Monday, January 24, 2022

How to setup rtsp-simple-server service for publishing from gstreamer using the vaapi encoder

The rtsp-simple-server README instructions on is a little sparse on publishing as a systemd service using Gstreamer and the vaapi plugin. I spent some time trying to get the service to run properly. This post documents the steps I used on an Intel system board running Ubuntu 20.

Install GStreamer

  1. Optional. If Gstreamer has not been installed, then follow the instructions on

  2. If the GStreamer VAAPI plugin has not been installed, run the following command in a Terminal:

    $ sudo apt install gstreamer1.0-vaapi

 Download and install rtsp-simple-server

  1. Using a browser, download and extract the rtsp-simple-server binary from the github repo into a folder, e.g. /path/to/rtsp/

    The files rtsp-simple-server and the rtsp-simple-server.yml are extracted out into the directory /path/to/rtsp/.

  2. Open up a Terminal. At the prompt, change directory to the extracted location.

    $ cd /path/to/rtsp/

  3. Move the binary to the folder /usr/local/bin/

    $ sudo mv rtsp-simple-server /usr/local/bin/

  4. Move the configuration file to the folder /usr/local/etc/

    $ sudo mv rtsp-simple-server.yml /usr/local/etc/

Configure rtsp-simple-server to publish from gstreamer

  1. Open up a Terminal. At the prompt, change directory to the directory /usr/local/etc/.

    $ cd /usr/local/etc/

  2. Using a text editor, edit the configuration file rtsp-simple-server.yml. Create a new path name e.g. mystream under the paths key.

            runOnDemand: gst-launch-1.0 v4l2src device=/dev/video0 ! 'video/x-raw,framerate=30/1,width=320,height=240' ! videoconvert ! vaapih264enc ! h264parse ! rtspclientsink location=rtsp://localhost:$RTSP_PORT/$RTSP_PATH
            runOnDemandRestart: yes

  3. In the runOnDemand key, type in the Gstreamer pipeline to read from a video source, perform encoding and finally to publish to the rtsp server.

    gst-launch-1.0 v4l2src device=/dev/video0 ! 'video/x-raw,framerate=30/1,width=320,height=240' ! videoconvert ! vaapih264enc bitrate=200000 ! h264parse ! rtspclientsink location=rtsp://localhost:$RTSP_PORT/$RTSP_PATH
    Note 1: device points to the video source.
    Note 2: video/x-raw line specifies the video format, frame rate, and resolutions to use
    Note 3: videoconvert converts the color space
    Note 4: vaapih264 performs the video encoding using the Intel GPU
    Note 5: rtspclientsink publishes the video to the rtsp server

  4. Save and close the configuration file.

Create and start the rtsp-simple-server service

  1.  Open up a Terminal. Type in the following to create the systemd service.

    sudo tee /etc/systemd/system/rtsp-simple-server.service >/dev/null << EOF
    ExecStart=/usr/local/bin/rtsp-simple-server /usr/local/etc/rtsp-simple-server.yml

  2. To enable and start the service, run the following:

    $ sudo systemctl enable rtsp-simple-server
    $ sudo systemctl start rtsp-simple-server

Optional. Define LIBVA environment variables

On some boards, when using the vaapi encoding plugin, gstreamer may not run with the error message:

WARNING: erroneous pipeline: no element "vaapih264enc"

In this case, setting the environment variables LIBVA_DRIVERS_PATH and LIBVA_DRIVER_NAME for the service may solve the problem. An example of the command to create the rtsp-simple-server service with the environment variables is shown below:

sudo tee /etc/systemd/system/rtsp-simple-server.service >/dev/null << EOF
ExecStart=/usr/local/bin/rtsp-simple-server /usr/local/etc/rtsp-simple-server.yml

Monday, January 17, 2022

gstreamer command to encode videos using an Intel GPU on Ubuntu

An alternative to ffmpeg is the gstreamer library, which comes with optional plug-ins to perform video encoding using Intel GPUs. 

Gstreamer can be installed on Ubuntu by following instructions on

Assuming gstreamer has been installed on Ubuntu, you can run the following command to save the video into an output.mp4 video file.

$ gst-launch-1.0 \
v4l2src device=/dev/video0 num-buffers=300 ! \
'video/x-raw,framerate=10/1,width=1280,height=720' ! \
videoconvert ! \
vaapih264enc ! \
h264parse ! \
filesink location=output.mp4

Note 1: device specifies the video source /dev/video0 and num-buffers specifies the number of frames to read.

Note 2: The line video/x-raw specifies the format, frame rate and resolution to read from the video source.

Note 3: vaapih264enc specifies the Intel Video Accelerated encoder to use.

Note 4: filesink location specifies the output video file.

While the gstreamer command is processing the video, in another terminal, run the command to monitor the Intel GPU.

$ sudo intel_gpu_top

As shown above, the printout in red indicates the GPU is being used.

Caution: On some Intel boards I have tested, sometimes running the gstreamer vaapih264enc plugin resulted in the following error message even though the plugin has been installed:

WARNING: erroneous pipeline: no element "vaapih264enc"

In my case, I managed to resolve that error by setting the following environment variables before running the encoding command:

$ export LIBVA_DRIVERS_PATH=/usr/lib/x86_64-linux-gnu/dri/

$ export LIBVA_DRIVER_NAME=i965