[Matroska-devel] Certain Files Play Too Fast or Too Slow With Haali's Media Splitter

Mike Matsnev mike at po.cs.msu.su
Wed Mar 7 22:58:19 CET 2007

Carlos Garza wrote:
> Hello.  I've noticed that certain files created using
> Gabest's Matroska Muxer play either too fast or too
> slow using Haali's Splitter.  Furthermore, I've
> noticed that these files, muxed from MOV or WMV files,
> when viewed using mkvinfo, have a default duration of
> 0.000ms.
> (MKVInfo) |  + Default duration: 0.000ms (1.#IO fps
> for a video track) at 4564
> The files play fine using Gabest's Matroska Splitter
> and MPLayer (the SVQ3 encoded files do not play in
> MPlayer however).  It appears to me that Haali's
> Splitter gives the files a default framerate of ~25fps
> when a default duration is not found.  This means that
> files that should play at 15fps play too fast and the
> files that should play at 30fps play too slow. 
> Remuxing the files using mkvmerge does not help.
> The problem occurs whether or not there is an audio
> stream present.  Interestingly, when there is an audio
> stream (muxed directly from the media file or added
> later) the audio plays normally.  Although, the audio
> may or may not have a default duration element
> associated with it according to mkvinfo.
> I could add a timecode file to give it a default fps
> that closely matches the average fps but weird things
> happens to the video (the video pauses randomly) when
> I do this.  I could extract and edit the timecodes of
> the files but this is a bit intensive when one has a
> lot of files.
> Of course, this is no longer a problem for me since
> I'm moving to Linux.  However, I thought others may or
> may not have the same problem so I decided to let you
> know about it so you can either correct it or ignore
> it.
DefaultDuration is not used for playback, in Matroska
each frame has its own timestamp, and it is passed
directly to the decoder. So I'd suspect a problem with
timestamps in the file.

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