Script for copying subtitles between mkv files

yoink-subs.sh

#!/bin/bash

###
# Copies subtitles from mkv files in from/ folder to mkv files in to/ folder
# Output mkv files are saved in an out/ folder
###

# Get file lists
source_files=(from/*)
source_files=( "${source_files[@]##*/}" )
target_files=(to/*)
target_files=( "${target_files[@]##*/}" )

# Check amount of files in each folder is the same
if [ ! ${#source_files[@]} -eq ${#target_files[@]} ]; then
  echo "ERROR: Amount of files is different"
  exit 1
fi

# Print file associations for confirmation
for i in ${!source_files[@]}; do
  printf "\e[1m\e[38;5;14m$(expr $i + 1). \e[0m\e[38;5;2m${source_files[$i]}\e[0m\e[1m -> \e[0m\e[38;5;10m${target_files[$i]}\n"
done

# Warning confirmation
echo ""
printf "\e[1m\e[38;5;9m!!! Make sure the episodes match. \e[0m"
read -p "Press ENTER to continue or CTRL+C to quit"

# