{"abstract":"PCM packet boundaries disappear when residual frames are flattened.","category":"PCM sample encoding","checks":8,"contract":"Encode frame-major PCM residuals with independent per-channel amplitude predictors and frame-index resets; preserve residual frame shape.","evaluation_group":"s3-pcm-pcm-channel-predictor","failed_approach":"Appending predictor levels emits amplitudes rather than residual fields.","family":"s3-pcm-pcm-channel-predictor-residual-shape","id":"FA-49356","implementations":{"attempt":{"sha256":"17369e53a1871a0546d710b19008af5a5d7ea3fafd7f96f1d010563750013ce1","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(frames, seeds, resets):\n    state=list(seeds)\n    out=[]\n    for index,frame in enumerate(frames):\n        if index in resets:\n            state=list(seeds)\n        residual=[]\n        for channel,sample in enumerate(frame):\n            residual.append(sample-state[channel])\n            state[channel]=sample\n        out.append(list(state))\n    return [out,state]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([[5, 10], [7, 9]], [2, 8], [])), [[[3, 2], [2, -1]], [7, 9]])\ncheck('oracle 2', solve(*([[2, 4], [3, 8], [7, 9]], [1, 2], [1])), [[[1, 2], [2, 6], [4, 1]], [7, 9]])\ncheck('oracle 3', solve(*([], [3, 4], [])), [[], [3, 4]])\ncheck('oracle 4', solve(*([[1], [3], [2]], [0], [2])), [[[1], [2], [2]], [2]])\ncheck('oracle 5', solve(*([[-2, 3], [0, 1]], [-1, 4], [])), [[[-1, -1], [2, -2]], [0, 1]])\ncheck('oracle 6', solve(*([[1, 2, 3]], [3, 2, 1], [0])), [[[-2, 0, 2]], [1, 2, 3]])\ncheck('oracle 7', solve(*([[0, 0], [0, 0]], [1, -1], [])), [[[-1, 1], [0, 0]], [0, 0]])\nif N == 1: check('variant packet 1', solve(*[[[5, 10], [7, 9], [5, 10], [7, 9]], [2, 8], []]), [[[3, 2], [2, -1], [-2, 1], [2, -1]], [7, 9]])\nif N == 2: check('variant packet 2', solve(*[[[5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9]], [2, 8], []]), [[[3, 2], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1]], [7, 9]])\nif N == 3: check('variant packet 3', solve(*[[[5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9]], [2, 8], []]), [[[3, 2], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1]], [7, 9]])\nif N == 4: check('variant packet 4', solve(*[[[5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9]], [2, 8], []]), [[[3, 2], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1]], [7, 9]])\nif N == 5: check('variant packet 5', solve(*[[[5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9]], [2, 8], []]), [[[3, 2], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1]], [7, 9]])\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":"de494612b4f07b9e1683eb6b24a93e476a663b7f98f8747abaf7d1c08ae80358","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(frames, seeds, resets):\n    state=list(seeds)\n    out=[]\n    for index,frame in enumerate(frames):\n        if index in resets:\n            state=list(seeds)\n        residual=[]\n        for channel,sample in enumerate(frame):\n            residual.append(sample-state[channel])\n            state[channel]=sample\n        out.extend(residual)\n    return [out,state]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([[5, 10], [7, 9]], [2, 8], [])), [[[3, 2], [2, -1]], [7, 9]])\ncheck('oracle 2', solve(*([[2, 4], [3, 8], [7, 9]], [1, 2], [1])), [[[1, 2], [2, 6], [4, 