{"abstract":"Encoder feeds its residual back as next amplitude predictor.","category":"PCM sample encoding","checks":8,"contract":"Generate signed PCM residuals relative to the previous amplitude; reset at explicit sample positions and return the final amplitude continuation seed.","contract_signature":"samples, initial, reset_positions","evaluation_group":"s3-pcm-pcm-delta-generation","failed_approach":"Resetting predictor each sample destroys adjacent-sample differencing.","family":"s3-pcm-pcm-delta-generation-predictor-feedback","id":"FA-49256","implementations":{"attempt":{"sha256":"25dbe4ee46a1f003293be1d4fa18517358ec873b4347647d0efaa81a0a6f3556","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(samples, initial, reset_positions):\n    previous=initial\n    out=[]\n    for i,sample in enumerate(samples):\n        if i in reset_positions:\n            previous=initial\n        out.append(sample-previous)\n        previous=initial\n    return [out,previous]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([12, 11, 14], 10, [])), [[2, -1, 3], 14])\ncheck('oracle 2', solve(*([3, 7, 9, 5], 2, [2])), [[1, 4, 7, -4], 5])\ncheck('oracle 3', solve(*([], -7, [])), [[], -7])\ncheck('oracle 4', solve(*([-3, -4], -2, [])), [[-1, -1], -4])\ncheck('oracle 5', solve(*([0, 0], 5, [1])), [[-5, -5], 0])\ncheck('oracle 6', solve(*([1], 0, [])), [[1], 1])\ncheck('oracle 7', solve(*([1, 2, 3], 4, [0, 1, 2])), [[-3, -2, -1], 3])\nif N == 1: check('variant packet 1', solve(*[[12, 11, 14, 12, 11, 14], 10, []]), [[2, -1, 3, -2, -1, 3], 14])\nif N == 2: check('variant packet 2', solve(*[[12, 11, 14, 12, 11, 14, 12, 11, 14], 10, []]), [[2, -1, 3, -2, -1, 3, -2, -1, 3], 14])\nif N == 3: check('variant packet 3', solve(*[[12, 11, 14, 12, 11, 14, 12, 11, 14, 12, 11, 14], 10, []]), [[2, -1, 3, -2, -1, 3, -2, -1, 3, -2, -1, 3], 14])\nif N == 4: check('variant packet 4', solve(*[[12, 11, 14, 12, 11, 14, 12, 11, 14, 12, 11, 14, 12, 11, 14], 10, []]), [[2, -1, 3, -2, -1, 3, -2, -1, 3, -2, -1, 3, -2, -1, 3], 14])\nif N == 5: check('variant packet 5', solve(*[[12, 11, 14, 12, 11, 14, 12, 11, 14, 12, 11, 14, 12, 11, 14, 12, 11, 14], 10, []]), [[2, -1, 3, -2, -1, 3, -2, -1, 3, -2, -1, 3, -2, -1, 3, -2, -1, 3], 14])\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":"3ea318d7880767555de677fa300fd5e8a3afd1e3c0a549f7eb36851b5406bb20","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(samples, initial, reset_positions):\n    previous=initial\n    out=[]\n    for i,sample in enumerate(samples):\n        if i in reset_positions:\n            previous=initial\n        out.append(sample-previous)\n        previous=sample-previous\n    return [out,previous]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([12, 11, 14], 10, [])), [[2, -1, 3], 14])\ncheck('oracle 2', solve(*([3, 7, 9, 5], 2, [2])), [[1, 4, 7, -4], 5])\ncheck('oracle 3', solve(*([], -7, [])), [[], -7])\ncheck('oracle 4', solve(*([-3, -4], -2, [])), [[-1, -1], -4])\ncheck('oracle 5', solve(*([0, 0], 5, [1])), [[-5, -5], 0])\ncheck('oracle 6', solve(*([1], 0, [])), [[1], 1])\ncheck('oracle 7', solve(*([1, 2, 3], 4, [0, 1, 2])), [[-3, -2, -1], 3])\nif N == 1: check('variant packet 1', solve(*[[12, 11, 14, 12, 11, 14], 10, []]), [[2, -1, 3, -2, -1, 3], 14])\nif N == 2: check('variant packet 2', solve(*[[12, 11, 14, 12, 11, 14, 12, 11, 14], 10, []]), [[2, -1, 3, -2, -1, 3, -2, -1, 3], 14])\nif N == 3: check('variant packet 3', solve(*[[12, 11, 14, 12, 11, 14, 12, 11, 14, 12, 11, 14], 10, []]), [[2, -1, 3, -2, -1, 3, -2, -1, 3, -2, -1, 3], 14])\nif N == 4: check('variant packet 4', solve(*[[12, 11, 14, 12, 11, 14, 12, 11, 14, 12, 11, 14, 12, 11, 14], 10, []]), [[2, -1, 3, -2, -1, 3, -2, -1, 3, -2, -1, 3, -2, -1, 3], 14])\nif N == 5: