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View Full Version : Video run time differs when extracted from MKV container


MegatronUK
9th September 2007, 16:06
I have several mkv files, all containing either an xvid or divx5 video track (29.97fps) and a single aac (5.1) audio track. Run time when played back through mplayer or vlc is approx ~24 minutes.

As I want to watch these files on a stand alone player which does not support mkv, I'm in the process of converting them into basic avi containers.

I use the mkvtoolnix package and mkvextract to extract both of the tracks, however when the two files are extracted from the mkv container, they differ in length considerably; the audio track is ~24 minutes, while the video track is somehow only 19 minutes long.

Obviously when I remux the files back into an avi container, they are quite out of sync, yet play fine in the original container.

Any ideas what is happening? Is Matroska somehow able to sync the shorter run time of the video up to the longer audio track? If it does, then I'm very impressed, but a little bewildered as to how it is doing it!

setarip_old
9th September 2007, 18:42
Hi!

Based on the difficulty you've described, it would probably be easier for you to go back to the original source material you used to create the MKV files - and simply use that same original source material to create the desired .AVIs...

KoD
10th September 2007, 13:53
It's obvious those files are vfr ones, they don't have a constant 29.97 fps.