README.md 10.9 KB
Newer Older
1

David Trattnig's avatar
David Trattnig committed
2
3
4
5
<!-- TOC -->autoauto- [AURA Engine](#aura-engine)auto    - [Features](#features)auto        - [Play tracks from multiple sources](#play-tracks-from-multiple-sources)auto        - [Blank Detenction / Silence Detecter](#blank-detenction--silence-detecter)auto        - [Auto Pilot](#auto-pilot)auto        - [Dynamically switching of source channels](#dynamically-switching-of-source-channels)auto        - [Multiple Recorders](#multiple-recorders)auto        - [Stream to an Icecast Server](#stream-to-an-icecast-server)auto        - [Multichannel Line-out](#multichannel-line-out)auto    - [Architecture](#architecture)auto            - [Required Data Sources](#required-data-sources)auto            - [Provided API Endpoints](#provided-api-endpoints)auto    - [Installation](#installation)auto        - [Hardware Requirements](#hardware-requirements)auto        - [Software Requirements](#software-requirements)auto        - [Getting Started](#getting-started)auto            - [Install System Packages](#install-system-packages)auto            - [Install Python Packages](#install-python-packages)auto            - [Setup Database](#setup-database)auto            - [Alternative Sound Servers](#alternative-sound-servers)auto            - [Configuration](#configuration)auto        - [Hardware](#hardware)auto            - [Soundcard](#soundcard)auto            - [Hard/Soft](#hardsoft)auto            - [Line In](#line-in)auto            - [Recordings](#recordings)auto            - [Streams](#streams)auto        - [Running the Engine](#running-the-engine)auto        - [Logging](#logging)auto    - [Development](#development)auto        - [Components](#components)auto    - [Frequently Asked Questions](#frequently-asked-questions)auto        - [ALSA Settings](#alsa-settings)auto            - [In the Liquidsoap Logs I get 'Error when starting output output_lineout_0: Failure("Error while setting open_pcm: Device or resource busy")!'. What does it mean?](#in-the-liquidsoap-logs-i-get-error-when-starting-output-output_lineout_0-failureerror-while-setting-open_pcm-device-or-resource-busy-what-does-it-mean)auto            - [How can I find the audio device IDs, required for settings in engine.ini?](#how-can-i-find-the-audio-device-ids-required-for-settings-in-engineini)auto    - [Resources](#resources)autoauto<!-- /TOC -->


# AURA Engine
6

David Trattnig's avatar
David Trattnig committed
7
8
Aura Engine is a play-out engine as part of Automated Radio (Aura) system,
specifically build for the requirements of community radios.
9
10
11

## Features

David Trattnig's avatar
David Trattnig committed
12
13
14
15
16
17
### Play tracks from multiple sources

It's possible to air playlists with music or recordings stored on the **filessystem**,
via external **streams** or live from a **studio**.

### Blank Detenction / Silence Detecter
18

David Trattnig's avatar
David Trattnig committed
19
20
21
22
23
24
25
The engine offers a simple way to detect scenarios where no music is on air.
It possible to configure the sensitivity of the Silence Detector and automatically
transition play-out to a Fallback Playlist (see Auto Pilot).

### Auto Pilot

In case there is no schedule delivered by Steering, engine provides multiple
26
27
fallback handling scenarios. The available fallbacks are evaluated in following order:

David Trattnig's avatar
David Trattnig committed
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
1. **Timeslot Fallback**: //TODO explain
2. **Show Fallback**: //TODO explain
3. **Station Fallback**: //TODO explain

### Dynamically switching of source channels

    TODO extend: * switch the soundserver at the correct time to a given source for a specific show

### Multiple Recorders

    TODO extend:  * record what is broadcasted


### Stream to an Icecast Server

    TODO extend:  * stream to an icecast server

### Multichannel Line-out

    TODO extend:  * play to line-out
48
49
50
51
52
53
54
55
56


## Architecture

AURA Engine as part of the AURA Radio Suite uses an modulear architecture
based on a REST API. All external information is retrieved using JSON data-structures.

