{
  "release": "CTR-1",
  "format": {
    "container": "MP4",
    "codec": "H.264",
    "pixel_format": "yuv420p",
    "audio": false,
    "width": 640,
    "height": 360,
    "fps": 10,
    "frames_per_clip": 40,
    "duration_seconds": 4
  },
  "frame_origin": 0,
  "interval_convention": "[start_frame,end_frame_exclusive); t in seconds = frame / 10",
  "encoder": "ffmpeg version 8.0 Copyright (c) 2000-2025 the FFmpeg developers",
  "cases": [
    {
      "id": "C01",
      "file": "media/C01.mp4",
      "sha256": "b5c516edbee1650cda4e120aa7d3dd58388cb2bf45aece305df4c1f7617af687",
      "title": "Empty divider",
      "group": "synthetic control",
      "family": "control-1",
      "provenance": "Procedural RGB frames from this script. No camera capture or generative model.",
      "annotations": [],
      "task": "Expect a constant frame throughout.",
      "label_basis": "construction",
      "license": "https://creativecommons.org/publicdomain/zero/1.0/"
    },
    {
      "id": "C02",
      "file": "media/C02.mp4",
      "sha256": "1541f2ec38c7770cb163f3ee16409da9e284a99e6bfd30fddd99a1510e6ceee6",
      "title": "Divider crossing",
      "group": "synthetic control",
      "family": "control-2",
      "provenance": "Procedural RGB frames from this script. No camera capture or generative model.",
      "annotations": [
        {
          "label": "left edge at or right of x=320",
          "start_frame": 24,
          "end_frame_exclusive": 40
        }
      ],
      "task": "Follow the amber square across the center line.",
      "label_basis": "construction",
      "license": "https://creativecommons.org/publicdomain/zero/1.0/"
    },
    {
      "id": "C03",
      "file": "media/C03.mp4",
      "sha256": "000ca1d75c6b4c04738ca1b93fdc87386ee7c7505b7b00a9e2ee11c99e8225a7",
      "title": "Two-second hold",
      "group": "synthetic control",
      "family": "control-3",
      "provenance": "Procedural RGB frames from this script. No camera capture or generative model.",
      "annotations": [
        {
          "label": "cyan rectangle visible",
          "start_frame": 10,
          "end_frame_exclusive": 30
        }
      ],
      "task": "Check the inclusive onset and exclusive release frame.",
      "label_basis": "construction",
      "license": "https://creativecommons.org/publicdomain/zero/1.0/"
    },
    {
      "id": "C04",
      "file": "media/C04.mp4",
      "sha256": "b1a0c5fd4d5f7e7b0d345ee8fe38374ebd49db80e79c0f1001ad9f624fcbd541",
      "title": "Repeat pulse",
      "group": "synthetic control",
      "family": "control-4",
      "provenance": "Procedural RGB frames from this script. No camera capture or generative model.",
      "annotations": [
        {
          "label": "square visible",
          "start_frame": 5,
          "end_frame_exclusive": 12
        },
        {
          "label": "square visible",
          "start_frame": 22,
          "end_frame_exclusive": 29
        }
      ],
      "task": "Two appearances separated by ten empty frames.",
      "label_basis": "construction",
      "license": "https://creativecommons.org/publicdomain/zero/1.0/"
    },
    {
      "id": "C05",
      "file": "media/C05.mp4",
      "sha256": "023d1d82ea9a49ee11cfe55ff1d07185f095a5fca3e1f178e6a87a62b055d45a",
      "title": "Overlapping paths",
      "group": "synthetic control",
      "family": "control-5",
      "provenance": "Procedural RGB frames from this script. No camera capture or generative model.",
      "annotations": [
        {
          "label": "rectangles overlap",
          "start_frame": 16,
          "end_frame_exclusive": 27
