Also, what timestamp were they using for this comparison? EXIF data? Filename (some cameras store the filename of images/videos as the datetime it was taken)? F

Also, what timestamp were they using for this comparison? EXIF data? Filename (some cameras store the filename of images/videos as the datetime it was taken)? Filesystem time it was written, and was that on the camera or when the files were dumped to a computer and saved there one after another sequentially? There could be several potential sources for this "timestamp," but I haven't seen the one they are talking about actually mentioned.