Plugins

Plugins make it easy to customize Trunk Recorder and have it better fit you workflow. There are some built-in Plugins that are included in Trunk Recorder and also ones that the Community has developed.

The Built-in Plugins are compiled and installed when you setup Trunk Recorder. Follow the instructions for the Community Plugins to install them. In order to load a plugin when you start Trunk Recorder, you need to add a plugins section to your config.json file. A Plugin JSON Object is add for each of the Plugins you wish to load. The Plugin Object tells Trunk Recorder how to load it and its configuration.

{
  Global Configs

  "sources": [{ Source Object }, { Source Object }],
  "systems": [{ System Object }, { System Object }],
  "plugins": [{ Plugin Object }]
}

Plugin Object

Key	Required	Default Value	Type	Description
library	✓		string	the name of the library that contains the plugin.
name	✓		string	the name of the plugin. This name is used to find the `<name>_plugin_new` method that creates a new instance of the plugin.
enabled		true	true / false	control whether a configured plugin is enabled or disabled
				Additional elements can be added, they will be passed into the `parse_config` method of the plugin.

Built-in Plugins

Rdio Scanner Plugin

Name: rdioscanner_uploader Library: librdioscanner_uploader.so

This plugin makes it easy to connect Trunk Recorder with Rdio Scanner. It uploads recordings and the information about them. The following additional settings are required:

Key	Required	Default Value	Type	Description
server	✓		string	The URL for uploading to Rdio Scanner. The default is an empty string. It should be the same URL as the one you are using to access Rdio Scanner.
systems	✓		array	This is an array of objects, where each is a system that should be passed to Rdio Scanner. More information about what should be in each object is in the following table.

Rdio Scanner System Object:

Key	Required	Type	Description
systemId	✓	number	System ID for Rdio Scanner.
apiKey	✓	string	System-specific API key for uploading calls to Rdio Scanner. See the ApiKey section in the Rdio Scanner administrative dashboard for the value it should be.
shortName	✓	string	This should match the shortName of a system that is defined in the main section of the config file.

Example Plugin Object:

        {
          "name": "rdioscanner_uploader",
          "library": "librdioscanner_uploader.so",
          "server": "http://127.0.0.1",
          "systems": [{
                  "shortName": "test",
                  "apiKey": "fakekey",
                  "systemId": 411
          }

simplestream Plugin

Name: simplestream Library: libsimplestream.so

This plugin streams uncompressed audio (16 bit Int, 8 kHz, mono) to UDP or TCP ports in real time as it is being recorded by trunk-recorder. It can be configured to stream audio from all talkgroups and systems being recorded or only specified talkgroups and systems. TGID information can be prepended to the audio data to allow the receiving program to take action based on the TGID. Audio from different Systems should be streamed to different UDP/TCP ports to prevent crosstalk and interleaved audio from talkgroups with the same TGID on different systems.

This plugin does not, by itself, stream audio to any online services. Because it sends uncompressed PCM audio, it is not bandwidth efficient and is intended mostly to send audio to other programs running on the same computer as trunk-recorder or to other computers on the LAN. The programs receiving PCM audio from this plugin may play it on speakers, compress it and stream it to an online service, etc.

NOTE 1: In order for this plugin to work, the audioStreaming option in the Global Configs section (see above) must be set to true.

NOTE 2: trunk-recorder passes analog audio to this plugin at 16 kHz sample rate and digital audio at 8 kHz sample rate. Since the audio data being streamed doesn't contain the sample rate, analog and digital audio should be configured to be sent to different ports to receivers that are matched to the same sample rate.

Key	Required	Default Value	Type	Description
streams	✓		array	This is an array of objects, where each is an audio stream that will be sent to a specific IP address and UDP port. More information about what should be in each object is in the following table.

Audio Stream Object:

Key	Required	Default Value	Type	Description
address	✓		string	IP address to send this audio stream to. Use "127.0.0.1" to send to the same computer that trunk-recorder is running on.
port	✓		number	UDP or TCP port that this stream will send audio to.
TGID	✓		number	Audio from this Talkgroup ID will be sent on this stream. Set to 0 to stream all recorded talkgroups.
sendTGID		false	true / false	When set to true, the TGID will be prepended in long integer format (4 bytes, little endian) to the audio data each time a packet is sent.
shortName			string	shortName of the System that audio should be streamed for. This should match the shortName of a system that is defined in the main section of the config file. When omitted, all Systems will be streamed to the address and port configured. If TGIDs from Systems overlap, each system must be sent to a different port to prevent interleaved audio for talkgroups from different Systems with the same TGID.
useTCP		false	true / false	When set to true, TCP will be used instead of UDP.

