From 391030b1bc04357f0a98904ed6e4ca4b1930e9ec Mon Sep 17 00:00:00 2001
From: Markus Birth <mbirth@gmail.com>
Date: Sun, 18 Feb 2018 21:55:56 +0100
Subject: [PATCH] Script for Dolby5.1-to-Stereo downmix in "night mode".

---
 ffdownmix.sh | 12 ++++++++++++
 1 file changed, 12 insertions(+)
 create mode 100755 ffdownmix.sh

diff --git a/ffdownmix.sh b/ffdownmix.sh
new file mode 100755
index 0000000..56fc687
--- /dev/null
+++ b/ffdownmix.sh
@@ -0,0 +1,12 @@
+#!/bin/sh
+# Found: https://superuser.com/questions/852400/properly-downmix-5-1-to-stereo-using-ffmpeg
+# and http://forum.doom9.org/showthread.php?t=168267
+
+ATSC_MODE="pan=stereo|FL<1.0*FL+0.707*FC+0.707*BL|FR<1.0*FR+0.707*FC+0.707*BR"
+NIGHT_MODE="pan=stereo|FL=FC+0.30*FL+0.30*BL|FR=FC+0.30*FR+0.30*BR"
+
+ffmpeg -report -loglevel verbose -i "$1" -map 0:a:1 -c:a aac -b:a 160k -ar 44100 -ac 2 -af $NIGHT_MODE "${1}_2ch.m4a"
+
+
+# Merge with:
+# ffmpeg -i original_file.mkv -i audio_eng_downmix.m4a -i audio_ger_downmix.m4a -map 0 -map 1:0 -map 2:0 -codec copy -metadata:s:a:2 title="English (night mode)" -metadata:s:a:2 language=eng -metadata:s:a:3 title="Deutsch (Nachtmodus)" -metadata:s:a:3 language="ger" output_file.mkv