This is a work in progress project intended to make it easy to integrate networked cameras into an OBS Studio broadcast with minimal configuration.
Having previously used the dvswitch set of tools to do multi-camera live mixed video, I wanted to see if I could get a similar model working with OBS Studio.
The project consists of two components: an RTSP server that runs on a sender node to share camera streas, and an OBS plugin that provides a source giving easy access to these streams.
The rtsp-sender daemon is a GStreamer based RTSP server used to
share one or more cameras. It can be invoked with:
rtsp-sender [ -p PORT ] -c CONFIG_FILE
The configuration file is a simple ini-style file describing the
streams to export. Each section describes a URI path provided by the
RTSP server. The pipeline key sets a GStreamer pipeline used to
produce the RTP payloads. The publish key provides the mDNS service
name to advertise the stream as.
The appropriate pipeline will depend on the capabilities of the video capture device you're using and the desired video resolution/frame rate. A good place to start is by listing the capabilities with the following command:
v4l2-ctl -d /dev/video0 --list-formats-ext
(or whatever file name your capture device uses). From there, it will depend on the formats supported:
-
If the device supports MGPG, a pipeline like the following will work (with appropriate adjustments for resolution and framerate):
v4l2src device=/dev/video0 ! image/jpeg,width=1280,height=720,framerate=30/1 ! rtpjpegpay name=pay0 -
If the device supports H264, use the following:
v4l2src device=/dev/video0 ! video/x-h264,width=1920,height=1080,framerate=30/1 ! h264parse ! rtph264pay name=pay0 -
For cameras supporting raw YUYV, we can encode to JPEG with a pipeline like the following:
v4l2src device=/dev/video0 ! video/x-raw,format=(string)YUY2,width=1280,height=720,framerate=10/1 ! jpegenc ! rtpjpegpay name=pay0
In theory, you should be able to send raw video using the rtpvrawpay
element, but I couldn't get that to work reliably.
As well as serving the streams via RTSP, the daemon also advertises the streams via mDNS (also known as Bonjour) using Avahi. You can get a listing of the cameras available on the local network with the following command:
avahi-browse -rt _obs-source._sub._rtsp._tcp
The remote-source.so plugin should be copied to the OBS plugin
directory (probably /usr/lib/x86_64-linux-gnu/obs-plugins or
similar).
When installed, a new "Remote Source" source type will be available. When you add a source of this type to a scene, it will provide a list of named camera streams advertised on the network. If you want to use the same camera in multiple scenes, I suggest copy/pasting the source rather than creating a new source for the same stream.
The source continues to monitor whether the camera's service name is being advertised. When it stops being advertised, the source disconnects from the RTSP server. When the name is advertised again, the source will immediately reconnect.
This means that you can start OBS without ensuring all the camera machines are running. As each system on the network starts, the streams will integrate into the scenes set up in previous sessions.
I would like to implement some kind of tally light system. This is partly implemented, with the plugin keeping track of when a source becomes active (i.e. part of the scene currently on display), and communicating that state back to the associated RTSP server.
Currently the state changes are printed to the log, but it would be good to extend this to something the camera operator could see.