1]], [7, 9]])\ncheck('oracle 3', solve(*([], [3, 4], [])), [[], [3, 4]])\ncheck('oracle 4', solve(*([[1], [3], [2]], [0], [2])), [[[1], [2], [2]], [2]])\ncheck('oracle 5', solve(*([[-2, 3], [0, 1]], [-1, 4], [])), [[[-1, -1], [2, -2]], [0, 1]])\ncheck('oracle 6', solve(*([[1, 2, 3]], [3, 2, 1], [0])), [[[-2, 0, 2]], [1, 2, 3]])\ncheck('oracle 7', solve(*([[0, 0], [0, 0]], [1, -1], [])), [[[-1, 1], [0, 0]], [0, 0]])\nif N == 1: check('variant packet 1', solve(*[[[5, 10], [7, 9], [5, 10], [7, 9]], [2, 8], []]), [[[3, 2], [2, -1], [-2, 1], [2, -1]], [7, 9]])\nif N == 2: check('variant packet 2', solve(*[[[5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9]], [2, 8], []]), [[[3, 2], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1]], [7, 9]])\nif N == 3: check('variant packet 3', solve(*[[[5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9]], [2, 8], []]), [[[3, 2], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1]], [7, 9]])\nif N == 4: check('variant packet 4', solve(*[[[5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9]], [2, 8], []]), [[[3, 2], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1]], [7, 9]])\nif N == 5: check('variant packet 5', solve(*[[[5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9]], [2, 8], []]), [[[3, 2], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1]], [7, 9]])\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":"50d3cb87f732a5b90400db4699553dde86c336ef316bec10605a966ab1197203","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(frames, seeds, resets):\n    state=list(seeds)\n    out=[]\n    for index,frame in enumerate(frames):\n        if index in resets:\n            state=list(seeds)\n        residual=[]\n        for channel,sample in enumerate(frame):\n            residual.append(sample-state[channel])\n            state[channel]=sample\n        out.append(residual)\n    return [out,state]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('oracle 1', solve(*([[5, 10], [7, 9]], [2, 8], [])), [[[3, 2], [2, -1]], [7, 9]])\ncheck('oracle 2', solve(*([[2, 4], [3, 8], [7, 9]], [1, 2], [1])), [[[1, 2], [2, 6], [4, 1]], [7, 9]])\ncheck('oracle 3', solve(*([], [3, 4], [])), [[], [3, 4]])\ncheck('oracle 4', solve(*([[1], [3], [2]], [0], [2])), [[[1], [2], [2]], [2]])\ncheck('oracle 5', solve(*([[-2, 3], [0, 1]], [-1, 4], [])), [[[-1, -1], [2, -2]], [0, 1]])\ncheck('oracle 6', solve(*([[1, 2, 3]], [3, 2, 1], [0])), [[[-2, 0, 2]], [1, 2, 3]])\ncheck('oracle 7', solve(*([[0, 0], [0, 0]], [1, -1], [])), [[[-1, 1], [0, 0]], [0, 0]])\nif N == 1: check('variant packet 1', solve(*[[[5, 10], [7, 9], [5, 10], [7, 9]], [2, 8], []]), [[[3, 2], [2, -1], [-2, 1], [2, -1]], [7, 9]])\nif N == 2: check('variant packet 2', solve(*[[[5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9]], [2, 8], []]), [[[3, 2], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1]], [7, 9]])\nif N == 3: check('variant packet 3', solve(*[[[5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9]], [2, 8], []]), [[[3, 2], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1]], [7, 9]])\nif N == 4: check('variant packet 4', solve(*[[[5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9]], [2, 8], []]), [[[3, 2], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1]], [7, 9]])\nif N == 5: check('variant packet 5', solve(*[[[5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9], [5, 10], [7, 9]], [2, 8], []]), [[[3, 2], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1], [-2, 1], [2, -1]], [7, 9]])\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":"Stipulated finite model; no claim of hardware timing or full file-format conformance. 