JSON Format Export

If using Windows, we recommend using 7-Zip to unzip the exported labels.

Label Coordinates

In the JSON format, label coordinates are normalized to be between 0 and 1. This means that the corners of the frame or image correspond to the coordinates (1,1), (1,0), (0,0), (0,1) regardless of frame dimensions.

To get the pixel values of normalized coordinates:

• The x and h coordinates of a label should be multiplied by the pixel width of the frame or image.
• The y and w coordinates of a label should be multiplied by the pixel height of the frame or image.

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Format of Exported Labels

The last_edited_by and last_edited_at fields are updated only when the label or its nested attributes are modified in the Label Editor. If the SDK is used to update the label, these fields must be updated manually.

The tables below provide descriptions of all values contained JSON format exports.

Exports of label versions for which the data unit was deleted vary from the examples shown below - the data_type is deleted, while image groups and image sequences only contain a single data_unit.

Exported labels include several unique identifiers that nest. The root of each label starts with the object_hash for the Ontology object or classification.

Single Images

The export contains a list of JSON objects, with each JSON object representing a single data unit and containing detailed information for all exported labels.

The example below describes all the keys for a single exported data unit.

[
    {
        "classification_answers": {},
        "created_at": "2025-01-07 16:12:23",
        "data_hash": "f3132c00-069f-4a95-8e21-30c13078d84d",
        "data_title": "Image3.jpg",
        "data_type": "image",
        "data_units": {
        },
        "dataset_hash": "3c35b0f2-64fc-4a58-9b9d-f7181d73f1e5",
        "dataset_title": "New Welsh Whales",
        "is_image_sequence": null,
        "is_valid": true,
        "label_hash": "0f5a5e62-a3e0-4481-932f-1093f7c1d170",
        "label_status": "LABEL_IN_PROGRESS",
        "last_edited_at": "2025-01-07 16:12:23",
        "object_actions": {},
        "object_answers": {},
        "video_link": null
    }
]

Key	Description	Notes
label_hash	The Label Row hash	The ‘hash’ represents a unique identifier
created_at	Time and date the label was created
last_edited_at	Time and date the label was last edited
dataset_hash	The Dataset’s hash	The ‘hash’ represents a unique identifier
data_type	The data unit’s file format	Always “video” for videos
is_image_sequence	”true” when the data unit is an image sequence	Always “null” for images
video_link	Contains a private cloud URL for videos	Always “null” for images
data_units	List of all files the data unit is composed of	Details of the export information for `data_units“ can be found below.
object_answers	All the attributes in this data unit	The object attributes are identified using their hash
classification_answers	All the classifications in a particular data unit	The classification labels are identified using their hash
object_actions	The number of states a dynamic attribute can be in.	A change in state occurs each time the attribute answer changes. The objectHash within the object_actions is the attribute answer’s ID.
label_status	Indicates whether the data unit has been labeled.
export_history	Contains a record of the export history for this data unit	Exporting labels to confirm export history generates an export history entry.
export_hash	The hash for this particular export instance	The ‘hash’ represents a unique identifier
exported_at	The date and time when a particular export instance took place.

data_units

The data_units key contains all files that compose the data unit. For a given image there is only ever a single element in this list. This element contains the following information.

data_units here refer to individual files that compose a data unit, as defined in our glossary, and are not to be confused with data units elsewhere in the platform. Encord will update this nomenclature soon, but we always communicate changes to all customers first.

"data_units": {
      "9c588f63-ad87-4987-a074-06ba0d6980cd": {
        "data_hash": "9c588f63-ad87-4987-a074-06ba0d6980cd",
        "data_title": "dom-hbf.jpg",
        "data_type": "image",
        "data_sequence": 0,
        "labels": { },
        "data_fps": "23.976023976023978" ,
        "data_duration": "29.0786",
        "data_link": "www.my-private-cloud.com/how-to-make-apple-pie.mp4",
        "width": 512,
        "height": 512
      }
}  

Key	Description	Notes
data_hash	The file’s hash	The ‘hash’ represents a unique identifier
data_title	The file’s title
data_type	The file type
data_sequence	The sequence number of this file within the data unit	Always 0 for images, as single images are composed of a single file by definition
labels	A container for the image’s label information	This contains the label information for the image.
data_link	A link to the file stored in your private cloud
width	The width of the image in pixel (px)
height	The height of the image in pixel (px)

labels

labels contains all object labels, classification labels, and attributes present in the image.

"labels": {
      "0": {
        "objects": { },
        "classifications": [ ]
      }
}  

Key	Description	Notes
objects	A list of label objects in this frame	Contains geometric information for object labels
classifications	A list of classifications applying to image as a whole

objects

objects contains all object label information for the image. A key with the name of the object shape is always present - bounding_box in the example below. All shapes contain coordinates for each vertex.

Navigate to the ontology shapes section to see how all ontology classes are represented in the exported file.

The example below shows a single object instance.

{
"objects": [
{
"featureHash": "Aav9W+cC",
"objectHash": "cTkqn7d7",
"name": "Cherries",
"value": "cherries",
"color": "#595feb",
"shape": "bounding_box",
"confidence": 1,
"frame": 0,
"createdBy": "[e-mail]",
"createdAt": "Wed, 28 May 2025 08:51:53 GMT",
"lastEditedBy": "[e-mail]",
"lastEditedAt": "Wed, 28 May 2025 08:51:53 GMT",
"manualAnnotation": true,
"boundingBox": {
  "x": 0.34688227662041876,
  "y": 0.4167629800853485,
  "w": 0.29148041861853874,
  "h": 0.41461619320558957
}
}
]
}

Key	Description	Notes
objectHash	The specific label’s hash	The ‘hash’ represents a unique identifier
featureHash	The Ontology object’s hash	Corresponds to the FeatureNodeHash in the ontology
name	The object’s name	As specified in the ontology
value	The name given to the object
color	The color used to draw the object	As specified in the ontology
shape	The Ontology class used to create the object	As specified in the ontology
confidence	The confidence score for this object	A confidence score of 1 is given for all labels created manually. More info can be found here
frame	The frame number of the data unit where the label appears	A frame number of 0 represents the first frame of the data unit. Images always have a frame number of 0.
createdBy	The email of the user that created this object
createdAt	Date and time the object was created
lastEditedBy	The email of the user that last edited this object
lastEditedAt	Date and time the object was last edited
manualAnnotation	A field indicating whether the object was drawn manually or not	true means it was drawn manually, while false means it was created using a model or an automated labeling technique
boundingBox	A list containing the coordinates for the bounding box	Refer to the Ontology shapes section for more details

classifications

classifications contains all classification information for the image.

The following example shows a single object instance.

"classifications": [
  {
        "name": "Time of day",
        "value": "time_of_day",
        "createdAt":"Tue, 10 Oct 2023 14:16:14 GMT",
        "createdBy": "[e-mail]",
        "confidence": "1",
        "featureHash": "wUS7p9B6",
        "lastEditedAt": "Tue, 10 Oct 2023 14:16:14 GMT",
        "classificationHash": "jiOiEq76",
        "manualAnnotation": true
      }
]  

Key	Description	Notes
name	The classification’s name	As specified in the ontology
value	The classification value	Same as the name
createdAt	Time and day the classification was created
createdBy	The email of the user that created this classification
confidence	The confidence score for this classification	A confidence score of 1 is given for all labels created manually. More info can be found here
featureHash	The classification instance hash	Corresponds to the FeatureNodeHash in the Ontology
lastEditedAt	Time and date of the last time this classification was edited
classificationHash	The classification instance hash hash
manualAnnotation	A field indicating whether the object was drawn manually or not	true means it was drawn manually, while false means it was created using a model or an automated labeling technique

object_answers

object_answers is a list of objects that have at least one nested attribute and contains information for all attributes. Expanding object_answers reveals the following:

"object_answers": {
  "Gqh06ypx"
      "objectHash": "Gqh06ypx",
      "classifications" [ 
        "name": "Size",
        "value": "size",
        "answers": "Medium",
        "featureHash": "GZnFumFq",
        "manualAnnotation": true
      ]
}  

Key	Description	Notes
objectHash	The hash of the object containing the attributes	The ‘hash’ represents a unique identifier
classifications	A list of attributes related to the object. Includes Dynamic attributes and Relation attributes	Not to be confused with classifications as defined in our glossary, which apply to a frame
name	The attribute name
value	The attribute value	Always the same as the name
answers	The value(s) the attribute(s) were set to	If the attribute was a radio button, the answer is the option selected by the annotator
featureHash	The attribute’s hash	The ‘hash’ represents a unique identifier
manualAnnotation	A field indicating whether the object was drawn manually or not	true means it was drawn manually, while false means it was created using a model or an automated labeling technique

classification_answers

Contains a list of classifications that apply to entire frames or slices. classification_answer is represented by its hash. Expanding classification_answers reveals the following:

"classification_answers": {
  "OFX2jzwE": {
    "classificationHash": "OFX2jzwE", 
    "classifications": [{
      "name": "Time of day", 
      "value": "time_of_day", 
      "answers": [{
        "name": "Night", 
        "value": "night", 
        "featureHash": "j/7dpSmi"}],    
    "featureHash": "uZmB5YZC", 
    "manualAnnotation": true
    }]
  }
}

Key	Description	Notes
classificationHash	The classification’s hash	Corresponds to the featureNodeHash in the Ontology
classifications	A list of classification information
name	The classification name	As set in the Ontology (Quality in the example above)
value	The classification value	Always the same as the classification name
answers	A list of all classification answers	”answers” refer to the values the classification were set to.
name	The name of the classification answer	”Night” in the example above
value	The classification answer’s value	Always the same as the classifications answer’s name
featureHash	The hash for the particular classification answer	Included in answers
featureHash	The hash for the particular classification
manualAnnotation	”true” for all manually created labels. “false” for all labels created with automated labeling techniques

export_history

The export_history contains a list of all exports for this data unit, the first entry being the current export. Each instance contains the following:

"export_history": {
  "0"
      "export_hash": "Gqh06ypx",
      "exported_at": "Mon, 02 Oct 2023 13:47:45 UTC",
      "user_email": "[e-mail]"
}  

Key	Description	Notes
export_hash	The export instance’s hash	The ‘hash’ represents a unique identifier
exported_at	Date and time of the export
user_email	The email of the user that made this export

---

Image Groups & Image Sequences

The export contains a list of JSON objects, with each JSON object representing a single image group or image sequence, and containing detailed information for all exported labels.

