Rename volume adjustment scripts

dotfiles/bin/change-volume

@@ -0,0 +1,59 @@
+#!/usr/bin/env bash
+
+# Re-encodes the audio, modify the volume based on the supplied db delta. If
+# given a video file then the file is copied as-is. If you want to bring the
+# max_volume to 0 db then call analyze-volume prior to this and pass a delta
+# based on the reported max_volume.
+#
+# Inspired by https://superuser.com/a/323127 and https://superuser.com/a/1312885
+
+if which tput >/dev/null 2>&1; then
+    ncolors=$(tput colors)
+fi
+if [ -t 1 ] && [ -n "$ncolors" ] && [ "$ncolors" -ge 8 ]; then
+    RED="$(tput setaf 1)"
+    GREEN="$(tput setaf 2)"
+    YELLOW="$(tput setaf 3)"
+    BLUE="$(tput setaf 4)"
+    MAGENTA="$(tput setaf 5)"
+    CYAN="$(tput setaf 6)"
+    BOLD="$(tput bold)"
+    NORMAL="$(tput sgr0)"
+else
+    RED=""
+    GREEN=""
+    YELLOW=""
+    BLUE=""
+    MAGENTA=""
+    CYAN=""
+    BOLD=""
+    NORMAL=""
+fi
+
+if [[ $1 == "" ]]; then
+    printf "${BOLD}${RED}Usage: change-volume <video or audio filename> <output name> <volume delta in db>${NORMAL}\n"
+    exit 1
+fi
+
+filename=$(basename -- "$1")
+extension="${filename##*.}"
+filename="${filename%.*}"
+
+output_name="$2"
+delta_db="$3"
+
+if [[ $output_name == "" ]]; then
+    output="${filename}_normalized_audio.$extension"
+else
+    output="${output_name}.$extension"
+fi
+
+printf "\n${YELLOW}${BOLD}Modifying audio volume in $filename.$extension | output: $output | delta: $delta_db${NORMAL}\n"
+
+# Since we're re-encoding the audio we have to specify a codec to use.
+cmd="ffmpeg -y -stats -loglevel level+error -i \"$filename.$extension\" -af \"volume=${delta_db}dB\" -c:v copy -c:a aac -map 0 \"$output\""
+printf "\n${BOLD}Running: $cmd\n\n${NORMAL}"
+eval $cmd
+
+printf "\n${GREEN}${BOLD}Done modifying volume in $filename.$extension | output: $output | delta: $delta_db${NORMAL}\n"
+