Error in video length, quick fix?

[Fazermint]

Hey there, new here. I've got a weird problem with some of my video files that most likely has a simple solution.

So here's the problem. I've got some .mp4 files (anime). The video information in windows explorer says that the length is twice as long as it is supposed to be. When I play them in WMP, the tracking bar indicates that it is indeed twice as long, but if I put the tracking bar at a point beyond the real length, the video restarts. So there's no empty video track or anything, there just seems to be a problem with the information. When I play the files on my TV, the correct length is displayed and tracking works fine.

I could fix the problem by editing the video. That solution generates new files with the correct length, but it takes more time than I'd like. Is there a simple way to fix the length of the movie without generating new files?

[Baldrick]

Try remux them with mp4box. Add the mp4 in for example mymp4boxgui. Make/mux a new mp4.

[Fazermint]

I looked at the files in the GUI you suggested. Remuxing didn't fix the problem, as the GUI also believes the video track is 2x the length.

[Baldrick]

Try edit it with avidemux. Open it, set start and stop. Under video and audio choose copy. Save as new mp4.

[Fazermint]

Avidemux did the trick. It recognized the true length of the files, so the rest went smoothly. Many thanks for your help, Baldrick!