The example below describes all the keys for a single exported data unit.

[
  {
    "label_hash": "781dd0ff-e4c2-48f1-bcd1-09f2f0756701",
    "created_at": "2023-03-23 11:42:14",
    "last_edited_at": "2023-10-02 13:53:03",
    "dataset_hash": "4a4141ed-8d8b-4518-b1f7-97a5c53e992b",
    "dataset_title": "cooking_image_sequences",
    "data_title": "image-group-67bdc95d",
    "data_hash": "9c588f63-ad87-4987-a074-06ba0d6980cd",
    "data_type": "image_group",
    "is_image_sequence": null,
    "image_sequence_link": "www.my-private-cloud.com/how-to-make-apple-pie.mp4",
    "data_units": { },
    "classification_answers": { },
    "object_actions": { },
    "label_status": "LABELLED",
    "export_history": [
      {
        "export_hash": "02b56519-9664-4e38-9713-4817a5caf648",
        "exported_at": "Mon, 02 Oct 2023 14:35:30 UTC",
        "user_email": "[e-mail]"
      },
      {
        "export_hash": "2e0ee531-41ce-4ce9-a859-b6b47697e5d2",
        "exported_at": "Mon, 02 Oct 2023 13:47:45 UTC",
        "user_email": "[e-mail]"
      }
    ],
    "export_hash": "02b56519-9664-4e38-9713-4817a5caf648",
    "exported_at": "Mon, 02 Oct 2023 14:35:30 UTC",
  }
]

Key	Description	Notes
label_hash	The Label Row hash	The ‘hash’ represents a unique identifier
created_at	Time and date the label was created
last_edited_at	Time and date the label was last edited
dataset_hash	The dataset’s hash	The ‘hash’ represents a unique identifier
data_type	The data unit’s file format	Always “img_group” for image groups and image sequences
is_image_sequence	true when the data unit is an image sequence	false for all other types of data, including image groups. This is what distinguishes image groups and image sequences in your export
video_link	Contains a link to file storage location if file is a video	Always “null” for image groups and image sequences
data_units	List of all files the data unit is composed of	Details of the export information for data units can be found below.
object_answers	All the attributes in this data unit	The object attributes are identified using their hash
classification_answers	All the classifications in a particular data unit	The classification labels are identified using their hash
object_actions	The number of states a dynamic attribute can be in.	A change in state occurs each time the attribute answer changes. The objectHash within the object_actions is the attribute answer’s ID.
label_status	Indicates whether the data unit has been labeled.
export_history	Contains a record of the export history for this data unit	Exporting labels to confirm export history generates an export history entry.
export_hash	The hash for this particular export instance	The ‘hash’ represents a unique identifier
exported_at	The date and time when a particular export instance took place.

---

data_units

The data_units key contains a list of all files that compose the image group or image sequence (sometimes referred to as frames). It contains the following information.

data_units here refer to individual files that compose a data unit, as defined in our glossary, and are not to be confused with data units elsewhere in the platform. Encord will update this nomenclature soon, but we always communicate changes to all customers first.

"data_units": {
      "9c588f63-ad87-4987-a074-06ba0d6980cd": {
        "data_hash": "9c588f63-ad87-4987-a074-06ba0d6980cd",
        "data_title": "rhein-hafen.jpg4",
        "data_type": "image/jpg",
        "data_sequence": 0,
        "labels": { },
        "data_link": "www.my-private-cloud.com/how-to-make-apple-pie.mp4",
        "width": 512,
        "height": 512
      }
}  

Key	Description	Notes
data_hash	The file’s hash	The ‘hash’ represents a unique identifier
data_title	The file’s title
data_type	The file type
data_sequence	The sequence number of this file within the data unit	0 represents the first file
labels	A list of all frames contained in image group or sequence, and any labels on each frame	This contains the label information for each frame.
width	The width of the frame in pixel (px)
height	The height of the frame in pixel (px)

labels

Each number within labels represents an individual frame within the image group or sequence. Each frame contains the following:

"labels": {
      "0": {
        "objects": { },
        "classifications": [ ],
        "metadata":{ }
      }
}  

Key	Description	Notes
objects	A list of label objects in this frame	Contains geometric information for object labels
classifications	A list of classifications applying to the entire frame	Is the same value for all instances of this classification.

objects

objects contains label information for all object instances in a frame. A key with the name of the object shape is always present - bounding_box in the example below. All shapes contain coordinates for each vertex.

Navigate to the Ontology shapes section to see how all Ontology classes are represented in the exported file.

The example below shows a single object instance.

"objects": [
      {
        "name": "Apple",
        "color": "#D33115",
        "shape":"bounding_box",
        "value": "apple",
        "boundingBox": {
          "0": {
            "h": 0.3235,
            "w": 0.1697,
            "x": 0.0153,
            "y": 0.254,   
          }
        },
        "createdAt": "Thu, 07 Sep 2023 09:47:35 GMT",
        "createdBy": "[e-mail]",
        "confidence": "1",
        "objectHash": "P6gqJT/3",
        "featureHash": "jiOiEq76",
        "manualAnnotation": true
      }
]  

Key	Description	Notes
name	The object’s name	As specified in the ontology
color	The color used to draw the object	As specified in the ontology
shape	The Ontology class used to create the object	As specified in the ontology
value	The name given to the object
createdAt	Date and time the object was created
createdBy	The email of the user that created this object
confidence	The confidence score for this object	A confidence score of 1 is given for all labels created manually. More info can be found here
objectHash	The specific label’s hash	The ‘hash’ represents a unique identifier
featureHash	The Ontology object’s hash	Corresponds to the FeatureNodeHash in the ontology
manualAnnotation	A field indicating whether the object was drawn manually or not	true means it was drawn manually, while false means it was created using a model or an automated labeling technique
boundingBox	A list containing the coordinates for the bounding box	Refer to the Ontology shapes section for more details

classifications

classifications contains all frame level classification information for the image group or sequence.

The example below shows a single classification instance.

"classifications": [
      {
        "name": "Time of day",
        "value": "time_of_day",
        "createdAt":"Tue, 10 Oct 2023 14:16:14 GMT",
        "createdBy": "[e-mail]",
        "confidence": "1",
        "featureHash": "wUS7p9B6",
        "lastEditedAt": "Tue, 10 Oct 2023 14:16:14 GMT",
        "classificationHash": "jiOiEq76",
        "manualAnnotation": true
      }
]  

Key	Description	Notes
name	The classification’s name	As specified in the ontology
value	The classification value	Same as the name
createdAt	Time and day the classification was created
createdBy	The email of the user that created this classification
confidence	The confidence score for this classification	A confidence score of 1 is given for all labels created manually. More info can be found here
featureHash	The classification instance hash	Corresponds to the FeatureNodeHash in the Ontology
lastEditedAt	Time and date of the last time this classification was edited
classificationHash	The classification instance hash hash
manualAnnotation	A field indicating whether the object was drawn manually or not	true means it was drawn manually, while false means it was created using a model or an automated labeling technique

object_answers

object_answers is a list of objects that have at least one nested attribute and contains information for all attributes. Expanding object_answers reveals the following:

"object_answers": {
  "Gqh06ypx"
      "objectHash": "Gqh06ypx",
      "classifications" [{ 
        "name": "Size",
        "value": "size",
        "answers": "Medium",
        "featureHash": "GZnFumFq",
        "manualAnnotation": true
  }]
}  

Key	Description	Notes
objectHash	The hash of the object containing the attributes	The ‘hash’ represents a unique identifier
classifications	A list of attributes related to the object. Includes Dynamic attributes and Relation attributes	Not to be confused with classifications as defined in our glossary, which apply to a frame
name	The attribute name
value	The attribute value	Always the same as the name
answers	The value(s) the attribute(s) were set to	If the attribute was a radio button, the answer is the option selected by the annotator
featureHash	The attribute’s hash	The ‘hash’ represents a unique identifier
manualAnnotation	A field indicating whether the object was drawn manually or not	true means it was drawn manually, while false means it was created using a model or an automated labeling technique

classification_answers

Contains a list of classifications that apply to entire frames or slices. classification_answer is represented by its hash. Expanding classification_answers reveals the following:

