{"abstract":"Decoded preroll frames before the seek target are shown to the viewer.","category":"Media timeline seeking","checks":4,"contract":"After decoding from a preceding keyframe, suppress presentation frames [PTS,payload] before target while retaining an exact-target frame.","contract_signature":"frames, target","evaluation_group":"xmed-seek-discard-preroll-presentation","failed_approach":"Strict suppression also discards the exact requested presentation timestamp.","family":"xmed-seek-discard-preroll-presentation","id":"FA-11216","implementations":{"attempt":{"sha256":"446d5df28753aa44d150a9bfdf1e3b3acf787ec2f815e5b815421d26c9f18bbc","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(frames, target):\n    return [f for f in frames if f[0]>target]\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']], 10)),[[10, 'b'], [12, 'c']])\ncheck('fixture 2',solve(*([[1, 'a']], 0)),[[1, 'a']])\ncheck('fixture 3',solve(*([[1, 'a']], 2)),[])\ncheck('fixture 4',solve(*([], 0)),[])\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":"f218200091fdc1e76be1eb9a9a58200a529cac4d5931dadee57ac3a82881fe51","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(frames, target):\n    return list(frames)\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']], 10)),[[10, 'b'], [12, 'c']])\ncheck('fixture 2',solve(*([[1, 'a']], 0)),[[1, 'a']])\ncheck('fixture 3',solve(*([[1, 'a']], 2)),[])\ncheck('fixture 4',solve(*([], 0)),[])\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-seek-discard-preroll-presentation","generated_at":"2026-09-29T14:38:46.021499+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":"Decoded preroll frames before the seek target are shown to the viewer.","sha256":"4e77710fff60ececbdcbe49b14d056969b4cbf8a0b8805c1695a480d31afbd20","title":"Seek discard preroll presentation · 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":38.085,"exit_code":1,"observations":[{"actual":[[12,"c"]],"check":"fixture 1","expected":[[10,"b"],[12,"c"]],"passed":false},{"actual":[[1,"a"]],"check":"fixture 2","expected":[[1,"a"]],"passed":true},{"actual":[],"check":"fixture 3","expected":[],"passed":true},{"actual":[],"check":"fixture 4","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [[12, \"c\"]], \"expected\": [[10, \"b\"], [12, \"c\"]], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [[1, \"a\"]], \"expected\": [[1, \"a\"]], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.906,"exit_code":1,"observations":[{"actual":[[8,"a"],[10,"b"],[12,"c"]],"check":"fixture 1","expected":[[10,"b"],[12,"c"]],"passed":false},{"actual":[[1,"a"]],"check":"fixture 2","expected":[[1,"a"]],"passed":true},{"actual":[[1,"a"]],"check":"fixture 3","expected":[],"passed":false},{"actual":[],"check":"fixture 4","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [[8, \"a\"], [10, \"b\"], [12, \"c\"]], \"expected\": [[10, \"b\"], [12, \"c\"]], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [[1, \"a\"]], \"expected\": [[1, \"a\"]], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [[1, \"a\"]], \"expected\": [], \"passed\": false}, {\"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."}}