{"abstract":"A-law negative input omits its complement offset at quantization boundaries.","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.","evaluation_group":"s3-pcm-pcm-alaw-code-selection","failed_approach":"Applying the offset to positive samples breaks positive low bins.","family":"s3-pcm-pcm-alaw-code-selection-negative-magnitude-rule","id":"FA-49866","implementations":{"attempt":{"sha256":"9e13219722da37ecbfaa5ec83c0a1c5ba6e0f0d5236b95cc8f7f3a76cdcf6401","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=(abs(sample)-1)>>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<2 else 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"},"broken":{"sha256":"595b66b88707c2a78b05b691f686c5b12128a60a51452e38dd2c97dca96cc736","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 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<2 else 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"},"fixed":{"sha256":"df99ba847feb88c82ec2203b6e947d4ae1167b17d32ccde326bc8d136c175a7b","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<2 else 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-negative-magnitude-rule","generated_at":"2026-09-29T14:45:03.879506+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 negative magnitude rule.","root_cause":"A-law negative input omits its complement offset at quantization boundaries.","sha256":"c46a1788e822427e26fa5a645533b78f1bff68d9421a3b58105e3de25bf429b6","title":"Pcm alaw code selection: negative magnitude rule · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":40.379,"exit_code":1,"observations":[{"actual":[218,213,85,213,85],"check":"oracle 1","expected":[213,213,85,212,85],"passed":false},{"actual":[218,90,197,69],"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":[250,234,138],"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":[202,117,154,5],"check":"oracle 7","expected":[245,117,133,5],"passed":false},{"actual":[218,213,85,213,85,218,213,85,213,85],"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\": [218, 213, 85, 213, 85], \"expected\": [213, 213, 85, 212, 85], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [218, 90, 197, 69], \"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\": [250, 234, 138], \"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\": [202, 117, 154, 5], \"expected\": [245, 117, 133, 5], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [218, 213, 85, 213, 85, 218, 213, 85, 213, 85], \"expected\": [213, 213, 85, 212, 85, 213, 213, 85, 212, 85], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.373,"exit_code":1,"observations":[{"actual":[213,213,85,212,84],"check":"oracle 1","expected":[213,213,85,212,85],"passed":false},{"actual":[197,69,197,69],"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":[229,149,181],"check":"oracle 5","expected":[229,149,181],"passed":true},{"actual":[213,85,210,93],"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":[213,213,85,212,84,213,213,85,212,84],"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, 213, 85, 212, 84], \"expected\": [213, 213, 85, 212, 85], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [197, 69, 197, 69], \"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\": [229, 149, 181], \"expected\": [229, 149, 181], \"passed\": true}, {\"check\": \"oracle 6\", \"actual\": [213, 85, 210, 93], \"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, 213, 85, 212, 84, 213, 213, 85, 212, 84], \"expected\": [213, 213, 85, 212, 85, 213, 213, 85, 212, 85], \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":37.91,"exit_code":0,"observations":[{"actual":[213,213,85,212,85],"check":"oracle 1","expected":[213,213,85,212,85],"passed":true},{"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":[213,85,210,82],"check":"oracle 6","expected":[213,85,210,82],"passed":true},{"actual":[245,117,133,5],"check":"oracle 7","expected":[245,117,133,5],"passed":true},{"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":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [213, 213, 85, 212, 85], \"expected\": [213, 213, 85, 212, 85], \"passed\": true}, {\"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, 210, 82], \"expected\": [213, 85, 210, 82], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [245, 117, 133, 5], \"expected\": [245, 117, 133, 5], \"passed\": true}, {\"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\": true}\n"}},"verified":true,"visibility":"public"}