"classification_answers": {
  "OFX2jzwE": {
    "classificationHash": "OFX2jzwE", 
    "classifications": [{
      "name": "Quality", 
      "value": "quality", 
      "answers": [{
        "name": "out of focus", 
        "value": "out_of_focus", 
        "featureHash": "j/7dpSmi"}],    
    "featureHash": "uZmB5YZC", 
    "manualAnnotation": true
    }]
  }
}

Key	Description	Notes
classificationHash	The classification’s hash	The ‘hash’ represents a unique identifier
classifications	A list of classifications information
name	The classification name	As set in the Ontology (Quality in the example above)
value	The classification value	Always the same as the classification name
answers	A list of all classification answers	”answers” refer to the values the classifications were set to.
name	The name of the classification answer	”out of focus” in the example above
value	The classification answer’s value	Always the same as the classification answer’s name
featureHash	The hash for the particular classification answer	Included in answers
featureHash	The hash for the particular classification
manualAnnotation	”true” for all manually created labels. “false” for all labels created with automated labeling techniques

export_history

The export_history contains a list of all exports for this data unit, the first entry being the current export. Each instance contains the following:

"export_history": {
  "0"
      "export_hash": "Gqh06ypx",
      "exported_at": "Mon, 02 Oct 2023 13:47:45 UTC",
      "user_email": "[e-mail]"
}  

Key	Description	Notes
export_hash	The export instance’s hash	The ‘hash’ represents a unique identifier
exported_at	Date and time of the export
user_email	The email of the user that made this export

---

Videos

The export contains a list of JSON objects, with each JSON object representing a single data unit and containing detailed information for all exported labels.

The example below describes all the keys for a single exported data unit.

[
  {
    "label_hash": "781dd0ff-e4c2-48f1-bcd1-09f2f0756701",
    "created_at": "2023-03-23 11:42:14",
    "last_edited_at": "2023-10-02 13:53:03",
    "dataset_hash": "4a4141ed-8d8b-4518-b1f7-97a5c53e992b",
    "dataset_title": "cooking_videos",
    "data_title": "how-to-make-apple-pie.mp4",
    "data_hash": "9c588f63-ad87-4987-a074-06ba0d6980cd",
    "data_type": "video",
    "is_image_sequence": null,
    "video_link": "www.my-private-cloud.com/how-to-make-apple-pie.mp4",
    "data_units": { },
    "classification_answers": { },
    "object_actions": { },
    "label_status": "LABELLED",
    "export_history": [
      {
        "export_hash": "02b56519-9664-4e38-9713-4817a5caf648",
        "exported_at": "Mon, 02 Oct 2023 14:35:30 UTC",
        "user_email": "[e-mail]"
      },
      {
        "export_hash": "2e0ee531-41ce-4ce9-a859-b6b47697e5d2",
        "exported_at": "Mon, 02 Oct 2023 13:47:45 UTC",
        "user_email": "[e-mail]"
      }
    ],
    "export_hash": "02b56519-9664-4e38-9713-4817a5caf648",
    "exported_at": "Mon, 02 Oct 2023 14:35:30 UTC",
  }
]

Key	Description	Notes
label_hash	The Label Row hash	The ‘hash’ represents a unique identifier
created_at	Time and date the label was created
last_edited_at	Time and date the label was last edited
dataset_hash	The Dataset’s hash	The ‘hash’ represents a unique identifier
data_type	The data unit’s file format	Always “video” for videos
is_image_sequence	”true” when the data unit is an image sequence	Always “null” for videos
video_link	Link to the video saved on your private cloud	Always “null” for all other file types
data_units	List of all files the data unit is composed of	Details of the export information for `data_units“ can be found below.
object_answers	All the attributes in this data unit	The object attributes are identified using their hash
classification_answers	All the classifications in a particular data unit	The classification labels are identified using their hash
object_actions	The number of states a dynamic attribute can be in.	A change in state occurs each time the attribute answer changes. The objectHash within the object_actions is the attribute answer’s ID.
label_status	Indicates whether the data unit has been labeled.
export_history	Contains a record of the export history for this data unit	Exporting labels to confirm export history generates an export history entry.
export_hash	The hash for this particular export instance	The ‘hash’ represents a unique identifier
exported_at	The date and time when a particular export instance took place.

---

data_units

The data_units key contains all files that compose the data unit. For a given video there is only a single element in this list. This element contains the following information.

data_units here refer to individual files that compose a data unit, as defined in our glossary, and are not to be confused with data unit elsewhere in the platform. Encord will update this nomenclature soon, but we always communicate changes to all customers first.

"data_units": {
      "9c588f63-ad87-4987-a074-06ba0d6980cd": {
        "data_hash": "9c588f63-ad87-4987-a074-06ba0d6980cd",
        "data_title": "how-to-make-apple-pie.mp4",
        "data_type": "video/mp4",
        "data_sequence": 0,
        "labels": { },
        "data_fps": "23.976023976023978" ,
        "data_duration": "29.0786",
        "data_link": "www.my-private-cloud.com/how-to-make-apple-pie.mp4",
        "width": 512,
        "height": 512
      }
}  

Key	Description	Notes
data_hash	The file’s hash	The ‘hash’ represents a unique identifier
data_title	The file’s title
data_type	The file type
data_sequence	The sequence number of this file within the data unit	0 represents the first file
labels	A list of all frames contained in the video and any labels on each frame	This contains the label information for each frame.
data_fps	The frames per second for this video
data_duration	The video length	In seconds
data_link	A link to the file stored in your private cloud
width	The width of the frame in pixel (px)
height	The height of the frame in pixel (px)

labels

Each number within labels represents an individual frame within the data unit. Each frame contains the following:

"labels": {
      "0": {
        "objects": { },
        "classifications": [ ],
        "metadata":{ }
      }
}  

Key	Description	Notes
objects	A list of label objects in this frame	Contains geometric information for object labels
classifications	A list of classifications applying to the entire frame	Is the same value for all instances of this classification.

objects

objects contains label information for all object instances in a frame. A key with the name of the object shape is always present - bounding_box in the example below. All shapes contain coordinates for each vertex.

Navigate to the Ontology shapes section to see how all Ontology classes are represented in the exported file.

The following example shows a single object instance.

"objects": [
  {
        "name": "Apple",
        "color": "#D33115",
        "shape":"bounding_box",
        "value": "apple",
        "boundingBox": {
          "0": {
            "h": 0.3235,
            "w": 0.1697,
            "x": 0.0153,
            "y": 0.254,   
          }
        },
        "createdAt": "Thu, 07 Sep 2023 09:47:35 GMT",
        "createdBy": "[e-mail]",
        "confidence": "1",
        "objectHash": "P6gqJT/3",
        "featureHash": "jiOiEq76",
        "manualAnnotation": true
      }
]  

Key	Description	Notes
name	The object’s name	As specified in the ontology
color	The color used to draw the object	As specified in the ontology
shape	The ontology class used to create the object	As specified in the ontology
value	The name given to the object
createdAt	Date and time the object was created
createdBy	The email of the user that created this object
confidence	The confidence score for this object	A confidence score of 1 is given for all labels created manually. More info can be found here
objectHash	The specific label’s hash	The ‘hash’ represents a unique identifier
featureHash	The Ontology object’s hash	Corresponds to the FeatureNodeHash in the ontology
manualAnnotation	A field indicating whether the object was drawn manually or not	true means it was drawn manually, while false means it was created using a model or an automated labeling technique
boundingBox	A list containing the coordinates for the bounding box	Refer to the Ontology shapes section for more details

classifications

classifications contains all frame level classification information for the video.

The example below shows a single classification instance.

