{"abstract":"The packet sync prefix is dropped before packed sample codes.","category":"PCM sample encoding","checks":8,"contract":"Pack unsigned codes fitting width 1..7 most-significant bit first after an explicit bit prefix; return octets, significant-bit count and zero tail padding count.","contract_signature":"codes, width, prefix","evaluation_group":"s3-pcm-subbyte-code-packer","failed_approach":"Restoring the prefix in reverse wire order corrupts sync bits.","family":"s3-pcm-subbyte-code-packer-preserve-prefix","id":"FA-48841","implementations":{"attempt":{"sha256":"2cbf58241b7c3ae18d85b79259611accd4047a3f4205e96083546574fc19cd23","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(codes, width, prefix):\n    bits = list(reversed(prefix))\n    for code in codes:\n        bits.extend((code >> shift) & 1 for shift in range(width-1,-1,-1))\n    padding = (-len(bits)) % 8\n    bits += [0] * padding\n    out = []\n    for start in range(0,len(bits),8):\n        out.append(sum(bits[start+j] << (7-j) for j in range(8)))\n    return [out, len(prefix)+len(codes)*width, padding]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([0, 1, 7], 3, [1, 0])), [[129, 224], 11, 5])\ncheck('oracle 2', solve(*([5, 2], 3, [])), [[168], 6, 2])\ncheck('oracle 3', solve(*([], 3, [])), [[], 0, 0])\ncheck('oracle 4', solve(*([15, 0], 4, [])), [[240], 8, 0])\ncheck('oracle 5', solve(*([1], 1, [1, 1, 0])), [[208], 4, 4])\ncheck('oracle 6', solve(*([0, 3, 2, 1], 2, [0])), [[28, 128], 9, 7])\ncheck('oracle 7', solve(*([17, 3], 5, [1, 0, 1])), [[177, 24], 13, 3])\nif N == 1: check('variant packet 1', solve(*[[0, 1, 7, 0, 1, 7], 3, [1, 0]]), [[129, 224, 240], 20, 4])\nif N == 2: check('variant packet 2', solve(*[[0, 1, 7, 0, 1, 7, 0, 1, 7], 3, [1, 0]]), [[129, 224, 240, 120], 29, 3])\nif N == 3: check('variant packet 3', solve(*[[0, 1, 7, 0, 1, 7, 0, 1, 7, 0, 1, 7], 3, [1, 0]]), [[129, 224, 240, 120, 60], 38, 2])\nif N == 4: check('variant packet 4', solve(*[[0, 1, 7, 0, 1, 7, 0, 1, 7, 0, 1, 7, 0, 1, 7], 3, [1, 0]]), [[129, 224, 240, 120, 60, 30], 47, 1])\nif N == 5: check('variant packet 5', solve(*[[0, 1, 7, 0, 1, 7, 0, 1, 7, 0, 1, 7, 0, 1, 7, 0, 1, 7], 3, [1, 0]]), [[129, 224, 240, 120, 60, 30, 15], 56, 0])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"a79a7c74d6cc94116eefe9f087350bb9dd5268a11511786b562129adb1107c70","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(codes, width, prefix):\n    bits = []\n    for code in codes:\n        bits.extend((code >> shift) & 1 for shift in range(width-1,-1,-1))\n    padding = (-len(bits)) % 8\n    bits += [0] * padding\n    out = []\n    for start in range(0,len(bits),8):\n        out.append(sum(bits[start+j] << (7-j) for j in range(8)))\n    return [out, len(prefix)+len(codes)*width, padding]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([0, 1, 7], 3, [1, 0])), [[129, 224], 11, 5])\ncheck('oracle 2', solve(*([5, 2], 3, [])), [[168], 6, 2])\ncheck('oracle 3', solve(*([], 3, [])), [[], 0, 0])\ncheck('oracle 4', solve(*([15, 0], 4, [])), [[240], 8, 0])\ncheck('oracle 5', solve(*([1], 1, [1, 1, 0])), [[208], 4, 4])\ncheck('oracle 6', solve(*([0, 3, 2, 1], 2, [0])), [[28, 128], 9, 7])\ncheck('oracle 7', solve(*([17, 3], 5, [1, 0, 1])), [[177, 24], 13, 3])\nif N == 1: check('variant packet 1', solve(*[[0, 1, 7, 0, 1, 7], 3, [1, 0]]), [[129, 224, 240], 20, 4])\nif N == 2: check('variant packet 2', solve(*[[0, 1, 7, 0, 1, 7, 0, 1, 7], 3, [1, 0]]), [[129, 224, 240, 120], 29, 3])\nif N == 3: check('variant packet 3', solve(*[[0, 1, 7, 0, 1, 7, 0, 1, 7, 0, 1, 7], 3, [1, 0]]), [[129, 224, 240, 120, 60], 38, 2])\nif N == 4: check('variant packet 4', solve(*[[0, 1, 7, 0, 1, 7, 0, 1, 7, 0, 1, 7, 0, 1, 7], 3, [1, 0]]), [[129, 224, 240, 120, 60, 30], 47, 1])\nif N == 5: check('variant packet 5', solve(*[[0, 1, 7, 0, 1, 7, 0, 1, 7, 0, 1, 7, 0, 1, 7, 0, 1, 7], 3, [1, 0]]), [[129, 224, 240, 120, 60, 30, 15], 56, 0])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"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.