{"abstract":"Block alignment is checked at the enclosing chunk instead of first PCM byte.","category":"PCM sample encoding","checks":8,"contract":"For stipulated AIFF-like sound chunks, exclude the eight-byte offset/block preamble and offset prefix, count complete PCM frames and inspect absolute block alignment.","evaluation_group":"s3-pcm-aiff-pcm-offset-block","failed_approach":"Checking offset alone ignores absolute placement.","family":"s3-pcm-aiff-pcm-offset-block-block-alignment","id":"FA-49511","implementations":{"attempt":{"sha256":"4cfa1101dc1afae41f938eb9bcb9df58d3118bfd995d8713e66277f516a25058","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(blocks, frame_bytes):\n    out=[]\n    for chunk_start,chunk_size,offset,block_size in blocks:\n        start=chunk_start+8+offset\n        usable=max(0,chunk_size-8-offset)\n        frames=usable//frame_bytes\n        remainder=usable%frame_bytes\n        aligned=(block_size==0 or offset%block_size==0)\n        out.append([start,frames,remainder,aligned])\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([[100, 27, 3, 1]], 4)), [[111, 4, 0, True]])\ncheck('oracle 2', solve(*([[12, 20, 0, 4], [16, 19, 1, 4]], 4)), [[20, 3, 0, True], [25, 2, 2, False]])\ncheck('oracle 3', solve(*([[0, 7, 0, 0]], 2)), [[8, 0, 0, True]])\ncheck('oracle 4', solve(*([], 4)), [])\ncheck('oracle 5', solve(*([[5, 31, 7, 8]], 3)), [[20, 5, 1, False]])\ncheck('oracle 6', solve(*([[10, 12, 8, 0]], 2)), [[26, 0, 0, True]])\ncheck('oracle 7', solve(*([[0, 16, 0, 16]], 4)), [[8, 2, 0, False]])\nif N == 1: check('variant packet 1', solve(*[[[100, 27, 3, 1], [100, 27, 3, 1]], 4]), [[111, 4, 0, True], [111, 4, 0, True]])\nif N == 2: check('variant packet 2', solve(*[[[100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1]], 4]), [[111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True]])\nif N == 3: check('variant packet 3', solve(*[[[100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1]], 4]), [[111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True]])\nif N == 4: check('variant packet 4', solve(*[[[100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1]], 4]), [[111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True]])\nif N == 5: check('variant packet 5', solve(*[[[100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1]], 4]), [[111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True]])\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":"47b5b692e973deabad9f017e3b1a7f282daf2b2e376ea6db66927a4b30d1db01","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(blocks, frame_bytes):\n    out=[]\n    for chunk_start,chunk_size,offset,block_size in blocks:\n        start=chunk_start+8+offset\n        usable=max(0,chunk_size-8-offset)\n        frames=usable//frame_bytes\n        remainder=usable%frame_bytes\n        aligned=(block_size==0 or chunk_start%block_size==0)\n        out.append([start,frames,remainder,aligned])\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([[100, 27, 3, 1]], 4)), [[111, 4, 0, True]])\ncheck('oracle 2', solve(*([[12, 20, 0, 4], [16, 19, 1, 4]], 4)), [[20, 3, 0, True], [25, 2, 2, False]])\ncheck('oracle 3', solve(*([[0, 7, 0, 0]], 2)), [[8, 0, 0, True]])\ncheck('oracle 4', solve(*([], 4)), [])\ncheck('oracle 5', solve(*([[5, 31, 7, 8]], 3)), [[20, 5, 1, False]])\ncheck('oracle 6', solve(*([[10, 12, 8, 0]], 2)), [[26, 0, 0, True]])\ncheck('oracle 7', solve(*([[0, 16, 0, 16]], 4)), [[8, 2, 0, False]])\nif N == 1: check('variant packet 1', solve(*[[[100, 27, 3, 1], [100, 27, 3, 1]], 4]), [[111, 4, 0, True], [111, 4, 0, True]])\nif N == 2: check('variant packet 2', solve(*[[[100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1]], 4]), [[111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True]])\nif N == 3: check('variant packet 3', solve(*[[[100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1]], 