Problem with storing x264 stream into a mkv file

Tim Müller tim at
Wed Jun 18 04:36:34 PDT 2014

On Wed, 2014-06-18 at 13:08 +0200, Marcin Kolny wrote:


> Hello, I've got    problem with storing x264 udp stream into a mkv
> file. My pipeline:
> gst-launch-1.0 udpsrc caps=application/x-rtp ! rtph264depay !
> video/x-h264, alignment=nal ! h264parse ! capsfilter caps="video/x\
> -h264, alignment=au, stream-format=avc" !  matroskamux ! fakesink
> dump=true
> ERROR: from element /GstPipeline:pipeline0/GstUDPSrc:udpsrc0: Internal
> data flow error. streaming task paused, reason not-negotiated (-4)

What version is this with? Have you tried with git master?

I suspect what's happening is that rtph264depay/h264parse first output
incomplete caps (without width/height) and only add them later. Possibly
matroskamux also wants a framerate in the caps which it won't get here.

Why are you forcing the depayloader to output alignment=nal btw?
rtph264depay ! h264parse ! matroskamux  should negotiate the right
format automatically. rtph264depay can output AVC.

You might also want an rtpjitterbuffer before the depayloader btw.


Tim Müller, Centricular Ltd -

More information about the gstreamer-devel mailing list