Please help with uridecodebin pipeline (I would like to prevent re-encoding)

[stic at free.fr]

Hi all,

I have following pipeline:
uridecodebin name=uridecodebin ! queue ! matroskamux name=mux ! decodebin ! videoconvert ! videoscale ! eglglessink name=videosink

The source stream is a rtsp uri transporting h264 video data.
I try to build this pipeline because I would like then to be able to record to a file the h264 video data BEFORE it is decoded and sent to the videosink (would like to prevent re-encoding !)

But this fails with following error:

W/GStreamer+basesrc(2246): 0:00:18.677825943 0x77956860 gstbasesrc.c:2867:gst_base_src_loop:<udpsrc3> error: Internal data flow error.
W/GStreamer+basesrc(2246): 0:00:18.678039566 0x77956860 gstbasesrc.c:2867:gst_base_src_loop:<udpsrc3> error: streaming task paused, reason not-linked (-1)

I also tried to return false with uridecodebin autoplug-continue signal to allow it to pass through data, but still same error.

Please can you give me some hints on how I could achieve this ?
Any help would be greatly appreciated.

Thank you so much.