From 066ea49ab80f843f93a913b621f5ee87454040b2 Mon Sep 17 00:00:00 2001
From: Luke Tidd <luket@google.com>
Date: Sun, 23 Apr 2023 10:56:05 -0400
Subject: [PATCH] init - has the wrong tracks but a good start

---
 split_tracks | 136 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100755 split_tracks

diff --git a/split_tracks b/split_tracks
new file mode 100755
index 0000000..6136204
--- /dev/null
+++ b/split_tracks
@@ -0,0 +1,136 @@
+# split_tracks splits each track of the library.
+#
+# The library is mirrored for each type of split.
+# karaoke: reduces the volume of the vocals by 80% and remixes it
+# drum only: just the drums
+# no drum: everything but the drums
+
+#!/bin/bash
+
+function make_drum() {
+  mkdir -p "${dest_dir['no drums']}"
+  quiet_drums="${actual_work_dir}/quiet drums.wav"
+  wav_name="$(sed 's/\.flac$/.wav/' <<< "$file_name")"
+  mixed_wav="${dest_dir['no drums']}/${wav_name}"
+  final_opus="$(sed 's/\.wav$/.opus/' <<< "$mixed_wav")"
+
+  echo sox -v "$volume_reduction_factor" "$drum_track" "$quiet_drums"
+  sox -v "$volume_reduction_factor" "$drum_track" "$quiet_drums"
+  echo sox -m "${no_drums[@]}" "$quiet_drums" "$mixed_wav"
+  sox -m "${no_drums[@]}" "$quiet_drums" "$mixed_wav"
+  rm -r "$quiet_drums"
+  echo opusenc --comp 10 --downmix-stereo \
+      --title "'${tags[TITLE]}'" --artist "'${tags[ARTIST]}'" \
+      --album "'${tags[ALBUM]}'" --tracknumber "'${tags[TRACKNUMBER]}'" \
+      --date "'${tags[DATE]}'" "'$mixed_wav'" "'$final_opus'"
+  opusenc --comp 10 --downmix-stereo \
+      --title "${tags[TITLE]}" --artist "${tags[ARTIST]}" \
+      --album "${tags[ALBUM]}" --tracknumber "${tags[TRACKNUMBER]}" \
+      --date "${tags[DATE]}" "$mixed_wav" "$final_opus"
+  rm "$mixed_wav"
+}
+
+function make_karaoke() {
+  mkdir -p "${dest_dir[karaoke]}"
+  quiet_vocals="${actual_work_dir}/quiet vocals.wav"
+  wav_name="$(sed 's/\.flac$/.wav/' <<< "$file_name")"
+  mixed_wav="${dest_dir['karaoke']}/${wav_name}"
+  final_opus="$(sed 's/\.wav$/.opus/' <<< "$mixed_wav")"
+  echo sox -v "$volume_reduction_factor" "$vocal_track" "$quiet_vocals"
+  sox -v "$volume_reduction_factor" "$vocal_track" "$quiet_vocals"
+  sox -m "${karaoke}" "$quiet_vocals" "$mixed_wav"
+  rm -r "$quiet_vocals"
+  echo opusenc --comp 10 --downmix-stereo \
+      --title "'${tags[TITLE]}'" --artist "'${tags[ARTIST]}'" \
+      --album "'${tags[ALBUM]}'" --tracknumber "'${tags[TRACKNUMBER]}'" \
+      --date "'${tags[DATE]}'" "'$mixed_wav'" "'$final_opus'"
+  opusenc --comp 10 --downmix-stereo \
+      --title "${tags[TITLE]}" --artist "${tags[ARTIST]}" \
+      --album "${tags[ALBUM]}" --tracknumber "${tags[TRACKNUMBER]}" \
+      --date "${tags[DATE]}" "$mixed_wav" "$final_opus"
+  rm "$mixed_wav"
+}
+
+volume_reduction_factor='0.3'
+src_library="${HOME}/flac"
+work_dir="${HOME}/split"
+actual_work_dir="${work_dir}/htdemucs_ft"
+
+type -P 'demucs' || (
+  printf 'No demucs in path.\nInstall with `pip install demucs` or something.\n\n' >&2
+  exit 1
+)
+
+find "$src_library" -type f -name '*.flac' | while read -r file; do
+  echo $file
+  # file is full original path + filename
+  src_dir="$(dirname "$file")"
+  file_name="$(basename "$file")"
+  unset tags
+  unset dest_dir
+
+  declare -A tags
+  while read -r line; do
+    tag_type="$(cut -d= -f1 <<< "$line")"
+    tag_val="$(cut -d= -f2- <<< "$line")"
+    tags[$tag_type]="$tag_val"
+  done < <(metaflac --list --block-type=VORBIS_COMMENT "$file" | grep 'comment\[' | cut -d: -f2- | sed 's/^ //')
+
+  declare -a ensure
+  ensure=( TRACKNUMBER TITLE DATE ALBUM ARTIST )
+  for tag_type in "${ensure[@]}"; do
+    if [[ -z "${tags[$tag_type]}" ]]; then
+      $tags[$tag_type]="missing $tag_type"
+    fi
+  done
+
+  declare -A dest_dir
+  dest_dir['karaoke']="${src_dir//flac/karaoke}"
+  dest_dir['drums only']="${src_dir//flac/drums only}"
+  dest_dir['no drums']="${src_dir//flac/no drums}"
+
+  # demucs -n htdemucs_ft -o "$work_dir" --filename '{track} {stem}.{ext}' -j2 -d cpu --clip-mode rescale -- "$file"
+  unset files karaoke nodrums
+  declare -a files karaoke nodrums
+  readarray -t files < <(find "$work_dir" -type f -name '*.wav')
+  unset vocal_track
+  unset drum_track
+
+  for file in "${files[@]}"; do
+    echo file: "$file"
+    if ! grep -Eq 'drums\.wav$' <<< "$file"; then
+      echo no drums.wav
+      nodrums+=("$file") 
+    else
+      echo yes drums.wav
+      drum_track="$file"
+    fi
+
+    if ! grep -Eq 'vocals\.wav$' <<< "$file"; then
+      echo no vocal
+      karaoke+=("$file")
+    else
+      vocal_track="$file"
+    fi
+  done 
+
+  for i in "${nodrums[@]}"; do
+    printf 'Drum practice: %s\n' "$i"
+  done
+  if [[ -z "$drum_track" ]]; then
+    printf 'No drum track. Will not create a drum practice file.\n'
+  else
+    make_drum
+  fi
+  for i in "${karaoke[@]}"; do
+    printf 'Karaoke practice: %s\n' "$i"
+  done
+  if [[ ! "$vocal_track" ]]; then
+    printf 'No vocal track. Will not create a karaoke file.\n'
+  else
+    make_karaoke
+  fi
+
+  exit 0
+done
+