{"abstract":"With a non-zero phase, fields are attributed as if the cadence started at A.","category":"Broadcast timecode arithmetic","checks":9,"contract":"Fields carry film frames in A2 B3 C2 D3 cadence; film frame 0 has cadence position phase and starts at field 0. Video frame v consists of fields 2v and 2v+1. For order \"upper\" field 2v is the top field; for \"lower\" field 2v is the bottom field. Return [film frame in top field, film frame in bottom field, \"clean\" or \"mixed\"]; a negative v returns None.","evaluation_group":"w2-broadcast-timecode-arithmetic-reverse-telecine","failed_approach":"Offsetting by the phase index instead of its field position misreads the table.","family":"w2-broadcast-timecode-arithmetic-reverse-telecine-cadence-base-offset","id":"FA-78581","implementations":{"attempt":{"sha256":"5957a790fd4d05543d0a17cc1453d2da0dd6c2d6751db10f54c2492cc72fae99","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(v, phase, order):\n    if v<0:\n        return None\n    base=[0,2,5,7][phase]\n    def film(f):\n        g,w=divmod(f+phase,10)\n        return 4*g+[0,0,1,1,1,2,2,3,3,3][w]-phase\n    top,bottom=film(2*v),film(2*v+1)\n    if order=='lower':\n        top,bottom=bottom,top\n    return [top,bottom,'clean' if top==bottom else 'mixed']\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: cadence base offset', [0, 1, 'upper'], [0, 0, 'clean']), ('regression variant: cadence base offset', [12, 3, 'lower'], [10, 9, 'mixed']), ('partial repair probe: cadence base offset', [16, 3, 'upper'], [12, 13, 'mixed']), ('partial repair variant: cadence base offset', [15, 1, 'upper'], [12, 12, 'clean']), ('boundary control', [0, 0, 'upper'], [0, 0, 'clean']), ('boundary control', [2, 0, 'upper'], [1, 2, 'mixed']), ('normal control', [2, 0, 'lower'], [2, 1, 'mixed']), ('normal control', [24, 0, 'upper'], [19, 19, 'clean']), ('normal control', [23, 0, 'lower'], [19, 18, 'mixed'])], [('regression: cadence base offset', [4, 3, 'lower'], [3, 3, 'clean']), ('regression variant: cadence base offset', [26, 3, 'upper'], [20, 21, 'mixed']), ('partial repair probe: cadence base offset', [10, 2, 'upper'], [8, 8, 'clean']), ('partial repair variant: cadence base offset', [17, 1, 'upper'], [13, 14, 'mixed']), ('boundary control', [2, 0, 'upper'], [1, 2, 'mixed']), ('boundary control', [2, 0, 'lower'], [2, 1, 'mixed']), ('normal control', [1, 0, 'upper'], [1, 1, 'clean']), ('normal control', [-4, 0, 'upper'], None), ('normal control', [-5, 0, 'lower'], None)], [('regression: cadence base offset', [16, 3, 'upper'], [12, 13, 'mixed']), ('regression variant: cadence base offset', [20, 2, 'upper'], [16, 16, 'clean']), ('partial repair probe: cadence base offset', [30, 3, 'lower'], [24, 24, 'clean']), ('partial repair variant: cadence base offset', [28, 2, 'lower'], [23, 22, 'mixed']), ('boundary control', [2, 0, 'lower'], [2, 1, 'mixed']), ('boundary control', [0, 0, 'upper'], [0, 0, 'clean']), ('normal control', [4, 0, 'upper'], [3, 3, 'clean']), ('normal control', [6, 0, 'upper'], [5, 5, 'clean']), ('normal control', [25, 0, 'lower'], [20, 20, 'clean'])], [('regression: cadence base offset', [10, 2, 'upper'], [8, 8, 'clean']), ('regression variant: cadence base offset', [29, 1, 'lower'], [23, 23, 'clean']), ('partial repair probe: cadence base offset', [12, 3, 'lower'], [10, 9, 'mixed']), ('partial repair variant: cadence base offset', [12, 1, 'upper'], [9, 10, 'mixed']), ('boundary control', [0, 0, 'upper'], [0, 0, 'clean']), ('boundary control', [2, 0, 'upper'], [1, 2, 'mixed']), ('normal control', [-5, 3, 'lower'], None), ('normal control', [28, 0, 'upper'], [22, 23, 'mixed']), ('normal control', [8, 0, 