This daemon handles the processing of audio and video streams from multiple sources, enabling real-time streaming and recording. It is designed to run on edge servers, typically in environments such as lecture halls, and uses off-the-shelf hardware for cost efficiency and flexibility.
'streamd' uses GStreamer for capturing from live sources, multiplexing, processing, and streaming via SRT.
The overall design off the daemon focuses on simplicity and clearity, avoiding
leaky abstractions on top of GStreamer. The user should know the basic concepts
of GStreamer and be able to construct simple pipelines via gst-launch-1.0.
The daemon provides a Prometheus metrics endpoint which includes CPU, Memory, I/O, SRT Connection, and pipeline metrics.
The pipeline's filter graph only contains functionality required for basic
live-streaming. Processing elements are packed into reusable bins (see gstreamer_bins.go).
Bins usually resemble physical components such as sources or splitters.
Features like scheduled recordings are out of scope to reduce complexity and increase resilience.
This is a filter graph from a streamd instance with hardware acceleration enabled.
┌───────────────────────────────────────────────────────┐
│ streamd │
└───────────────────────────────────────────────────────┘
┌───────────────────────────┐┌──────────────────────────┐
│ GStreamer Framework ││ │
└───────────────────────────┘│ Decklink Library │
┌───────────────────────────┐│ │
│ VA API ││ │
└───────────────────────────┘└──────────────────────────┘
┌───────────────────────────────────────────────────────┐
│ ┌───────────┐┌───────────┐┌────────────┐┌─────────┐ │
│ │ V4L2 ││ Decklink ││ ALSA ││ DRM │ │
│ │ Subsystem ││ ││ Subsystem ││ │ │
│ └───────────┘└───────────┘└────────────┘└─────────┘ │
│ Kernel │
└───────────────────────────────────────────────────────┘
┌───────────────────────────────────────────────────────┐
│ Hardware │
└───────────────────────────────────────────────────────┘
streamd only runs on a Linux distribution and architecture supported by Go. To
compile the daemon, install all dependencies or enter the nix development shell
and run go build.
If you have nix/nixos just enter the development shell with nix-shell in the repository root.
- Go
- A working C compiler
- pkg-config
- Glib
- GStreamer
- GStreamer Plugins Ugly
- GStreamer Plugins Bad
- GStreamer Plugins Base
- GStreamer Plugins Good
- GStreamer libav
Take a look at nix.shell in the repository root for a detailed list.
The following flags configure the streamd daemon:
-audio-enc-bitrate int
Video encoding bitrate in Kbps (default 96)
-http-port string
Port at which to listen for HTTP requests (default "8080")
-hw-accel
Enable hardware acceleration and offload processing tasks onto the GPU or a DSP
-port-cam-srt string
SRT listing port for camera stream (default "7002")
-port-comb-srt string
SRT listing port for combined stream (default "7000")
-port-present-srt string
SRT listing port for presentation stream (default "7001")
-source-audio string
GStreamer element factory name for the audio source (default "audiotestsrc")
-source-audio-opts string
GStreamer element properties for audio source
-source-cam string
GStreamer element factory name for the camera source (default "videotestsrc")
-source-cam-opts string
GStreamer element properties for camera source
-source-present string
GStreamer element factory name for the presentation source (default "videotestsrc")
-source-present-opts string
GStreamer element properties for presentation source
-listen-cidr string
CIDR containing Address to listen for all srt requests. E.g. 100.64.0.0/10 for tailnets. If unset, [::] will be listened on.
-video-enc-bitrate int
Video encoding bitrate in Kbps (default 6000)
For details on SRT URIs, see: https://github.com/hwangsaeul/libsrt/blob/master/docs/srt-live-transmit.md.
-
HTTP GET /metrics
Prometheus metrics endpoint. -
HTTP GET /graph?details=<OPTIONAL_DETAILS_QUERY>
Retrieve the current filter graph astext/vnd.graphviz.OPTIONAL_DETAILS_QUERYoptions:media-typecapsnon-default-paramsstatesfull-paramsallverbose
streamd -hw-accel \
-source-cam v4l2src -source-cam-opts "device=/dev/video0" \
-source-present v4l2src -source-present-opts "device=/dev/video2" \
-source-audio alsasrc -source-audio-opts "device=hw:2,0"