"classifications": [
  {
        "name": "Time of day",
        "value": "time_of_day",
        "createdAt":"Tue, 10 Oct 2023 14:16:14 GMT",
        "createdBy": "[e-mail]",
        "confidence": "1",
        "featureHash": "wUS7p9B6",
        "lastEditedAt": "Tue, 10 Oct 2023 14:16:14 GMT",
        "classificationHash": "jiOiEq76",
        "manualAnnotation": true
      }
]  

Key	Description	Notes
name	The classification’s name	As specified in the ontology
value	The classification value	Same as the name
createdAt	Time and day the classification was created
createdBy	The email of the user that created this classification
confidence	The confidence score for this classification	A confidence score of 1 is given for all labels created manually. More info can be found here
featureHash	The classification instance hash	Corresponds to the FeatureNodeHash in the Ontology
lastEditedAt	Time and date of the last time this classification was edited
classificationHash	The classification instance hash hash
manualAnnotation	A field indicating whether the object was drawn manually or not	true means it was drawn manually, while false means it was created using a model or an automated labeling technique

object_answers

object_answers is a list of objects that have at least one nested attribute and contains information for all attributes. Expanding object_answers reveals the following:

"object_answers": {
  "Gqh06ypx"
      "objectHash": "Gqh06ypx",
      "classifications" [ 
        "name": "Size",
        "value": "size",
        "answers": "Medium",
        "featureHash": "GZnFumFq",
        "manualAnnotation": true
      ]
}  

Key	Description	Notes
objectHash	The hash of the object containing the attributes	The ‘hash’ represents a unique identifier
classifications	A list of attributes related to the object	Not to be confused with classifications as defined in our glossary, which apply to a frame
name	The attribute name
value	The attribute value	Always the same as the name
answers	The value(s) the attribute(s) were set to	If the attribute was a radio button, the answer is the option selected by the annotator
featureHash	The attribute’s hash	The ‘hash’ represents a unique identifier
manualAnnotation	A field indicating whether the object was drawn manually or not	true means it was drawn manually, while false means it was created using a model or an automated labeling technique

classification_answers

Contains a list of classifications that apply to entire frames or slices. classification_answer is represented by its hash. Expanding classification_answers reveals the following:

"classification_answers": {
  "OFX2jzwE": {
    "classificationHash": "OFX2jzwE", 
    "classifications": [{
      "name": "Quality", 
      "value": "quality", 
      "answers": [{
        "name": "out of focus", 
        "value": "out_of_focus", 
        "featureHash": "j/7dpSmi"}],    
    "featureHash": "uZmB5YZC", 
    "manualAnnotation": true
    }]
  }
}

Key	Description	Notes
classificationHash	The classification’s hash	The ‘hash’ represents a unique identifier
classifications	A list of classifications information
name	The classification name	As set in the ontology (Quality in the example above)
value	The classification value	Always the same as the classification name
answers	A list of all classification answers	”answers” refer to the values the classifications were set to.
name	The name of the classification answer	”out of focus” in the example above
value	The classification answer’s value	Always the same as the classification answer’s name
featureHash	The hash for the particular classification answer	Included in answers
featureHash	The hash for the particular classification
manualAnnotation	”true” for all manually created labels. “false” for all labels created with automated labeling techniques

export_history

The export_history contains a list of all exports for this data unit, the first entry being the current export. Each instance contains the following:

"export_history": {
  "0"
      "export_hash": "Gqh06ypx",
      "exported_at": "Mon, 02 Oct 2023 13:47:45 UTC",
      "user_email": "[e-mail]"
}  

Key	Description	Notes
export_hash	The export instance’s hash	The ‘hash’ represents a unique identifier
exported_at	Date and time of the export
user_email	The email of the user that made this export

---

DICOM

The export contains a list of JSON objects, with each JSON object representing a single data unit and containing detailed information for all exported labels.

The following example describes all the keys for a single exported data unit.

[
  {
    "label_hash": "781dd0ff-e4c2-48f1-bcd1-09f2f0756701",
    "created_at": "2023-03-23 11:42:14",
    "last_edited_at": "2023-10-02 13:53:03",
    "dataset_hash": "4a4141ed-8d8b-4518-b1f7-97a5c53e992b",
    "dataset_title": "BB: CT thin slices",
    "data_title": "9c58",
    "data_hash": "9c588f63-ad87-4987-a074-06ba0d6980cd",
    "data_type": "dicom",
    "is_image_sequence": null,
    "video_link": null,
    "data_units": { },
    "classification_answers": { },
    "object_actions": { },
    "label_status": "LABELLED",
    "export_history": [
      {
        "export_hash": "02b56519-9664-4e38-9713-4817a5caf648",
        "exported_at": "Mon, 02 Oct 2023 14:35:30 UTC",
        "user_email": "[e-mail]"
      },
      {
        "export_hash": "2e0ee531-41ce-4ce9-a859-b6b47697e5d2",
        "exported_at": "Mon, 02 Oct 2023 13:47:45 UTC",
        "user_email": "[e-mail]"
      }
    ],
    "export_hash": "02b56519-9664-4e38-9713-4817a5caf648",
    "exported_at": "Mon, 02 Oct 2023 14:35:30 UTC",
  }
]

Key	Description	Notes
label_hash	The Label Row hash	The ‘hash’ represents a unique identifier
created_at	Time and date the label was created
last_edited_at	Time and date the label was last edited
dataset_hash	The dataset’s hash	The ‘hash’ represents a unique identifier
data_type	The data unit’s file format	Always “dicom” in a DICOM series
is_image_sequence	”true” when the data unit is an image sequence	Always “null” for a DICOM series
video_link	Link to the video or image sequence	Always “null” for a DICOM series
data_units	List of all files the data unit is composed of	Details of the export information for `data_units“ can be found below.
object_answers	All the object attributes in this data unit	The object attribute are identified using their hash
classification_answers	All the classifications in a particular data unit	The classification labels are identified using their hash
object_actions	The number of states a dynamic attribute can be in.	A change in state occurs each time the attribute answer changes. The objectHash within the object_actions is the attribute answer’s ID.
label_status	Indicates whether the data unit has been labeled.
export_history	Contains a record of the export history for the data unit	Exporting labels to confirm export history generates an export history entry.
export_hash	The hash for this particular export instance	The ‘hash’ represents a unique identifier
exported_at	The date and time when a particular export instance took place.

---

data_units

The data_units key contains all files that compose the data unit.

data_units here refer to individual files that compose a data unit, as defined in our glossary, and are not to be confused with data units elsewhere in the platform. Encord will update this nomenclature soon, but we always communicate changes to all customers first.

"data_units": {
      "9c588f63-ad87-4987-a074-06ba0d6980cd": {
        "data_hash": "9c588f63-ad87-4987-a074-06ba0d6980cd",
        "data_title": "9c58",
        "data_type": "application/dicom",
        "data_sequence": 0,
        "labels": { },
        "metadata": {  },
        "data_links": { },
        "width": 512,
        "height": 512
      }
}  

Key	Description	Notes
data_hash	The file’s hash	The ‘hash’ represents a unique identifier
data_title	The file’s title
data_type	The file type
data_sequence	The sequence number of this file within the data unit	0 represents the first file
labels	A list of all slices contained in the series and any labels on each slice	This contains the label information for each slice.
metadata	The DICOM series metadata.	Contains the ID for the patient, the study, and the series.
data_links	Links to all slices within the series, ordered by their sequence number
width	The width of the slice in pixel (px)
height	The height of the slice in pixel (px)

labels

Each number within labels represents an individual slice or frame within the data unit. Each slice or frame contains the following:

"labels": {
      "0": {
        "objects": { },
        "classifications": [ ],
        "metadata":{ }
      }
}  

Key	Description	Notes
objects	A list of label objects on this slice	Contains geometric information for object labels
classifications	A list of classifications applying to the entire slice or frame	Is the same value for all instances of this classification.
metadata	Slice specific metadata

objects

objects contains label information for all object instances in a frame. A key with the name of the object shape is always present - polygon in the example below. All shapes contain coordinates for each vertex.

Navigate to the Ontology shapes section to see how all Ontology classes are represented in the exported file.

The example below shows a single object instance.

"objects": [
  {
        "name": "lungs",
        "color": "#D33115",
        "shape":"polygon",
        "value": "lungs",
        "polygon": {
          "0": {
            "x": 0.2423,
            "y": 0.5115,
          },
          "1": {
            "x": 0.4167,
            "y": 0.4218,   
          }
        },
        "createdAt": "Thu, 07 Sep 2023 09:47:35 GMT",
        "createdBy": "[e-mail]",
        "confidence": "1",
        "objectHash": "mQ+yKcF5",
        "featureHash": "pRwpsg1H",
        "manualAnnotation": true
      }
]  

Key	Description	Notes
name	The object’s name	As specified in the ontology
color	The color used to draw the object	As specified in the ontology
shape	The ontology class used to create the object	As specified in the ontology
value	The name given to the object
polygon	A list containing the x and y coordinates of each vertex on the polygon	Refer to the Ontology shapes section for more details
createdAt	Date and time the object was created
createdBy	The email of the user that created this object
confidence	The confidence score for this object	A confidence score of 1 is given for all labels created manually. More info can be found here
objectHash	The specific label’s hash	The ‘hash’ represents a unique identifier
featureHash	The ontology object’s hash	Corresponds to the FeatureNodeHash in the ontology
manualAnnotation	A field indicating whether the object was drawn manually or not	true means it was drawn manually, while false means it was created using a model or an automated labeling technique

classifications

classifications contains all frame level classification information for the slice.

The example below shows a single classification instance.