'upper'], [6, 7, 'mixed'])], [('regression: cadence base offset', [30, 3, 'lower'], [24, 24, 'clean']), ('regression variant: cadence base offset', [15, 1, 'upper'], [12, 12, 'clean']), ('partial repair probe: cadence base offset', [26, 3, 'upper'], [20, 21, 'mixed']), ('partial repair variant: cadence base offset', [22, 3, 'upper'], [17, 18, 'mixed']), ('boundary control', [2, 0, 'upper'], [1, 2, 'mixed']), ('boundary control', [2, 0, 'lower'], [2, 1, 'mixed']), ('normal control', [-2, 1, 'upper'], None), ('normal control', [19, 0, 'lower'], [15, 15, 'clean']), ('normal control', [22, 0, 'upper'], [17, 18, 'mixed'])]]\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":"c49d15d903aef848e9ad099153055cf318203180db399eafcf42964546c25d75","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(v, phase, order):\n    if v<0:\n        return None\n    base=[0,2,5,7][phase]\n    def film(f):\n        g,w=divmod(f,10)\n        return 4*g+[0,0,1,1,1,2,2,3,3,3][w]-phase\n    top,bottom=film(2*v),film(2*v+1)\n    if order=='lower':\n        top,bottom=bottom,top\n    return [top,bottom,'clean' if top==bottom else 'mixed']\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: cadence base offset', [0, 1, 'upper'], [0, 0, 'clean']), ('regression variant: cadence base offset', [12, 3, 'lower'], [10, 9, 'mixed']), ('partial repair probe: cadence base offset', [16, 3, 'upper'], [12, 13, 'mixed']), ('partial repair variant: cadence base offset', [15, 1, 'upper'], [12, 12, 'clean']), ('boundary control', [0, 0, 'upper'], [0, 0, 'clean']), ('boundary control', [2, 0, 'upper'], [1, 2, 'mixed']), ('normal control', [2, 0, 'lower'], [2, 1, 'mixed']), ('normal control', [24, 0, 'upper'], [19, 19, 'clean']), ('normal control', [23, 0, 'lower'], [19, 18, 'mixed'])], [('regression: cadence base offset', [4, 3, 'lower'], [3, 3, 'clean']), ('regression variant: cadence base offset', [26, 3, 'upper'], [20, 21, 'mixed']), ('partial repair probe: cadence base offset', [10, 2, 'upper'], [8, 8, 'clean']), ('partial repair variant: cadence base offset', [17, 1, 'upper'], [13, 14, 'mixed']), ('boundary control', [2, 0, 'upper'], [1, 2, 'mixed']), ('boundary control', [2, 0, 'lower'], [2, 1, 'mixed']), ('normal control', [1, 0, 'upper'], [1, 1, 'clean']), ('normal control', [-4, 0, 'upper'], None), ('normal control', [-5, 0, 'lower'], None)], [('regression: cadence base offset', [16, 3, 'upper'], [12, 13, 'mixed']), ('regression variant: cadence base offset', [20, 2, 'upper'], [16, 16, 'clean']), ('partial repair probe: cadence base offset', [30, 3, 'lower'], [24, 24, 'clean']), ('partial repair variant: cadence base offset', [28, 2, 'lower'], [23, 22, 'mixed']), ('boundary control', [2, 0, 'lower'], [2, 1, 'mixed']), ('boundary control', [0, 0, 'upper'], [0, 0, 'clean']), ('normal control', [4, 0, 'upper'], [3, 3, 'clean']), ('normal control', [6, 0, 'upper'], [5, 5, 'clean']), ('normal control', [25, 0, 'lower'], [20, 20, 'clean'])], [('regression: cadence base offset', [10, 2, 'upper'], [8, 8, 'clean']), ('regression variant: cadence base offset', [29, 1, 'lower'], [23, 23, 'clean']), ('partial repair probe: cadence base offset', [12, 3, 'lower'], [10, 9, 'mixed']), ('partial repair variant: cadence base offset', [12, 1, 'upper'], [9, 10, 'mixed']), ('boundary control', [0, 0, 'upper'], [0, 0, 'clean']), ('boundary control', [2, 0, 'upper'], [1, 2, 'mixed']), ('normal control', [-5, 3, 'lower'], None), ('normal control', [28, 0, 'upper'], [22, 23, 'mixed']), ('normal control', [8, 0, 'upper'], [6, 7, 'mixed'])], [('regression: cadence base offset', [30, 3, 'lower'], [24, 24, 'clean']), ('regression variant: cadence base offset', [15, 