The detections of Step 2 are kept, so each change of settings is applied to the whole video in seconds with Re-track.
Press Settings….
Set Number of animals (0 = ?) to 2 and press Apply.
A note appears below Re-track: the settings changed, and the video has not been tracked with them yet.
Press Re-track. The status line now reads Re-tracked N frames with mode lite: K track IDs.
With the number of animals known, no more than 2 IDs are ever given out, and no ID is retired. A fly that reappears after its partner covered it gets its own ID back.
Check the result as in Step 2, especially around contacts. If needed, change one more setting at a time, Apply and Re-track:
| What you see | Try |
|---|---|
| A fly’s ID is lost when it walks fast | Raise Max distance (px) |
| An ID jumps to the other fly | Lower Max distance (px) |
| The detector misses a fly for many frames | Raise Max age (frames) |
Classes are animals (e.g. male / female) |
Tick Match within class only |
The Tracker Settings guide explains every setting.
Check the settings on a second video (pair02.mp4): Run tracking, and look again. Settings that only fit one video are a trap.
In the settings window, press Save… and save the settings, for example as D:\experiment\two_flies.yaml.
Export this video if you want it now: choose an Output folder, keep Save detections ticked, and press Export CSV. Render video writes the video with IDs and trails drawn on it — useful for checking the result, or for a presentation.
The saved file holds only settings, for example:
config_version: 2
tracker:
mode: lite
lifecycle:
max_age: 10
min_hits: 2
population: 2
...