Auto-blur will automatically pick up faces without you needing to select anyone. Currently Identity Cloak covers 90-95% of faces.
On some occasions, you may find that people's faces aren't being picked up by Identity Cloak's auto-face recognition. Identity Cloak identifies faces of being 50+ pixels or full facial features. On some occasions, you may have part of someone's face from their profile which is also less than 50 pixels (depending on the quality of the cameras the recording has come from) which means their faces aren't being picked up. Thus when someone moves their face may go from being recognised by Identity Cloak as a face to not being recognised. You will need to go in manually and redact these faces.
We are currently working on improving this to 95-98% of faces being recognised in our future releases.