{"abstract":"Frame-pair fields restart halfway through each second.","category":"Broadcast timecode arithmetic","checks":9,"contract":"Convert a frame count (any integer, wrapped modulo 24 hours) to HH:MM:SS:FF. For fps above 30 the frame field counts frame pairs (frame//2) and the last separator is \".\" for the second frame of a pair and \":\" otherwise.","contract_signature":"frames, fps","evaluation_group":"w2-broadcast-timecode-arithmetic-frames-to-label","failed_approach":"Rounding up the pair index groups frames into the wrong pairs.","family":"w2-broadcast-timecode-arithmetic-frames-to-label-pair-index","id":"FA-78386","implementations":{"attempt":{"sha256":"6e0296b77f07de5ba939619e2efb8b5fd110297999412d4728f64ef7a4dc3d60","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(frames, fps):\n    day=24*3600*fps\n    frames%=day\n    fr=frames%fps\n    s=frames//fps\n    hh,mm,ss=s//3600,s//60%60,s%60\n    if fps>30:\n        return '%02d:%02d:%02d%s%02d'%(hh,mm,ss,'.' if fr%2 else ':',(fr+1)//2)\n    return '%02d:%02d:%02d:%02d'%(hh,mm,ss,fr)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: pair index', [3, 50], '00:00:00.01'), ('regression variant: pair index', [4147205, 48], '00:00:00.02'), ('partial repair probe: pair index', [216007, 60], '01:00:00.03'), ('partial repair variant: pair index', [-1, 50], '23:59:59.24'), ('boundary control', [0, 25], '00:00:00:00'), ('boundary control', [30, 30], '00:00:01:00'), ('normal control', [-1, 25], '23:59:59:24'), ('normal control', [1803, 30], '00:01:00:03'), ('normal control', [8166989, 30], '03:37:12:29')], [('regression: pair index', [2, 50], '00:00:00:01'), ('regression variant: pair index', [-5184003, 60], '23:59:59.28'), ('partial repair probe: pair index', [8640011, 50], '00:00:00.05'), ('partial repair variant: pair index', [49, 50], '00:00:00.24'), ('boundary control', [-1, 25], '23:59:59:24'), ('boundary control', [0, 25], '00:00:00:00'), ('normal control', [5184000, 60], '00:00:00:00'), ('normal control', [-4622105, 30], '05:12:09:25'), ('normal control', [2, 30], '00:00:00:02')], [('regression: pair index', [216007, 60], '01:00:00.03'), ('regression variant: pair index', [1, 48], '00:00:00.00'), ('partial repair probe: pair index', [3745221, 48], '21:40:25.10'), ('partial repair variant: pair index', [-4147203, 48], '23:59:59.22'), ('boundary control', [2160000, 25], '00:00:00:00'), ('boundary control', [-1, 25], '23:59:59:24'), ('normal control', [2592005, 30], '00:00:00:05'), ('normal control', [2592000, 30], '00:00:00:00'), ('normal control', [1, 25], '00:00:00:01')], [('regression: pair index', [8640011, 50], '00:00:00.05'), ('regression variant: pair index', [2, 48], '00:00:00:01'), ('partial repair probe: pair index', [4147205, 48], '00:00:00.02'), ('partial repair variant: pair index', [180007, 50], '01:00:00.03'), ('boundary control', [30, 30], '00:00:01:00'), ('boundary control', [2160000, 25], '00:00:00:00'), ('normal control', [48, 48], '00:00:01:00'), ('normal control', [2591999, 30], '23:59:59:29'), ('normal control', [2073605, 24], '00:00:00:05')], [('regression: pair index', [3745221, 48], '21:40:25.10'), ('regression variant: pair index', [-4147203, 48], '23:59:59.22'), ('partial repair probe: pair index', [4319999, 50], '23:59:59.24'), ('partial repair variant: pair index', [4320005, 50], '00:00:00.02'), ('boundary control', [0, 25], '00:00:00:00'), ('boundary control', [30, 30], '00:00:01:00'), ('normal control', [0, 48], '00:00:00:00'), ('normal control', [29, 30], '00:00:00:29'), ('normal control', [2, 25], '00:00:00:02')]]\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":"aa9e78120c16f2f0a59bc563641293b6474b3a3d6d600284a878a4aca1ebe22b","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(frames, fps):\n    