#### Required Data Sources

David Trattnig's avatar
David Trattnig committed
57
58
59
60
61
The AURA Project "**Dashboard**" provides the GUI to organize shows, schedules/timelsots
and organize uploads in form of playlists. Those playlists can be organized in timeslots
using a fancy calendar interface.

These data-sources need to be configurated in the "engine.ini" configuration file:
62
63
64
65
66
67
68
69
70
71
72
73
74
75

    # The URL to get the Calendar via PV/Steering
    calendarurl="http://localhost:8000/api/v1/playout"

    # The URL to get show details via PV/Steering
    api_show_url="http://localhost:8000/api/v1/shows/${ID}/"

The AURA Project "**Tank**" on the other hand delivers information on the tracks, playlists
to be played and its meta-data:

    # The URL to get playlist details via Tank
    importerurl="http://localhost:8040/api/v1/shows/${SLUG}/playlists"


David Trattnig's avatar
David Trattnig committed
76
More information you can find here: <https://gitlab.servus.at/autoradio/meta/blob/master/api-definition.md>
77
78
79
80
81
82
83
84
85
86
87
88
89


#### Provided API Endpoints

**Soundserverstate:** Returns true and false values of the internal In- and Outputs  

    /api/v1/soundserver_state

**Trackservice:**

/api/v1/trackservice/<selected_date>  
/api/v1/trackservice/

90
91
## Installation

92
### Hardware Requirements
93

94
95
96
This depends on how many audio sources and targets you are going to use, but for the most 
common scenarios any current hardware should be sufficient. For the audio devices it is 
required to use an interface which has supported ALSA drivers.
97

David Trattnig's avatar
David Trattnig committed
98
Aura Engine is tested with following audio devices
99

100
101
102
103
* ASUS Xonar DGX, 
* Roland Duo-Capture Ex 
* Onboard Soundcard (HDA Intel ALC262)
* Native Instruments Komplete Audio 6
104

105
### Software Requirements
106

107
108
109
110
**Operating System:** Any linux system with ALSA, PulseAudio or Jack2 support should work. 
It is tested and coded on Debian Stretch and Ubuntu 18.0 with Python 3.6+.

### Getting Started
111
112

```bash
113
git clone https://gitlab.servus.at/autoradio/engine
114
115
```

116
117
118
119
#### Install System Packages

On a Debian / Ubuntu machine:

120
121
```bash
sudo apt install \
122
123
124
125
126
127
128
    git \
    python3 python3-pip \
    redis-server \
    liquidsoap liquidsoap-plugin-icecast \
    mariadb-server libmariadbclient-dev \
    quelcom \
    liquidsoap-plugin-alsa liquidsoap-plugin-pulseaudio
129
130
131
```


132
**File Formats:** Depending on what stream you are going to send, and what recordings you are going to use:
133
134
135
136
137
138
139
140
141
```bash
sudo apt install \
    liquidsoap-plugin-aac # for aac support
    liquidsoap-plugin-flac # for flac support
    liquidsoap-plugin-lame liquidsoap-plugin-mad # for mp3 support
    liquidsoap-plugin-opus # for opus support
    liquidsoap-plugin-vorbis # for ogg support
```

142
To simply install support for all available file formats do:
143
144
145
146
147
148

```bash
sudo apt install \
    liquidsoap-plugin-all
```

149

150
#### Install Python Packages
151

Gottfried Gaisbauer's avatar
Gottfried Gaisbauer committed
152
```bash
153
sudo pip3 install -r requirements.txt
154
155
```

156

157
#### Setup Database
158

159

Gottfried Gaisbauer's avatar
Gottfried Gaisbauer committed
160
```bash
161
162
mysql -u root -p

Gottfried Gaisbauer's avatar
Gottfried Gaisbauer committed
163
164
165
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';  
Gottfried Gaisbauer's avatar
Gottfried Gaisbauer committed
166
```
167

