[FFmpeg-user] ffmpeg split file retains original length

[Jonathan Livni]

The following question is also tracked here:
http://video.stackexchange.com/questions/14847/ffmpeg-split-file-retains-original-length

I've extracted 30m from a 1h long video using the following ffmpeg command:

ffmpeg -ss 0 -t 00:30:00 -i in.mp4 -acodec copy -vcodec copy out.mp4

The split was successful and out.mp4 was created with the first 30m.
However... even though the video stops after 30m, all video players show
the video length as still being 1h long, and so does Windows Explorer when
the file is selected.


*How come the video length shown is different than the actual video
length?How can I adjust it so they will match?*

I'm on Win7 using ffmpeg 64bit static from Feb 10th 2015