day=24*3600*fps\n    frames%=day\n    fr=frames%fps\n    s=frames//fps\n    hh,mm,ss=s//3600,s//60%60,s%60\n    if fps>30:\n        return '%02d:%02d:%02d%s%02d'%(hh,mm,ss,'.' if fr%2 else ':',fr%(fps//2))\n    return '%02d:%02d:%02d:%02d'%(hh,mm,ss,fr)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: pair index', [3, 50], '00:00:00.01'), ('regression variant: pair index', [4147205, 48], '00:00:00.02'), ('partial repair probe: pair index', [216007, 60], '01:00:00.03'), ('partial repair variant: pair index', [-1, 50], '23:59:59.24'), ('boundary control', [0, 25], '00:00:00:00'), ('boundary control', [30, 30], '00:00:01:00'), ('normal control', [-1, 25], '23:59:59:24'), ('normal control', [1803, 30], '00:01:00:03'), ('normal control', [8166989, 30], '03:37:12:29')], [('regression: pair index', [2, 50], '00:00:00:01'), ('regression variant: pair index', [-5184003, 60], '23:59:59.28'), ('partial repair probe: pair index', [8640011, 50], '00:00:00.05'), ('partial repair variant: pair index', [49, 50], '00:00:00.24'), ('boundary control', [-1, 25], '23:59:59:24'), ('boundary control', [0, 25], '00:00:00:00'), ('normal control', [5184000, 60], '00:00:00:00'), ('normal control', [-4622105, 30], '05:12:09:25'), ('normal control', [2, 30], '00:00:00:02')], [('regression: pair index', [216007, 60], '01:00:00.03'), ('regression variant: pair index', [1, 48], '00:00:00.00'), ('partial repair probe: pair index', [3745221, 48], '21:40:25.10'), ('partial repair variant: pair index', [-4147203, 48], '23:59:59.22'), ('boundary control', [2160000, 25], '00:00:00:00'), ('boundary control', [-1, 25], '23:59:59:24'), ('normal control', [2592005, 30], '00:00:00:05'), ('normal control', [2592000, 30], '00:00:00:00'), ('normal control', [1, 25], '00:00:00:01')], [('regression: pair index', [8640011, 50], '00:00:00.05'), ('regression variant: pair index', [2, 48], '00:00:00:01'), ('partial repair probe: pair index', [4147205, 48], '00:00:00.02'), ('partial repair variant: pair index', [180007, 50], '01:00:00.03'), ('boundary control', [30, 30], '00:00:01:00'), ('boundary control', [2160000, 25], '00:00:00:00'), ('normal control', [48, 48], '00:00:01:00'), ('normal control', [2591999, 30], '23:59:59:29'), ('normal control', [2073605, 24], '00:00:00:05')], [('regression: pair index', [3745221, 48], '21:40:25.10'), ('regression variant: pair index', [-4147203, 48], '23:59:59.22'), ('partial repair probe: pair index', [4319999, 50], '23:59:59.24'), ('partial repair variant: pair index', [4320005, 50], '00:00:00.02'), ('boundary control', [0, 25], '00:00:00:00'), ('boundary control', [30, 30], '00:00:01:00'), ('normal control', [0, 48], '00:00:00:00'), ('normal control', [29, 30], '00:00:00:29'), ('normal control', [2, 25], '00:00:00:02')]]\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-frames-to-label-pair-index","generated_at":"2026-09-29T14:49:34.690763+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.","root_cause":"The pair index wraps modulo half the rate instead of halving the frame.","sha256":"3283c6052d5b9e0cf617f02ba679b9c233e79ce7b20a9826fa83770a2100c6bc","title":"Frame count to timecode label with frame pairs: pair index · 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":40.398,"exit_code":1,"observations":[{"actual":"00:00:00.02","check":"regression: pair index","expected":"00:00:00.01","passed":false},{"actual":"00:00:00.03","check":"regression variant: pair index","expected":"00:00:00.02","passed":false},{"actual":"01:00:00.04","check":"partial repair probe: pair index","expected":"01:00:00.03","passed":false},{"actual":"23:59:59.25","check":"partial