168
#### Alternative Sound Servers
169

170
Beside ALSA the sound servers **Jack Audio** and **Pulse Audio** are supported.
171

172
**Using JACK:**
Gottfried Gaisbauer's avatar
Gottfried Gaisbauer committed
173

174
Install the JACK daemon and GUI:
Gottfried Gaisbauer's avatar
Gottfried Gaisbauer committed
175
```bash
176
    sudo apt-get install jackd qjackctl 
Gottfried Gaisbauer's avatar
Gottfried Gaisbauer committed
177
```
178

179
180
Please ensure to enable "*realtime process priority*" when installing JACK to keep latency low.
Now, you are able to configure your hardware settings using following command:
181

182
183
184
```bash
    qjackctl
```
185

186
Next you need to install the JACK plugin for Liquidsoap:
187

188
189
190
191
```bash
sudo apt install \
    liquidsoap-plugin-jack
```
192

193

194
#### Configuration
195

196
Run
197

198
199
200
```bash
  sh init.sh
```
201

202
203
This creates the folder */var/audio* and copies some default configuration
to */etc/aura/engine.ini*
204

205
After that, you have to edit the settings in */etc/aura/engine.ini*. Ensure to take your time to carefully review those settings!
206
207
208



209
210
211

### Hardware

212
#### Soundcard
Gottfried Gaisbauer's avatar
newline    
Gottfried Gaisbauer committed
213

214
#### Hard/Soft
Gottfried Gaisbauer's avatar
newline    
Gottfried Gaisbauer committed
215

216
217
218
219
220
221
222
223
224
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 may help you to find correct ALSA settings.

#### Line In

You can configure up to **five** line ins. Your hardware should support that. When you use JACK, you will see the additional elements popping up when viewing your connections (with e.g. Patchage).

#### 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.
225

226
#### Streams
227

228
You can configure up to **five** streams. You find the settings in the engine.ini. You can choose between different streaming formats.
229
230


231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302


### Running the Engine ###

To start the AuRa Engine execute:

    systemctl start aura-lqs
    systemctl start aura-engine  

and on system boot run following:

    systemctl enable aura-lqs
    systemctl enable aura-engine

The first service starts the LiquidSoap Engine, while the latter boots the actual AuRa Engine.

### Logging

You can access the service logs using:

    journalctl -u aura-lqs

and

    journalctl -u aura-engine

respectively.



## Development

To run the LiquidSoap code during develpment execute:
    ./run.sh

### Components ###


**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. It records everything and streams everything depending on your settings in aura.ini.







## Frequently Asked Questions ##

### ALSA Settings

#### In the Liquidsoap Logs I get 'Error when starting output output_lineout_0: Failure("Error while setting open_pcm: Device or resource busy")!'. What does it mean?

You probably have set a wrong or occupied device ID.


#### How can I find the audio device IDs, required for settings in engine.ini?

* **ALSA**: You can get the device numbers or IDs by executing:

    cat /proc/asound/cards

* **Pulse Audio**: You might not need this for Pulse Audio, but still, to see all available devices use:

    pactl list



**If you cannot find correct ALSA settings**  
303
Well, this is - at least for me - a hard one. I could not manage to find correct ALSA settings for the above mentioned soundcards. The best experience i had with the ASUS Xonar DGX, but still very problematic (especially the first couple of minutes after starting liquidsoap). Since i enabled JACK support i only use that. It is also a bit of trial and error, but works pretty much out of the box.
304

305
306
**If you experience 'hangs' or other artefacts on the output signal**
 * reduce the quality (especially, when hangs are on the stream) or
307
 * install the realtime kernel with
308

309
310
311
312
   ```bash
   apt install linux-image-rt-amd64
   reboot
   ```
313

314
   or
315
316
317
318
319
320
321
322
323
 * invest in better hardware


## Resources ##

* **Python**: https://docs.python.org/
* **Redis**: https://redis.io/
* **Liquidsoap**: https://www.liquidsoap.info/doc-1.4.0/
* **Jack Audio**: https://jackaudio.org/