        }
      ],
      "task": "Separate two colored tracks through partial occlusion.",
      "label_basis": "construction",
      "license": "https://creativecommons.org/publicdomain/zero/1.0/"
    },
    {
      "id": "C06",
      "file": "media/C06.mp4",
      "sha256": "16d23332a454a3c2dd1a78a536b98a2fe882486ca8ab8c46781d8a7ef9dfe3a9",
      "title": "Luminance step",
      "group": "synthetic control",
      "family": "control-6",
      "provenance": "Procedural RGB frames from this script. No camera capture or generative model.",
      "annotations": [
        {
          "label": "gray frame",
          "start_frame": 15,
          "end_frame_exclusive": 20
        }
      ],
      "task": "Isolate a full-frame illumination change.",
      "label_basis": "construction",
      "license": "https://creativecommons.org/publicdomain/zero/1.0/"
    },
    {
      "id": "F01",
      "file": "media/F01.mp4",
      "sha256": "9396c42ba5abdd965659f978958d9bed22ae0de5882d3434f60e5d9a3d48a258",
      "title": "Approach lane",
      "group": "field excerpt",
      "family": "Temporary_traffic_signal_at_Colonel_By_Drive.webm",
      "creator": "137a",
      "license": "https://creativecommons.org/publicdomain/zero/1.0/",
      "source_page": "https://commons.wikimedia.org/wiki/File:Temporary_traffic_signal_at_Colonel_By_Drive.webm",
      "source_sha256": "9fcef2db704442d3de1974c385fda1afce096f2dd93e9201d91dbee51e70d953",
      "source_interval_seconds": [
        1,
        5
      ],
      "changes": "Four-second excerpt, resized, sampled to 10 fps, H.264 encode, sound removed.",
      "task": "Red signal at right; traffic approaches in the left lane.",
      "annotations": [
        {
          "label": "red signal lit",
          "start_frame": 10,
          "end_frame_exclusive": 11
        },
        {
          "label": "red signal lit",
          "start_frame": 20,
          "end_frame_exclusive": 21
        },
        {
          "label": "first approaching sedan front bumper reaches y=270 within x=[0,320)",
          "start_frame": 27,
          "end_frame_exclusive": 28
        }
      ],
      "label_basis": "Scene landmarks at sampled frames. No exhaustive object tracks or event boundaries. The single specified bumper crossing was inspected frame by frame. Coordinate origin is top left, in decoded pixels."
    },
    {
      "id": "F02",
      "file": "media/F02.mp4",
      "sha256": "9fdd6a1cac1041bceb48f2b11267461383b397cc68d986539b09f500c1d17b16",
      "title": "Waiting lane",
      "group": "field excerpt",
      "family": "Temporary_traffic_signal_at_Colonel_By_Drive.webm",
      "creator": "137a",
      "license": "https://creativecommons.org/publicdomain/zero/1.0/",
      "source_page": "https://commons.wikimedia.org/wiki/File:Temporary_traffic_signal_at_Colonel_By_Drive.webm",
      "source_sha256": "9fcef2db704442d3de1974c385fda1afce096f2dd93e9201d91dbee51e70d953",
      "source_interval_seconds": [
        10,
        14
      ],
      "changes": "Four-second excerpt, resized, sampled to 10 fps, H.264 encode, sound removed.",
      "task": "A light-colored vehicle waits on the right while opposing traffic passes.",
      "annotations": [
        {
          "label": "light vehicle present at right",
          "start_frame": 10,
          "end_frame_exclusive": 11
        },
        {
          "label": "light vehicle present at right",
          "start_frame": 20,
          "end_frame_exclusive": 21
        }
      ],
      "label_basis": "Scene landmarks at sampled frames. No exhaustive object tracks or event boundaries."