check('variant packet 5', solve(*[[12, 11, 14, 12, 11, 14, 12, 11, 14, 12, 11, 14, 12, 11, 14, 12, 11, 14], 10, []]), [[2, -1, 3, -2, -1, 3, -2, -1, 3, -2, -1, 3, -2, -1, 3, -2, -1, 3], 14])\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-delta-generation-predictor-feedback","generated_at":"2026-09-29T14:44:58.354946+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":"Encoder feeds its residual back as next amplitude predictor.","sha256":"3e8e5412c7e63fb7c65a068674289e5499ec598f00e5691b1e503b29d9ae6d54","title":"Pcm delta generation: predictor feedback · 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":43.865,"exit_code":1,"observations":[{"actual":[[2,1,4],10],"check":"oracle 1","expected":[[2,-1,3],14],"passed":false},{"actual":[[1,5,7,3],2],"check":"oracle 2","expected":[[1,4,7,-4],5],"passed":false},{"actual":[[],-7],"check":"oracle 3","expected":[[],-7],"passed":true},{"actual":[[-1,-2],-2],"check":"oracle 4","expected":[[-1,-1],-4],"passed":false},{"actual":[[-5,-5],5],"check":"oracle 5","expected":[[-5,-5],0],"passed":false},{"actual":[[1],0],"check":"oracle 6","expected":[[1],1],"passed":false},{"actual":[[-3,-2,-1],4],"check":"oracle 7","expected":[[-3,-2,-1],3],"passed":false},{"actual":[[2,1,4,2,1,4],10],"check":"variant packet 1","expected":[[2,-1,3,-2,-1,3],14],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[2, 1, 4], 10], \"expected\": [[2, -1, 3], 14], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[1, 5, 7, 3], 2], \"expected\": [[1, 4, 7, -4], 5], \"passed\": false}, {\"check\": \"oracle 3\", \"actual\": [[], -7], \"expected\": [[], -7], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [[-1, -2], -2], \"expected\": [[-1, -1], -4], \"passed\": false}, {\"check\": \"oracle 5\", \"actual\": [[-5, -5], 5], \"expected\": [[-5, -5], 0], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [[1], 0], \"expected\": [[1], 1], \"passed\": false}, {\"check\": \"oracle 7\", \"actual\": [[-3, -2, -1], 4], \"expected\": [[-3, -2, -1], 3], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [[2, 1, 4, 2, 1, 4], 10], \"expected\": [[2, -1, 3, -2, -1, 3], 14], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":42.047,"exit_code":1,"observations":[{"actual":[[2,9,5],5],"check":"oracle 1","expected":[[2,-1,3],14],"passed":false},{"actual":[[1,6,7,-2],-2],"check":"oracle 2","expected":[[1,4,7,-4],5],"passed":false},{"actual":[[],-7],"check":"oracle 3","expected":[[],-7],"passed":true},{"actual":[[-1,-3],-3],"check":"oracle 4","expected":[[-1,-1],-4],"passed":false},{"actual":[[-5,-5],-5],"check":"oracle 5","expected":[[-5,-5],0],"passed":false},{"actual":[[1],1],"check":"oracle 6","expected":[[1],1],"passed":true},{"actual":[[-3,-2,-1],-1],"check":"oracle 7","expected":[[-3,-2,-1],3],"passed":false},{"actual":[[2,9,5,7,4,10],10],"check":"variant packet 1","expected":[[2,-1,3,-2,-1,3],14],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[2, 9, 5], 5], \"expected\": [[2, -1, 3], 14], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[1, 6, 7, -2], -2], \"expected\": [[1, 4, 7, -4], 5], \"passed\": false}, {\"check\": \"oracle 3\", \"actual\": [[], -7], \"expected\": [[], -7], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [[-1, -3], -3], \"expected\": [[-1, -1], -4], \"passed\": false}, {\"check\": \"oracle 5\", \"actual\": [[-5, -5], -5], \"expected\": [[-5, -5], 0], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [[1], 1], \"expected\": [[1], 1], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [[-3, -2, -1], -1], \"expected\": [[-3, -2, -1], 3], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [[2, 9, 5, 7, 4, 10], 10], \"expected\": [[2, -1, 3, -2, -1, 3], 14], \"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."}}