"classifications": [
  {
        "name": "State",
        "value": "state",
        "createdAt":"Tue, 10 Oct 2023 14:16:14 GMT",
        "createdBy": "[e-mail]",
        "confidence": "1",
        "featureHash": "wUS7p9B6",
        "lastEditedAt": "Tue, 10 Oct 2023 14:16:14 GMT",
        "classificationHash": "jiOiEq76",
        "manualAnnotation": true
      }
]  

Key	Description	Notes
name	The classification’s name	As specified in the ontology
value	The classification value	Same as the name
createdAt	Time and day the classification was created
createdBy	The email of the user that created this classification
confidence	The confidence score for this classification	A confidence score of 1 is given for all labels created manually. More info can be found here
featureHash	The classification instance hash	Corresponds to the FeatureNodeHash in the ontology
lastEditedAt	Time and date of the last time this classification was edited
classificationHash	The classification instance hash hash
manualAnnotation	A field indicating whether the object was drawn manually or not	true means it was drawn manually, while false means it was created using a model or an automated labeling technique

metadata

"metadata": {
      "dicom_instance_uid": "1.3.9.1.4.7.14219.5.2.8.1600.1202.0357967439694942",
      "multiframe_frame_number": "null",
      "file_uri":"cord-dicoms/H7sLTXjYbrou3GhfmHRiuE5m92/5adba3dd-09f6-5c95-b954-e76542fe0ed7",
      "width": "512",
      "height": "512",
}  

Key	Description	Notes
dicom_instance_uid	The DICOM instance UID	DICOM tag value (0008,0018). More information can be found here
multiframe_frame_number	A field indicating the frame number when the JSON contains only a single label	Displays null when each slice has its only expandable labels instance
file_uri	This slice’s URI	Identifies this slice
height	The slice’s height (in pixel)	DICOM tag value (0028,0010). More information can be found here
width	The slice’s width (in pixel)	DICOM tag value (0028,0011). More information can be found here

metadata

The slice metadata contains information on the DICOM study, the DICOM series, as well as the patient.

"metadata": {
      "patient_id": "ENC-ORD-LUV-031023",
      "study_uid": "null",
      "series_uid":"cord-dicoms/H7sLTXjYbrou3GhfmHRiuE5m92/5adba3dd-09f6-5c95-b954-e76542fe0ed7",
}  

Key	Description	Notes
patient_id	The patient ID	DICOM tag value (0010,0020). More information can be found here
study_uid	The DICOM study’s ID	DICOM tag value (0020,000D). More information can be found here
series_uid	The DICOM series’ ID	DICOM tag value (0020,000E). More information can be found here

object_answers

object_answers is a list of objects that have at least one nested attribute and contains information for all attributes. Expanding object_answers reveals the following:

"object_answers": {
  "Gqh06ypx"
      "objectHash": "Gqh06ypx",
      "classifications" [ 
        "name": "Size",
        "value": "size",
        "answers": "Medium",
        "featureHash": "GZnFumFq",
        "manualAnnotation": true
      ]
}  

Key	Description	Notes
objectHash	The hash of the object containing the attributes	The ‘hash’ represents a unique identifier
classifications	A list of attributes related to the object. Includes Dynamic attributes and Relation attributes.	Not to be confused with classifications as defined in our glossary, which apply to a frame
name	The attribute name
value	The attribute value	Always the same as the name
answers	The value(s) the attribute(s) were set to	If the attribute was a radio button, the answer is the option selected by the annotator
featureHash	The attribute’s hash	The ‘hash’ represents a unique identifier
manualAnnotation	A field indicating whether the object was drawn manually or not	true means it was drawn manually, while false means it was created using a model or an automated labeling technique

classification_answers

classification_answers a list of frame classifications in which each classification is represented by its hash. Expanding classification_answers reveals the following:

"classification_answers": {
  "OFX2jzwE": {
    "classificationHash": "OFX2jzwE", 
    "classifications": [{
      "name": "Quality", 
      "value": "quality", 
      "answers": [{
        "name": "out of focus", 
        "value": "out_of_focus", 
        "featureHash": "j/7dpSmi"}],    
    "featureHash": "uZmB5YZC", 
    "manualAnnotation": true
    }]
  }
}

Key	Description	Notes
classificationHash	The classification’s hash	The ‘hash’ represents a unique identifier
classifications	A list of information about the classification
name	The classification name	As set in the ontology (Quality in the example above)
value	The classification value	Always the same as the classification name
answers	A list of all classification answers	”answers” refer to the values the classification were set to.
name	The name of the classification answer	”out of focus” in the example above
value	The classification answer’s value	Always the same as the classification answer’s name
featureHash	The hash for the particular classification answer	Included in answers
featureHash	The hash for the particular classification
manualAnnotation	true for all manually created labels. false for all labels created with automated labeling techniques

export_history

The export_history contains a list of all exports for this data unit, the first entry being the current export. Each instance contains the following:

"export_history": {
  "0"
      "export_hash": "Gqh06ypx",
      "exported_at": "Mon, 02 Oct 2023 13:47:45 UTC",
      "user_email": "[e-mail]"
}  

Key	Description	Notes
export_hash	The export instance’s hash	The ‘hash’ represents a unique identifier
exported_at	Date and time of the export
user_email	The email of the user that made this export

---

Audio

The export contains a list of JSON objects, with each JSON object representing a single data unit and containing detailed information for all exported labels.

The example below describes all the keys for a single exported data unit.

[
    {
        "classification_answers": {},
        "created_at": "2025-01-09 15:58:20",
        "data_hash": "ffd810f4-f503-46ac-b54f-bd5f8057f440",
        "data_title": "beautiful-tune.mp3",
        "data_type": "audio",
        "data_units": {
        },
        "dataset_hash": "3696067a-7e68-4d25-b09d-517877e13f06",
        "dataset_title": "Music",
        "is_image_sequence": null,
        "is_valid": true,
        "label_hash": "a384bab6-9443-4932-a862-c5c18f39c88b",
        "label_status": "LABELLED",
        "last_edited_at": "2025-01-09 15:58:35",
        "object_actions": {},
        "object_answers": {}
    }
]

Key	Description	Notes
label_hash	The Label Row hash	The ‘hash’ represents a unique identifier
created_at	Time and date the label was created
last_edited_at	Time and date the label was last edited
dataset_hash	The Dataset’s hash	The ‘hash’ represents a unique identifier
data_type	The data unit’s file format	Always “video” for videos
is_image_sequence	”true” when the data unit is an image sequence	Always “null” for images
video_link	Contains a private cloud URL for videos	Always “null” for images
data_units	List of all files the data unit is composed of	Details of the export information for `data_units“ can be found below.
object_answers	All the attributes in this data unit	The object attributes are identified using their hash
classification_answers	All the classifications in a particular data unit	The classification labels are identified using their hash
object_actions	The number of states a dynamic attribute can be in.	A change in state occurs each time the attribute answer changes. The objectHash within the object_actions is the attribute answer’s ID.
label_status	Indicates whether the data unit has been labeled.
export_history	Contains a record of the export history for this data unit	Exporting labels to confirm export history generates an export history entry.
export_hash	The hash for this particular export instance	The ‘hash’ represents a unique identifier
exported_at	The date and time when a particular export instance took place.

classification_answers

classification_answers a list of frame classifications in which each classification is represented by its hash. Expanding classification_answers reveals the following:

"classification_answers": {
    "yRY6RT5j": {
        "classificationHash": "yRY6RT5j",
        "classifications": [
            {
                "answers": [
                    {
                        "featureHash": "h6dn9yfZ",
                        "name": "No ",
                        "value": "no_"
                    }
                ],
                "featureHash": "+n1+XoVr",
                "manualAnnotation": true,
                "name": "Good Song?",
                "value": "good_song?"
            }
        ],
        "confidence": null,
        "createdAt": "Thu, 09 Jan 2025 15:58:27 GMT",
        "createdBy": "[e-mail]",
        "featureHash": "lQS4psvP",
        "lastEditedAt": "Thu, 09 Jan 2025 15:58:27 GMT",
        "lastEditedBy": "[e-mail]",
        "manualAnnotation": true,
        "range": [
            [
                0,
                132963
            ]
        ]
    }
},

Key	Description	Notes
classificationHash	The classification’s hash	The ‘hash’ represents a unique identifier
classifications	A list of information about the classification
name	The classification name	As set in the ontology (Quality in the example above)
value	The classification value	Always the same as the classification name
answers	A list of all classification answers	”answers” refer to the values the classification were set to.
name	The name of the classification answer	”out of focus” in the example above
value	The classification answer’s value	Always the same as the classification answer’s name
featureHash	The hash for the particular classification answer	Included in answers
featureHash	The hash for the particular classification
manualAnnotation	true for all manually created labels. false for all labels created with automated labeling techniques
range	The time span on which the classification label is applied	Measured in milliseconds (ms)

data_units

The data_units key contains all files that compose the data unit. For a given image there is only ever a single element in this list. This element contains the following information.

data_units here refer to individual files that compose a data unit, as defined in our glossary, and are not to be confused with data units elsewhere in the platform. Encord will update this nomenclature soon, but we always communicate changes to all customers first.