    },
    {
      "id": "F03",
      "file": "media/F03.mp4",
      "sha256": "c2c89eed1dae06b5d061f25f06947ee5083196f43ca224c5d4388676d95fc12c",
      "title": "Oncoming lights",
      "group": "field excerpt",
      "family": "Cars_Passing_by_at_Night.webm",
      "creator": "Maximilian Schönherr",
      "license": "https://creativecommons.org/licenses/by-sa/4.0/",
      "source_page": "https://commons.wikimedia.org/wiki/File:Cars_Passing_by_at_Night.webm",
      "source_sha256": "f15a2299b70fe4f43b87e411ccc05641d34e4dd74139c3247acf61f630e3b3c0",
      "source_interval_seconds": [
        2,
        6
      ],
      "changes": "Four-second excerpt, resized, sampled to 10 fps, H.264 encode, sound removed.",
      "task": "Night street with lit storefront at left and traffic approaching.",
      "annotations": [
        {
          "label": "street and lit storefront visible",
          "start_frame": 10,
          "end_frame_exclusive": 11
        },
        {
          "label": "street and lit storefront visible",
          "start_frame": 20,
          "end_frame_exclusive": 21
        }
      ],
      "label_basis": "Scene landmarks at sampled frames. No exhaustive object tracks or event boundaries."
    },
    {
      "id": "F04",
      "file": "media/F04.mp4",
      "sha256": "96625dffd185de2e1bd542b92b5411dc18f7f00ca80998dc3dbe345850cc1f7a",
      "title": "Signal queue",
      "group": "field excerpt",
      "family": "Cars_Passing_by_at_Night.webm",
      "creator": "Maximilian Schönherr",
      "license": "https://creativecommons.org/licenses/by-sa/4.0/",
      "source_page": "https://commons.wikimedia.org/wiki/File:Cars_Passing_by_at_Night.webm",
      "source_sha256": "f15a2299b70fe4f43b87e411ccc05641d34e4dd74139c3247acf61f630e3b3c0",
      "source_interval_seconds": [
        9,
        13
      ],
      "changes": "Four-second excerpt, resized, sampled to 10 fps, H.264 encode, sound removed.",
      "task": "View down the road toward red lights and waiting traffic.",
      "annotations": [
        {
          "label": "queue scene visible",
          "start_frame": 10,
          "end_frame_exclusive": 11
        },
        {
          "label": "queue scene visible",
          "start_frame": 20,
          "end_frame_exclusive": 21
        }
      ],
      "label_basis": "Scene landmarks at sampled frames. No exhaustive object tracks or event boundaries."
    },
    {
      "id": "F05",
      "file": "media/F05.mp4",
      "sha256": "10dcb353e15bbed99653f21e5d80593b47643ff401e4d8a44b6c092e913b12a6",
      "title": "High view, first interval",
      "group": "field excerpt",
      "family": "Dean_Street_timelapse_Albury_NSW.webm",
      "creator": "Thennicke",
      "license": "https://creativecommons.org/publicdomain/zero/1.0/",
      "source_page": "https://commons.wikimedia.org/wiki/File:Dean_Street_timelapse_Albury_NSW.webm",
      "source_sha256": "d7c226e29a1d114ecb399d0ba14174879f882c81f7e42e35ead09690075e2951",
      "source_interval_seconds": [
        1,
        5
      ],
      "changes": "Four-second excerpt, resized, sampled to 10 fps, H.264 encode, sound removed.",
      "task": "Elevated night timelapse. Observe the bright intersection near the lower center.",
      "annotations": [
        {
          "label": "illuminated junction visible",
          "start_frame": 10,
          "end_frame_exclusive": 11
        },
        {
          "label": "illuminated junction visible",
          "start_frame": 20,
          "end_frame_exclusive": 21
        }
      ],
      "label_basis": "Scene landmarks at sampled frames. No exhaustive object tracks or event boundaries."
