{"abstract":"Trimmed media retains source timestamps instead of beginning at the trim-relative timeline.","category":"Media timeline seeking","checks":4,"contract":"Select frames whose presentation starts lie in half-open trim interval and rebase their timestamps by subtracting trim start.","contract_signature":"frames, start, end","evaluation_group":"xmed-media-trim-rebases-timestamps","failed_approach":"Inclusive ending timestamps retain the first frame belonging to the next clip.","family":"xmed-media-trim-rebases-timestamps","id":"FA-11256","implementations":{"attempt":{"sha256":"73b04697f7c5b98700f509b5514de6d8b87771ebcce19c5327ee282e1fde5809","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(frames, start, end):\n    return [[t-start,payload] for t,payload in frames if start<=t<=end]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([[8, 'a'], [10, 'b'], [12, 'c'], [14, 'd']], 10, 14)),[[0, 'b'], [2, 'c']])\ncheck('fixture 2',solve(*([[5, 'a']], 5, 6)),[[0, 'a']])\ncheck('fixture 3',solve(*([], 0, 1)),[])\ncheck('fixture 4',solve(*([[1, 'a']], 1, 1)),[])\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":"7ff5de57997c331be915324fed6953477b31783510d7993d2bfa0f4b54d19c57","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(frames, start, end):\n    return [[t,payload] for t,payload in frames if start<=t<end]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([[8, 'a'], [10, 'b'], [12, 'c'], [14, 'd']], 10, 14)),[[0, 'b'], [2, 'c']])\ncheck('fixture 2',solve(*([[5, 'a']], 5, 6)),[[0, 'a']])\ncheck('fixture 3',solve(*([], 0, 1)),[])\ncheck('fixture 4',solve(*([[1, 'a']], 1, 1)),[])\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":" 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":"xmed-media-trim-rebases-timestamps","generated_at":"2026-09-29T14:38:46.260954+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic local media controller stage; metadata and downloaded data are supplied explicitly. No external player, service or codec is required.","root_cause":"Trimmed media retains source timestamps instead of beginning at the trim-relative timeline.","sha256":"b80111302678d19193aa6f81ad86ef49efacbef0260750d3f1ac75172f1e9748","title":"Media trim rebases timestamps · case 01","variant":1,"variant_policy":"The five numbered cases rerun the same authored boundary fixtures; they are reproducibility runs, not independent input variants.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":39.167,"exit_code":1,"observations":[{"actual":[[0,"b"],[2,"c"],[4,"d"]],"check":"fixture 1","expected":[[0,"b"],[2,"c"]],"passed":false},{"actual":[[0,"a"]],"check":"fixture 2","expected":[[0,"a"]],"passed":true},{"actual":[],"check":"fixture 3","expected":[],"passed":true},{"actual":[[0,"a"]],"check":"fixture 4","expected":[],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [[0, \"b\"], [2, \"c\"], [4, \"d\"]], \"expected\": [[0, \"b\"], [2, \"c\"]], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [[0, \"a\"]], \"expected\": [[0, \"a\"]], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [[0, \"a\"]], \"expected\": [], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.58,"exit_code":1,"observations":[{"actual":[[10,"b"],[12,"c"]],"check":"fixture 1","expected":[[0,"b"],[2,"c"]],"passed":false},{"actual":[[5,"a"]],"check":"fixture 2","expected":[[0,"a"]],"passed":false},{"actual":[],"check":"fixture 3","expected":[],"passed":true},{"actual":[],"check":"fixture 4","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [[10, \"b\"], [12, \"c\"]], \"expected\": [[0, \"b\"], [2, \"c\"]], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [[5, \"a\"]], \"expected\": [[0, \"a\"]], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [], \"expected\": [], \"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."}}