"data_units": {
  "ffd810f4-f503-46ac-b54f-bd5f8057f440": {
      "audio_bit_depth": 32,
      "audio_codec": "mp3float",
      "audio_num_channels": 2,
      "audio_sample_rate": 44100,
      "data_duration": 132.96327,
      "data_hash": "ffd810f4-f503-46ac-b54f-bd5f8057f440",
      "data_link": "gs://cord-ai-platform.appspot.com/cord-audio-prod/iaDJxNNrMuQMtFPcP9oszw2OCHm2/6e235f70-8ade-4bb6-8d76-d3010d7deda3",
      "data_sequence": 0,
      "data_title": "beautiful-tune.mp3",
      "data_type": "audio/mpeg",
      "labels": {}
  }
}

Key	Description	Notes
data_hash	The file’s hash	The ‘hash’ represents a unique identifier
data_title	The file’s title
data_type	The file type
data_sequence	The sequence number of this file within the data unit	Always 0 for images, as single images are composed of a single file by definition
labels	A container for the image’s label information	This contains the label information for the image.
data_link	A link to the file stored in your private cloud
width	The width of the image in pixel (px)
height	The height of the image in pixel (px)

object_answers

object_answers contains all the object labels that have at least one nested attribute and contains information for all attributes. Expanding object_answers reveals the following:

"object_answers": {
    "zcmSZzvI": {
        "classifications": [],
        "confidence": null,
        "createdAt": "Thu, 09 Jan 2025 15:58:24 GMT",
        "createdBy": "[e-mail]",
        "featureHash": "1uLJrW4C",
        "lastEditedAt": "Thu, 09 Jan 2025 15:58:24 GMT",
        "lastEditedBy": "[e-mail]",
        "manualAnnotation": true,
        "objectHash": "zcmSZzvI",
        "range": [
                    [
                        14287,
                        51843
                    ]
        ]
    }
}

Key	Description	Notes
objectHash	The hash of the object containing the attributes	The ‘hash’ represents a unique identifier
classifications	A list of attributes related to the object.	Not to be confused with classifications as defined in our glossary, which apply to a frame
name	The attribute name
value	The attribute value	Always the same as the name
answers	The value(s) the attribute(s) were set to	If the attribute was a radio button, the answer is the option selected by the annotator
featureHash	The attribute’s hash	The ‘hash’ represents a unique identifier
manualAnnotation	A field indicating whether the object was drawn manually or not	true means it was drawn manually, while false means it was created using a model or an automated labeling technique
range	The time span on which the object label is applied	Measured in milliseconds (ms)

Text

The export contains a list of JSON objects, with each JSON object representing a single data unit and containing detailed information for all exported labels.

The example below describes all the keys for a single exported data unit.

[
    {
        "classification_answers": {},
        "created_at": "2025-01-11 14:58:20",
        "data_hash": "ffd810f4-f503-46ac-b54f-bd5f8057f440",
        "data_title": "encord-website.html",
        "data_type": "plain_text",
        "data_units": {
        },
        "dataset_hash": "3696067a-7e68-4d25-b09d-517877e13f06",
        "dataset_title": "HTML Text",
        "is_image_sequence": null,
        "is_valid": true,
        "label_hash": "a384bab6-9443-4932-a862-c5c18f39c88b",
        "label_status": "LABELLED",
        "last_edited_at": "2025-01-09 15:58:35",
        "object_actions": {},
        "object_answers": {}
    }
]

Key	Description	Notes
label_hash	The Label Row hash	The ‘hash’ represents a unique identifier
created_at	Time and date the label was created
last_edited_at	Time and date the label was last edited
dataset_hash	The Dataset’s hash	The ‘hash’ represents a unique identifier
data_type	The data unit’s file format	Always “video” for videos
is_image_sequence	”true” when the data unit is an image sequence	Always “null” for images
video_link	Contains a private cloud URL for videos	Always “null” for images
data_units	List of all files the data unit is composed of	Details of the export information for `data_units“ can be found below.
object_answers	All the attributes in this data unit	The object attributes are identified using their hash
classification_answers	All the classifications in a particular data unit	The classification labels are identified using their hash
object_actions	The number of states a dynamic attribute can be in.	A change in state occurs each time the attribute answer changes. The objectHash within the object_actions is the attribute answer’s ID.
label_status	Indicates whether the data unit has been labeled.
export_history	Contains a record of the export history for this data unit	Exporting labels to confirm export history generates an export history entry.
export_hash	The hash for this particular export instance	The ‘hash’ represents a unique identifier
exported_at	The date and time when a particular export instance took place.

classification_answers

classification_answers a list of frame classifications in which each classification is represented by its hash. Expanding classification_answers reveals the following:

"classification_answers": {
    "EpcchMiS": {
        "classificationHash": "EpcchMiS",
        "classifications": [
            {
                "answers": [
                    {
                        "featureHash": "4EbpTJ8E",
                        "name": "Single Extension",
                        "value": "single_extension"
                    }
                ],
                "featureHash": "/Kt0x2uF",
                "manualAnnotation": true,
                "name": "HTML Type",
                "value": "html_type"
            }
        ],
        "confidence": null,
        "createdAt": "Tue, 07 Jan 2025 12:25:12 GMT",
        "createdBy": "[e-mail]",
        "featureHash": "yboRL9Pm",
        "lastEditedAt": "Tue, 07 Jan 2025 12:25:12 GMT",
        "lastEditedBy": "[e-mail]",
        "manualAnnotation": true,
        "range": [
            [
                0,
                0
            ]
        ]
    }
}

Key	Description	Notes
classificationHash	The classification’s hash	The ‘hash’ represents a unique identifier
classifications	A list of information about the classification
name	The classification name	As set in the ontology (Quality in the example above)
value	The classification value	Always the same as the classification name
answers	A list of all classification answers	”answers” refer to the values the classification were set to.
name	The name of the classification answer	”out of focus” in the example above
value	The classification answer’s value	Always the same as the classification answer’s name
featureHash	The hash for the particular classification answer	Included in answers
featureHash	The hash for the particular classification
manualAnnotation	true for all manually created labels. false for all labels created with automated labeling techniques
range	The frame range on which the classification label is applied

data_units

The data_units key contains all files that compose the data unit. For a given image there is only ever a single element in this list. This element contains the following information.

data_units here refer to individual files that compose a data unit, as defined in our glossary, and are not to be confused with data units elsewhere in the platform. Encord will update this nomenclature soon, but we always communicate changes to all customers first.

"data_units": {
  "ffd810f4-f503-46ac-b54f-bd5f8057f440": {
      "audio_bit_depth": 32,
      "audio_codec": "mp3float",
      "audio_num_channels": 2,
      "audio_sample_rate": 44100,
      "data_duration": 132.96327,
      "data_hash": "ffd810f4-f503-46ac-b54f-bd5f8057f440",
      "data_link": "gs://cord-ai-platform.appspot.com/cord-audio-prod/iaDJxNNrMuQMtFPcP9oszw2OCHm2/6e235f70-8ade-4bb6-8d76-d3010d7deda3",
      "data_sequence": 0,
      "data_title": "beautiful-tune.mp3",
      "data_type": "audio/mpeg",
      "labels": {}
  }
}

Key	Description	Notes
data_hash	The file’s hash	The ‘hash’ represents a unique identifier
data_title	The file’s title
data_type	The file type
data_sequence	The sequence number of this file within the data unit	Always 0 for images, as single images are composed of a single file by definition
labels	A container for the image’s label information	This contains the label information for the image.
data_link	A link to the file stored in your private cloud
width	The width of the image in pixel (px)
height	The height of the image in pixel (px)

object_answers

object_answers contains all the object labels that have at least one nested attribute and contains information for all attributes. Expanding object_answers reveals the following:

"object_answers": {
    "YFfOG14v": {
        "classifications": [],
        "confidence": null,
        "createdAt": "Tue, 07 Jan 2025 12:25:36 GMT",
        "createdBy": "[e-mail]",
        "featureHash": "AZfKc9b7",
        "lastEditedAt": "Tue, 07 Jan 2025 12:25:36 GMT",
        "lastEditedBy": "[e-mail]",
        "manualAnnotation": true,
        "objectHash": "YFfOG14v",
        "range": [],
        "range_html": [
            {
                "end": {
                    "node": "/html[1]/body[1]/div[1]/div[1]/div[1]/main[1]/div[2]/div[1]/section[1]/section[1]/article[1]/section[1]/section[1]/p[1]/text()[1]",
                    "offset": 245
                },
                "start": {
                    "node": "/html[1]/body[1]/div[1]/div[1]/div[1]/main[1]/div[2]/div[1]/section[1]/section[1]/article[1]/section[1]/section[1]/p[1]/text()[1]",
                    "offset": 125
                }
            }
        ]
    }
}

Key	Description	Notes
objectHash	The hash of the object containing the attributes	The ‘hash’ represents a unique identifier
classifications	A list of attributes related to the object.	Not to be confused with classifications as defined in our glossary, which apply to a frame
name	The attribute name
value	The attribute value	Always the same as the name
answers	The value(s) the attribute(s) were set to	If the attribute was a radio button, the answer is the option selected by the annotator
featureHash	The attribute’s hash	The ‘hash’ represents a unique identifier
manualAnnotation	A field indicating whether the object was drawn manually or not	true means it was drawn manually, while false means it was created using a model or an automated labeling technique
range	The frame range on which the object label is applied
range_html	Provides detailed information about the specific section of the text file being labeled
start	Start point of the label
end	End point of the label
offset	An integer that specifies the character position within the identified node	For example { "offset": 125 } means the label starts / ends at the 125th character in the node

