I'm willing to believe they toss out the video - after they process it and extract all the positioning and timing information. Toss the bulky vid and keep the metadata.

In fact - similar to how a police officer might erase a recording so the most reliable testimony is their thoughts‡ - once the original video is lost, the metadata becomes the only source of truth.

‡(At ~40 minute mark, the officer describes how he transcribes then erases tape recordings)