{"abstract":"Converted 16mm footage shows three times too many feet.","category":"Broadcast timecode arithmetic","checks":9,"contract":"Frames per foot: 35mm4 16, 35mm2 32, 16mm 40. An int frame count converts to \"[-]F+ff\" (feet, two-digit frames, sign in front for negatives); a string \"[-]F+ff\" converts to a signed frame count, with ff below frames per foot (else None). \"-0+05\" means -5.","evaluation_group":"w2-broadcast-timecode-arithmetic-feet-frames","failed_approach":"Fixing only the feet leaves the frame field reduced modulo 16.","family":"w2-broadcast-timecode-arithmetic-feet-frames-foot-divisor","id":"FA-78536","implementations":{"attempt":{"sha256":"1b5f1df2e8ec1359f006eaf09a50bd0f17832f9dd2441066498f983234eef56c","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(value, gauge):\n    per={'35mm4':16,'35mm2':32,'16mm':40}[gauge]\n    if isinstance(value,int):\n        sign='-' if value<0 else ''\n        v=abs(value)\n        return '%s%d+%02d'%(sign,v//per,v%16)\n    ft,fr=value.split('+')\n    if int(fr)>=per:\n        return None\n    n=abs(int(ft))*per+int(fr)\n    return -n if ft.startswith('-') else n\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: foot divisor', [-43, '16mm'], '-1+03'), ('regression variant: foot divisor', [999, '16mm'], '24+39'), ('partial repair probe: foot divisor', [39, '16mm'], '0+39'), ('partial repair variant: foot divisor', [4080, '35mm2'], '127+16'), ('boundary control', [16, '35mm4'], '1+00'), ('boundary control', ['1+15', '35mm4'], 31), ('normal control', [-1, '35mm4'], '-0+01'), ('normal control', ['0+16', '35mm4'], None), ('normal control', ['2+39', '16mm'], 119)], [('regression: foot divisor', [-40, '16mm'], '-1+00'), ('regression variant: foot divisor', [31, '35mm2'], '0+31'), ('partial repair probe: foot divisor', [999, '16mm'], '24+39'), ('partial repair variant: foot divisor', [40, '16mm'], '1+00'), ('boundary control', [-1, '35mm4'], '-0+01'), ('boundary control', ['0+16', '35mm4'], None), ('normal control', [-1, '35mm2'], '-0+01'), ('normal control', [1, '16mm'], '0+01'), ('normal control', ['100+16', '16mm'], 4016)], [('regression: foot divisor', [-32, '35mm2'], '-1+00'), ('regression variant: foot divisor', [41, '16mm'], '1+01'), ('partial repair probe: foot divisor', [31, '35mm2'], '0+31'), ('partial repair variant: foot divisor', [1422, '16mm'], '35+22'), ('boundary control', ['-0+05', '35mm4'], -5), ('boundary control', ['2+39', '16mm'], 119), ('normal control', [0, '16mm'], '0+00'), ('normal control', ['100+16', '35mm2'], 3216), ('normal control', ['-3+31', '35mm4'], None)], [('regression: foot divisor', [39, '16mm'], '0+39'), ('regression variant: foot divisor', [999, '35mm2'], '31+07'), ('partial repair probe: foot divisor', [41, '16mm'], '1+01'), ('partial repair variant: foot divisor', [2711, '16mm'], '67+31'), ('boundary control', ['1+15', '35mm4'], 31), ('boundary control', [16, '35mm4'], '1+00'), ('normal control', ['1+00', '35mm4'], 16), ('normal control', ['-0+16', '35mm4'], None), ('normal control', ['1+16', '35mm2'], 48)], [('regression: foot divisor', [33, '35mm2'], '1+01'), ('regression variant: foot divisor', [-35, '35mm2'], '-1+03'), ('partial repair probe: foot divisor', [2612, '35mm2'], '81+20'), ('partial repair variant: foot divisor', [3865, '16mm'], '96+25'), ('boundary control', ['0+16', '35mm4'], None), ('boundary control', [-1, '35mm4'], '-0+01'), ('normal control', ['0+00', '35mm2'], 0), ('normal control', ['-0+15', '35mm4'], -15), ('normal control', ['-3+16', '35mm4'], None)]]\nfor label, args, expected in fixtures[N-1]:\n    check(label, 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":"63a97ff5199d95cf0aebe6c9ea6cc8de888195bba82ee7af51f971961c834616","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(value, gauge):\n    per={'35mm4':16,'35mm2':32,'16mm':40}[gauge]\n    if isinstance(value,int):\n        sign='-' if