PDF

[
  {
    "label_hash": "f0159daf-a1c2-43e3-b516-633d5f3e513a",
    "created_at": "2025-08-28 08:32:24",
    "last_edited_at": "2025-11-18 11:56:16",
    "dataset_hash": "cbfa26a0-3608-473d-a8ae-aa40649aedc4",
    "dataset_title": "Documents",
    "data_title": "lyrics.pdf",
    "data_hash": "e7f7ce04-45b4-4645-af71-24d9159f32c2",
    "data_type": "application/pdf",
    "is_image_sequence": null,
    "video_link": null,
    "data_units": {},
    "classification_answers": {},
    "object_actions": {},
    "object_answers": {},
    "label_status": "LABEL_IN_PROGRESS",
    "export_history": [],
    "export_hash": null,
    "exported_at": null,
    "branch_name": "main",
    "backing_item_uuid": "d3b340a5-786d-44f6-b097-e569672c2948",
    "is_valid": true
  }
]

Key	Description	Notes
label_hash	The Label Row hash	The ‘hash’ represents a unique identifier
created_at	Time and date the label was created
last_edited_at	Time and date the label was last edited
dataset_hash	The Dataset’s hash	The ‘hash’ represents a unique identifier
data_type	The data unit’s file format. In this case PCD scene	Always “video” for videos
is_image_sequence	”true” when the data unit is an image sequence	Always “null” for images
video_link	Contains a private cloud URL for videos	Always “null” for images
data_units	List of all files the data unit is composed of	Details of the export information for `data_units“ can be found below.
object_answers	All the attributes in this data unit	The object attributes are identified using their hash
classification_answers	All the classifications in a particular data unit	The classification labels are identified using their hash
object_actions	The number of states a dynamic attribute can be in.	A change in state occurs each time the attribute answer changes. The objectHash within the object_actions is the attribute answer’s ID.
label_status	Indicates whether the data unit has been labeled.
export_history	Contains a record of the export history for this data unit	Exporting labels to confirm export history generates an export history entry.
export_hash	The hash for this particular export instance	The ‘hash’ represents a unique identifier
exported_at	The date and time when a particular export instance took place.
branch_name	The name of the branch the label is on
backing_item_uuid	The unique ID of the scene in Encord’s storage on

data_units

The data_units key contains all files that compose the data unit. For a given image there is only ever a single element in this list. This element contains the following information.

data_units here refer to individual files that compose a data unit, as defined in our glossary, and are not to be confused with data units elsewhere in the platform. Encord will update this nomenclature soon, but we always communicate changes to all customers first.

{
"data_units": {
  "e7f7ce04-45b4-4645-af71-24d9159f32c2": {
    "data_hash": "e7f7ce04-45b4-4645-af71-24d9159f32c2",
    "data_title": "NeverGonnaGiveYouUp.pdf",
    "data_type": "",
    "data_sequence": 0,
    "labels": {}
  }
}
}

Key	Description	Notes
data_hash	The file’s hash	The ‘hash’ represents a unique identifier
data_title	The file’s title
data_type	The file type
data_sequence	The sequence number of this file within the data unit
labels	A container for the image’s label information. See the relevant Ontology Shapes section for more information	This contains the label information for the frame.

PCD

[
  {
    "label_hash": "f0159daf-a1c2-43e3-b516-633d5f3e513a",
    "created_at": "2025-08-28 08:32:24",
    "last_edited_at": "2025-11-18 11:56:16",
    "dataset_hash": "cbfa26a0-3608-473d-a8ae-aa40649aedc4",
    "dataset_title": "Nuscenes",
    "data_title": "scene-0553",
    "data_hash": "e7f7ce04-45b4-4645-af71-24d9159f32c2",
    "data_type": "scene",
    "is_image_sequence": null,
    "video_link": null,
    "data_units": {},
    "classification_answers": {},
    "object_actions": {},
    "object_answers": {},
    "label_status": "LABEL_IN_PROGRESS",
    "export_history": [],
    "export_hash": null,
    "exported_at": null,
    "branch_name": "main",
    "backing_item_uuid": "d3b340a5-786d-44f6-b097-e569672c2948",
    "is_valid": true
  }
]

Key	Description	Notes
label_hash	The Label Row hash	The ‘hash’ represents a unique identifier
created_at	Time and date the label was created
last_edited_at	Time and date the label was last edited
dataset_hash	The Dataset’s hash	The ‘hash’ represents a unique identifier
data_type	The data unit’s file format. In this case PCD scene	Always “video” for videos
is_image_sequence	”true” when the data unit is an image sequence	Always “null” for images
video_link	Contains a private cloud URL for videos	Always “null” for images
data_units	List of all files the data unit is composed of	Details of the export information for `data_units“ can be found below.
object_answers	All the attributes in this data unit	The object attributes are identified using their hash
classification_answers	All the classifications in a particular data unit	The classification labels are identified using their hash
object_actions	The number of states a dynamic attribute can be in.	A change in state occurs each time the attribute answer changes. The objectHash within the object_actions is the attribute answer’s ID.
label_status	Indicates whether the data unit has been labeled.
export_history	Contains a record of the export history for this data unit	Exporting labels to confirm export history generates an export history entry.
export_hash	The hash for this particular export instance	The ‘hash’ represents a unique identifier
exported_at	The date and time when a particular export instance took place.
branch_name	The name of the branch the label is on
backing_item_uuid	The unique ID of the scene in Encord’s storage on

data_units

The data_units key contains all files that compose the data unit. For a given image there is only ever a single element in this list. This element contains the following information.

data_units here refer to individual files that compose a data unit, as defined in our glossary, and are not to be confused with data units elsewhere in the platform. Encord will update this nomenclature soon, but we always communicate changes to all customers first.

{
"data_units": {
  "e7f7ce04-45b4-4645-af71-24d9159f32c2": {
    "data_hash": "e7f7ce04-45b4-4645-af71-24d9159f32c2",
    "data_title": "scene-0553",
    "data_type": "",
    "data_sequence": 0,
    "labels": {}
  }
}
}

Key	Description	Notes
data_hash	The file’s hash	The ‘hash’ represents a unique identifier
data_title	The file’s title
data_type	The file type
data_sequence	The sequence number of this file within the data unit
labels	A container for the image’s label information. See the relevant Ontology Shapes section for more information	This contains the label information for the frame.

---

Ontology Shapes

Exports contain the Ontology shape coordinates used to create the label.

Bounding Box

x and y represent coordinates of the top-left corner of the box. h and w respectively represent the height and width of the box.

 "boundingBox": {
    "h": 0.118,
    "w": 0.1643,
    "x": 0.6985,
    "y": 0.6204
 }

Polygon

This is a legacy field used by existing customers. We recommend new customers use the polygons field below.

The polygon list contains the x and y coordinates for all vertices in a simple polygon. For complex polygons, see the polygons field below.

"polygon": {
  "0": {
    "x": 0.2423,
    "y": 0.5115,
  },
  "1": {
    "x": 0.4167,
    "y": 0.4218,   
          },
  "2": {
    "x": 0.5821,
    "y": 0.4641,   
          },
  "3": {
    "x": 0.5808,
    "y": 0.5756,   
          },
  "4": {
    "x": 0.4564,
    "y": 0.6397,   
          }
  }

Polygons

Polygons can have complex shapes, including being enclosed in one another, and encompassing separate regions. In each case the polygon’s coordinates are arranged in a different way.

Polyline

Polylines contain the x and y coordinates for each vertex.

 "polyline": {
  "0": {
    "x": 0.2423,
    "y": 0.5115,
  },
  "1": {
    "x": 0.4167,
    "y": 0.4218,   
          },
  "2": {
    "x": 0.5821,
    "y": 0.4641,   
          },
  "3": {
    "x": 0.5808,
    "y": 0.5756,   
          },
  "4": {
    "x": 0.4564,
    "y": 0.6397,   
          }
  }

Keypoint

Keypoints are represented in the export using only x and y coordinates.

 "point": {
    "0": {
      "x": 0.3192,
      "y": 0.1547,
  }
 }

Rotatable Bounding Box

x and y represent the coordinates of the top-left corner of the unrotated box. h and w respectively represent the height and width of the box, while theta represents the angle of clockwise rotation of the bounding box about the center of the box.

 "rotatableBoundingBox": {
    "h": 0.118,
    "w": 0.1643,
    "x": 0.6985,
    "y": 6204,
    "theta": 305.7762
 }

Bitmask

The rleString encodes the Bitmask label, and has to be decoded. See our SDK documentation to learn how to decode an rleString.

"objects": [
      {
        "bitmask": {
          "rleString": "02220N:0F20N",
          "top": 0,
          "left": 0,
          "width": 6,
          "height": 6
        }
      }
  ]  

Object Primitive

Object primitives are referred to as skeletons in the export. Each point on the object primitive is represented in the export using x and y coordinates.

Below is an example of an object primitive with 3 points.

"skeleton": {
  "0": {
    "x": 0.5719,
    "y": 0.7615,
    "name": "point_0",
    "color": "#fcc400",
    "value": "point_0",
    "featureHash": "qPCTeIci"
    },
    "1": {
    "x": 0.5428,
    "y": 0.6734,
    "name": "point_1",
    "color": "#fcc400",
    "value": "point_1",
    "featureHash": "o1NKWqKP",
    "invisible": true
    },
    "2": {
    "x": 0.4865,
    "y": 0.6464,
    "name": "point_2",
    "color": "#fcc400",
    "value": "point_2",
    "featureHash": "9bgJBA85",
    "occluded": true
    }
}

Key	Description	Notes
name	Name of this point	As set in the Ontology
color	The hexadecimal color code used to represent this point	As set in the Ontology
featureHash	The hash for this particular point	the ‘hash’ is a unique identifier
occluded	This point is marked as occluded	if the point was left on the default setting (visible) this key is omitted
invisible	This point is marked as invisible	if the point was left on the default setting (visible) this key is omitted

Cuboid

Cuboid labels are 3D labels and therefore contain the position, orientation, and dimensions of the cuboid.

