7, 8, 14, 15], 4, True)), [[0, 1, 7, -7, -1, 0], [False, False, False, False, False, True]])
check('oracle 2', solve(*([15, 0, 8], 4, False)), [[0, 0, -7], [False, False, False]])
check('oracle 3', solve(*([31, 16, 17], 4, True)), [[0, 0, 1], [True, False, False]])
check('oracle 4', solve(*([], 4, True)), [[], []])
check('oracle 5', solve(*([0, 3, 4, 6, 7], 3, True)), [[0, 3, -3, -1, 0], [False, False, False, False, True]])
check('oracle 6', solve(*([255, 128, 254, 127], 8, False)), [[0, -127, -1, 127], [False, False, False, False]])
check('oracle 7', solve(*([255], 8, True)), [[0], [True]])
if N == 1: check('variant packet 1', solve(*[[0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15], 4, True]), [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True]])
if N == 2: check('variant packet 2', solve(*[[0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15], 4, True]), [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True]])
if N == 3: check('variant packet 3', solve(*[[0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15], 4, True]), [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True]])
if N == 4: check('variant packet 4', solve(*[[0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15], 4, True]), [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True]])
if N == 5: check('variant packet 5', solve(*[[0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15, 0, 1, 7, 8, 14, 15], 4, True]), [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, True, False, False, False, False, False, 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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| oracle 1 | [[0, 1, 7, -7, -1, 0], [False, False, False, False, False, True]] | [[0, 1, 7, -7, -1, 0], [False, False, False, False, False, True]] | Passed |
| oracle 2 | [[0, 0, -7], [False, False, False]] | [[0, 0, -7], [False, False, False]] | Passed |
| oracle 3 | [[0, 0, 1], [True, False, False]] | [[0, 0, 1], [True, False, False]] | Passed |
| oracle 4 | [[], []] | [[], []] | Passed |
| oracle 5 | [[0, 3, -3, -1, 0], [False, False, False, False, True]] | [[0, 3, -3, -1, 0], [False, False, False, False, True]] | Passed |
| oracle 6 | [[0, -127, -1, 127], [False, False, False, False]] | [[0, -127, -1, 127], [False, False, False, False]] | Passed |
| oracle 7 | [[0], [True]] | [[0], [True]] | Passed |
| variant packet 1 | [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True]] | [[0, 1, 7, -7, -1, 0, 0, 1, 7, -7, -1, 0], [False, False, False, False, False, True, False, False, False, False, False, True]] | Passed |
SHA-256 / e991dcf69ef6c0014180a5e9626eb25028eb8dc585a04e5476bb6788b9e02244
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 2026-09-29T14:44:55.277062+00:00.
Case digest / dcd199db5453441281ace0b89bdfc2639b5064d07049999decd8219ca7e7ec64