repair variant: pair index","expected":"23:59:59.24","passed":false},{"actual":"00:00:00:00","check":"boundary control","expected":"00:00:00:00","passed":true},{"actual":"00:00:01:00","check":"boundary control","expected":"00:00:01:00","passed":true},{"actual":"23:59:59:24","check":"normal control","expected":"23:59:59:24","passed":true},{"actual":"00:01:00:03","check":"normal control","expected":"00:01:00:03","passed":true},{"actual":"03:37:12:29","check":"normal control","expected":"03:37:12:29","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: pair index\", \"actual\": \"00:00:00.02\", \"expected\": \"00:00:00.01\", \"passed\": false}, {\"check\": \"regression variant: pair index\", \"actual\": \"00:00:00.03\", \"expected\": \"00:00:00.02\", \"passed\": false}, {\"check\": \"partial repair probe: pair index\", \"actual\": \"01:00:00.04\", \"expected\": \"01:00:00.03\", \"passed\": false}, {\"check\": \"partial repair variant: pair index\", \"actual\": \"23:59:59.25\", \"expected\": \"23:59:59.24\", \"passed\": false}, {\"check\": \"boundary control\", \"actual\": \"00:00:00:00\", \"expected\": \"00:00:00:00\", \"passed\": true}, {\"check\": \"boundary control\", \"actual\": \"00:00:01:00\", \"expected\": \"00:00:01:00\", \"passed\": true}, {\"check\": \"normal control\", \"actual\": \"23:59:59:24\", \"expected\": \"23:59:59:24\", \"passed\": true}, {\"check\": \"normal control\", \"actual\": \"00:01:00:03\", \"expected\": \"00:01:00:03\", \"passed\": true}, {\"check\": \"normal control\", \"actual\": \"03:37:12:29\", \"expected\": \"03:37:12:29\", \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.634,"exit_code":1,"observations":[{"actual":"00:00:00.03","check":"regression: pair index","expected":"00:00:00.01","passed":false},{"actual":"00:00:00.05","check":"regression variant: pair index","expected":"00:00:00.02","passed":false},{"actual":"01:00:00.07","check":"partial repair probe: pair index","expected":"01:00:00.03","passed":false},{"actual":"23:59:59.24","check":"partial repair variant: pair index","expected":"23:59:59.24","passed":true},{"actual":"00:00:00:00","check":"boundary control","expected":"00:00:00:00","passed":true},{"actual":"00:00:01:00","check":"boundary control","expected":"00:00:01:00","passed":true},{"actual":"23:59:59:24","check":"normal control","expected":"23:59:59:24","passed":true},{"actual":"00:01:00:03","check":"normal control","expected":"00:01:00:03","passed":true},{"actual":"03:37:12:29","check":"normal control","expected":"03:37:12:29","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: pair index\", \"actual\": \"00:00:00.03\", \"expected\": \"00:00:00.01\", \"passed\": false}, {\"check\": \"regression variant: pair index\", \"actual\": \"00:00:00.05\", \"expected\": \"00:00:00.02\", \"passed\": false}, {\"check\": \"partial repair probe: pair index\", \"actual\": \"01:00:00.07\", \"expected\": \"01:00:00.03\", \"passed\": false}, {\"check\": \"partial repair variant: pair index\", \"actual\": \"23:59:59.24\", \"expected\": \"23:59:59.24\", \"passed\": true}, {\"check\": \"boundary control\", \"actual\": \"00:00:00:00\", \"expected\": \"00:00:00:00\", \"passed\": true}, {\"check\": \"boundary control\", \"actual\": \"00:00:01:00\", \"expected\": \"00:00:01:00\", \"passed\": true}, {\"check\": \"normal control\", \"actual\": \"23:59:59:24\", \"expected\": \"23:59:59:24\", \"passed\": true}, {\"check\": \"normal control\", \"actual\": \"00:01:00:03\", \"expected\": \"00:01:00:03\", \"passed\": true}, {\"check\": \"normal control\", \"actual\": \"03:37:12:29\", \"expected\": \"03:37:12:29\", \"passed\": true}], \"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."}}