H.264 UDP recording improvements?

[Gerard Toonstra]

Hi all,

I'm attempting to record a UDPSRC stream from an IP camera to disk without
re-encoding the stream. This is on a PC that has relatively limited CPU
capacity left, as it's also
doing other complex things with the video. So preserving CPU utilization is
what I'm trying to do.

On the internet, I found one topic where someone else was looking for the
same thing, but this didn't help me much in the end.

http://lists.freedesktop.org/archives/gstreamer-devel/2012-May/035999.html

and:

http://lists.freedesktop.org/archives/gstreamer-devel/2010-June/027112.html


when I use the "rtph264depay ! h264parse ! matroskamux ! filesink"
pipeline, it fails on caps negotiation. This is because matroskamux doesn't
have access to the encoding parameters. I had
expected h264parse to produce those.

When I start a desktop capture and copy the sprop-params across, the above
pipeline works flawlessly. I don't have those details from the IP camera,
however, I can only specify width/height.
I can get matroskamux to work if I also specify framerate in
"video/x-h264,width=640,height=360,framerate=25/1".  It seems to write to
the file, but it is not playable. ffplay and mplayer complain
about missing encoding parameters (surprise) or "no frame!" errors.  This
is I think due to missing "codec_data", as specified here:

http://gstreamer-devel.966125.n4.nabble.com/Setting-codec-data-in-h264-caps-for-qtmux-td4525597.html

Setting "config-interval" on h264parse did not help.

So, what i now use is the following:

gst-launch-0.10 udpsrc multicast-group=239.255.12.12 auto-multicast=true
port=5004 !
"application/x-rtp,media=(string)video,clock-rate=(int)90000,encoding-name=(string)H264,payload=(int)96"
! gstrtpjitterbuffer drop-on-latency=true latency=40 ! rtph264depay !
h264parse ! "video/x-h264,width=(int)640,height=(int)360" ! filesink
location=movie.264 sync=false

This produces a movie.264 file and this is playable through mplayer.
However, I'm seeing different results if I use kdenlive for editing for
example, which plays 1 fps, so I'd prefer the mux to be used.

Is there a way to:
- add the codec_data by adding something in the pipeline?
- extract the codec_data from the RTP stream and just pass that to the
muxer?

Rgds,

G>
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