{"abstract":"Locating to sixteenth 4 sets the clock position to 4 instead of 24.","category":"MIDI event timing","checks":8,"contract":"Input a list of messages: [\"start\"], [\"continue\"], [\"stop\"], [\"clock\"] or [\"spp\", lsb, msb]. start resets the position to 0 and runs; continue runs from the current position; stop halts; clock advances the position by one clock only while running; a song position pointer (in sixteenth notes, 6 clocks each, 14-bit lsb/msb) is honoured only while stopped. Return [position in clocks, running, quarter notes = position // 24]; unknown messages return None.","contract_signature":"x","evaluation_group":"w2-midi-event-timing-clock-transport","failed_approach":"Multiplying by 24 treats the pointer as quarter notes.","family":"w2-midi-event-timing-clock-transport-pointer-units","id":"FA-81581","implementations":{"attempt":{"sha256":"8a64968b9e20af6252dd8c35bd6a24bced459cc787ed5fa1f3fe8c910baf0dc7","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    if not isinstance(x, list):\n        return None\n    pos = 0\n    running = False\n    for msg in x:\n        kind = msg[0]\n        if kind == 'start':\n            pos = 0\n            running = True\n        elif kind == 'continue':\n            running = True\n        elif kind == 'stop':\n            running = False\n        elif kind == 'clock':\n            if running:\n                pos += 1\n        elif kind == 'spp':\n            if not running:\n                pos = 24 * ((msg[2] << 7) | msg[1])\n        else:\n            return None\n    return [pos, running, pos // 24]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[([['start'], ['clock'], ['clock']], [2, True, 0]), ([['clock'], ['clock']], [0, False, 0]), ([['start'], ['clock'], ['stop'], ['clock'], ['continue'], ['clock']], [2, True, 0]), ([['spp', 4, 0], ['continue'], ['clock']], [25, True, 1]), ([['spp', 1, 1]], [774, False, 32]), ([['start'], ['spp', 8, 0], ['clock']], [1, True, 0]), ([['start'], ['clock'], ['stop'], ['start'], ['clock']], [1, True, 0]), ([['stop'], ['spp', 3, 0], ['continue'], ['clock'], ['clock']], [20, True, 0])], [([['spp', 0, 1], ['continue']], [768, True, 32]), ([['start'], ['spp', 8, 0], ['clock']], [1, True, 0]), ([['start'], ['clock'], ['stop'], ['start'], ['clock']], [1, True, 0]), ([['spp', 16, 0], ['start']], [0, True, 0]), ([['stop'], ['spp', 3, 0], ['continue'], ['clock'], ['clock']], [20, True, 0]), ([['reset']], None), ([], [0, False, 0]), ([['spp', 127, 127]], [98298, False, 4095])], [([['spp', 1, 1]], [774, False, 32]), ([['reset']], None), ([], [0, False, 0]), ([['start'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock']], [25, True, 1]), ([['spp', 127, 127]], [98298, False, 4095]), ([['spp', 4, 0], ['continue'], ['stop'], ['continue'], ['clock']], [25, True, 1]), ([['continue'], ['clock']], [1, True, 0]), ([['start'], ['stop'], ['continue'], ['clock']], [1, True, 0])], [([['spp', 4, 0], ['continue'], ['clock']], [25, True, 1]), ([['spp', 0, 1], ['continue']], [768, True, 32]), ([['spp', 1, 1]], [774, False, 32]), ([['stop'], ['spp', 3, 0], ['continue'], ['clock'], ['clock']], [20, True, 0]), ([['spp', 4, 0], ['continue'], ['stop'], ['continue'], ['clock']], [25, True, 1]), ([['start'], ['clock'], ['clock'], ['stop'], ['spp', 2, 0], ['continue'], ['clock']], [13, True, 0]), ([['continue'], ['clock']], [1, True, 0]), ([['start'], ['stop'], ['continue'], ['clock']], [1, True, 0])], [([['start'], ['clock'], ['clock']], [2, True, 0]), ([['spp', 4, 0], ['continue'], ['clock']], [25, True, 1]), ([['spp', 0, 1], ['continue']], [768, True, 32]), ([['spp', 1, 1]], [774, False, 32]), ([['stop'], ['spp', 3, 0], ['continue'], ['clock'], ['clock']], [20, True, 