Video files deleted after watching a DVR once, and only audio files remain?

[jakieface]

This question is from a relatively computer illiterate person, so please take that into account when answering. I want to know if there is a reason that video files might automatically delete themselves after the first time they are viewed on a cd. To explain, I got copies of a small city's city council meeting on DVR. I watched the video once and ejected the DVR. When I put the DVR back in the computer later to watch it again, the video was not there. The only files shown in the menu are now audio files. Can someone please explain to me what happened, or if I am doing something wrong?

[LigH.de]

There may be a reason that you can see the video in a DVD Recorder, but not on a PC: You may have forgotten to "finalize" the disk after recording. Windows PC's prefer the ISO-9660 file system, but this is only written to a DVD-R after you finalize the disk; until that, the DVD Recorder only wrote the UDF file system with partially defined video files.

At least that would be my guess. But I must confess, I wonder which kind of audio files are available to you in this case. More details, please...