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":"s3-pcm-pcm-channel-predictor-residual-shape","generated_at":"2026-09-29T14:44:59.249457+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Offline PCM interchange uses these exact bounded packet and sample representation decisions.","repair":"Use the stated conversion contract at residual shape.","root_cause":"PCM packet boundaries disappear when residual frames are flattened.","sha256":"77b20ca67bc02d07790f76470929348c6267a357a279a22286977b0e511f88e5","title":"Pcm channel predictor: residual shape · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":42.071,"exit_code":1,"observations":[{"actual":[[[5,10],[7,9]],[7,9]],"check":"oracle 1","expected":[[[3,2],[2,-1]],[7,9]],"passed":false},{"actual":[[[2,4],[3,8],[7,9]],[7,9]],"check":"oracle 2","expected":[[[1,2],[2,6],[4,1]],[7,9]],"passed":false},{"actual":[[],[3,4]],"check":"oracle 3","expected":[[],[3,4]],"passed":true},{"actual":[[[1],[3],[2]],[2]],"check":"oracle 4","expected":[[[1],[2],[2]],[2]],"passed":false},{"actual":[[[-2,3],[0,1]],[0,1]],"check":"oracle 5","expected":[[[-1,-1],[2,-2]],[0,1]],"passed":false},{"actual":[[[1,2,3]],[1,2,3]],"check":"oracle 6","expected":[[[-2,0,2]],[1,2,3]],"passed":false},{"actual":[[[0,0],[0,0]],[0,0]],"check":"oracle 7","expected":[[[-1,1],[0,0]],[0,0]],"passed":false},{"actual":[[[5,10],[7,9],[5,10],[7,9]],[7,9]],"check":"variant packet 1","expected":[[[3,2],[2,-1],[-2,1],[2,-1]],[7,9]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[[5, 10], [7, 9]], [7, 9]], \"expected\": [[[3, 2], [2, -1]], [7, 9]], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[[2, 4], [3, 8], [7, 9]], [7, 9]], \"expected\": [[[1, 2], [2, 6], [4, 1]], [7, 9]], \"passed\": false}, {\"check\": \"oracle 3\", \"actual\": [[], [3, 4]], \"expected\": [[], [3, 4]], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [[[1], [3], [2]], [2]], \"expected\": [[[1], [2], [2]], [2]], \"passed\": false}, {\"check\": \"oracle 5\", \"actual\": [[[-2, 3], [0, 1]], [0, 1]], \"expected\": [[[-1, -1], [2, -2]], [0, 1]], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [[[1, 2, 3]], [1, 2, 3]], \"expected\": [[[-2, 0, 2]], [1, 2, 3]], \"passed\": false}, {\"check\": \"oracle 7\", \"actual\": [[[0, 0], [0, 0]], [0, 0]], \"expected\": [[[-1, 1], [0, 0]], [0, 0]], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [[[5, 10], [7, 9], [5, 10], [7, 9]], [7, 9]], \"expected\": [[[3, 2], [2, -1], [-2, 1], [2, -1]], [7, 9]], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":42.471,"exit_code":1,"observations":[{"actual":[[3,2,2,-1],[7,9]],"check":"oracle 1","expected":[[[3,2],[2,-1]],[7,9]],"passed":false},{"actual":[[1,2,2,6,4,1],[7,9]],"check":"oracle 2","expected":[[[1,2],[2,6],[4,1]],[7,9]],"passed":false},{"actual":[[],[3,4]],"check":"oracle 3","expected":[[],[3,4]],"passed":true},{"actual":[[1,2,2],[2]],"check":"oracle 4","expected":[[[1],[2],[2]],[2]],"passed":false},{"actual":[[-1,-1,2,-2],[0,1]],"check":"oracle 