{"abstract":"The first segment uses the general exponent rule instead of its special mantissa shift.","category":"PCM sample encoding","checks":8,"contract":"Stipulated bounded A-law-style PCM encoder with negative complement offset, thirteen-bit working magnitude, segment-specific shifts and alternating wire mask.","contract_signature":"samples","evaluation_group":"s3-pcm-pcm-alaw-code-selection","failed_approach":"Shifting every nonzero segment one extra bit loses mantissa resolution.","family":"s3-pcm-pcm-alaw-code-selection-small-segment-shift","id":"FA-49876","implementations":{"attempt":{"sha256":"423d64fa7074262276cfd2233551357b0ada6634f89fef2278fe68983e684e76","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(samples):\n    out=[]\n    for sample in samples:\n        negative=sample<0\n        magnitude=(-sample-1 if negative else sample)>>3\n        magnitude=min(magnitude,4095)\n        segment=0\n        while segment<7 and magnitude>=(32<<segment):\n            segment+=1\n        shift=1 if segment==0 else segment+1\n        mantissa=(magnitude>>shift)&15\n        code=(0 if negative else 128)|(segment<<4)|mantissa\n        out.append(code^85)\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([0, 8, -8, 16, -16],)), [213, 213, 85, 212, 85])\ncheck('oracle 2', solve(*([256, -256, 264, -264],)), [197, 90, 197, 69])\ncheck('oracle 3', solve(*([32767, -32768, 40000, -40000],)), [170, 42, 170, 42])\ncheck('oracle 4', solve(*([],)), [])\ncheck('oracle 5', solve(*([1024, 2048, 8192],)), [229, 149, 181])\ncheck('oracle 6', solve(*([1, -1, 127, -128],)), [213, 85, 210, 82])\ncheck('oracle 7', solve(*([512, -513, 4096, -4097],)), [245, 117, 133, 5])\nif N == 1: check('variant packet 1', solve(*[[0, 8, -8, 16, -16, 0, 8, -8, 16, -16]]), [213, 213, 85, 212, 85, 213, 213, 85, 212, 85])\nif N == 2: check('variant packet 2', solve(*[[0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16]]), [213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85])\nif N == 3: check('variant packet 3', solve(*[[0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16]]), [213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85])\nif N == 4: check('variant packet 4', solve(*[[0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16]]), [213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85])\nif N == 5: check('variant packet 5', solve(*[[0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16]]), [213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85])\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":"10af32bd85fa99c1a7bd0de9510d10666889758f26d126f7c4edd3658fba5d47","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(samples):\n    out=[]\n    for sample in samples:\n        negative=sample<0\n        magnitude=(-sample-1 if negative else sample)>>3\n        magnitude=min(magnitude,4095)\n        segment=0\n        while segment<7 and magnitude>=(32<<segment):\n            segment+=1\n        shift=segment\n        mantissa=(magnitude>>shift)&15\n        code=(0 if negative else 128)|(segment<<4)|mantissa\n        out.append(code^85)\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([0, 8, -8, 16, -16],)), [213, 213, 85, 212, 85])\ncheck('oracle 2', solve(*([256, -256, 264, -264],)), [197, 90, 197, 69])\ncheck('oracle 3', solve(*([32767, -32768, 40000, -40000],)), [170, 42, 170, 42])\ncheck('oracle 4', solve(*([],)), [])\ncheck('oracle 5', solve(*([1024, 2048, 8192],)), [229, 149, 181])\ncheck('oracle 6', solve(*([1, -1, 127, -128],)), [213, 85, 210, 82])\ncheck('oracle 7', solve(*([512, -513, 4096, -4097],)), [245, 117, 133, 5])\nif N == 1: check('variant packet 1', solve(*[[0, 8, -8, 16, -16, 0, 8, -8, 16, -16]]), [213, 213, 85, 212, 85, 213, 213, 85, 212, 85])\nif N == 2: check('variant packet 2', solve(*[[0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16]]), [213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85])\nif N == 3: check('variant packet 3', solve(*[[0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16]]), [213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85])\nif