playing, seeking form a non closed mkv file

Sebastian Dröge sebastian at
Thu Apr 3 00:17:20 PDT 2014

On Do, 2014-04-03 at 07:44 +0200, Edward Hervey wrote:
> Hi,
> On Wed, 2014-04-02 at 19:11 +0200, Peter BOCZ wrote:
> > 
> > Hi,
> > 
> > i  have a problem, let me introduce it form an example. I have a
> > pipeline, which is recording video from a source to a file in matroska
> > format. Meanwhile it is still recording the video i want to play back it
> > from a different pipeline (maybe form another process), and it is
> > working. But if I want to seek, play backward it is not working.
> > Sometimes it's freezing, sometimes i get "gray" picture (decoded B frame
> > whitout I frame). I know if i stop the recording as it have to (eos
> > ....), and the file will be closed, everything is good, if I didn't stop
> > the pipleline well, i have the same problems. As i see (know) the
> > problem is that in an unclosed file the seek_indexes are not reachable.
> > My idea is to rewrite matroskademux and every time we seek parse the
> > reachable part of the file like in the matrokskamux, and build the
> > seek_indexes to be able to seek as a closed one.
> > Would you except such patch to gstreamer ?
>   "rewrite" might be a bit too strong of a word :)
>   Extending matroskademux to support progressively growing files would
> be nice though. I think we already have this kind of support for some of
> the demuxers (avidemux maybe ?).

The only part missing for that is scanning the file when seeking on a
file without seek table IIRC. Apart from that matroskademux should
support incomplete files properly already, and that part shouldn't be
too hard to implement if someone wants to do it :)

Sebastian Dröge, Centricular Ltd -
Expertise, Straight from the Source
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