5","expected":[[[-1,-1],[2,-2]],[0,1]],"passed":false},{"actual":[[-2,0,2],[1,2,3]],"check":"oracle 6","expected":[[[-2,0,2]],[1,2,3]],"passed":false},{"actual":[[-1,1,0,0],[0,0]],"check":"oracle 7","expected":[[[-1,1],[0,0]],[0,0]],"passed":false},{"actual":[[3,2,2,-1,-2,1,2,-1],[7,9]],"check":"variant packet 1","expected":[[[3,2],[2,-1],[-2,1],[2,-1]],[7,9]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[3, 2, 2, -1], [7, 9]], \"expected\": [[[3, 2], [2, -1]], [7, 9]], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [[1, 2, 2, 6, 4, 1], [7, 9]], \"expected\": [[[1, 2], [2, 6], [4, 1]], [7, 9]], \"passed\": false}, {\"check\": \"oracle 3\", \"actual\": [[], [3, 4]], \"expected\": [[], [3, 4]], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [[1, 2, 2], [2]], \"expected\": [[[1], [2], [2]], [2]], \"passed\": false}, {\"check\": \"oracle 5\", \"actual\": [[-1, -1, 2, -2], [0, 1]], \"expected\": [[[-1, -1], [2, -2]], [0, 1]], \"passed\": false}, {\"check\": \"oracle 6\", \"actual\": [[-2, 0, 2], [1, 2, 3]], \"expected\": [[[-2, 0, 2]], [1, 2, 3]], \"passed\": false}, {\"check\": \"oracle 7\", \"actual\": [[-1, 1, 0, 0], [0, 0]], \"expected\": [[[-1, 1], [0, 0]], [0, 0]], \"passed\": false}, {\"check\": \"variant packet 1\", \"actual\": [[3, 2, 2, -1, -2, 1, 2, -1], [7, 9]], \"expected\": [[[3, 2], [2, -1], [-2, 1], [2, -1]], [7, 9]], \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":40.716,"exit_code":0,"observations":[{"actual":[[[3,2],[2,-1]],[7,9]],"check":"oracle 1","expected":[[[3,2],[2,-1]],[7,9]],"passed":true},{"actual":[[[1,2],[2,6],[4,1]],[7,9]],"check":"oracle 2","expected":[[[1,2],[2,6],[4,1]],[7,9]],"passed":true},{"actual":[[],[3,4]],"check":"oracle 3","expected":[[],[3,4]],"passed":true},{"actual":[[[1],[2],[2]],[2]],"check":"oracle 4","expected":[[[1],[2],[2]],[2]],"passed":true},{"actual":[[[-1,-1],[2,-2]],[0,1]],"check":"oracle 5","expected":[[[-1,-1],[2,-2]],[0,1]],"passed":true},{"actual":[[[-2,0,2]],[1,2,3]],"check":"oracle 6","expected":[[[-2,0,2]],[1,2,3]],"passed":true},{"actual":[[[-1,1],[0,0]],[0,0]],"check":"oracle 7","expected":[[[-1,1],[0,0]],[0,0]],"passed":true},{"actual":[[[3,2],[2,-1],[-2,1],[2,-1]],[7,9]],"check":"variant packet 1","expected":[[[3,2],[2,-1],[-2,1],[2,-1]],[7,9]],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 1\", \"actual\": [[[3, 2], [2, -1]], [7, 9]], \"expected\": [[[3, 2], [2, -1]], [7, 9]], \"passed\": true}, {\"check\": \"oracle 2\", \"actual\": [[[1, 2], [2, 6], [4, 1]], [7, 9]], \"expected\": [[[1, 2], [2, 6], [4, 1]], [7, 9]], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [[], [3, 4]], \"expected\": [[], [3, 4]], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [[[1], [2], [2]], [2]], \"expected\": [[[1], [2], [2]], [2]], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [[[-1, -1], [2, -2]], [0, 1]], \"expected\": [[[-1, -1], [2, -2]], [0, 1]], \"passed\": true}, {\"check\": \"oracle 6\", \"actual\": [[[-2, 0, 2]], [1, 2, 3]], \"expected\": [[[-2, 0, 2]], [1, 2, 3]], \"passed\": true}, {\"check\": \"oracle 7\", \"actual\": [[[-1, 1], [0, 0]], [0, 0]], \"expected\": [[[-1, 1], [0, 0]], [0, 0]], \"passed\": true}, {\"check\": \"variant packet 1\", \"actual\": [[[3, 2], [2, -1], [-2, 1], [2, -1]], [7, 9]], \"expected\": [[[3, 2], [2, -1], [-2, 1], [2, -1]], [7, 9]], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}