FA-10866 / Audio frame buffers / Open access
Frame padding preserves shape · case 01
Padding inserts scalar zero where downstream code expects a complete frame.
ROOT CAUSE
Padding inserts scalar zero where downstream code expects a complete frame.
VERIFIED REPAIR
Apply the explicit PCM/playback contract: Pad a frame-major buffer to at least size frames with signed-PCM zero frames of channels width; never truncate.
Unsuccessful approach: A padding operation also trims an already-long buffer.
Case contract
Pad a frame-major buffer to at least size frames with signed-PCM zero frames of channels width; never truncate.
Why this case matters
A pure Python local audio pipeline stage with explicit sample formats and frame conventions; no real-time device or signal-spectrum claims.
1 / The failure
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(frames, size, channels):
return [list(f) for f in frames]+[0]*max(0,size-len(frames))
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*([[1, 2]], 3, 2)),[[1, 2], [0, 0], [0, 0]])
check('fixture 2',solve(*([], 1, 3)),[[0, 0, 0]])
check('fixture 3',solve(*([[1], [2]], 1, 1)),[[1], [2]])
check('fixture 4',solve(*([], 0, 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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | [[1, 2], 0, 0] | [[1, 2], [0, 0], [0, 0]] | Failed |
| fixture 2 | [0] | [[0, 0, 0]] | Failed |
| fixture 3 | [[1], [2]] | [[1], [2]] | Passed |
| fixture 4 | [] | [] | Passed |
SHA-256 / ac796b11ee37169f5a1afb48847e544350c39671bfeb8a0235a63028f8932e3c
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(frames, size, channels):
return [list(f) for f in frames[:size]]+[[0]*channels for i in range(max(0,size-len(frames)))]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*([[1, 2]], 3, 2)),[[1, 2], [0, 0], [0, 0]])
check('fixture 2',solve(*([], 1, 3)),[[0, 0, 0]])
check('fixture 3',solve(*([[1], [2]], 1, 1)),[[1], [2]])
check('fixture 4',solve(*([], 0, 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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | [[1, 2], [0, 0], [0, 0]] | [[1, 2], [0, 0], [0, 0]] | Passed |
| fixture 2 | [[0, 0, 0]] | [[0, 0, 0]] | Passed |
| fixture 3 | [[1]] | [[1], [2]] | Failed |
| fixture 4 | [] | [] | Passed |
SHA-256 / 9ee6e51a9152efb78c0714a3b5b07ba6291437d4943c0a3eb7a78b3b3a63f688
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(frames, size, channels):
return [list(f) for f in frames]+[[0]*channels for i in range(max(0,size-len(frames)))]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1',solve(*([[1, 2]], 3, 2)),[[1, 2], [0, 0], [0, 0]])
check('fixture 2',solve(*([], 1, 3)),[[0, 0, 0]])
check('fixture 3',solve(*([[1], [2]], 1, 1)),[[1], [2]])
check('fixture 4',solve(*([], 0, 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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1 | [[1, 2], [0, 0], [0, 0]] | [[1, 2], [0, 0], [0, 0]] | Passed |
| fixture 2 | [[0, 0, 0]] | [[0, 0, 0]] | Passed |
| fixture 3 | [[1], [2]] | [[1], [2]] | Passed |
| fixture 4 | [] | [] | Passed |
SHA-256 / aa0b6928738eacba6daa0eef4f04efd259d289b9dae1af3280e49e0655016c45
Verification & scope
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 2026-09-29T14:38:42.944428+00:00.
Case digest / 2e71bcf68c7a69b3ad0f7bbebafe124bf97864cf88858833fb56806d54d98f76