1, 'upper'], [12, 12, 'clean']), ('partial repair probe: cadence base offset', [26, 3, 'upper'], [20, 21, 'mixed']), ('partial repair variant: cadence base offset', [22, 3, 'upper'], [17, 18, 'mixed']), ('boundary control', [2, 0, 'upper'], [1, 2, 'mixed']), ('boundary control', [2, 0, 'lower'], [2, 1, 'mixed']), ('normal control', [-2, 1, 'upper'], None), ('normal control', [19, 0, 'lower'], [15, 15, 'clean']), ('normal control', [22, 0, 'upper'], [17, 18, 'mixed'])]]\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":"717508c1327311356cebb18158e849b30eb6c25670a178e670e60ec740e8e272","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(v, phase, order):\n    if v<0:\n        return None\n    base=[0,2,5,7][phase]\n    def film(f):\n        g,w=divmod(f+base,10)\n        return 4*g+[0,0,1,1,1,2,2,3,3,3][w]-phase\n    top,bottom=film(2*v),film(2*v+1)\n    if order=='lower':\n        top,bottom=bottom,top\n    return [top,bottom,'clean' if top==bottom else 'mixed']\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: cadence base offset', [0, 1, 'upper'], [0, 0, 'clean']), ('regression variant: cadence base offset', [12, 3, 'lower'], [10, 9, 'mixed']), ('partial repair probe: cadence base offset', [16, 3, 'upper'], [12, 13, 'mixed']), ('partial repair variant: cadence base offset', [15, 1, 'upper'], [12, 12, 'clean']), ('boundary control', [0, 0, 'upper'], [0, 0, 'clean']), ('boundary control', [2, 0, 'upper'], [1, 2, 'mixed']), ('normal control', [2, 0, 'lower'], [2, 1, 'mixed']), ('normal control', [24, 0, 'upper'], [19, 19, 'clean']), ('normal control', [23, 0, 'lower'], [19, 18, 'mixed'])], [('regression: cadence base offset', [4, 3, 'lower'], [3, 3, 'clean']), ('regression variant: cadence base offset', [26, 3, 'upper'], [20, 21, 'mixed']), ('partial repair probe: cadence base offset', [10, 2, 'upper'], [8, 8, 'clean']), ('partial repair variant: cadence base offset', [17, 1, 'upper'], [13, 14, 'mixed']), ('boundary control', [2, 0, 'upper'], [1, 2, 'mixed']), ('boundary control', [2, 0, 'lower'], [2, 1, 'mixed']), ('normal control', [1, 0, 'upper'], [1, 1, 'clean']), ('normal control', [-4, 0, 'upper'], None), ('normal control', [-5, 0, 'lower'], None)], [('regression: cadence base offset', [16, 3, 'upper'], [12, 13, 'mixed']), ('regression variant: cadence base offset', [20, 2, 'upper'], [16, 16, 'clean']), ('partial repair probe: cadence base offset', [30, 3, 'lower'], [24, 24, 'clean']), ('partial repair variant: cadence base offset', [28, 2, 'lower'], [23, 22, 'mixed']), ('boundary control', [2, 0, 'lower'], [2, 1, 'mixed']), ('boundary control', [0, 0, 'upper'], [0, 0, 'clean']), ('normal control', [4, 0, 'upper'], [3, 3, 'clean']), ('normal control', [6, 0, 'upper'], [5, 5, 'clean']), ('normal control', [25, 0, 'lower'], [20, 20, 'clean'])], [('regression: cadence base offset', [10, 2, 'upper'], [8, 8, 'clean']), ('regression variant: cadence base offset', [29, 1, 'lower'], [23, 23, 'clean']), ('partial repair probe: cadence base offset', [12, 3, 'lower'], [10, 9, 'mixed']), ('partial repair variant: cadence base offset', [12, 1, 'upper'], [9, 10, 'mixed']), ('boundary control', [0, 0, 'upper'], [0, 0, 'clean']), ('boundary control', [2, 0, 'upper'], [1, 2, 'mixed']), ('normal control', [-5, 3, 'lower'], None), ('normal control', [28, 0, 'upper'], [22, 23, 'mixed']), ('normal control', [8, 0, 'upper'], [6, 7, 'mixed'])], [('regression: cadence base offset', [30, 3, 'lower'], [24, 24, 'clean']), ('regression variant: cadence base offset', [15, 1, 'upper'], [12, 12, 'clean']), ('partial repair probe: cadence base offset', [26, 3, 'upper'], [20, 21, 'mixed']), ('partial repair variant: cadence