    },
    {
      "id": "F06",
      "file": "media/F06.mp4",
      "sha256": "15262530ecedef3a2050f10b5ad2737a7719834975b3700aa258aa34070df74f",
      "title": "High view, later interval",
      "group": "field excerpt",
      "family": "Dean_Street_timelapse_Albury_NSW.webm",
      "creator": "Thennicke",
      "license": "https://creativecommons.org/publicdomain/zero/1.0/",
      "source_page": "https://commons.wikimedia.org/wiki/File:Dean_Street_timelapse_Albury_NSW.webm",
      "source_sha256": "d7c226e29a1d114ecb399d0ba14174879f882c81f7e42e35ead09690075e2951",
      "source_interval_seconds": [
        8,
        12
      ],
      "changes": "Four-second excerpt, resized, sampled to 10 fps, H.264 encode, sound removed.",
      "task": "Later interval from the same timelapse. Preserve playback order across the cut.",
      "annotations": [
        {
          "label": "illuminated junction visible",
          "start_frame": 10,
          "end_frame_exclusive": 11
        },
        {
          "label": "illuminated junction visible",
          "start_frame": 20,
          "end_frame_exclusive": 21
        }
      ],
      "label_basis": "Scene landmarks at sampled frames. No exhaustive object tracks or event boundaries."
    },
    {
      "id": "M01",
      "file": "media/M01.mp4",
      "sha256": "b7ae2869bba02a5dd54722561cffe6d09b3ae503cb11c4a7a831b516f9e72d0a",
      "title": "Gray approach",
      "group": "altered field",
      "parent": "F01",
      "family": "Temporary_traffic_signal_at_Colonel_By_Drive.webm",
      "creator": "137a",
      "source_page": "https://commons.wikimedia.org/wiki/File:Temporary_traffic_signal_at_Colonel_By_Drive.webm",
      "license": "https://creativecommons.org/publicdomain/zero/1.0/",
      "changes": "Chroma removed throughout.",
      "task": "Compare with F01. Chroma removed throughout.",
      "annotations": [
        {
          "label": "grayscale",
          "start_frame": 0,
          "end_frame_exclusive": 40
        }
      ],
      "label_basis": "Edit timeline relative to the delivered clip."
    },
    {
      "id": "M02",
      "file": "media/M02.mp4",
      "sha256": "314d1ddbe99009e80cef464f5de2256d8e5f558f9de1723815d23c0ae78fbc48",
      "title": "Masked approach",
      "group": "altered field",
      "parent": "F01",
      "family": "Temporary_traffic_signal_at_Colonel_By_Drive.webm",
      "creator": "137a",
      "source_page": "https://commons.wikimedia.org/wiki/File:Temporary_traffic_signal_at_Colonel_By_Drive.webm",
      "license": "https://creativecommons.org/publicdomain/zero/1.0/",
      "changes": "Lower-left quadrant covered for two seconds.",
      "task": "Compare with F01. Lower-left quadrant covered for two seconds.",
      "annotations": [
        {
          "label": "black quadrant",
          "start_frame": 10,
          "end_frame_exclusive": 30
        }
      ],
      "label_basis": "Edit timeline relative to the delivered clip."
    },
    {
      "id": "M03",
      "file": "media/M03.mp4",
      "sha256": "5e90fc25f8d1a408d843737d31bf1496d0e3b72a11cdfdd70943dc1110df0a19",
      "title": "Held night frame",
      "group": "altered field",
      "parent": "F04",
      "family": "Cars_Passing_by_at_Night.webm",
      "creator": "Maximilian Schönherr",
      "source_page": "https://commons.wikimedia.org/wiki/File:Cars_Passing_by_at_Night.webm",
      "license": "https://creativecommons.org/licenses/by-sa/4.0/",
      "changes": "Frame 9 held across frames 10 through 29; the stream continues.",
      "task": "Compare with F04. Frame 9 held across frames 10 through 29; the stream continues.",
      "annotations": [
        {
          "label": "inserted hold",
          "start_frame": 10,
          "end_frame_exclusive": 30
        }
      ],
      "label_basis": "Edit timeline relative to the delivered clip."
    }
  ]
}