The format the recorder wroteRecorders write into formats of their own making, and an ordinary player will usually refuse them. Re-encode the file, or point a camera at the screen, and pixels shift, timing shifts, and frame references shift with them. The native file comes off, and a copy that opens anywhere goes with it.
The box's own clockMore claims turn on the clock than on anything else a disk holds. Clocks drift. They are typed in wrong on installation day. Very often nobody moves them for British Summer Time. A stamp reading 02:10 does not prove that anything happened at 02:10. The offset is measured against a reference at acquisition, and the figure goes in the report.
Continuity, kept on paperAn exhibit reference. MD5 and SHA-256, top and tail. Every handover dated on the record. Notes taken while the work went on. And anything produced from the master gets an exhibit reference of its own.
The material that would not readA report that steps round the gaps is worth nothing to an adjuster. Material that has been overwritten will not come back. Nor will encrypted material with no key to it. Where the box recorded nothing at all, nothing can be produced. The report says which of those it is, and marks any pictures that return without their timings.