base offset', [22, 3, 'upper'], [17, 18, 'mixed']), ('boundary control', [2, 0, 'upper'], [1, 2, 'mixed']), ('boundary control', [2, 0, 'lower'], [2, 1, 'mixed']), ('normal control', [-2, 1, 'upper'], None), ('normal control', [19, 0, 'lower'], [15, 15, 'clean']), ('normal control', [22, 0, 'upper'], [17, 18, 'mixed'])]]\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-reverse-telecine-cadence-base-offset","generated_at":"2026-09-29T14:49:36.642935+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":"Offset fields by the phase field position before the table lookup.","root_cause":"The field offset of the starting phase is not added.","sha256":"12e14c974b092e21c25757e3acb2ff21efcd1818cd4bb44cdc3bb1f24f15fe55","title":"Reverse telecine field attribution: cadence base offset · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":41.197,"exit_code":1,"observations":[{"actual":[-1,0,"mixed"],"check":"regression: cadence base offset","expected":[0,0,"clean"],"passed":false},{"actual":[8,8,"clean"],"check":"regression variant: cadence base offset","expected":[10,9,"mixed"],"passed":false},{"actual":[11,11,"clean"],"check":"partial repair probe: cadence base offset","expected":[12,13,"mixed"],"passed":false},{"actual":[11,12,"mixed"],"check":"partial repair variant: cadence base offset","expected":[12,12,"clean"],"passed":false},{"actual":[0,0,"clean"],"check":"boundary control","expected":[0,0,"clean"],"passed":true},{"actual":[1,2,"mixed"],"check":"boundary control","expected":[1,2,"mixed"],"passed":true},{"actual":[2,1,"mixed"],"check":"normal control","expected":[2,1,"mixed"],"passed":true},{"actual":[19,19,"clean"],"check":"normal control","expected":[19,19,"clean"],"passed":true},{"actual":[19,18,"mixed"],"check":"normal control","expected":[19,18,"mixed"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: cadence base offset\", \"actual\": [-1, 0, \"mixed\"], \"expected\": [0, 0, \"clean\"], \"passed\": false}, {\"check\": \"regression variant: cadence base offset\", \"actual\": [8, 8, \"clean\"], \"expected\": [10, 9, \"mixed\"], \"passed\": false}, {\"check\": \"partial repair probe: cadence base offset\", \"actual\": [11, 11, \"clean\"], \"expected\": [12, 13, \"mixed\"], \"passed\": false}, {\"check\": \"partial repair variant: cadence base offset\", \"actual\": [11, 12, \"mixed\"], \"expected\": [12, 12, \"clean\"], \"passed\": false}, {\"check\": \"boundary control\", \"actual\": [0, 0, \"clean\"], \"expected\": [0, 0, \"clean\"], \"passed\": true}, {\"check\": \"boundary control\", \"actual\": [1, 2, \"mixed\"], \"expected\": [1, 2, \"mixed\"], \"passed\": true}, {\"check\": \"normal control\", \"actual\": [2, 1, \"mixed\"], \"expected\": [2, 1, \"mixed\"], \"passed\": true}, {\"check\": \"normal control\", \"actual\": [19, 19, \"clean\"], \"expected\": [19, 19, \"clean\"], \"passed\": true}, {\"check\": \"normal control\", \"actual\": [19, 18, \"mixed\"], \"expected\": [19, 18, \"mixed\"], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.85,"exit_code":1,"observations":[{"actual":[-1,-1,"clean"],"check":"regression: cadence base offset","expected":[0,0,"clean"],"passed":false},{"actual":[7,6,"mixed"],"check":"regression variant: cadence base offset","expected":[10,9,"mixed"],"passed":false},{"actual":[10,10,"clean"],"check":"partial repair probe: cadence base offset","expected":[12,13,"mixed"],"passed":false},{"actual":[11,11,"clean"],"check":"partial repair variant: cadence base offset","expected":[12,12,"clean"],"passed":false},{"actual":[0,0,"clean"],"check":"boundary control","expected":[0,0,"clean"],"passed":true},{"actual":[1,2,"mixed"],"check":"boundary