Janus FTL Plugin

This is a work-in-progress Janus plugin to support the FTL "Faster-Than-Light" protocol developed for the Mixer live streaming service.

This protocol lets streamers deliver media to browser viewers with very low, often sub-second latency.

See my notes on the FTL protocol here.

Building

Dependencies

First, compile and install Janus.

Get Meson for building.

Install libavcodec library (sudo apt install libavcodec-dev on Ubuntu).

Building

By default during build we look for Janus in /opt/janus (the default install path), but this can be configured with the JANUS_PATH env var.

mkdir build/
meson build/
cd build
ninja

Installing

(from build/ directory)

sudo ninja install

Running

Just fire up Janus (/opt/janus/bin/janus), and the FTL plugin should automatically load - you should see this output:

FTL: Plugin initialized!
[...]
FTL: Ingest server is listening on port 8084

Now you ought to be able to point an FTL client at the ingest server and start streaming.

The default stream key is 123456789-aBcDeFgHiJkLmNoPqRsTuVwXyZ123456.

123456789 can be whatever "Channel ID" you'd like.

aBcDeFgHiJkLmNoPqRsTuVwXyZ123456 can be overridden by setting the FTL_SERVICE_DUMMY_HMAC_KEY environment variable.

See DummyServiceConnection.cpp for the default stream key retrieval mechanism.

For watching your stream from a browser, see janus-ftl-player.

Configuration

Configuration is achieved through environment variables.

Environment Variable	Supported Values	Notes
FTL_HOSTNAME	Valid hostname	The hostname of the machine running the FTL service. Defaults to system hostname.
FTL_SERVICE_CONNECTION	DUMMY: (default) Dummy service connection GLIMESH: Glimesh service connection	This configuration value determines which service FTL should plug into for operations such as stream key retrieval.
FTL_SERVICE_METADATAREPORTINTERVALMS	Time in milliseconds	Defaults to 4000, controls how often FTL stream metadata will be reported to the service.
FTL_SERVICE_DUMMY_HMAC_KEY	String, default: aBcDeFgHiJkLmNoPqRsTuVwXyZ123456	Key all FTL clients must use if service connection is DUMMY. The HMAC key is the part after the dash in a stream key.`
FTL_SERVICE_DUMMY_PREVIEWIMAGEPATH	/path/to/directory	The path where preview images of ingested streams will be stored if service connection is DUMMY. Defaults to ~/.ftl/previews
FTL_SERVICE_GLIMESH_HOSTNAME	Hostname value (ex. localhost, glimesh.tv)	This is the hostname the Glimesh service connection will attempt to reach.
FTL_SERVICE_GLIMESH_PORT	Port number, 1-65535.	This is the port used to communicate with the Glimesh service via HTTP/HTTPS.
FTL_SERVICE_GLIMESH_HTTPS	0: Use HTTP 1: Use HTTPS	Determines whether HTTPS is used to communicate with the Glimesh service.
FTL_SERVICE_GLIMESH_CLIENTID	String, OAuth Client ID returned by Glimesh app registration.	Used to authenticate to the Glimesh API.
FTL_SERVICE_GLIMESH_CLIENTSECRET	String, OAuth Client Secret returned by Glimesh app registration.	Used to authenticate to the Glimesh API.

Dockering

docker build -t janus-ftl
docker run --rm -p 8084:8084/tcp -p 8088:8088/tcp -p 9000-9100:9000-9100/udp -p 20000-20100:20000-20100/udp -e "DOCKER_IP=HOST.IP.ADDRESS.HERE" janus-ftl

Misc Notes

Streaming from OBS

Currently, there is no UI in OBS to set a custom FTL ingest endpoint.

In order to specify a custom FTL ingest server, you will need to edit the plugin_config\rtmp-services\services.json file. This is located in %AppData%\obs-studio\plugin_config\rtmp-services\services.json on Windows.

Add the following to the "services" array:

{
    "name": "YOUR NAME HERE",
    "common": false,
    "servers": [
        {
            "name": "SERVER NAME HERE",
            "url": "your.janus.hostname"
        }
    ],
    "recommended": {
        "keyint": 2,
        "output": "ftl_output",
        "max audio bitrate": 160,
        "max video bitrate": 8000,
        "profile": "main",
        "bframes": 0
    }
},

After you've made this change, you can start OBS and find your service listed in the OBS settings UI.

Include paths

If you use VS code with the C++ extension, these include paths should make intellisense happy.

"includePath": [
    "${workspaceFolder}/**",
    "/opt/janus/include/janus",
    "/usr/include/glib-2.0",
    "/usr/lib/x86_64-linux-gnu/glib-2.0/include"
]

License

Copyright (C) 2020  Hayden McAfee

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see <https://www.gnu.org/licenses/>.