Knowledge Base

Problem

EthoVision reports a large number of lost or missed samples during tracking, resulting in gaps or poor-quality trajectory data.

Details

This issue can occur when the source video has encoding inconsistencies, variable frame timing, or metadata mismatches that cause EthoVision to drop samples during playback or tracking. Affected versions include EthoVision XT (multiple versions). Distinct from the general 'Missed Samples vs. Dropped Frames' article because the root cause here is video encoding and the fix is re-encoding.

Solution

1. Identify the video file(s) associated with the problematic trials.
2. Re-encode the video using the same parameters (codec, frame rate, resolution) as the original, using a tool such as FFmpeg or VirtualDub.
3. Re-import or re-link the re-encoded video in EthoVision and retrack the affected trials.
4. Verify that sample loss is reduced or eliminated after re-encoding.
5. If the problem persists, check that the source frame rate exactly matches the EthoVision project frame rate setting.