value<0 else ''\n        v=abs(value)\n        return '%s%d+%02d'%(sign,v//16,v%16)\n    ft,fr=value.split('+')\n    if int(fr)>=per:\n        return None\n    n=abs(int(ft))*per+int(fr)\n    return -n if ft.startswith('-') else n\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: foot divisor', [-43, '16mm'], '-1+03'), ('regression variant: foot divisor', [999, '16mm'], '24+39'), ('partial repair probe: foot divisor', [39, '16mm'], '0+39'), ('partial repair variant: foot divisor', [4080, '35mm2'], '127+16'), ('boundary control', [16, '35mm4'], '1+00'), ('boundary control', ['1+15', '35mm4'], 31), ('normal control', [-1, '35mm4'], '-0+01'), ('normal control', ['0+16', '35mm4'], None), ('normal control', ['2+39', '16mm'], 119)], [('regression: foot divisor', [-40, '16mm'], '-1+00'), ('regression variant: foot divisor', [31, '35mm2'], '0+31'), ('partial repair probe: foot divisor', [999, '16mm'], '24+39'), ('partial repair variant: foot divisor', [40, '16mm'], '1+00'), ('boundary control', [-1, '35mm4'], '-0+01'), ('boundary control', ['0+16', '35mm4'], None), ('normal control', [-1, '35mm2'], '-0+01'), ('normal control', [1, '16mm'], '0+01'), ('normal control', ['100+16', '16mm'], 4016)], [('regression: foot divisor', [-32, '35mm2'], '-1+00'), ('regression variant: foot divisor', [41, '16mm'], '1+01'), ('partial repair probe: foot divisor', [31, '35mm2'], '0+31'), ('partial repair variant: foot divisor', [1422, '16mm'], '35+22'), ('boundary control', ['-0+05', '35mm4'], -5), ('boundary control', ['2+39', '16mm'], 119), ('normal control', [0, '16mm'], '0+00'), ('normal control', ['100+16', '35mm2'], 3216), ('normal control', ['-3+31', '35mm4'], None)], [('regression: foot divisor', [39, '16mm'], '0+39'), ('regression variant: foot divisor', [999, '35mm2'], '31+07'), ('partial repair probe: foot divisor', [41, '16mm'], '1+01'), ('partial repair variant: foot divisor', [2711, '16mm'], '67+31'), ('boundary control', ['1+15', '35mm4'], 31), ('boundary control', [16, '35mm4'], '1+00'), ('normal control', ['1+00', '35mm4'], 16), ('normal control', ['-0+16', '35mm4'], None), ('normal control', ['1+16', '35mm2'], 48)], [('regression: foot divisor', [33, '35mm2'], '1+01'), ('regression variant: foot divisor', [-35, '35mm2'], '-1+03'), ('partial repair probe: foot divisor', [2612, '35mm2'], '81+20'), ('partial repair variant: foot divisor', [3865, '16mm'], '96+25'), ('boundary control', ['0+16', '35mm4'], None), ('boundary control', [-1, '35mm4'], '-0+01'), ('normal control', ['0+00', '35mm2'], 0), ('normal control', ['-0+15', '35mm4'], -15), ('normal control', ['-3+16', '35mm4'], None)]]\nfor label, args, expected in fixtures[N-1]:\n    check(label, 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"},"fixed":{"sha256":"cf8c051b6d72eeedb11d74e2e582d0e5cd7b243aa65cf39d242d6fc281a326d3","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(value, gauge):\n    per={'35mm4':16,'35mm2':32,'16mm':40}[gauge]\n    if isinstance(value,int):\n        sign='-' if value<0 else ''\n        v=abs(value)\n        return '%s%d+%02d'%(sign,v//per,v%per)\n    ft,fr=value.split('+')\n    if int(fr)>=per:\n        return None\n    n=abs(int(ft))*per+int(fr)\n    return -n if ft.startswith('-') else n\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: foot divisor', [-43, '16mm'], '-1+03'), ('regression variant: foot divisor', [999, '16mm'], '24+39'), ('partial repair probe: foot divisor', [39, '16mm'], '0+39'), ('partial repair variant: foot divisor', [4080, '35mm2'], '127+16'), ('boundary control', [16, '35mm4'], '1+00'), ('boundary control', ['1+15', '35mm4'], 31), ('normal control', [-1, '35mm4'], '-0+01'), ('normal control', ['0+16', '35mm4'], None), ('normal control', ['2+39', '16mm'], 119)], [('regression: foot divisor', [-40, '16mm'], '-1+00'), ('regression variant: foot divisor', [31, '35mm2'], '0+31'), ('partial repair probe: