Info on normalization.

README.md

@@ -27,6 +27,7 @@ the requirements of community radios.
 - **Multichannel Line-out**
 - **Silence Detector** to avoid *Dead Air*
 - **Auto DJ** which plays random music when silence is detected
+- **ReplayGain** normalization done using passed [ReplayGain](https://en.wikipedia.org/wiki/ReplayGain) meta data
 - **API** to query Track-Service, monthly reports and information for displaying the Studio Clock (see [Engine API](https://gitlab.servus.at/aura/engine-api))
 - **Web Application for a Track Service** (see [AURA Player](https://gitlab.servus.at/aura/player))
 - **Web Application providing a Studio Clock** (see [Engine Clock](https://gitlab.servus.at/aura/engine-clock))

docs/engine-features.md

@@ -13,6 +13,7 @@ This page gives a more detailed overview of the Aura Engine features and how to
     - [Default Playlists](#default-playlists)
     - [Auto DJ](#auto-dj)
         - [Silence Detector](#silence-detector)
+    - [ReplayGain and LoudNorm Normalization](#replaygain-and-loudnorm-normalization)
     - [Monitoring](#monitoring)
         - [Send mails on errors and warnings](#send-mails-on-errors-and-warnings)
         - [Engine Health Information via Engine API](#engine-health-information-via-engine-api)
@@ -182,6 +183,13 @@ channel.
 > Note, all these fallback source are fully integrated with the Engine's playlog and track-service
 feature including indications from which fallback level some audio is broadcasted.
 
+## ReplayGain and LoudNorm Normalization
+
+If the played media files contain [ReplayGain](https://en.wikipedia.org/wiki/ReplayGain) meta information,
+then such audio is automatically normalized accordingly. Note, if you are using Engine in conjunction with
+[AURA Tank](https://gitlab.servus.at/aura/tank) then also a [LoudNorm](http://k.ylo.ph/2016/04/04/loudnorm.html) 
+normalization step is applied. In that case files are re-encoded by Tank itself.
+
 ## Monitoring
 
 You have following options to monitor the Engine: