{"abstract":"PCM line-code boundary checks the end of the bit cell rather than its first half.","category":"PCM sample encoding","checks":8,"contract":"Decode stipulated biphase-mark PCM transport cells: every cell must transition at its start, midcell transition is one, and final physical level carries across packets.","evaluation_group":"s3-pcm-pcm-biphase-mark-payload","failed_approach":"Requiring no boundary transition inverts line-code validity.","family":"s3-pcm-pcm-biphase-mark-payload-boundary-transition","id":"FA-50216","implementations":{"attempt":{"sha256":"b1d1e588c6bf85847606e4eeb7f9ea9f01da16afa9f9727723fb721ba985b9f0","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(cells, initial):\n    previous=initial\n    bits=[]\n    valid=[]\n    for first,second in cells:\n        boundary=first==previous\n        bit=int(first!=second)\n        bits.append(bit)\n        valid.append(boundary)\n        previous=second\n    return [bits,valid,previous]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([[1, 1], [0, 1], [0, 0]], 0)), [[0, 1, 0], [True, True, True], 0])\ncheck('oracle 2', solve(*([[0, 1], [1, 0]], 1)), [[1, 1], [True, False], 0])\ncheck('oracle 3', solve(*([[0, 0], [1, 1]], 0)), [[0, 0], [False, True], 1])\ncheck('oracle 4', solve(*([], 1)), [[], [], 1])\ncheck('oracle 5', solve(*([[1, 0], [1, 0]], 0)), [[1, 1], [True, True], 0])\ncheck('oracle 6', solve(*([[1, 1]], 1)), [[0], [False], 1])\ncheck('oracle 7', solve(*([[0, 0], [0, 1], [1, 1]], 1)), [[0, 1, 0], [True, False, False], 1])\nif N == 1: check('variant packet 1', solve(*[[[1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0]], 0]), [[0, 1, 0, 0, 1, 0], [True, True, True, True, True, True], 0])\nif N == 2: check('variant packet 2', solve(*[[[1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0]], 0]), [[0, 1, 0, 0, 1, 0, 0, 1, 0], [True, True, True, True, True, True, True, True, True], 0])\nif N == 3: check('variant packet 3', solve(*[[[1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0]], 0]), [[0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0], [True, True, True, True, True, True, True, True, True, True, True, True], 0])\nif N == 4: check('variant packet 4', solve(*[[[1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0]], 0]), [[0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0], [True, True, True, True, True, True, True, True, True, True, True, True, True, True, True], 0])\nif N == 5: check('variant packet 5', solve(*[[[1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0]], 0]), [[0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0], [True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True], 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":"cca878e47402d35936ea21f049304124726a610daa53c4e7330703584fe01299","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(cells, initial):\n    previous=initial\n    bits=[]\n    valid=[]\n    for first,second in cells:\n        boundary=second!=previous\n        bit=int(first!=second)\n        bits.append(bit)\n        valid.append(boundary)\n        previous=second\n    return [bits,valid,previous]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([[1, 1], [0, 1], [0, 0]], 0)), [[0, 1, 0], [True, True, True], 0])\ncheck('oracle 2', solve(*([[0, 1], [1, 0]], 1)), [[1, 1], [True, False], 0])\ncheck('oracle 3', solve(*([[0, 0], [1, 1]], 0)), [[0, 0], [False, True], 1])\ncheck('oracle 4', solve(*([], 1)), [[], [], 1])\ncheck('oracle 5', solve(*([[1, 0], [1, 0]], 0)), [[1, 1], [True, True], 0])\ncheck('oracle 6', solve(*([[1, 1]], 1)), [[0], [False], 1])\ncheck('oracle 7', solve(*([[0, 0], [0, 1], [1, 1]], 1)), [[0, 1, 0], [True, False, False], 1])\nif N == 1: check('variant packet 1', solve(*[[[1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0]], 0]), [[0, 1, 0, 0, 1, 0], [True, True, True, True, True, True], 0])\nif N == 2: check('variant packet 2', solve(*[[[1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0]], 0]), [[0, 1, 0, 0, 1, 0, 0, 1, 0], [True, True, True, True, True, True, True, True, True], 0])\nif N == 3: check('variant packet 3', solve(*[[[1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0]], 0]), [[0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0], [True, True, True, True, True, True, True, True, True, True, True, True], 0])\nif N == 4: check('variant packet 4', solve(*[[[1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0]], 0]), [[0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0], [True, True, True, True, True, True, True, True, True, True, True, True, True, True, True], 0])\nif N == 5: check('variant packet 5', solve(*[[[1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0]], 0]), [[0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0], [True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True], 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"},"fixed":{"sha256":"2a78a2c4ee8991745a7aa4c6cdd8040c7a862353d1154530c88053ccc07cac39","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(cells, initial):\n    previous=initial\n    bits=[]\n    valid=[]\n    for first,second in cells:\n        boundary=first!