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

Installation

Software

Operating System

Any sound supporting linux system 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

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';  

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 installation dir and database settings in aura.ini

aura.py

It is the server which is connected to the external programme source, to liquidsoap and is listening for redis pubsub messages.

Guru

The commandline tool for interacting with the server.

Liquidsoap

The heart of AURA Engine. It uses the built in mixer, to switch between different sources. A source can be a stream, the filesystem or linein

Hardware

Soundcard

AURA Engine ist tested with an ASUS Xonar DGX. It should work with every by ALSA supported soundcard. PulseAudio support is planned.

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 wav, flac, ogg or mp3 output

Streams

You can configure up to five streams. You find the settings in the engine.ini. You can choose between aac, aacplus, fdkaac, flac, mp3, ogg, opus stream

If you experience 'hangs' on the stream

• reduce the quality or
• invest in better hardware or
• install the realtime kernel

  apt install linux-image-rt-amd64
  reboot

  Should be sufficient.