AURA Engine

This piece of Software is part of 'AURA - AUtomated RAdio'.

AURA Engine does:

• requesting the programme from an external Source
• switches the soundserver at the correct time to a given source for a specific show
• records what is broadcasted
• streams to an icecast server
• plays to lineout

Installation

Software

Operating System

Any linux system with ALSA, pulseaudio or Jack2 support should work. It is tested and coded on a debian stretch

Packages

On a debian machine:

sudo apt install \
    git \
    python3 python3-pip \
    redis-server \
    liquidsoap liquidsoap-plugin-alsa liquidsoap-plugin-flac liquidsoap-plugin-icecast liquidsoap-plugin-pulseaudio \
    mariadb-server libmariadbclient-dev \
    quelcom

Python Packages

sudo pip3 install \
    Flask Flask-SQLAlchemy \
    mysqlclient redis simplejson \
    mutagen validators

Grab the code

git clone https://gitlab.servus.at/autoradio/engine

Set up a database

Command line way

mysql -u root -p

CREATE DATABASE aura_engine CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;  
CREATE USER 'aura'@'localhost' IDENTIFIED BY 'secure-password';  
GRANT ALL PRIVILEGES ON aura_engine.* TO 'aura'@'localhost';  

phpmyadmin / adminer way

Log into your phpmyadmin or adminer with correct privileges and create a database and a user for the aura engine.

Files and Folders

• Create the audio folder defined in your aura.ini

mkdir /var/audio
mkdir /etc/aura
cp {where you cloned the repo}/configuration/engine.ini /etc/aura/engine.ini
edit engine.ini to your needs

• Edit settings in aura.ini. Take your time for that.

aura.py

It is the server which is connected to the external programme source (e.g. aura steering and tank), to liquidsoap and is listening for redis pubsub messages. This precious little server is telling liquidsoap what to play and when.

Guru

The commandline tool for interacting with the server. Also provides the communication from Liquidsoap to the python (Command-)Server.

Liquidsoap

The heart of AURA Engine. It uses the built in mixer, to switch between different sources.

Find Help

LiquidSoap Reference: http://savonet.sourceforge.net/doc-svn/reference.html Python3.5 Reference: https://docs.python.org/3.5/

Hardware

Soundcard

AURA Engine ist tested with a ASUS Xonar DGX and a Roland Duo-Capture Ex. Both work well with jack and pulseaudio. For good experience with ALSA, you may need better hardware.

Hard/Soft

When you use ALSA, you will have to play around with ALSA settings. In the folder ./modules/liquidsoap is a scipt called alsa_settings_tester.liq. You can start it with 'liquidsoap -v --debug alsa_settings_tester.liq'. Changing and playing with settings can help you to find correct ALSA settings.

Recordings

You can configure up to five recorders. You find the settings in the main config file engine.ini. You can choose between different output formats.

Streams

You can configure up to five streams. You find the settings in the engine.ini. You can choose between different streaming formats.

If you experience 'hangs' on the stream

• reduce the quality or
• install the realtime kernel with

  apt install linux-image-rt-amd64
  reboot

  or
• invest in better hardware