FLV - too early end of movie

[Joar]

I have a problem with the end of a FLV-file. This is a movie downloaded from a TV-station three months ago. I have seen it several time, last time on Saturday, without any problems. On Sunday suddenly it only last for 13 min while the full length is about 45 min. I used the VLC-player and tried several other players. I converted it to mp4. I also downloaded a 1 month old backup. All agreeded that the movie was only 13 min. The file size (in bytes) has not changed.

Can it be any activation dato in the file that reduces the size after some time? Any other suggestions?