From 5d5ba2c95dfa0311a4aebfe012af7842c4f7b7ef Mon Sep 17 00:00:00 2001
From: Markus Birth <mbirth@gmail.com>
Date: Sun, 4 Mar 2018 18:20:34 +0100
Subject: [PATCH] Added scripts for MP3 loudness normalisation based on EBU
 R123 instead of ReplayGain. (lossless using mp3gain to modify values)

---
 mp3loud_track.sh  | 27 +++++++++++++++++++++++++++
 mp3loud_tracks.sh | 14 ++++++++++++++
 2 files changed, 41 insertions(+)
 create mode 100755 mp3loud_track.sh
 create mode 100755 mp3loud_tracks.sh

diff --git a/mp3loud_track.sh b/mp3loud_track.sh
new file mode 100755
index 0000000..690b00d
--- /dev/null
+++ b/mp3loud_track.sh
@@ -0,0 +1,27 @@
+#!/bin/sh
+# Install mp3gain from: https://launchpad.net/~flexiondotorg/+archive/ubuntu/audio
+# Install bs1770gain from package manager
+
+TARGET_LOUDNESS=-14
+
+# Normalise MP3 to 89 dB, add tags to file
+mp3gain -q -k -p -r -s i "$1" > /dev/null
+
+# Find actual EBU R128 loudness, show relative to $TARGET_LOUDNESS LUFS
+LOUDADJUST=`bs1770gain --norm $TARGET_LOUDNESS --xml "$1" | grep -m 1 integrated | sed -e 's/^.*lu="\(.*\)".*$/\1/'`
+echo "[$1] Deviation from $TARGET_LOUDNESS LUFS: $LOUDADJUST LU"
+
+# Calculate gain adjustment (in steps of 1.5 dB/~LU), round using printf
+GAINADJUST=`echo "scale=4;$LOUDADJUST / 1.5" | bc`
+GAINADJUST=`printf %0.f $GAINADJUST`
+
+# To ALWAYS stay BELOW -14 LUFS, use this:
+#GAINADJUST=`echo "$LOUDADJUST / 1.5" | bc`
+
+if [ "$GAINADJUST" -ne 0 ]; then
+    echo "[$1] Adjust gain by: $GAINADJUST"
+    # Use this call to have clipping-prevention which doesn't work when modifying gain directly
+    mp3gain -q -k -p -r -s i -m $GAINADJUST "$1"
+else
+    echo "[$1] No further adjustment necessary."
+fi
diff --git a/mp3loud_tracks.sh b/mp3loud_tracks.sh
new file mode 100755
index 0000000..772377f
--- /dev/null
+++ b/mp3loud_tracks.sh
@@ -0,0 +1,14 @@
+#!/bin/sh
+if [ "$#" = "0" ]; then
+    echo "Usage: $0 file1 [file2 file3 ... fileN]"
+    exit 1
+fi
+
+if [ -z "$CONCURRENCY_LEVEL" ]; then
+    CONCURRENCY_LEVEL=1
+fi
+
+echo "Processing using $CONCURRENCY_LEVEL processes..."
+nice -n2 find "$@" -print0 | xargs -0 -P $CONCURRENCY_LEVEL -n 1 -I {} /opt/mbirth/mp3loud_track.sh "{}"
+
+echo "All done."