Video Labeling Editor
Overview of the Video Labeling Editor in Ango Hub
Last updated
Overview of the Video Labeling Editor in Ango Hub
Last updated
Ango Hub provides a labeling editor with which video files can be annotated. The video editor will be opened when a user opens an asset with the following file extensions: .mp4, .mov, .webm, .mkv.
This article will exclusively go over Ango Hub’s video labeling interface. Features common to all labeling editors are instead explained here.
When dragging with the slider, the frame selected will only be loaded when you release the left mouse button.
You may also navigate to a specific frame by typing its number and pressing Enter or clicking outside of the text field:
The volume button allows you to change the volume of the audio when playing the file back. The "1x" button allows you to change the playback speed.
To the right, there is a three-dot menu. The menu options are:
Default Segment Length: When you create a new annotation, Ango Hub will have it automatically persist for the next 30 frames. You can change this default duration here.
Ango Hub does not load the entire video in memory right from the start, as that would be computationally expensive, delay loading, and would use unnecessary memory. Instead, Hub loads it chunk by chunk, buffering it.
You can see how much of the video has been downloaded (buffered) by looking at the playback bar as below:
The timeline view allows you to see the annotations throughout the video in a visual way.
When you create a new annotation, a new row will be added to the timeline view. You can click on the row to select its annotation, or click on the annotation to select its row:
Objects belonging to the same class are automatically grouped and collapsed. To see each object, click on the arrow:
Next to each object's class name, the first few characters of its unique Object ID will be visible. Hover over the characters to display and be able to copy to your clipboard the object's ID:
When you move the object, or change the answer in a frame-specific classification, a keyframe is added to the row, indicated by a white rhombus on the line:
To remove the keyframe, navigate to the frame where the keyframe is located, and click on the row or the annotation of which you'd like to delete the keyframe. A Remove Keyframe button will appear. Click on it to delete the keyframe:
You can mark a certain annotation as being "out of view". To do so, navigate to the frame where the annotation has gone out of view, then right-click on the annotation directly, or on the segment representing it on the timeline, click on the three-dot menu, and click on "Mark out of view"
To bring the annotation back, perform the same action – this time the menu item will be called "Mark in view":
Please note that when you mark an annotation out of view, while you cannot see it on the asset anymore, and it does not appear in the "Objects" list, you can still interact with it (for example to delete it, or mark it back in view) by right-clicking on the annotation segment in the timeline.
And even though nested classifications for out-of-view objects do not appear in the "Objects" view, they will appear in the final export, and in the context menu that opens when its segment is right-clicked.
Click and drag on the handles on the left/right side of the segment to shrink/extend the annotation duration:
You may give each annotation its own name by clicking on it and pressing "D" on your keyboard. Alternatively, you may right-click on it, click on the three-dot menu, and click on "Update Description".
Once you update an annotation's description, it will appear on the timeline:
The following are the labeling tools supported on videos:
From the Tools panel on the left sidebar, select a supported labeling tool. Then, follow the instructions found on each tool's docs page, linked to above.
If no tools are present in the project, only answer the questions in the Classifications panel.
Between keyframes, objects are automatically linearly interpolated. So for example, if you create a keyframe on frame 1 for an object on the top-left corner of the video, and in frame 100 of the same object being in the bottom-right corner of the video, Ango Hub will automatically fill in the contents of frames between 1-100 with interpolation, having the object smoothly move from one corner to the next.
Interpolation is currently only available for the Bounding Box, Polygon, Segmentation, and Point labeling tools.
When creating classifications such as radio, dropdown, and others, project managers may choose to make those classifications general (e.g., one response per video) or frame-specific (e.g. one response per frame.)
If the classification has been marked as "frame-specific", then it will appear in the timeline and it will behave like a tool-based object, with keyframes, in/out of view, etc.
A full list of keyboard shortcuts is available by clicking on the Keyboard button on the right side of the top bar:
The back and forward arrows allow you to move backwards and forwards one frame at a time, or to the beginning/end of the video. The Play button starts and stops playback. The slider allows you to move between frames by clicking on the playhead and dragging it to find the frame you need.