4]), [[111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True]])\nif N == 4: check('variant packet 4', solve(*[[[100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1]], 4]), [[111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True]])\nif N == 5: check('variant packet 5', solve(*[[[100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1]], 4]), [[111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True]])\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":"1cea7e9c0a73070746dd52c6d72784c4b2d83404b46a4ff5e2e8e84d7f37d423","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(blocks, frame_bytes):\n    out=[]\n    for chunk_start,chunk_size,offset,block_size in blocks:\n        start=chunk_start+8+offset\n        usable=max(0,chunk_size-8-offset)\n        frames=usable//frame_bytes\n        remainder=usable%frame_bytes\n        aligned=(block_size==0 or start%block_size==0)\n        out.append([start,frames,remainder,aligned])\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([[100, 27, 3, 1]], 4)), [[111, 4, 0, True]])\ncheck('oracle 2', solve(*([[12, 20, 0, 4], [16, 19, 1, 4]], 4)), [[20, 3, 0, True], [25, 2, 2, False]])\ncheck('oracle 3', solve(*([[0, 7, 0, 0]], 2)), [[8, 0, 0, True]])\ncheck('oracle 4', solve(*([], 4)), [])\ncheck('oracle 5', solve(*([[5, 31, 7, 8]], 3)), [[20, 5, 1, False]])\ncheck('oracle 6', solve(*([[10, 12, 8, 0]], 2)), [[26, 0, 0, True]])\ncheck('oracle 7', solve(*([[0, 16, 0, 16]], 4)), [[8, 2, 0, False]])\nif N == 1: check('variant packet 1', solve(*[[[100, 27, 3, 1], [100, 27, 3, 1]], 4]), [[111, 4, 0, True], [111, 4, 0, True]])\nif N == 2: check('variant packet 2', solve(*[[[100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1]], 4]), [[111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True]])\nif N == 3: check('variant packet 3', solve(*[[[100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1]], 4]), [[111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True]])\nif N == 4: check('variant packet 4', solve(*[[[100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1]], 4]), [[111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True]])\nif N == 5: check('variant packet 5', solve(*[[[100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1], [100, 27, 3, 1]], 4]), [[111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True], [111, 4, 0, True]])\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-aiff-pcm-offset-block-block-alignment","generated_at":"2026-09-29T14:45:00.566975+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 block alignment.","root_cause":"Block alignment is checked at the enclosing chunk instead of first PCM byte.","sha256":"349036a2477a8a06a5bceb49183cf472930e8d3e77d45cac2281575f713166b7","title":"Aiff pcm offset block: block alignment · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":37.98,"exit_code":1,"observations":[{"actual":[[111,4,0,true]],"check":"oracle 1","expected":[[111,4,0,true]],"passed":true},{"actual":[[20,3,0,true],[25,2,2,false]],"check":"oracle 2","expected":[[20,3,0,true],[25,2,2,false]],"passed":true},{"actual":[[8,0,0,true]],"check":"oracle 3","expected":[[8,0,0,true]],"passed":true},{"actual":[],"check":"oracle 4","expected":[],"passed":true},{"actual":[[20,5,1,false]],"check":"oracle 5","expected":[[20,5,1,false]],"passed":true},{"actual":[[26,0,0,true]],"check":"oracle 6","expected":[[26,0,0,true]],"passed":true},{"actual":[[8,2,0,true]],"check":"oracle 7","expected":[[8,2,0,false]],"passed":false},{"actual":[[111,4,0,true],[111,4,0,true]],"check":"variant packet 1","expected":[[111,4,0,true],[111,4,0,true]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[111, 4, 0, true]], \"expected\": [[111, 4, 0, true]], \"passed\": true}, {\"check\": \"oracle 2\", \"actual\": [[20, 3, 0, true], [25, 2, 2, false]], \"expected\": [[20, 3, 0, true], [25, 2, 2, false]], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [[8, 