foot divisor', [999, '16mm'], '24+39'), ('partial repair variant: foot divisor', [40, '16mm'], '1+00'), ('boundary control', [-1, '35mm4'], '-0+01'), ('boundary control', ['0+16', '35mm4'], None), ('normal control', [-1, '35mm2'], '-0+01'), ('normal control', [1, '16mm'], '0+01'), ('normal control', ['100+16', '16mm'], 4016)], [('regression: foot divisor', [-32, '35mm2'], '-1+00'), ('regression variant: foot divisor', [41, '16mm'], '1+01'), ('partial repair probe: foot divisor', [31, '35mm2'], '0+31'), ('partial repair variant: foot divisor', [1422, '16mm'], '35+22'), ('boundary control', ['-0+05', '35mm4'], -5), ('boundary control', ['2+39', '16mm'], 119), ('normal control', [0, '16mm'], '0+00'), ('normal control', ['100+16', '35mm2'], 3216), ('normal control', ['-3+31', '35mm4'], None)], [('regression: foot divisor', [39, '16mm'], '0+39'), ('regression variant: foot divisor', [999, '35mm2'], '31+07'), ('partial repair probe: foot divisor', [41, '16mm'], '1+01'), ('partial repair variant: foot divisor', [2711, '16mm'], '67+31'), ('boundary control', ['1+15', '35mm4'], 31), ('boundary control', [16, '35mm4'], '1+00'), ('normal control', ['1+00', '35mm4'], 16), ('normal control', ['-0+16', '35mm4'], None), ('normal control', ['1+16', '35mm2'], 48)], [('regression: foot divisor', [33, '35mm2'], '1+01'), ('regression variant: foot divisor', [-35, '35mm2'], '-1+03'), ('partial repair probe: foot divisor', [2612, '35mm2'], '81+20'), ('partial repair variant: foot divisor', [3865, '16mm'], '96+25'), ('boundary control', ['0+16', '35mm4'], None), ('boundary control', [-1, '35mm4'], '-0+01'), ('normal control', ['0+00', '35mm2'], 0), ('normal control', ['-0+15', '35mm4'], -15), ('normal control', ['-3+16', '35mm4'], None)]]\nfor label, args, expected in fixtures[N-1]:\n    check(label, 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 does not claim conformance to SMPTE or any broadcast standard. 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-broadcast-timecode-arithmetic-feet-frames-foot-divisor","generated_at":"2026-09-29T14:49:35.987406+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Timecode arithmetic errors misplace edits, commercial breaks and captions against the broadcast clock.","repair":"Divide by the gauge frames-per-foot for both fields.","root_cause":"The formatter divides by the 35mm 4-perf value for every gauge.","sha256":"b89dc2b3a0094e3a1c4d5d501cbb2a405fb8801bf35ecb816d84d3f404e25704","title":"Film feet and frames conversion: foot divisor · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":38.714,"exit_code":1,"observations":[{"actual":"-1+11","check":"regression: foot divisor","expected":"-1+03","passed":false},{"actual":"24+07","check":"regression variant: foot divisor","expected":"24+39","passed":false},{"actual":"0+07","check":"partial repair probe: foot divisor","expected":"0+39","passed":false},{"actual":"127+00","check":"partial repair variant: foot divisor","expected":"127+16","passed":false},{"actual":"1+00","check":"boundary control","expected":"1+00","passed":true},{"actual":31,"check":"boundary control","expected":31,"passed":true},{"actual":"-0+01","check":"normal control","expected":"-0+01","passed":true},{"actual":null,"check":"normal control","expected":null,"passed":true},{"actual":119,"check":"normal control","expected":119,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: foot divisor\", \"actual\": \"-1+11\", \"expected\": \"-1+03\", \"passed\": false}, {\"check\": \"regression variant: foot divisor\", \"actual\": \"24+07\", \"expected\": \"24+39\", \"passed\": false}, {\"check\": \"partial repair probe: foot divisor\", \"actual\": \"0+07\", \"expected\": \"0+39\", \"passed\": false}, {\"check\": \"partial repair variant: foot divisor\", \"actual\": \"127+00\", \"expected\": \"127+16\", \"passed\": false}, {\"check\": \"boundary