N == 4: check('variant packet 4', solve(*[[0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16]]), [213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85])\nif N == 5: check('variant packet 5', solve(*[[0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16, 0, 8, -8, 16, -16]]), [213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85, 213, 213, 85, 212, 85])\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-alaw-code-selection-small-segment-shift","generated_at":"2026-09-29T14:45:04.164617+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 first segment uses the general exponent rule instead of its special mantissa shift.","sha256":"f1a9825b18b4f625888f3479d306a9e4f23487862afcd49f006e6c7b98f2f83f","title":"Pcm alaw code selection: small segment shift · 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":40.405,"exit_code":1,"observations":[{"actual":[213,213,85,212,85],"check":"oracle 1","expected":[213,213,85,212,85],"passed":true},{"actual":[205,90,205,77],"check":"oracle 2","expected":[197,90,197,69],"passed":false},{"actual":[170,42,170,42],"check":"oracle 3","expected":[170,42,170,42],"passed":true},{"actual":[],"check":"oracle 4","expected":[],"passed":true},{"actual":[237,157,189],"check":"oracle 5","expected":[229,149,181],"passed":false},{"actual":[213,85,210,82],"check":"oracle 6","expected":[213,85,210,82],"passed":true},{"actual":[253,125,141,13],"check":"oracle 7","expected":[245,117,133,5],"passed":false},{"actual":[213,213,85,212,85,213,213,85,212,85],"check":"variant packet 1","expected":[213,213,85,212,85,213,213,85,212,85],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [213, 213, 85, 212, 85], \"expected\": [213, 213, 85, 212, 85], \"passed\": true}, {\"check\": \"oracle 2\", \"actual\": [205, 90, 205, 77], \"expected\": [197, 90, 197, 69], \"passed\": false}, {\"check\": \"oracle 3\", \"actual\": [170, 42, 170, 42], \"expected\": [170, 42, 170, 42], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [237, 157, 189], \"expected\": [229, 149, 181], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [213, 85, 210, 82], \"expected\": [213, 85, 210, 82], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [253, 125, 141, 13], \"expected\": [245, 117, 133, 5], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [213, 213, 85, 212, 85, 213, 213, 85, 212, 85], \"expected\": [213, 213, 85, 212, 85, 213, 213, 85, 212, 85], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":37.596,"exit_code":1,"observations":[{"actual":[213,212,85,215,84],"check":"oracle 1","expected":[213,213,85,212,85],"passed":false},{"actual":[197,90,197,69],"check":"oracle 2","expected":[197,90,197,69],"passed":true},{"actual":[170,42,170,42],"check":"oracle 3","expected":[170,42,170,42],"passed":true},{"actual":[],"check":"oracle 4","expected":[],"passed":true},{"actual":[229,149,181],"check":"oracle 5","expected":[229,149,181],"passed":true},{"actual":[213,85,218,90],"check":"oracle 6","expected":[213,85,210,82],"passed":false},{"actual":[245,117,133,5],"check":"oracle 7","expected":[245,117,133,5],"passed":true},{"actual":[213,212,85,215,84,213,212,85,215,84],"check":"variant packet 1","expected":[213,213,85,212,85,213,213,85,212,85],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [213, 212, 85, 215, 84], \"expected\": [213, 213, 85, 212, 85], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [197, 90, 197, 69], \"expected\": [197, 90, 197, 69], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [170, 42, 170, 42], \"expected\": [170, 42, 170, 42], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [229, 149, 181], \"expected\": [229, 149, 181], \"passed\": true}, {\"check\": \"oracle 6\", \"actual\": [213, 85, 218, 90], \"expected\": [213, 85, 210, 82], \"passed\": false}, {\"check\": \"oracle 7\", \"actual\": [245, 117, 133, 5], \"expected\": [245, 117, 133, 5], \"passed\": true}, {\"check\": \"variant packet 1\", \"actual\": [213, 212, 85, 215, 84, 213, 212, 85, 215, 84], \"expected\": [213, 213, 85, 212, 85, 213, 213, 85, 212, 85], \"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."}}