[gst-devel] Using mkv (mjpeg) files with gnlcomposition/gnlfilesource

Ron McOuat rmcouat at smartt.com
Fri Jul 2 18:06:00 CEST 2010


The camera is a live source so unless souphttpsrc detects a connection 
close causing it to send EOS the pipeline carries on forever. What I did 
is block the src pad of the queue2 (my_queue1) then injected the EOS in 
the sink pad of the next element. I am not sure if this is required but 
for my purposes I wanted to keep the src running. You have to wait for 
the EOS in the message handler to be sure matroskamux has finished 
writing the index at the end of file, sending EOS and immediately 
shutting down won't do it. The message handler is where you do the final 
shutting down.

Are you aware of mkvtools? You should be able to load them in from your 
distribution (yum, synaptic) depending on your flavor of Linux. There is 
also a GUI front end to these tools. The mkvinfo program will show the 
detailed structure of the file. Make a known good file with something 
like videotestsrc with a specific number of buffers so the EOS occurs 
normally - you should only need gst-launch and look at the overall 
structure of that file then compare to the ones you are building with 
the webcam source.


On 10-07-02 6:57 AM, Wes Miller wrote:
> Ron,
> As you suggested, I tried playing the mkv through totem.  It doesn't play.
> However, it will play using
>       gst-launch filesrc location=1.mkv ! matroskademux ! jpegdec !
> ffmpegcolorspace ! autovideosink
> I suppose this tells me something about how i recorded the mkv in the first
> place.  i used a gst_parse_launch()-ed pipe which I ended by sending an EOS
> to the pipeline.:
>       "souphttpsrc name=my_src "
>                  "! multipartdemux name=my_demux "
>                  "! image/jpeg,width=640,height=480 "
>                  "! tee name=t t. "
>                  "! queue2 name=my_queue1 "
>                  "! matroskamux name=my_mux "
>                  "! filesink name=my_sink t. "
>                  "! queue2 name=my_queue2 "
>                  "! appsink name=my_appsink "
> (the appsink allows me to record the timestamp on each frame).
> What did I miss?
> Wes

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