0]), ([['spp', 127, 127]], [98298, False, 4095]), ([['spp', 4, 0], ['continue'], ['stop'], ['continue'], ['clock']], [25, True, 1]), ([['start'], ['clock'], ['clock'], ['stop'], ['spp', 2, 0], ['continue'], ['clock']], [13, True, 0])]]\nfor i, (args, expected) in enumerate(fixtures[N-1]):\n    check(\"oracle %d\" % i, solve(args), expected)\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":"4c990213e7fb6f68f9e274bd8615495613dd4ed4514170af4d5542dc766c1f59","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    if not isinstance(x, list):\n        return None\n    pos = 0\n    running = False\n    for msg in x:\n        kind = msg[0]\n        if kind == 'start':\n            pos = 0\n            running = True\n        elif kind == 'continue':\n            running = True\n        elif kind == 'stop':\n            running = False\n        elif kind == 'clock':\n            if running:\n                pos += 1\n        elif kind == 'spp':\n            if not running:\n                pos = ((msg[2] << 7) | msg[1])\n        else:\n            return None\n    return [pos, running, pos // 24]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[([['start'], ['clock'], ['clock']], [2, True, 0]), ([['clock'], ['clock']], [0, False, 0]), ([['start'], ['clock'], ['stop'], ['clock'], ['continue'], ['clock']], [2, True, 0]), ([['spp', 4, 0], ['continue'], ['clock']], [25, True, 1]), ([['spp', 1, 1]], [774, False, 32]), ([['start'], ['spp', 8, 0], ['clock']], [1, True, 0]), ([['start'], ['clock'], ['stop'], ['start'], ['clock']], [1, True, 0]), ([['stop'], ['spp', 3, 0], ['continue'], ['clock'], ['clock']], [20, True, 0])], [([['spp', 0, 1], ['continue']], [768, True, 32]), ([['start'], ['spp', 8, 0], ['clock']], [1, True, 0]), ([['start'], ['clock'], ['stop'], ['start'], ['clock']], [1, True, 0]), ([['spp', 16, 0], ['start']], [0, True, 0]), ([['stop'], ['spp', 3, 0], ['continue'], ['clock'], ['clock']], [20, True, 0]), ([['reset']], None), ([], [0, False, 0]), ([['spp', 127, 127]], [98298, False, 4095])], [([['spp', 1, 1]], [774, False, 32]), ([['reset']], None), ([], [0, False, 0]), ([['start'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock'], ['clock']], [25, True, 1]), ([['spp', 127, 127]], [98298, False, 4095]), ([['spp', 4, 0], ['continue'], ['stop'], ['continue'], ['clock']], [25, True, 1]), ([['continue'], ['clock']], [1, True, 0]), ([['start'], ['stop'], ['continue'], ['clock']], [1, True, 0])], [([['spp', 4, 0], ['continue'], ['clock']], [25, True, 1]), ([['spp', 0, 1], ['continue']], [768, True, 32]), ([['spp', 1, 1]], [774, False, 32]), ([['stop'], ['spp', 3, 0], ['continue'], ['clock'], ['clock']], [20, True, 0]), ([['spp', 4, 0], ['continue'], ['stop'], ['continue'], ['clock']], [25, True, 1]), ([['start'], ['clock'], ['clock'], ['stop'], ['spp', 2, 0], ['continue'], ['clock']], [13, True, 0]), ([['continue'], ['clock']], [1, True, 0]), ([['start'], ['stop'], ['continue'], ['clock']], [1, True, 0])], [([['start'], ['clock'], ['clock']], [2, True, 0]), ([['spp', 4, 0], ['continue'], ['clock']], [25, True, 1]), ([['spp', 0, 1], ['continue']], [768, True, 32]), ([['spp', 1, 1]], [774, False, 32]), ([['stop'], ['spp', 3, 0], ['continue'], ['clock'], ['clock']], [20, True, 0]), ([['spp', 127, 127]], [98298, False, 4095]), ([['spp', 4, 0], ['continue'], ['stop'], ['continue'], ['clock']], [25, True, 1]), ([['start'], ['clock'], ['clock'], ['stop'], ['spp', 2, 0], ['continue'], ['clock']], [13, True, 0])]]\nfor i, (args, expected) in enumerate(fixtures[N-1]):\n    check(\"oracle %d\" % i, solve(args), expected)\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":"A deterministic bounded teaching model with a stipulated toy contract; it is not a complete Standard MIDI File or MIDI 1.0/2.0 implementation. 