{"abstract":"Decoded B-frames are displayed in decode order instead of presentation order.","category":"Media timeline seeking","checks":4,"contract":"Frames are [decode timestamp,presentation timestamp,payload]. Return stable presentation order, retaining input order for equal presentation timestamps.","evaluation_group":"xmed-presentation-order-distinct-from-decode","failed_approach":"Sorting decode timestamps explicitly preserves the wrong temporal order.","family":"xmed-presentation-order-distinct-from-decode","id":"FA-11206","implementations":{"attempt":{"sha256":"1345cc4cb6d1d14634d6a7cfedcf5180ebece535c119076e80c5b85215a7b2f4","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(frames):\n    return sorted(frames,key=lambda f:f[0])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([[0, 0, 'I'], [1, 2, 'P'], [2, 1, 'B']],)),[[0, 0, 'I'], [2, 1, 'B'], [1, 2, 'P']])\ncheck('fixture 2',solve(*([],)),[])\ncheck('fixture 3',solve(*([[2, 0, 'a'], [1, 0, 'b']],)),[[2, 0, 'a'], [1, 0, 'b']])\ncheck('fixture 4',solve(*([[0, 1, 'a']],)),[[0, 1, 'a']])\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":"9165d3187cd57f856d77719ddf599011dee539e208ce1f4f54161114e49ad06f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(frames):\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(*([[0, 0, 'I'], [1, 2, 'P'], [2, 1, 'B']],)),[[0, 0, 'I'], [2, 1, 'B'], [1, 2, 'P']])\ncheck('fixture 2',solve(*([],)),[])\ncheck('fixture 3',solve(*([[2, 0, 'a'], [1, 0, 'b']],)),[[2, 0, 'a'], [1, 0, 'b']])\ncheck('fixture 4',solve(*([[0, 1, 'a']],)),[[0, 1, 'a']])\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":"a4135958fcff2f968434bc00ab2fe84cbbff02fc7ec9fbec3f5d19900b02d0c2","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(frames):\n    return sorted(frames,key=lambda f:f[1])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1',solve(*([[0, 0, 'I'], [1, 2, 'P'], [2, 1, 'B']],)),[[0, 0, 'I'], [2, 1, 'B'], [1, 2, 'P']])\ncheck('fixture 2',solve(*([],)),[])\ncheck('fixture 3',solve(*([[2, 0, 'a'], [1, 0, 'b']],)),[[2, 0, 'a'], [1, 0, 'b']])\ncheck('fixture 4',solve(*([[0, 1, 'a']],)),[[0, 1, 'a']])\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-presentation-order-distinct-from-decode","generated_at":"2026-09-29T14:38:45.939253+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.","repair":"Preserve the media contract: Frames are [decode timestamp,presentation timestamp,payload]. Return stable presentation order, retaining input order for equal presentation timestamps.","root_cause":"Decoded B-frames are displayed in decode order instead of presentation order.","sha256":"9ae2e3a17a5c7fe7ddf6232aaf0afef514f657ad62b04c65716d17dade8c3ea9","title":"Presentation order distinct from decode · case 01","variant":1,"variant_policy":"The five numbered cases rerun the same authored boundary fixtures; they are reproducibility runs, not independent input variants.","verification":{"attempt":{"elapsed_ms":41.645,"exit_code":1,"observations":[{"actual":[[0,0,"I"],[1,2,"P"],[2,1,"B"]],"check":"fixture 1","expected":[[0,0,"I"],[2,1,"B"],[1,2,"P"]],"passed":false},{"actual":[],"check":"fixture 2","expected":[],"passed":true},{"actual":[[1,0,"b"],[2,0,"a"]],"check":"fixture 3","expected":[[2,0,"a"],[1,0,"b"]],"passed":false},{"actual":[[0,1,"a"]],"check":"fixture 4","expected":[[0,1,"a"]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [[0, 0, \"I\"], [1, 2, \"P\"], [2, 1, \"B\"]], \"expected\": [[0, 0, \"I\"], [2, 1, \"B\"], [1, 2, \"P\"]], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [[1, 0, \"b\"], [2, 0, \"a\"]], \"expected\": [[2, 0, \"a\"], [1, 0, \"b\"]], \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": [[0, 1, \"a\"]], \"expected\": [[0, 1, \"a\"]], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.327,"exit_code":1,"observations":[{"actual":[[0,0,"I"],[1,2,"P"],[2,1,"B"]],"check":"fixture 1","expected":[[0,0,"I"],[2,1,"B"],[1,2,"P"]],"passed":false},{"actual":[],"check":"fixture 2","expected":[],"passed":true},{"actual":[[2,0,"a"],[1,0,"b"]],"check":"fixture 3","expected":[[2,0,"a"],[1,0,"b"]],"passed":true},{"actual":[[0,1,"a"]],"check":"fixture 4","expected":[[0,1,"a"]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [[0, 0, \"I\"], [1, 2, \"P\"], [2, 1, \"B\"]], \"expected\": [[0, 0, \"I\"], [2, 1, \"B\"], [1, 2, \"P\"]], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [[2, 0, \"a\"], [1, 0, \"b\"]], \"expected\": [[2, 0, \"a\"], [1, 0, \"b\"]], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [[0, 1, \"a\"]], \"expected\": [[0, 1, \"a\"]], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":38.907,"exit_code":0,"observations":[{"actual":[[0,0,"I"],[2,1,"B"],[1,2,"P"]],"check":"fixture 1","expected":[[0,0,"I"],[2,1,"B"],[1,2,"P"]],"passed":true},{"actual":[],"check":"fixture 2","expected":[],"passed":true},{"actual":[[2,0,"a"],[1,0,"b"]],"check":"fixture 3","expected":[[2,0,"a"],[1,0,"b"]],"passed":true},{"actual":[[0,1,"a"]],"check":"fixture 4","expected":[[0,1,"a"]],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [[0, 0, \"I\"], [2, 1, \"B\"], [1, 2, \"P\"]], \"expected\": [[0, 0, \"I\"], [2, 1, \"B\"], [1, 2, \"P\"]], \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [[2, 0, \"a\"], [1, 0, \"b\"]], \"expected\": [[2, 0, \"a\"], [1, 0, \"b\"]], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [[0, 1, \"a\"]], \"expected\": [[0, 1, \"a\"]], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}