{"abstract":"PCM byte spans include the RIFF-style chunk header.","category":"PCM sample encoding","checks":8,"contract":"Locate PCM spans in a bounded RIFF-like list of chunk descriptors with eight-byte headers and even-byte padding, requiring a preceding format chunk.","contract_signature":"chunks, base","evaluation_group":"s3-pcm-riff-pcm-data-spans","failed_approach":"Skipping only the tag leaves the size field inside sample data.","family":"s3-pcm-riff-pcm-data-spans-chunk-header-skip","id":"FA-49466","implementations":{"attempt":{"sha256":"53361bb9139581ab066d6062a1984d83129d10a090bb06770e1e3a1fce80965e","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(chunks, base):\n    cursor=base\n    spans=[]\n    format_seen=False\n    for tag,size in chunks:\n        data_start=cursor+4\n        if tag=='fmt ':\n            format_seen=True\n        if tag=='data' and format_seen:\n            spans.append([data_start,size])\n        cursor=data_start+size+(size&1)\n    return [spans,cursor]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([['fmt ', 16], ['data', 3], ['data', 2]], 12)), [[[44, 3], [56, 2]], 58])\ncheck('oracle 2', solve(*([['JUNK', 3], ['fmt ', 16], ['data', 4]], 12)), [[[56, 4]], 60])\ncheck('oracle 3', solve(*([['data', 4], ['fmt ', 16], ['data', 2]], 0)), [[[44, 2]], 46])\ncheck('oracle 4', solve(*([], 12)), [[], 12])\ncheck('oracle 5', solve(*([['fmt ', 18], ['LIST', 5], ['data', 0]], 12)), [[[60, 0]], 60])\ncheck('oracle 6', solve(*([['fmt ', 16], ['data', 1], ['JUNK', 0], ['data', 1]], 0)), [[[32, 1], [50, 1]], 52])\ncheck('oracle 7', solve(*([['JUNK', 0]], 0)), [[], 8])\nif N == 1: check('variant packet 1', solve(*[[['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2]], 12]), [[[44, 3], [56, 2], [90, 3], [102, 2]], 104])\nif N == 2: check('variant packet 2', solve(*[[['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2]], 12]), [[[44, 3], [56, 2], [90, 3], [102, 2], [136, 3], [148, 2]], 150])\nif N == 3: check('variant packet 3', solve(*[[['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2]], 12]), [[[44, 3], [56, 2], [90, 3], [102, 2], [136, 3], [148, 2], [182, 3], [194, 2]], 196])\nif N == 4: check('variant packet 4', solve(*[[['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2]], 12]), [[[44, 3], [56, 2], [90, 3], [102, 2], [136, 3], [148, 2], [182, 3], [194, 2], [228, 3], [240, 2]], 242])\nif N == 5: check('variant packet 5', solve(*[[['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2]], 12]), [[[44, 3], [56, 2], [90, 3], [102, 2], [136, 3], [148, 2], [182, 3], [194, 2], [228, 3], [240, 2], [274, 3], [286, 2]], 288])\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":"6872e6646500a3868642456356b6341507a3df93e277ccb1474f67c83339a9f6","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(chunks, base):\n    cursor=base\n    spans=[]\n    format_seen=False\n    for tag,size in chunks:\n        data_start=cursor\n        if tag=='fmt ':\n            format_seen=True\n        if tag=='data' and format_seen:\n            spans.append([data_start,size])\n        cursor=data_start+size+(size&1)\n    return [spans,cursor]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([['fmt ', 16], ['data', 3], ['data', 2]], 12)), [[[44, 3], [56, 2]], 58])\ncheck('oracle 2', solve(*([['JUNK', 3], ['fmt ', 16], ['data', 4]], 12)), [[[56, 4]], 60])\ncheck('oracle 3', solve(*([['data', 4], ['fmt ', 16], ['data', 2]], 0)), [[[44, 2]], 46])\ncheck('oracle 4', solve(*([], 12)), [[], 12])\ncheck('oracle 5', solve(*([['fmt ', 18], ['LIST', 5], ['data', 0]], 12)), [[[60, 0]], 60])\ncheck('oracle 6', solve(*([['fmt ', 16], ['data', 1], ['JUNK', 0], ['data', 1]], 0)), [[[32, 1], [50, 1]], 52])\ncheck('oracle 7', solve(*([['JUNK', 0]], 0)), [[], 8])\nif N == 1: check('variant packet 1', solve(*[[['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2]], 12]), [[[44, 3], [56, 2], [90, 3], [102, 2]], 104])\nif N == 2: check('variant packet 2', solve(*[[['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2]], 12]), [[[44, 3], [56, 2], [90, 3], [102, 2], [136, 3], [148, 2]], 150])\nif N == 3: check('variant packet 3', solve(*[[['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2]], 12]), [[[44, 3], [56, 2], [90, 3], [102, 2], [136, 3], [148, 2], [182, 3], [194, 2]], 196])\nif