{"abstract":"Biphase PCM payload interprets midcell transition as zero.","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.","contract_signature":"cells, initial","evaluation_group":"s3-pcm-pcm-biphase-mark-payload","failed_approach":"Boundary transitions encode framing validity rather than data bits.","family":"s3-pcm-pcm-biphase-mark-payload-midcell-bit","id":"FA-50221","implementations":{"attempt":{"sha256":"c9b7f970483d539433f66d246c621561df62ce60d0e3579a117066b2d8b63b2f","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!=previous)\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":"1836029350ab5ff693fd54be7042acb349b818d76ed3321d4f146eb2b1ab92fd","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-midcell-bit","generated_at":"2026-09-29T14:45:07.297596+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":"Biphase PCM payload interprets midcell transition as zero.","sha256":"9193c4104863c210264fe89bdf70b84e42479496e36030700b90a88984adaec1","title":"Pcm biphase mark payload: midcell bit · 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":40.769,"exit_code":1,"observations":[{"actual":[[1,1,1],[true,true,true],0],"check":"oracle 1","expected":[[0,1,0],[true,true,true],0],"passed":false},{"actual":[[1,0],[true,false],0],"check":"oracle 2","expected":[[1,1],[true,false],0],"passed":false},{"actual":[[0,1],[false,true],1],"check":"oracle 3","expected":[[0,0],[false,true],1],"passed":false},{"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":[[1,0,0],[true,false,false],1],"check":"oracle 7","expected":[[0,1,0],[true,false,false],1],"passed":false},{"actual":[[1,1,1,1,1,1],[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":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[1, 1, 1], [true, true, true], 0], \"expected\": [[0, 1, 0], [true, true, true], 0], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[1, 0], [true, false], 0], \"expected\": [[1, 1], [true, false], 0], \"passed\": false}, {\"check\": \"oracle 3\", \"actual\": [[0, 1], [false, true], 1], \"expected\": [[0, 0], [false, true], 1], \"passed\": false}, {\"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\": [[1, 0, 0], [true, false, false], 1], \"expected\": [[0, 1, 0], [true, false, false], 1], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [[1, 1, 1, 1, 1, 1], [true, true, true, true, true, true], 0], \"expected\": [[0, 1, 0, 0, 1, 0], [true, true, true, true, true, true], 0], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.122,"exit_code":1,"observations":[{"actual":[[1,0,1],[true,true,true],0],"check":"oracle 1","expected":[[0,1,0],[true,true,true],0],"passed":false},{"actual":[[0,0],[true,false],0],"check":"oracle 2","expected":[[1,1],[true,false],0],"passed":false},{"actual":[[1,1],[false,true],1],"check":"oracle 3","expected":[[0,0],[false,true],1],"passed":false},{"actual":[[],[],1],"check":"oracle 4","expected":[[],[],1],"passed":true},{"actual":[[0,0],[true,true],0],"check":"oracle 5","expected":[[1,1],[true,true],0],"passed":false},{"actual":[[1],[false],1],"check":"oracle 6","expected":[[0],[false],1],"passed":false},{"actual":[[1,0,1],[true,false,false],1],"check":"oracle 7","expected":[[0,1,0],[true,false,false],1],"passed":false},{"actual":[[1,0,1,1,0,1],[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":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[1, 0, 1], [true, true, true], 0], \"expected\": [[0, 1, 0], [true, true, true], 0], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[0, 0], [true, false], 0], \"expected\": [[1, 1], [true, false], 0], \"passed\": false}, {\"check\": \"oracle 3\", \"actual\": [[1, 1], [false, true], 1], \"expected\": [[0, 0], [false, true], 1], \"passed\": false}, {\"check\": \"oracle 4\", \"actual\": [[], [], 1], \"expected\": [[], [], 1], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [[0, 0], [true, true], 0], \"expected\": [[1, 1], [true, true], 0], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [[1], [false], 1], \"expected\": [[0], [false], 1], \"passed\": false}, {\"check\": \"oracle 7\", \"actual\": [[1, 0, 1], [true, false, false], 1], \"expected\": [[0, 1, 0], [true, false, false], 1], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [[1, 0, 1, 1, 0, 1], [true, true, true, true, true, true], 0], \"expected\": [[0, 1, 0, 0, 1, 0], [true, true, true, true, true, true], 0], \"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."}}