control\", \"actual\": \"1+00\", \"expected\": \"1+00\", \"passed\": true}, {\"check\": \"boundary control\", \"actual\": 31, \"expected\": 31, \"passed\": true}, {\"check\": \"normal control\", \"actual\": \"-0+01\", \"expected\": \"-0+01\", \"passed\": true}, {\"check\": \"normal control\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"normal control\", \"actual\": 119, \"expected\": 119, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.826,"exit_code":1,"observations":[{"actual":"-2+11","check":"regression: foot divisor","expected":"-1+03","passed":false},{"actual":"62+07","check":"regression variant: foot divisor","expected":"24+39","passed":false},{"actual":"2+07","check":"partial repair probe: foot divisor","expected":"0+39","passed":false},{"actual":"255+00","check":"partial repair variant: foot divisor","expected":"127+16","passed":false},{"actual":"1+00","check":"boundary control","expected":"1+00","passed":true},{"actual":31,"check":"boundary control","expected":31,"passed":true},{"actual":"-0+01","check":"normal control","expected":"-0+01","passed":true},{"actual":null,"check":"normal control","expected":null,"passed":true},{"actual":119,"check":"normal control","expected":119,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: foot divisor\", \"actual\": \"-2+11\", \"expected\": \"-1+03\", \"passed\": false}, {\"check\": \"regression variant: foot divisor\", \"actual\": \"62+07\", \"expected\": \"24+39\", \"passed\": false}, {\"check\": \"partial repair probe: foot divisor\", \"actual\": \"2+07\", \"expected\": \"0+39\", \"passed\": false}, {\"check\": \"partial repair variant: foot divisor\", \"actual\": \"255+00\", \"expected\": \"127+16\", \"passed\": false}, {\"check\": \"boundary control\", \"actual\": \"1+00\", \"expected\": \"1+00\", \"passed\": true}, {\"check\": \"boundary control\", \"actual\": 31, \"expected\": 31, \"passed\": true}, {\"check\": \"normal control\", \"actual\": \"-0+01\", \"expected\": \"-0+01\", \"passed\": true}, {\"check\": \"normal control\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"normal control\", \"actual\": 119, \"expected\": 119, \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":37.839,"exit_code":0,"observations":[{"actual":"-1+03","check":"regression: foot divisor","expected":"-1+03","passed":true},{"actual":"24+39","check":"regression variant: foot divisor","expected":"24+39","passed":true},{"actual":"0+39","check":"partial repair probe: foot divisor","expected":"0+39","passed":true},{"actual":"127+16","check":"partial repair variant: foot divisor","expected":"127+16","passed":true},{"actual":"1+00","check":"boundary control","expected":"1+00","passed":true},{"actual":31,"check":"boundary control","expected":31,"passed":true},{"actual":"-0+01","check":"normal control","expected":"-0+01","passed":true},{"actual":null,"check":"normal control","expected":null,"passed":true},{"actual":119,"check":"normal control","expected":119,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: foot divisor\", \"actual\": \"-1+03\", \"expected\": \"-1+03\", \"passed\": true}, {\"check\": \"regression variant: foot divisor\", \"actual\": \"24+39\", \"expected\": \"24+39\", \"passed\": true}, {\"check\": \"partial repair probe: foot divisor\", \"actual\": \"0+39\", \"expected\": \"0+39\", \"passed\": true}, {\"check\": \"partial repair variant: foot divisor\", \"actual\": \"127+16\", \"expected\": \"127+16\", \"passed\": true}, {\"check\": \"boundary control\", \"actual\": \"1+00\", \"expected\": \"1+00\", \"passed\": true}, {\"check\": \"boundary control\", \"actual\": 31, \"expected\": 31, \"passed\": true}, {\"check\": \"normal control\", \"actual\": \"-0+01\", \"expected\": \"-0+01\", \"passed\": true}, {\"check\": \"normal control\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"normal control\", \"actual\": 119, \"expected\": 119, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}