=previous\n        bit=int(first!=second)\n        bits.append(bit)\n        valid.append(boundary)\n        previous=second\n    return [bits,valid,previous]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([[1, 1], [0, 1], [0, 0]], 0)), [[0, 1, 0], [True, True, True], 0])\ncheck('oracle 2', solve(*([[0, 1], [1, 0]], 1)), [[1, 1], [True, False], 0])\ncheck('oracle 3', solve(*([[0, 0], [1, 1]], 0)), [[0, 0], [False, True], 1])\ncheck('oracle 4', solve(*([], 1)), [[], [], 1])\ncheck('oracle 5', solve(*([[1, 0], [1, 0]], 0)), [[1, 1], [True, True], 0])\ncheck('oracle 6', solve(*([[1, 1]], 1)), [[0], [False], 1])\ncheck('oracle 7', solve(*([[0, 0], [0, 1], [1, 1]], 1)), [[0, 1, 0], [True, False, False], 1])\nif N == 1: check('variant packet 1', solve(*[[[1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0]], 0]), [[0, 1, 0, 0, 1, 0], [True, True, True, True, True, True], 0])\nif N == 2: check('variant packet 2', solve(*[[[1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0]], 0]), [[0, 1, 0, 0, 1, 0, 0, 1, 0], [True, True, True, True, True, True, True, True, True], 0])\nif N == 3: check('variant packet 3', solve(*[[[1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0]], 0]), [[0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0], [True, True, True, True, True, True, True, True, True, True, True, True], 0])\nif N == 4: check('variant packet 4', solve(*[[[1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0]], 0]), [[0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0], [True, True, True, True, True, True, True, True, True, True, True, True, True, True, True], 0])\nif N == 5: check('variant packet 5', solve(*[[[1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0], [1, 1], [0, 1], [0, 0]], 0]), [[0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0], [True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True], 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-pcm-biphase-mark-payload-boundary-transition","generated_at":"2026-09-29T14:45:07.006049+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.","repair":"Use the stated conversion contract at boundary transition.","root_cause":"PCM line-code boundary checks the end of the bit cell rather than its first half.","sha256":"114f38c238ae45fe221d5f77c13b67dc3d1bc6260263594d45dda62e16699b73","title":"Pcm biphase mark payload: boundary transition · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":40.217,"exit_code":1,"observations":[{"actual":[[0,1,0],[false,false,false],0],"check":"oracle 1","expected":[[0,1,0],[true,true,true],0],"passed":false},{"actual":[[1,1],[false,true],0],"check":"oracle 2","expected":[[1,1],[true,false],0],"passed":false},{"actual":[[0,0],[true,false],1],"check":"oracle 3","expected":[[0,0],[false,true],1],"passed":false},{"actual":[[],[],1],"check":"oracle 4","expected":[[],[],1],"passed":true},{"actual":[[1,1],[false,false],0],"check":"oracle 5","expected":[[1,1],[true,true],0],"passed":false},{"actual":[[0],[true],1],"check":"oracle 6","expected":[[0],[false],1],"passed":false},{"actual":[[0,1,0],[false,true,true],1],"check":"oracle 7","expected":[[0,1,0],[true,false,false],1],"passed":false},{"actual":[[0,1,0,0,1,0],[false,false,false,false,false,false],0],"check":"variant packet 1","expected":[[0,1,0,0,1,0],[true,true,true,true,true,true],0],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[0, 1, 0], [false, false, false], 0], \"expected\": [[0, 1, 0], [true, true, true], 0], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[1, 1], [false, true], 0], \"expected\": [[1, 1], [true, false], 0], \"passed\": false}, {\"check\": \"oracle 3\", \"actual\": [[0, 0], [true, false], 1], \"expected\": [[0, 0], [false, true], 1], \"passed\": false}, {\"check\": \"oracle 4\", \"actual\": [[], [], 1], \"expected\": [[], [], 1], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [[1, 1], [false, false], 