Plugin Object Example #1:

This example will stream audio from talkgroup 58914 on system "CountyTrunked" to the local machine on UDP port 9123.

        {
          "name":"simplestream",
          "library":"libsimplestream.so",
          "streams":[{
            "TGID":58914,
            "address":"127.0.0.1",
            "port":9123,
            "sendTGID":false,
            "shortName":"CountyTrunked"}
        }

Plugin Object Example #2:

This example will stream audio from talkgroup 58914 from System CountyTrunked to the local machine on UDP port 9123 and stream audio from talkgroup 58916 from System "StateTrunked" to the local machine on UDP port 9124.

        {
          "name":"simplestream",
          "library":"libsimplestream.so",
          "streams":[{
            "TGID":58914,
            "address":"127.0.0.1",
            "port":9123,
            "sendTGID":false,
            "shortName":"CountyTrunked"},
           {"TGID":58916,
            "address":"127.0.0.1",
            "port":9124,
            "sendTGID":false,
            "shortName":"StateTrunked"}
          ]}
        }

Plugin Object Example #3:

This example will stream audio from talkgroups 58914 and 58916 from all Systems to the local machine on the same UDP port 9123. It will prepend the TGID to the audio data in each UDP packet so that the receiving program can differentiate the two audio streams (the receiver may decide to only play one depending on priority, mix the two streams, play one left and one right, etc.)

        {
          "name":"simplestream",
          "library":"libsimplestream.so",
          "streams":[{
            "TGID":58914,
            "address":"127.0.0.1",
            "port":9123,
            "sendTGID":true},
           {"TGID":58916,
            "address":"127.0.0.1",
            "port":9123,
            "sendTGID":true}
          ]}
        }

Plugin Object Example #4:

This example will stream audio from all talkgroups being recorded on System CountyTrunked to the local machine on UDP port 9123. It will prepend the TGID to the audio data in each UDP packet so that the receiving program can decide which ones to play or otherwise handle)

        {
          "name":"simplestream",
          "library":"libsimplestream.so",
          "streams":[{
            "TGID":0,
            "address":"127.0.0.1",
            "port":9123,
            "sendTGID":true,
            "shortName":"CountyTrunked"}
        }

Example - Sending Audio to pulseaudio

pulseaudio is the default sound system on many Linux computers, including the Raspberry Pi. If configured to do so, pulseaudio can accept raw audio via TCP connection using the module-simple-protocol-tcp module. Each TCP connection will show up as a different "application" in the pavucontrol volume mixer.

An example command to set up pulseaudio to receive 8 kHz digital audio from simplestream on TCP port 9125 (for 16 kHz analog audio, use rate=16000):

pacmd load-module module-simple-protocol-tcp sink=1 playback=true port=9125 format=s16le rate=8000 channels=1

The matching simplestream config to send audio from talkgroup 58918 to TCP port 9125 would then be something like this:

        {
          "name":"simplestream",
          "library":"libsimplestream.so",
          "streams":[{
            "TGID":58918,
            "address":"127.0.0.1",
            "port":9125,
            "sendTGID":false,
            "shortName":"CountyTrunked",
            "useTCP":true}
        }

Community Plugins

MQTT Status: Publishes the current status of a Trunk Recorder instance over MQTT
MQTT Statistics: Publishes statistics about a Trunk Recorder instance over MQTT
Decode rates logger: Logs trunking control channel decode rates to a CSV file, and includes a PHP file that outputs an SVG graph
Daily call log and live Web page: Creates a daily log of calls (instead of just individual JSON files) and includes an updating PHP Web page w/audio player
Prometheus exporter: Publishes statistics to a metrics endpoint via HTTP

Plugins

Plugin Object​

Built-in Plugins​

Rdio Scanner Plugin​

Example Plugin Object:​

simplestream Plugin​

Plugin Object Example #1:​

Plugin Object Example #2:​

Plugin Object Example #3:​

Plugin Object Example #4:​

Example - Sending Audio to pulseaudio​

Community Plugins​