Creating an annotation task

  1. Create an annotation task pressing Create new task button on the tasks page or on the project page.

  2. Specify parameters of the task:

    Basic configuration


    The name of the task to be created.


    The project that this task will be related with.


    There are two ways of working with labels (available only if the task is not related to the project):

    • The Constructor is a simple way to add and adjust labels. To add a new label click the Add label button.

      You can set a name of the label in the Label name field and choose a color for each label.

      If necessary you can add an attribute and set its properties by clicking Add an attribute:

      The following actions are available here:

      1. Set the attribute’s name.
      2. Choose the way to display the attribute:
        • Select — drop down list of value
        • Radio — is used when it is necessary to choose just one option out of few suggested.
        • Checkbox — is used when it is necessary to choose any number of options out of suggested.
        • Text — is used when an attribute is entered as a text.
        • Number — is used when an attribute is entered as a number.
      3. Set values for the attribute. The values could be separated by pressing Enter. The entered value is displayed as a separate element which could be deleted by pressing Backspace or clicking the close button (x). If the specified way of displaying the attribute is Text or Number, the entered value will be displayed as text by default (e.g. you can specify the text format).
      4. Checkbox Mutable determines if an attribute would be changed frame to frame.
      5. You can delete the attribute by clicking the close button (x).

      Click the Continue button to add more labels. If you need to cancel adding a label - press the Cancel button. After all the necessary labels are added click the Done button. After clicking Done the added labels would be displayed as separate elements of different colour. You can edit or delete labels by clicking Update attributes or Delete label.

    • The Raw is a way of working with labels for an advanced user. Raw presents label data in json format with an option of editing and copying labels as a text. The Done button applies the changes and the Reset button cancels the changes.

    In Raw and Constructor mode, you can press the Copy button to copy the list of labels.

    Select files

    Press tab My computer to choose some files for annotation from your PC. If you select tab Connected file share you can choose files for annotation from your network. If you select Remote source , you’ll see a field where you can enter a list of URLs (one URL per line). If you upload a video or dataset with images and select Use cache option, you can attach a manifest.jsonl file. You can find how to prepare it here.

    Data formats for a 3D task

    To create a 3D task, you need to use the following directory structures:

          IMAGE_00  # unknown dirname, Generally image_01.png can be under IMAGE_00, IMAGE_01, IMAGE_02, IMAGE_03, etc
                  image_01.png # or any other image
        3D, DEFAULT DATAFORMAT Option 1
        3D, DEFAULT DATAFORMAT Option 2
                context_1.png  # or any other name

    Advanced configuration

    Use zip chunks

    Force to use zip chunks as compressed data. Actual for videos only.

    Use cache

    Defines how to work with data. Select the checkbox to switch to the “on-the-fly data processing”, which will reduce the task creation time (by preparing chunks when requests are received) and store data in a cache of limited size with a policy of evicting less popular items. See more here.

    Image Quality

    Use this option to specify quality of uploaded images. The option helps to load high resolution datasets faster. Use the value from 5 (almost completely compressed images) to 100 (not compressed images).

    Overlap Size

    Use this option to make overlapped segments. The option makes tracks continuous from one segment into another. Use it for interpolation mode. There are several options for using the parameter:

    • For an interpolation task (video sequence). If you annotate a bounding box on two adjacent segments they will be merged into one bounding box. If overlap equals to zero or annotation is poor on adjacent segments inside a dumped annotation file, you will have several tracks, one for each segment, which corresponds to the object.
    • For an annotation task (independent images). If an object exists on overlapped segments, the overlap is greater than zero and the annotation is good enough on adjacent segments, it will be automatically merged into one object. If overlap equals to zero or annotation is poor on adjacent segments inside a dumped annotation file, you will have several bounding boxes for the same object. Thus, you annotate an object on the first segment. You annotate the same object on second segment, and if you do it right, you will have one track inside the annotations. If annotations on different segments (on overlapped frames) are very different, you will have two shapes for the same object. This functionality works only for bounding boxes. Polygons, polylines, points don’t support automatic merge on overlapped segments even the overlap parameter isn’t zero and match between corresponding shapes on adjacent segments is perfect.

    Segment size

    Use this option to divide a huge dataset into a few smaller segments. For example, one job cannot be annotated by several labelers (it isn’t supported). Thus using “segment size” you can create several jobs for the same annotation task. It will help you to parallel data annotation process.

    Start frame

    Frame from which video in task begins.

    Stop frame

    Frame on which video in task ends.

    Frame Step

    Use this option to filter video frames. For example, enter 25 to leave every twenty fifth frame in the video or every twenty fifth image.

    Chunk size

    Defines a number of frames to be packed in a chunk when send from client to server. Server defines automatically if empty.

    Recommended values:

    • 1080p or less: 36
    • 2k or less: 8 - 16
    • 4k or less: 4 - 8
    • More: 1 - 4

    Dataset Repository

    URL link of the repository optionally specifies the path to the repository for storage (default: annotation / <dump_file_name> .zip). The .zip and .xml file extension of annotation are supported. Field format: URL [PATH] example: [1/2/3/4/annotation.xml]

    Supported URL formats :


    The task will be highlighted in red after creation if annotation isn’t synchronized with the repository.

    Use LFS

    If the annotation file is large, you can create a repository with LFS support.

    Issue tracker

    Specify full issue tracker’s URL if it’s necessary.

    Push Submit button and it will be added into the list of annotation tasks. Then, the created task will be displayed on a tasks page:

  3. The tasks page contains elements and each of them relates to a separate task. They are sorted in creation order. Each element contains: task name, preview, progress bar, button Open, and menu Actions. Each button is responsible for a in menu Actions specific function:

    • Dump Annotation and Export as a dataset — download annotations or annotations and images in a specific format. The following formats are available:
    • Upload annotation is available in the same formats as in Dump annotation.
      • CVAT accepts both video and image sub-formats.
      • Point Cloud Format 1.0 (Available in 3d task)
      • Velodyn points format 1.0 (Available in 3d task)
    • Automatic Annotation — automatic annotation with OpenVINO toolkit. Presence depends on how you build CVAT instance.
    • Export task — Export a task into a zip archive. Read more in the export/import a task section.
    • Move to project — Moving the task to the project (can be used to move a task from one project to another). Note that attributes reset during the moving process. In case of label mismatch, you can create or delete necessary labels in the project/task. Some task labels can be matched with the target project labels.
    • Delete — delete task.

Push Open button to go to task details.