N == 4: check('variant packet 4', solve(*[[['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2]], 12]), [[[44, 3], [56, 2], [90, 3], [102, 2], [136, 3], [148, 2], [182, 3], [194, 2], [228, 3], [240, 2]], 242])\nif N == 5: check('variant packet 5', solve(*[[['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2], ['fmt ', 16], ['data', 3], ['data', 2]], 12]), [[[44, 3], [56, 2], [90, 3], [102, 2], [136, 3], [148, 2], [182, 3], [194, 2], [228, 3], [240, 2], [274, 3], [286, 2]], 288])\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-riff-pcm-data-spans-chunk-header-skip","generated_at":"2026-09-29T14:45:00.410271+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":"PCM byte spans include the RIFF-style chunk header.","sha256":"48151fe0e79848cf779558576ad612831d65fd703db4b8dc567bfa76f2ca770e","title":"Riff pcm data spans: chunk header skip · 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":39.462,"exit_code":1,"observations":[{"actual":[[[36,3],[44,2]],46],"check":"oracle 1","expected":[[[44,3],[56,2]],58],"passed":false},{"actual":[[[44,4]],48],"check":"oracle 2","expected":[[[56,4]],60],"passed":false},{"actual":[[[32,2]],34],"check":"oracle 3","expected":[[[44,2]],46],"passed":false},{"actual":[[],12],"check":"oracle 4","expected":[[],12],"passed":true},{"actual":[[[48,0]],48],"check":"oracle 5","expected":[[[60,0]],60],"passed":false},{"actual":[[[24,1],[34,1]],36],"check":"oracle 6","expected":[[[32,1],[50,1]],52],"passed":false},{"actual":[[],4],"check":"oracle 7","expected":[[],8],"passed":false},{"actual":[[[36,3],[44,2],[70,3],[78,2]],80],"check":"variant packet 1","expected":[[[44,3],[56,2],[90,3],[102,2]],104],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[[36, 3], [44, 2]], 46], \"expected\": [[[44, 3], [56, 2]], 58], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[[44, 4]], 48], \"expected\": [[[56, 4]], 60], \"passed\": false}, {\"check\": \"oracle 3\", \"actual\": [[[32, 2]], 34], \"expected\": [[[44, 2]], 46], \"passed\": false}, {\"check\": \"oracle 4\", \"actual\": [[], 12], \"expected\": [[], 12], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [[[48, 0]], 48], \"expected\": [[[60, 0]], 60], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [[[24, 1], [34, 1]], 36], \"expected\": [[[32, 1], [50, 1]], 52], \"passed\": false}, {\"check\": \"oracle 7\", \"actual\": [[], 4], \"expected\": [[], 8], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [[[36, 3], [44, 2], [70, 3], [78, 2]], 80], \"expected\": [[[44, 3], [56, 2], [90, 3], [102, 2]], 104], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":41.196,"exit_code":1,"observations":[{"actual":[[[28,3],[32,2]],34],"check":"oracle 1","expected":[[[44,3],[56,2]],58],"passed":false},{"actual":[[[32,4]],36],"check":"oracle 2","expected":[[[56,4]],60],"passed":false},{"actual":[[[20,2]],22],"check":"oracle 3","expected":[[[44,2]],46],"passed":false},{"actual":[[],12],"check":"oracle 4","expected":[[],12],"passed":true},{"actual":[[[36,0]],36],"check":"oracle 5","expected":[[[60,0]],60],"passed":false},{"actual":[[[16,1],[18,1]],20],"check":"oracle 6","expected":[[[32,1],[50,1]],52],"passed":false},{"actual":[[],0],"check":"oracle 7","expected":[[],8],"passed":false},{"actual":[[[28,3],[32,2],[50,3],[54,2]],56],"check":"variant packet 1","expected":[[[44,3],[56,2],[90,3],[102,2]],104],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[[28, 3], [32, 2]], 34], \"expected\": [[[44, 3], [56, 2]], 58], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[[32, 4]], 36], \"expected\": [[[56, 4]], 60], \"passed\": false}, {\"check\": \"oracle 3\", \"actual\": [[[20, 2]], 22], \"expected\": [[[44, 2]], 46], \"passed\": false}, {\"check\": \"oracle 4\", \"actual\": [[], 12], \"expected\": [[], 12], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [[[36, 0]], 36], \"expected\": [[[60, 0]], 60], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [[[16, 1], [18, 1]], 20], \"expected\": [[[32, 1], [50, 1]], 52], \"passed\": false}, {\"check\": \"oracle 7\", \"actual\": [[], 0], \"expected\": [[], 8], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [[[28, 3], [32, 2], [50, 3], [54, 2]], 56], \"expected\": [[[44, 3], [56, 2], [90, 3], [102, 2]], 104], \"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."}}