control","expected":[1,2,"mixed"],"passed":true},{"actual":[2,1,"mixed"],"check":"normal control","expected":[2,1,"mixed"],"passed":true},{"actual":[19,19,"clean"],"check":"normal control","expected":[19,19,"clean"],"passed":true},{"actual":[19,18,"mixed"],"check":"normal control","expected":[19,18,"mixed"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: cadence base offset\", \"actual\": [-1, -1, \"clean\"], \"expected\": [0, 0, \"clean\"], \"passed\": false}, {\"check\": \"regression variant: cadence base offset\", \"actual\": [7, 6, \"mixed\"], \"expected\": [10, 9, \"mixed\"], \"passed\": false}, {\"check\": \"partial repair probe: cadence base offset\", \"actual\": [10, 10, \"clean\"], \"expected\": [12, 13, \"mixed\"], \"passed\": false}, {\"check\": \"partial repair variant: cadence base offset\", \"actual\": [11, 11, \"clean\"], \"expected\": [12, 12, \"clean\"], \"passed\": false}, {\"check\": \"boundary control\", \"actual\": [0, 0, \"clean\"], \"expected\": [0, 0, \"clean\"], \"passed\": true}, {\"check\": \"boundary control\", \"actual\": [1, 2, \"mixed\"], \"expected\": [1, 2, \"mixed\"], \"passed\": true}, {\"check\": \"normal control\", \"actual\": [2, 1, \"mixed\"], \"expected\": [2, 1, \"mixed\"], \"passed\": true}, {\"check\": \"normal control\", \"actual\": [19, 19, \"clean\"], \"expected\": [19, 19, \"clean\"], \"passed\": true}, {\"check\": \"normal control\", \"actual\": [19, 18, \"mixed\"], \"expected\": [19, 18, \"mixed\"], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":44.126,"exit_code":0,"observations":[{"actual":[0,0,"clean"],"check":"regression: cadence base offset","expected":[0,0,"clean"],"passed":true},{"actual":[10,9,"mixed"],"check":"regression variant: cadence base offset","expected":[10,9,"mixed"],"passed":true},{"actual":[12,13,"mixed"],"check":"partial repair probe: cadence base offset","expected":[12,13,"mixed"],"passed":true},{"actual":[12,12,"clean"],"check":"partial repair variant: cadence base offset","expected":[12,12,"clean"],"passed":true},{"actual":[0,0,"clean"],"check":"boundary control","expected":[0,0,"clean"],"passed":true},{"actual":[1,2,"mixed"],"check":"boundary control","expected":[1,2,"mixed"],"passed":true},{"actual":[2,1,"mixed"],"check":"normal control","expected":[2,1,"mixed"],"passed":true},{"actual":[19,19,"clean"],"check":"normal control","expected":[19,19,"clean"],"passed":true},{"actual":[19,18,"mixed"],"check":"normal control","expected":[19,18,"mixed"],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: cadence base offset\", \"actual\": [0, 0, \"clean\"], \"expected\": [0, 0, \"clean\"], \"passed\": true}, {\"check\": \"regression variant: cadence base offset\", \"actual\": [10, 9, \"mixed\"], \"expected\": [10, 9, \"mixed\"], \"passed\": true}, {\"check\": \"partial repair probe: cadence base offset\", \"actual\": [12, 13, \"mixed\"], \"expected\": [12, 13, \"mixed\"], \"passed\": true}, {\"check\": \"partial repair variant: cadence base offset\", \"actual\": [12, 12, \"clean\"], \"expected\": [12, 12, \"clean\"], \"passed\": true}, {\"check\": \"boundary control\", \"actual\": [0, 0, \"clean\"], \"expected\": [0, 0, \"clean\"], \"passed\": true}, {\"check\": \"boundary control\", \"actual\": [1, 2, \"mixed\"], \"expected\": [1, 2, \"mixed\"], \"passed\": true}, {\"check\": \"normal control\", \"actual\": [2, 1, \"mixed\"], \"expected\": [2, 1, \"mixed\"], \"passed\": true}, {\"check\": \"normal control\", \"actual\": [19, 19, \"clean\"], \"expected\": [19, 19, \"clean\"], \"passed\": true}, {\"check\": \"normal control\", \"actual\": [19, 18, \"mixed\"], \"expected\": [19, 18, \"mixed\"], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}