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DWE_OS does not officially support streaming with GStreamer. The following steps are for Linux and Windows only.NOTE: Stream quality may suffer as a result.
GStreamer can be very complex/elaborate, even to set up one video stream. Many of the Quality of Life features like multiple streams and live recordings are much simpler and come with a user interface on Discovery
1

Check DWE_OS 2.0

After following the DWE_OS 2.0 setup, continue to next steps.
Note down the port(s) being streamed to.
2

Install GStreamer

Within the terminal, run:
sudo apt update
Then run the following to install GStreamer:
sudo apt install gstreamer1.0-plugins-base gstreamer1.0-plugins-good gstreamer1.0-plugins-ugly gstreamer1.0-libav gstreamer1.0-tools
To verify the GStreamer setup, open CMD and run the following:
gst-launch-1.0 --version
This should result in an output like:
gst-launch-1.0 version 1.16.2
GStreamer 1.16.2
https://launchpad.net/distros/ubuntu/+source/gstreamer1.0
3

Identify Variables for GStreamer Command Line

In order to link up connected devices video streams, you will first configure DWE OS.
1
First identify your laptop / desktop IP address, which we will be populating into the DWE OS software.This can be done by running the following:
ip addr
You will be met with many addresses, look through them, specifically addresses following the text: inet.
It will most likely be in the format 192.168.x.xx
2
You will want to replace the collected IP in DWE OS under IP address, and take note of the port you are streaming to. (Default 5600)
Remember to create the streaming endpoint with the (+) button once the fields are filled!
In this example the collected IP is 192.168.5.55, and the port is 5600DWE OS Endpoints
The Port field being set to 5601 is automatic with the program, the only endpoint being streamed to have the camera icon next to them and a trash button to delete them.
3
The format of GStreamer is as follows:
gst-launch-1.0 [FLAGS] [SOURCE] ! [FILTER] ! [SINK]
With the port in mind, there are a few parameters for the GStreamer command to be aware of.Vital Flags:
  • -v(Verbose): Prints stream info so you can see what resolution.format is being negotiated between elements.
  • -e(EOS - End of Stream): Crucial for recording. If you press Ctrl+C without this flag, your file might be corrupted (missing headers). This flag forces a clean shutdown.
  • --help-all: Lists every single element available on your system.
Sources (Input):
  • videotestsrc: Generates a test pattern (color bars, static, etc.).
  • Param: pattern=smpte (or snow, ball, etc.)
  • autovideosrc / v4l2src: Your webcam (Linux).
  • Param: device=/dev/video0
  • filesrc: Reads a local file.
  • Param: location=./video.mp4
  • udpsrc: Receives data over the network via UDP.
    • Param: port=5600 (The port to listen on).
    • Param: caps="..." (Essential! Tells GStreamer what the raw bytes actually are).
    • Param: buffer-size=524288 (Increases buffer to prevent packet loss on high-res streams).
      • Standard buffer sizes for H264 is 96 and MJPEG is 26
Sinks (Output)
  • autovideosink: Opens a window and plays the video.
  • fakesink: Discards data (useful for testing if a pipeline runs without errors).
  • filesink: Writes to a file.
  • Param: location=output.mp4
  • udpsink: Streams over the network.
Essentials (Filters/Converters)
  • videoconvert: Converts colorspaces (e.g., from YUV to RGB). If you get a “could not link” error, throw this in the middle.
  • videoscale: Resizes video.
  • capsfilter: Forces a specific format. Syntax: video/x-raw,width=1920,height=1080.
  • rtp[format]depay: Depayloader. unwraps RTP network packets to reveal the stream inside.
    • Examples: rtpjpegdepay (for MJPEG), rtph264depay (for H.264).
  • [format]dec: Decoder. Decompresses video into raw pixels for display.
    • Examples: jpegdec, avdec_h264.
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Here are a couple example lines to test your GStreamer:Test Pattern
gst-launch-1.0 -v videotestsrc ! videoconvert ! autovideosink
Webcam Display (If available)
gst-launch-1.0 -v v4l2src ! videoconvert ! autovideosink
Webcam Force 720p 30fps
gst-launch-1.0 -v v4l2src ! image/jpeg,width=1280,height=720,framerate=30/1 ! jpegdec ! videoconvert ! autovideosink
For higher resolutions, the video output is usually compressed MJPEG.image/jpeg accept the compressed format from the camera.jpegdec adds a decoder to turn that JPEG stream back into Raw Video so the window can display it.
Record Webcam
gst-launch-1.0 -e v4l2src ! videoconvert ! x264enc ! mp4mux ! filesink location=test.mp4
This will record in the background, to finish the clip, press Ctrl + C, and it will be in the directory currently.In this case the file is named test.mp4, which we can check for existence with ls -lh test.mp4
4

Setting up streaming from DWE OS

With an understanding of GStreamer commands, we can begin setting up the video stream specficially with DWE OS.
Remember to set your own IP as the IP in the streaming endpoint!
Depending on the video codec (MJPEC / H264) specified in DWE OS, run either of the following:MJPEG
gst-launch-1.0 udpsrc port=5600 caps="application/x-rtp, encoding-name=JPEG, payload=26" ! rtpjpegdepay ! jpegdec ! autovideosink
H264
gst-launch-1.0 udpsrc port=5600 caps="application/x-rtp, encoding-name=H264, payload=96" ! rtph264depay ! avdec_h264 ! autovideosink
Remember to replace the port number in the command line with the port being streamed to!
You should now have a live stream from you camera in a window!
5

Setting up recording

To record a stream, once again the video codec matters!You will know a stream is being recorded should your terminal contain text similar to this:GStreamer RecordingMJPEGFor MKV
gst-launch-1.0 -e udpsrc port=5600 caps="application/x-rtp, encoding-name=JPEG, payload=26" ! rtpjpegdepay ! jpegparse ! matroskamux ! filesink location=output_mjpeg.mkv
The line above is for an MKV format, as AVI is incredibly finicky with GStreamer and requires the output data to be formatted very specifically. While possible, MJPEG to AVI is much simpler in Discovery, as it is the default output.
H264For MKV
gst-launch-1.0 -e udpsrc port=5600 caps="application/x-rtp, encoding-name=H264, payload=96" ! rtph264depay ! h264parse ! matroskamux ! filesink location=output_h264.mkv
For MP4
gst-launch-1.0 -e udpsrc port=5600 caps="application/x-rtp, encoding-name=H264, payload=96" ! rtph264depay ! h264parse ! video/x-h264,stream-format=avc ! mp4mux ! filesink location=video.mp4
6

Success!

Wonderful! You should now have the building blocks to set up a stream and recording with GStreamer!
Warning:With GStreamer, a single camera setup already requires quite a bit of work, and recording multiple streams at once would also require quite a bit of work and development.We recommend Discovery should your camera setups become complex.

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