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

The rtsp-simple-server README instructions on https://github.com/aler9/rtsp-simple-server 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 https://gstreamer.freedesktop.org/documentation/installing/on-linux.html?gi-language=c.
   
   
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 https://github.com/aler9/rtsp-simple-server 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.
   
   

   paths:
       mystream:
           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
   [Unit]
   After=network.target
   [Service]
   ExecStart=/usr/local/bin/rtsp-simple-server /usr/local/etc/rtsp-simple-server.yml
   [Install]
   WantedBy=multi-user.target
   EOF
   

   
   
   
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
[Unit]
After=network.target
[Service]
EnvironmentName="LIBVA_DRIVERS_PATH=/usr/lib/x86_64-linux-gnu/dri/"
EnvironmentName="LIBVA_DRIVER_NAME=i965"
ExecStart=/usr/local/bin/rtsp-simple-server /usr/local/etc/rtsp-simple-server.yml
[Install]
WantedBy=multi-user.target
EOF

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  https://gstreamer.freedesktop.org/documentation/installing/on-linux.html?gi-language=c

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