What are bookmarks?
Introduction
This support article aims to describe what bookmarks are in Swing Catalyst and Motion Catalyst, and what they are used for. There are some differences between Motion Catalyst and Swing Catalyst, but the fundamentals around how the bookmarks function and their features are the same, meaning this article can be used for both software’s.
Example screenshot from Motion Catalyst of a counter movement jump recording
What are bookmarks?
Bookmarks are used to identify key points in a recording. For certain sports & activities, the bookmarks correlate to specific phases in the activity, or simply indicate start and end of movement.
For counter movement jump (as pictured), these phases are: unweighting, braking, propulsion, takeoff, and landing.
If we look more closely the screenshots above, we see that there are a number of arrows above the playback timeline, each arrow, or bookmark, correlate to different phases of the recorded activity.
The number of bookmarks available depend on the activity. Certain activities have more bookmarks than others. Additionally, bookmarks are set automatically for certain activities. We are working to improve this, so the list below is subject to change.
Currently the sports and activities that have automatic bookmarks are:
| Sport / Activity | Default Bookmarks | Identified from |
|---|---|---|
| Fitness: Counter Movement Jump | Automatic | Force data |
| Fitness: Squat Jump | Automatic | Force data |
| Fitness: Isometric mid-thigh pull | Automatic | Force data |
| Fitness: Dynamic & Static balance | Automatic | Force data |
| Fitness: Upper Body Plank | Automatic | Force data |
| Ski jump | Automatic | Force data |
| Baseball: Batting | Automatic | Force data |
| Golf swing | Automatic (10 positions) | Motion capture |
Golf swings are the exception in this list: their bookmarks come from the tracked body pose rather than from force data, so no force plate is needed. A golf swing recording with motion capture gets ten bookmarks covering the swing from take away to finish, instead of the three that older recordings have. See Golf swing phase detection for how that works, what happens to markers you positioned yourself, and how to go back.
The bookmark positions are stored in the database for each recording and in any exported take (recording with data) file.
How do I set bookmarks?
To change or manually set the bookmark positions:
“Unlock” the bookmarks by pressing the “bookmarks” button.
Once selected you can change the position of the bookmarks by dragging the arrow(s).
When finished, make sure to “lock” the bookmarks again by deselecting the “bookmarks” icon, exiting the “edit bookmark” mode.
To put the positions back to the activity’s defaults, open the marker menu with the three-dot button at the end of the recording’s row (tooltip “More marker actions”) and choose “Use the default markers for this activity”. On a golf swing that item reads “Use old 3-point markers” instead, because the preset it restores is the three markers golf recordings used before swing phase detection existed.
Either way you are asked to confirm first, since any positions you set yourself are replaced. On a golf swing the question also covers the detected swing phases it discards.
Grey bookmarks indicate that they haven’t been set, or changed.
Where the current bookmarks came from
While the bookmarks are unlocked, a short label tells you the state of the bookmarks for that recording:
- Set manually means you placed them, or they are the activity’s defaults.
- Phases detected means the software placed them from motion capture. This applies to golf swings only.
- Edited by you means they were detected and you have since moved at least one of them.
Anything you moved by hand stays where you put it. Detected phases are not written over your own markers on their own: the software either asks first or waits for you to run detection yourself.
Other buttons on the playback bar
Golf swing recordings have more controls. All of them are covered in Golf swing phase detection .
- The detect button on the playback bar, tooltip Detect swing phases from motion capture, finds the ten swing positions and places the bookmarks for you. The unlocked bookmark bar has the same action per recording, labelled Detect phases, or Redo detection on a recording that has been detected before.
- Restore my earlier markers, in the marker menu, puts back the bookmarks the recording had before detection ran, including any you had moved yourself.
The crop button on the playback bar is not golf specific. On any recording with at least two bookmarks spaced far enough apart, Crop playback to the marked range trims the scrubber to the part of the clip between the first and last bookmark, so you are not scrolling through the walk-up. Click it again for a small margin either side, and again to switch it off. The three states are described in Golf swing phase detection .
The bookmarks are also represented in the data graphs as vertical lines, indicating where in the recording the different phases are in time (X axis of the graph):
The position of the first and (or) last bookmark decide how much data is displayed in the databoxes. The duration before the first bookmark and after the last bookmark depends on the activity and sport, but changing this manually can be helpful to view certain parts of a recording. This is especially helpful for recordings done under the “free movement” activity, which can be up to 30 seconds in duration.
Note: We are only changing what we are looking at “in time”, none of the stored data is actually changed in any way.
For more details on how to view and manipulate the graphs please see this article .
Why should I set bookmarks?
To allow easy playback synchronization between recordings we recommend setting bookmarks.
For example, say you want to view two recordings side by side of of a counter movement jump performed by two different users where you wish to synchronize the playback around a specific phase.
Click the “Synchronize” button.
Select the phase / bookmark you wish to synchronize on.
Press play.
Note: The amount of available bookmarks, and name of the phases varies depending on the sport and activity.
Example synchronizing bookmarks to impact for two golf swings:
This can be done for any sport or activity. For more details on “compare mode” please see the “layouts” section of our user guide .