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Multi-frame point

Alex Cota Updated by Alex Cota

You can use the Multi-frame point tool for annotating very detailed objects and their movement in a video. The Multi-frame point tool provides more granularity than the Multi-frame bounding box tool.

Video point tool

The following is not supported:

  • Text or dropdown classifications in export
  • Toggle on/off Point on a selection of frames
  • Undo/redo actions
  • Change an existing Point class
  • Copy/paste a Point on multiple frames at a time
  • Create Multi-frame point via the API
  • Exports for mixed media (e.g. videos & images in the same project)

Import your video data

First, create your project in Labelbox and ensure your videos are in .mp4 format. First, create your project in Labelbox and ensure your videos are in .mp4 format. To learn how to import your video files directly, see Direct upload. To learn how to import your video URLs via JSON, see Import via JSON. To learn how to attach metadata to your imported videos, see Asset metadata via JSON.

To learn how to import programmatically, see Bulk add data rows.

Free tier users will be able to load videos with up to 20,000 frames and 30fps.

Set up Multi-frame point

  1. Create a project.
  2. Select "Editor" as your label editor.
  3. Click "Add object" and name the object class.
  4. Select "Point" as your labeling tool.
  5. [OPTIONAL] Create nested classifications. Note: only Radio and Checklist are supported.
  6. Click "Confirm".
  7. Click "Complete setup".

How it works

There are two main components to creating multi-frame points:

  • The selected frames to persist the point
  • The point position on the frames

A keyframe is a frame on the timeline where a change occurs. Interpolated (tweened) frames are the ones between two keyframes. Labelbox uses interpolation to incrementally adjust the position of a point between two keyframes.

When a keyframe is created, a white dot on the frame distinguishes keyframes from all other frames.

Apply point to one or more frames
  • Apply a point at a single keyframe. By default, when you apply a point when a single frame is selected, that point will persist at the same position across all subsequent frames until the end of the video.
  • Apply a point to a set of frames. When you select a set of frames on the timeline and apply a point to the selection, the point will persist at the same position across each frame in the selection.
  • Toggle on/off a point. When an item in the video goes out of frame then reappears 1 or more frames later, use the toggle icon to turn on/off the point for that item. Note: Toggle on/off is only possible when a single frame is selected. You cannot toggle the point on or off when multiple frames are selected.
  • Copy/paste a point. When you copy and paste a point from one frame to another, it will be pasted at the same position. A new point instance is created out of the copied object and, by default, the point will persist until the last frame in the video. Note: Copy/paste on multiple frames at a time is not supported.
Edit a point position
  • Edit a point. When you select one or multiple frames, you can adjust the position of a point in the frame selection. When these changes are made, Labelbox treats the selected frame(s) as a new keyframe or group, and interpolates the point’s position between any preceding and following keyframes.
  • Change position mid-sequence. When you change the position of the point in the middle of the sequence, Labelbox uses interpolation (also known as tweening) to incrementally adjust the point to its new position. The updated point position will persist until the end of the sequence.
  • Insert point between interpolated frames. When you adjust the position of a point between two already interpolated keyframes, Labelbox will interpolate the point to adjust for the newly inserted keyframe.
Delete point

Right click on the point to delete the entire instance of the point in every frame it appears. You can also do this with the backspace key.

Create instances

When a video is loaded in the Editor, you can create multiple instances of a Point object.

  1. Select the point class from the "Tools" panel.
  2. Select the same point class again.
  3. Draw the next instance of the point.

Export labels

For instructions on how to access your multi-frame point labels and a sample Point label export, see our docs on Video export formats.

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