"cuboid": {
  {
  "cuboid": {
    "position": [4.537997746722736, -4.036436904027065, 1.0422150246829245],
    "orientation": [7.400697375091305e-17, 2.0779014832905546e-16, 2.5017234942760873],
    "size": [2.9918133567776724, 2.386963438734146, 1.4666344382239702]
    }
  }
}

Key	Description	Notes
position	The X,Y, Z coordinates of the cuboid’s center	Expressed in the world coordinate system
orientation	Euler angles (Roll, Pitch, Yaw) of the label’s orientation	In units of radians
size	Dimensions of the cuboid in its local coordinate frame.	Length along the cuboid’s local X-axis, width along the cuboid’s local Y-axis, height along the cuboid’s local Z-axis

Segmentation

Segmentations are exported as rleStrings. See our section on exporting Bitmasks & Segmentations to learn more.

{
  "segmentation": "bj41o000000000000O1000O11O00001O00O1001O000001O00000000000000000000000O10000000O10000000000000000000000000000000000O1000000001OO1000O100000O10000000000000000000000001OO1000O1OSO0l0200000O1000000000000000000000000O10",
  "shape": "segmentation"
}

Export Bitmasks & Segmentations

Bitmask labels are exported as rleStrings. See our SDK documentation to learn how to decode an rleString.

We strongly recommend exporting Bitmask labels using the Encord SDK. Bitmasks are exported in the JSON format.

Use the COCO API to decode Bitmasks when using the COCO export format.

Exporting Data Groups

When exporting Data Group labels, 1 JSON file the Data Group plus 1 JSON for each data unit in the Data Group are generated.

Data Groups Label Export

[
  {
    "label_hash": "c401d331-71f7-46c0-a279-40bc33ff4565",
    "branch_name": "main",
    "created_at": "2026-01-09 14:35:59",
    "last_edited_at": "2026-01-09 16:41:52",
    "dataset_hash": "6d1cfc37-afd3-481c-8984-55721c272ca9",
    "dataset_title": "Surgery Videos",
    "data_title": "Patient 1",
    "data_hash": "faa047cf-b980-408a-2fb7-01e59a55a3c4",
    "backing_item_uuid": "ab8450fa-ca17-4o24-9c4b-82c5441491ae",
    "data_type": "group",
    "is_image_sequence": null,
    "data_units": {
      "faa047cf-b980-408a-8fb7-01e59a35a3c4": {
        "data_hash": "faa047cf-b980-408a-8fb7-01e5gda35a3c4",
        "data_title": "Patient 1",
        "data_type": "application/vnd.encord.data.group",
        "data_sequence": 0,
        "labels": {},
        "metadata": {
          "children": [
            {
              "data_hash": "10a19807-7d3b-4be5-9hb0-ab23c22b06b",
              "name": "surgery_1",
              "label_hash": "0ea6dac2-7186-42ba-85f7-b94560f0f28b",
              "layout_key": "1"
            },
            {
              "data_hash": "20f42de1-d795-4e58-b70e-130af35c910",
              "name": "surgery_2",
              "label_hash": "97c007da-932c-4a8d-a221-9ec212d7d30",
              "layout_key": "2"
            },
            {
              "data_hash": "d0d19621-7d53-4b25-af54-454ae125caf7",
              "name": "surgery_3",
              "label_hash": "8c49a5ce-7bbc-4051-84fe-c21582218329",
              "layout_key": "3"
            }
          ]
        }
      }
    },
    "object_answers": {
      "4+ss5MKZ": {
        "objectHash": "4+ss5MKZ",
        "featureHash": "/tay334G",
        "classifications": [],
        "range": [],
        "createdAt": null,
        "createdBy": "[e-mail]",
        "lastEditedAt": "Tue, 07 Jan 2025 12:25:36 GMT",
        "lastEditedBy": "[e-mail]",
        "spaces": {
          "929bf651-8702-4c3d-ac1c-2debfb4d7991": {
            "type": "frame",
            "range": [
              [0, 2]
            ]
          }
        }
      }
    },
    "classification_answers": {
      "8f2a1b9c-4d5e-6f7a-8b9c-0d1e2f3a4b5c": {
        "classificationHash": "8f2a1b9c-4d5e-6f7a-8b9c-0d1e2f3a4b5c",
        "classificationName": "Type of Surgery",
        "featureHash": "g9h8i7j6",
        "manualAnnotation": true,
        "answers": [
          {
            "featureHash": "k5l4m3n2",
            "name": "Heart",
            "value": "heart"
          }
        ]
      }
    },
    "object_actions": {},
    "label_status": "LABEL_IN_PROGRESS",
    "is_valid": true,
    "spaces": {
      "b2bcfcbd-b2df-4690-aa17-3d4a8f055a74": {
        "labels": {},
        "space_type": "video",
        "child_info": {
          "layout_key": "1",
          "file_name": "surgery_1"
        },
        "number_of_frames": 2182,
        "width": 1280,
        "height": 720
      },
      "929bf651-8702-4c3d-ac1c-2debfb4d7991": {
        "labels": {
          "0": {
            "objects": [
              {
                "objectHash": "4+ss5MKZ",
                "featureHash": "/tay334G",
                "name": "New object",
                "color": "#D33115",
                "value": "new_object",
                "createdAt": "Fri, 09 Jan 2026 14:35:59 UTC",
                "confidence": 1,
                "lastEditedAt": "Fri, 09 Jan 2026 14:35:59 UTC",
                "shape": "bounding_box",
                "createdBy": "[e-mail]",
                "lastEditedBy": "[e-mail]",
                "manualAnnotation": true,
                "boundingBox": {
                  "h": 0.2,
                  "w": 0.3,
                  "x": 0.6,
                  "y": 0.4
                }
              }
            ],
            "classifications": []
          }
        },
        "space_type": "video",
        "child_info": {
          "layout_key": "2",
          "file_name": "surgery_2"
        },
        "number_of_frames": 3239,
        "width": 1280,
        "height": 720
      },
      "ff9b7c98-67c0-4c16-a4cb-0ae3b7ab42ab": {
        "labels": {},
        "space_type": "video",
        "child_info": {
          "layout_key": "3",
          "file_name": "surgery_3"
        },
        "number_of_frames": 1558,
        "width": 640,
        "height": 360
      }
    }
  }
]

Key	Description	Notes
label_hash	The Label Row hash	The ‘hash’ represents a unique identifier
branch_name	The branch the label belongs to	main is the default branch in non-Consensus Projects
created_at	Time and date the label was created
last_edited_at	Time and date the label was last edited
dataset_hash	The Dataset’s hash	The ‘hash’ represents a unique identifier
dataset_title	The name of the Dataset
data_title	The Data Group’s name
data_type	The data unit’s file format	Always group for Data Groups
is_image_sequence	”true” when the data unit is an image sequence	Always “null” for Data Groups
data_units	List of all files the Data Group is composed of	Details of the export information for data_units can be found below
data_hash	The Data Group hash.	The ‘hash’ represents a unique identifier for the Data Group
data_title	The Data Group’s name
data_type	The data unit’s file format	Always group for Data Groups
data_sequence	The sequence number of this file within the data unit.	0 represents the first file
labels	A list of all frames contained in the Data Group	This value is always 0
metadata	Lists the metadata on the Data Group
children	lists the data units contained in the Data Group	layout_key specifies where in the Data Group the data units appears in the Label Editor
object_answers	All the attributes in this data unit	The object attributes are identified using their hash
classification_answers	All the classifications in a particular data unit	The classification labels are identified using their hash
object_actions	The number of states a dynamic attribute can be in.	A change in state occurs each time the attribute answer changes. The objectHash within the object_actions is the attribute answer’s ID.
label_status	Indicates whether the data unit has been labeled
is_valid	Indicates whether the Data Group is valid
spaces	Root-level map of labeling spaces	Maps individual data spaces to metadata describing their structure and characteristics.
labels	Frame-level annotations	Keyed by frame number (as a string). Contains objects and classifications specific to that frame
space_type	The type of media in this space
child_info	Metadata linking the space to a child unit
number_of_frames	Total frames available in this space
width	The pixel width of the media
height	The pixel height of the media
layout_key	The unique identifier used to position the file within the Label Editor layout
file_name	The name of the specific file associated with this space.
type	The unit of measurement for the range	For example frame
range	The range the object or classification occurs on

Multi-Layer Data Groups

Multi-layer Data Groups contain a root key that contains properties pertaining to the Data Group as a whole.

Exporting Labels using the SDK

Go here to learn how to export labels using SDK.

Label Branches

The branch associated with the labels is specified using the branch_name key.

The main branch is always displayed first and is identified by the following value:

"branch_name": "main"