0], \"expected\": [[1, 1], [true, true], 0], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [[0], [true], 1], \"expected\": [[0], [false], 1], \"passed\": false}, {\"check\": \"oracle 7\", \"actual\": [[0, 1, 0], [false, true, true], 1], \"expected\": [[0, 1, 0], [true, false, false], 1], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [[0, 1, 0, 0, 1, 0], [false, false, false, false, false, false], 0], \"expected\": [[0, 1, 0, 0, 1, 0], [true, true, true, true, true, true], 0], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.596,"exit_code":1,"observations":[{"actual":[[0,1,0],[true,false,true],0],"check":"oracle 1","expected":[[0,1,0],[true,true,true],0],"passed":false},{"actual":[[1,1],[false,true],0],"check":"oracle 2","expected":[[1,1],[true,false],0],"passed":false},{"actual":[[0,0],[false,true],1],"check":"oracle 3","expected":[[0,0],[false,true],1],"passed":true},{"actual":[[],[],1],"check":"oracle 4","expected":[[],[],1],"passed":true},{"actual":[[1,1],[false,false],0],"check":"oracle 5","expected":[[1,1],[true,true],0],"passed":false},{"actual":[[0],[false],1],"check":"oracle 6","expected":[[0],[false],1],"passed":true},{"actual":[[0,1,0],[true,true,false],1],"check":"oracle 7","expected":[[0,1,0],[true,false,false],1],"passed":false},{"actual":[[0,1,0,0,1,0],[true,false,true,true,false,true],0],"check":"variant packet 1","expected":[[0,1,0,0,1,0],[true,true,true,true,true,true],0],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[0, 1, 0], [true, false, true], 0], \"expected\": [[0, 1, 0], [true, true, true], 0], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[1, 1], [false, true], 0], \"expected\": [[1, 1], [true, false], 0], \"passed\": false}, {\"check\": \"oracle 3\", \"actual\": [[0, 0], [false, true], 1], \"expected\": [[0, 0], [false, true], 1], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [[], [], 1], \"expected\": [[], [], 1], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [[1, 1], [false, false], 0], \"expected\": [[1, 1], [true, true], 0], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [[0], [false], 1], \"expected\": [[0], [false], 1], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [[0, 1, 0], [true, true, false], 1], \"expected\": [[0, 1, 0], [true, false, false], 1], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [[0, 1, 0, 0, 1, 0], [true, false, true, true, false, true], 0], \"expected\": [[0, 1, 0, 0, 1, 0], [true, true, true, true, true, true], 0], \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":39.541,"exit_code":0,"observations":[{"actual":[[0,1,0],[true,true,true],0],"check":"oracle 1","expected":[[0,1,0],[true,true,true],0],"passed":true},{"actual":[[1,1],[true,false],0],"check":"oracle 2","expected":[[1,1],[true,false],0],"passed":true},{"actual":[[0,0],[false,true],1],"check":"oracle 3","expected":[[0,0],[false,true],1],"passed":true},{"actual":[[],[],1],"check":"oracle 4","expected":[[],[],1],"passed":true},{"actual":[[1,1],[true,true],0],"check":"oracle 5","expected":[[1,1],[true,true],0],"passed":true},{"actual":[[0],[false],1],"check":"oracle 6","expected":[[0],[false],1],"passed":true},{"actual":[[0,1,0],[true,false,false],1],"check":"oracle 7","expected":[[0,1,0],[true,false,false],1],"passed":true},{"actual":[[0,1,0,0,1,0],[true,true,true,true,true,true],0],"check":"variant packet 1","expected":[[0,1,0,0,1,0],[true,true,true,true,true,true],0],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[0, 1, 0], [true, true, true], 0], \"expected\": [[0, 1, 0], [true, true, true], 0], \"passed\": true}, {\"check\": \"oracle 2\", \"actual\": [[1, 1], [true, false], 0], \"expected\": [[1, 1], [true, false], 0], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [[0, 0], [false, true], 1], \"expected\": [[0, 0], [false, true], 1], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [[], [], 1], \"expected\": [[], [], 1], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [[1, 1], [true, true], 0], \"expected\": [[1, 1], [true, true], 0], \"passed\": true}, {\"check\": \"oracle 6\", \"actual\": [[0], [false], 1], \"expected\": [[0], [false], 1], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [[0, 1, 0], [true, false, false], 1], \"expected\": [[0, 1, 0], [true, false, false], 1], \"passed\": true}, {\"check\": \"variant packet 1\", \"actual\": [[0, 1, 0, 0, 1, 0], [true, true, true, true, true, true], 0], \"expected\": [[0, 1, 0, 0, 1, 0], [true, true, true, true, true, true], 0], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}