{"abstract":"Recovered channel labels are swapped after lossless unlifting.","category":"PCM sample encoding","checks":8,"contract":"Invert the stipulated reversible PCM midpoint/side code, rejecting parity-mismatched triples and preserving L,R destination order.","contract_signature":"triples","evaluation_group":"s3-pcm-pcm-mid-side-unlifting","failed_approach":"Duplicating left discards recovered right information.","family":"s3-pcm-pcm-mid-side-unlifting-channel-order","id":"FA-49311","implementations":{"attempt":{"sha256":"1253eb03cd45e901b3b308ceda479cd8b08a4c0d9d071af9f778753c87e7c992","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(triples):\n    out=[]\n    for mid,side,parity in triples:\n        if parity!=(side&1):\n            out.append(None)\n            continue\n        right=mid-side//2\n        left=side+right\n        out.append([left,left])\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([[3, 3, 1], [3, -3, 1]],)), [[5, 2], [2, 5]])\ncheck('oracle 2', solve(*([[0, 0, 0], [1, 0, 0]],)), [[0, 0], [1, 1]])\ncheck('oracle 3', solve(*([[0, -5, 1]],)), [[-2, 3]])\ncheck('oracle 4', solve(*([],)), [])\ncheck('oracle 5', solve(*([[3, 2, 1], [3, 2, 0]],)), [None, [4, 2]])\ncheck('oracle 6', solve(*([[-2, -1, 1], [4, 1, 1]],)), [[-2, -1], [5, 4]])\ncheck('oracle 7', solve(*([[3, 0, 1]],)), [None])\nif N == 1: check('variant packet 1', solve(*[[[3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1]]]), [[5, 2], [2, 5], [5, 2], [2, 5]])\nif N == 2: check('variant packet 2', solve(*[[[3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1]]]), [[5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5]])\nif N == 3: check('variant packet 3', solve(*[[[3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1]]]), [[5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5]])\nif N == 4: check('variant packet 4', solve(*[[[3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1]]]), [[5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5]])\nif N == 5: check('variant packet 5', solve(*[[[3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1]]]), [[5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5]])\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":"741e03d81a6a779f7c1f2363c8f0bdb3421947c906acbe4abf107e5b53f66e27","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(triples):\n    out=[]\n    for mid,side,parity in triples:\n        if parity!=(side&1):\n            out.append(None)\n            continue\n        right=mid-side//2\n        left=side+right\n        out.append([right,left])\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([[3, 3, 1], [3, -3, 1]],)), [[5, 2], [2, 5]])\ncheck('oracle 2', solve(*([[0, 0, 0], [1, 0, 0]],)), [[0, 0], [1, 1]])\ncheck('oracle 3', solve(*([[0, -5, 1]],)), [[-2, 3]])\ncheck('oracle 4', solve(*([],)), [])\ncheck('oracle 5', solve(*([[3, 2, 1], [3, 2, 0]],)), [None, [4, 2]])\ncheck('oracle 6', solve(*([[-2, -1, 1], [4, 1, 1]],)), [[-2, -1], [5, 4]])\ncheck('oracle 7', solve(*([[3, 0, 1]],)), [None])\nif N == 1: check('variant packet 1', solve(*[[[3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1]]]), [[5, 2], [2, 5], [5, 2], [2, 5]])\nif N == 2: check('variant packet 2', solve(*[[[3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1]]]), [[5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5]])\nif N == 3: check('variant packet 3', solve(*[[[3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1]]]), [[5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5]])\nif N == 4: check('variant packet 4', solve(*[[[3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1]]]), [[5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5]])\nif N == 5: check('variant packet 5', solve(*[[[3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1], [3, 3, 1], [3, -3, 1]]]), [[5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5], [5, 2], [2, 5]])\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-mid-side-unlifting-channel-order","generated_at":"2026-09-29T14:44:58.899341+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":"Recovered channel labels are swapped after lossless unlifting.","sha256":"f0147c7c5430706fc3871b33dd3fdb040339ab25538a29a9a6c557e3087d39d2","title":"Pcm mid side unlifting: channel order · 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":46.198,"exit_code":1,"observations":[{"actual":[[5,5],[2,2]],"check":"oracle 1","expected":[[5,2],[2,5]],"passed":false},{"actual":[[0,0],[1,1]],"check":"oracle 2","expected":[[0,0],[1,1]],"passed":true},{"actual":[[-2,-2]],"check":"oracle 3","expected":[[-2,3]],"passed":false},{"actual":[],"check":"oracle 4","expected":[],"passed":true},{"actual":[null,[4,4]],"check":"oracle 5","expected":[null,[4,2]],"passed":false},{"actual":[[-2,-2],[5,5]],"check":"oracle 6","expected":[[-2,-1],[5,4]],"passed":false},{"actual":[null],"check":"oracle 7","expected":[null],"passed":true},{"actual":[[5,5],[2,2],[5,5],[2,2]],"check":"variant packet 1","expected":[[5,2],[2,5],[5,2],[2,5]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[5, 5], [2, 2]], \"expected\": [[5, 2], [2, 5]], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[0, 0], [1, 1]], \"expected\": [[0, 0], [1, 1]], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [[-2, -2]], \"expected\": [[-2, 3]], \"passed\": false}, {\"check\": \"oracle 4\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [null, [4, 4]], \"expected\": [null, [4, 2]], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [[-2, -2], [5, 5]], \"expected\": [[-2, -1], [5, 4]], \"passed\": false}, {\"check\": \"oracle 7\", \"actual\": [null], \"expected\": [null], \"passed\": true}, {\"check\": \"variant packet 1\", \"actual\": [[5, 5], [2, 2], [5, 5], [2, 2]], \"expected\": [[5, 2], [2, 5], [5, 2], [2, 5]], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":42.664,"exit_code":1,"observations":[{"actual":[[2,5],[5,2]],"check":"oracle 1","expected":[[5,2],[2,5]],"passed":false},{"actual":[[0,0],[1,1]],"check":"oracle 2","expected":[[0,0],[1,1]],"passed":true},{"actual":[[3,-2]],"check":"oracle 3","expected":[[-2,3]],"passed":false},{"actual":[],"check":"oracle 4","expected":[],"passed":true},{"actual":[null,[2,4]],"check":"oracle 5","expected":[null,[4,2]],"passed":false},{"actual":[[-1,-2],[4,5]],"check":"oracle 6","expected":[[-2,-1],[5,4]],"passed":false},{"actual":[null],"check":"oracle 7","expected":[null],"passed":true},{"actual":[[2,5],[5,2],[2,5],[5,2]],"check":"variant packet 1","expected":[[5,2],[2,5],[5,2],[2,5]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[2, 5], [5, 2]], \"expected\": [[5, 2], [2, 5]], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[0, 0], [1, 1]], \"expected\": [[0, 0], [1, 1]], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [[3, -2]], \"expected\": [[-2, 3]], \"passed\": false}, {\"check\": \"oracle 4\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [null, [2, 4]], \"expected\": [null, [4, 2]], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [[-1, -2], [4, 5]], \"expected\": [[-2, -1], [5, 4]], \"passed\": false}, {\"check\": \"oracle 7\", \"actual\": [null], \"expected\": [null], \"passed\": true}, {\"check\": \"variant packet 1\", \"actual\": [[2, 5], [5, 2], [2, 5], [5, 2]], \"expected\": [[5, 2], [2, 5], [5, 2], [2, 5]], \"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."}}