0, 0, true]], \"expected\": [[8, 0, 0, true]], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [[20, 5, 1, false]], \"expected\": [[20, 5, 1, false]], \"passed\": true}, {\"check\": \"oracle 6\", \"actual\": [[26, 0, 0, true]], \"expected\": [[26, 0, 0, true]], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [[8, 2, 0, true]], \"expected\": [[8, 2, 0, false]], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [[111, 4, 0, true], [111, 4, 0, true]], \"expected\": [[111, 4, 0, true], [111, 4, 0, true]], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":36.934,"exit_code":1,"observations":[{"actual":[[111,4,0,true]],"check":"oracle 1","expected":[[111,4,0,true]],"passed":true},{"actual":[[20,3,0,true],[25,2,2,true]],"check":"oracle 2","expected":[[20,3,0,true],[25,2,2,false]],"passed":false},{"actual":[[8,0,0,true]],"check":"oracle 3","expected":[[8,0,0,true]],"passed":true},{"actual":[],"check":"oracle 4","expected":[],"passed":true},{"actual":[[20,5,1,false]],"check":"oracle 5","expected":[[20,5,1,false]],"passed":true},{"actual":[[26,0,0,true]],"check":"oracle 6","expected":[[26,0,0,true]],"passed":true},{"actual":[[8,2,0,true]],"check":"oracle 7","expected":[[8,2,0,false]],"passed":false},{"actual":[[111,4,0,true],[111,4,0,true]],"check":"variant packet 1","expected":[[111,4,0,true],[111,4,0,true]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[111, 4, 0, true]], \"expected\": [[111, 4, 0, true]], \"passed\": true}, {\"check\": \"oracle 2\", \"actual\": [[20, 3, 0, true], [25, 2, 2, true]], \"expected\": [[20, 3, 0, true], [25, 2, 2, false]], \"passed\": false}, {\"check\": \"oracle 3\", \"actual\": [[8, 0, 0, true]], \"expected\": [[8, 0, 0, true]], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [[20, 5, 1, false]], \"expected\": [[20, 5, 1, false]], \"passed\": true}, {\"check\": \"oracle 6\", \"actual\": [[26, 0, 0, true]], \"expected\": [[26, 0, 0, true]], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [[8, 2, 0, true]], \"expected\": [[8, 2, 0, false]], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [[111, 4, 0, true], [111, 4, 0, true]], \"expected\": [[111, 4, 0, true], [111, 4, 0, true]], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":39.657,"exit_code":0,"observations":[{"actual":[[111,4,0,true]],"check":"oracle 1","expected":[[111,4,0,true]],"passed":true},{"actual":[[20,3,0,true],[25,2,2,false]],"check":"oracle 2","expected":[[20,3,0,true],[25,2,2,false]],"passed":true},{"actual":[[8,0,0,true]],"check":"oracle 3","expected":[[8,0,0,true]],"passed":true},{"actual":[],"check":"oracle 4","expected":[],"passed":true},{"actual":[[20,5,1,false]],"check":"oracle 5","expected":[[20,5,1,false]],"passed":true},{"actual":[[26,0,0,true]],"check":"oracle 6","expected":[[26,0,0,true]],"passed":true},{"actual":[[8,2,0,false]],"check":"oracle 7","expected":[[8,2,0,false]],"passed":true},{"actual":[[111,4,0,true],[111,4,0,true]],"check":"variant packet 1","expected":[[111,4,0,true],[111,4,0,true]],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[111, 4, 0, true]], \"expected\": [[111, 4, 0, true]], \"passed\": true}, {\"check\": \"oracle 2\", \"actual\": [[20, 3, 0, true], [25, 2, 2, false]], \"expected\": [[20, 3, 0, true], [25, 2, 2, false]], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [[8, 0, 0, true]], \"expected\": [[8, 0, 0, true]], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [[20, 5, 1, false]], \"expected\": [[20, 5, 1, false]], \"passed\": true}, {\"check\": \"oracle 6\", \"actual\": [[26, 0, 0, true]], \"expected\": [[26, 0, 0, true]], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [[8, 2, 0, false]], \"expected\": [[8, 2, 0, false]], \"passed\": true}, {\"check\": \"variant packet 1\", \"actual\": [[111, 4, 0, true], [111, 4, 0, true]], \"expected\": [[111, 4, 0, true], [111, 4, 0, true]], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}