For hands-on information see gstreamer.md

mat2gstreamer

Open camera by OpenCV and send it to UDP/RTP

• Preliminars for Ubuntu 14.04
  • Install gstreamer1.0 and 0.10: `add-apt-repository ppa:mc3man/gstffmpeg-keep && apt-get update && apt-get install libgstreamer1.0* gstreamer1.0* libgstreamer0.10* gstreamer0.10*``
  • Build opencv without gstreamer 0.10 support: -D WITH_GSTREAMER=ON -D WITH_GSTREAMER_0_10=OFF
• Configure the source code: Maybe you have another cameradevice, etc.
• Build: cmake . && make
• Run a standalone gstreamer udtsrc and display the video strea (sampling, depth, width, and height might differ): gst-launch-1.0 -v udpsrc port=5000 caps="application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)RAW, sampling=(string)BGR, depth=(string)8, width=(string)640, height=(string)480" ! rtpvrawdepay ! videoconvert ! ximagesink
• Notes
  • If the caps string is not correct, just open up a gstreamer udpsink for you webcam and investigate the caps section of the verbose output. This string needs to be put into the caps section of the udpsrc
  • Do not use gstreamer0.10

Hints

• Webcam example: gst-launch-1.0 v4l2src ! xvimagesink
• Get debug messages of gst-launch-1.0 with argument --gst-debug-level=5
• List available plugins: gst-inspect-1.0
• List features of a plugin: gst-inspect-1.0 <PLUGIN_NAME>
• videoconvert feature:
  • https://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-base-plugins/html/gst-plugins-base-plugins-videoconvert.html
  • This will output a test video (generated in YUY2 format) in a video window. If the video sink selected does not support YUY2 videoconvert will automatically convert the video to a format understood by the video sink: gst-launch-1.0 -v videotestsrc ! video/x-raw,format=YUY2 ! videoconvert ! autovideosink
• Plugin description: https://gstreamer.freedesktop.org/documentation/

Links

• HOT: http://www.einarsundgren.se/gstreamer-basic-real-time-streaming-tutorial/
• http://wiki.oz9aec.net/index.php/Gstreamer_cheat_sheet
• http://labs.isee.biz/index.php/Example_GStreamer_Pipelines
• http://processors.wiki.ti.com/index.php/Example_GStreamer_Pipelines
• https://en.wikipedia.org/wiki/GStreamer
• https://wiki.ubuntuusers.de/Gstreamer-1.0/
• http://stackoverflow.com/questions/37339184/how-to-write-opencv-mat-to-gstreamer-pipeline
• https://www.youtube.com/watch?v=ShAuAgjwCds
• http://stackoverflow.com/questions/23570572/using-custom-camera-in-opencv-via-gstreamer