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"s3-pcm-subbyte-code-packer-preserve-prefix","generated_at":"2026-09-29T14:44:54.651187+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Offline PCM interchange uses these exact bounded packet and sample representation decisions.","root_cause":"The packet sync prefix is dropped before packed sample codes.","sha256":"3c3a0db1a8ca05792d452a9efc9991dd51da3fdbc62320b6efc1f728ed989a26","title":"Subbyte code packer: preserve prefix · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":41.416,"exit_code":1,"observations":[{"actual":[[65,224],11,5],"check":"oracle 1","expected":[[129,224],11,5],"passed":false},{"actual":[[168],6,2],"check":"oracle 2","expected":[[168],6,2],"passed":true},{"actual":[[],0,0],"check":"oracle 3","expected":[[],0,0],"passed":true},{"actual":[[240],8,0],"check":"oracle 4","expected":[[240],8,0],"passed":true},{"actual":[[112],4,4],"check":"oracle 5","expected":[[208],4,4],"passed":false},{"actual":[[28,128],9,7],"check":"oracle 6","expected":[[28,128],9,7],"passed":true},{"actual":[[177,24],13,3],"check":"oracle 7","expected":[[177,24],13,3],"passed":true},{"actual":[[65,224,240],20,4],"check":"variant packet 1","expected":[[129,224,240],20,4],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[65, 224], 11, 5], \"expected\": [[129, 224], 11, 5], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[168], 6, 2], \"expected\": [[168], 6, 2], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [[], 0, 0], \"expected\": [[], 0, 0], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [[240], 8, 0], \"expected\": [[240], 8, 0], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [[112], 4, 4], \"expected\": [[208], 4, 4], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [[28, 128], 9, 7], \"expected\": [[28, 128], 9, 7], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [[177, 24], 13, 3], \"expected\": [[177, 24], 13, 3], \"passed\": true}, {\"check\": \"variant packet 1\", \"actual\": [[65, 224, 240], 20, 4], \"expected\": [[129, 224, 240], 20, 4], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.72,"exit_code":1,"observations":[{"actual":[[7,128],11,7],"check":"oracle 1","expected":[[129,224],11,5],"passed":false},{"actual":[[168],6,2],"check":"oracle 2","expected":[[168],6,2],"passed":true},{"actual":[[],0,0],"check":"oracle 3","expected":[[],0,0],"passed":true},{"actual":[[240],8,0],"check":"oracle 4","expected":[[240],8,0],"passed":true},{"actual":[[128],4,7],"check":"oracle 5","expected":[[208],4,4],"passed":false},{"actual":[[57],9,0],"check":"oracle 6","expected":[[28,128],9,7],"passed":false},{"actual":[[136,192],13,6],"check":"oracle 7","expected":[[177,24],13,3],"passed":false},{"actual":[[7,131,192],20,6],"check":"variant packet 1","expected":[[129,224,240],20,4],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[7, 128], 11, 7], \"expected\": [[129, 224], 11, 5], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[168], 6, 2], \"expected\": [[168], 6, 2], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [[], 0, 0], \"expected\": [[], 0, 0], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [[240], 8, 0], \"expected\": [[240], 8, 0], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [[128], 4, 7], \"expected\": [[208], 4, 4], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [[57], 9, 0], \"expected\": [[28, 128], 9, 7], \"passed\": false}, {\"check\": \"oracle 7\", \"actual\": [[136, 192], 13, 6], \"expected\": [[177, 24], 13, 3], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [[7, 131, 192], 20, 6], \"expected\": [[129, 224, 240], 20, 4], \"passed\": false}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}