reactivated fallback and callback from lqs, fixed multiple lineins on engine...

reactivated fallback and callback from lqs, fixed multiple lineins on engine level, having the problem that fallback does not start

README.md

@@ -26,11 +26,53 @@ sudo apt install \
     git \
     python3 python3-pip \
     redis-server \
-    liquidsoap liquidsoap-plugin-alsa liquidsoap-plugin-flac liquidsoap-plugin-icecast liquidsoap-plugin-pulseaudio \
+    liquidsoap liquidsoap-plugin-icecast \
     mariadb-server libmariadbclient-dev \
     quelcom
 ```
 
+##### Liquidsoap Plugins
+
+###### Soundcard
+How liquidsoap is using your soundcard is depending on what you are going to use:
+
+with ALSA:
+```bash
+sudo apt install \
+    liquidsoap-plugin-alsa liquidsoap-plugin-pulseaudio
+```
+
+With pulseaudio:
+```bash
+sudo apt install \
+    liquidsoap-plugin-pulseaudio
+```
+
+with jack:
+```bash
+sudo apt install \
+    liquidsoap-plugin-jack
+```
+
+###### File Formats
+
+Depending on what stream you are going to send, and what recordings you are going to use:
+```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
+```
+
+###### Simple
+
+```bash
+sudo apt install \
+    liquidsoap-plugin-all
+```
+
 
 #### Python Packages
 
@@ -61,7 +103,7 @@ 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.
+Log into your phpmyadmin or adminer with correct privileges, create a database and a user for the aura engine.
 
 #### Files and Folders
 
@@ -86,33 +128,62 @@ The commandline tool for interacting with the server. Also provides the communic
 
 #### Liquidsoap
 
-The heart of AURA Engine. It uses the built in mixer, to switch between different sources.
+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.
 
 #### Find Help
 
-LiquidSoap Reference: http://savonet.sourceforge.net/doc-svn/reference.html
-Python3.5 Reference: https://docs.python.org/3.5/ 
+##### Liquidsoap
+Reference: \
+http://savonet.sourceforge.net/doc-svn/reference.html
+##### Python
+Reference: \
+https://docs.python.org/3.5/ 
+
+#### Interfaces
+
+##### From Aura Engine
+
+_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/
+
+##### To Aura Engine
+
+Interfaces are needed from pv/steering to engine and from tank to engine. More informations you can find here: https://gitlab.servus.at/autoradio/meta/blob/master/api-definition.md
 
 ### 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.
+AURA Engine is tested with a ASUS Xonar DGX, a Roland Duo-Capture Ex and also on an Onboard Soundcard (HDA Intel ALC262). Both work well with jack and pulseaudio. For a 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. 
+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.
 
-### Recordings
+#### Streams
 
-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.
+You can configure up to **five** streams. You find the settings in the engine.ini. You can choose between different streaming formats.
 
-### Streams
+### Troubleshooting
 
-You can configure up to five streams. You find the settings in the engine.ini. You can choose between different streaming formats.
+**If you cannot find correct ALSA settings** \
+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.
 
-If you experience 'hangs' on the stream
- * reduce the quality or
+**If you experience 'hangs' or other artefacts on the output signal**
+ * reduce the quality (especially, when hangs are on the stream) or
  * install the realtime kernel with
    ```bash
    apt install linux-image-rt-amd64