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":"w2-midi-event-timing-clock-transport-pointer-units","generated_at":"2026-09-29T14:50:04.403518+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"MIDI sequencers, file readers and synth drivers depend on exact event ordering and tick/time arithmetic.","root_cause":"The pointer value in sixteenth notes is used directly as a clock count.","sha256":"61e2a08035482fbb0595b8494098d57a7e06ad6cb324fbffcd54701bb5595902","title":"MIDI clock transport and song position: song position taken as clocks · 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":39.233,"exit_code":1,"observations":[{"actual":[2,true,0],"check":"oracle 0","expected":[2,true,0],"passed":true},{"actual":[0,false,0],"check":"oracle 1","expected":[0,false,0],"passed":true},{"actual":[2,true,0],"check":"oracle 2","expected":[2,true,0],"passed":true},{"actual":[97,true,4],"check":"oracle 3","expected":[25,true,1],"passed":false},{"actual":[3096,false,129],"check":"oracle 4","expected":[774,false,32],"passed":false},{"actual":[1,true,0],"check":"oracle 5","expected":[1,true,0],"passed":true},{"actual":[1,true,0],"check":"oracle 6","expected":[1,true,0],"passed":true},{"actual":[74,true,3],"check":"oracle 7","expected":[20,true,0],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 0\", \"actual\": [2, true, 0], \"expected\": [2, true, 0], \"passed\": true}, {\"check\": \"oracle 1\", \"actual\": [0, false, 0], \"expected\": [0, false, 0], \"passed\": true}, {\"check\": \"oracle 2\", \"actual\": [2, true, 0], \"expected\": [2, true, 0], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [97, true, 4], \"expected\": [25, true, 1], \"passed\": false}, {\"check\": \"oracle 4\", \"actual\": [3096, false, 129], \"expected\": [774, false, 32], \"passed\": false}, {\"check\": \"oracle 5\", \"actual\": [1, true, 0], \"expected\": [1, true, 0], \"passed\": true}, {\"check\": \"oracle 6\", \"actual\": [1, true, 0], \"expected\": [1, true, 0], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [74, true, 3], \"expected\": [20, true, 0], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.745,"exit_code":1,"observations":[{"actual":[2,true,0],"check":"oracle 0","expected":[2,true,0],"passed":true},{"actual":[0,false,0],"check":"oracle 1","expected":[0,false,0],"passed":true},{"actual":[2,true,0],"check":"oracle 2","expected":[2,true,0],"passed":true},{"actual":[5,true,0],"check":"oracle 3","expected":[25,true,1],"passed":false},{"actual":[129,false,5],"check":"oracle 4","expected":[774,false,32],"passed":false},{"actual":[1,true,0],"check":"oracle 5","expected":[1,true,0],"passed":true},{"actual":[1,true,0],"check":"oracle 6","expected":[1,true,0],"passed":true},{"actual":[5,true,0],"check":"oracle 7","expected":[20,true,0],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 0\", \"actual\": [2, true, 0], \"expected\": [2, true, 0], \"passed\": true}, {\"check\": \"oracle 1\", \"actual\": [0, false, 0], \"expected\": [0, false, 0], \"passed\": true}, {\"check\": \"oracle 2\", \"actual\": [2, true, 0], \"expected\": [2, true, 0], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [5, true, 0], \"expected\": [25, true, 1], \"passed\": false}, {\"check\": \"oracle 4\", \"actual\": [129, false, 5], \"expected\": [774, false, 32], \"passed\": false}, {\"check\": \"oracle 5\", \"actual\": [1, true, 0], \"expected\": [1, true, 0], \"passed\": true}, {\"check\": \"oracle 6\", \"actual\": [1, true, 0], \"expected\": [1, true, 0], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [5, true, 0], \"expected\": [20, true, 0], \"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."}}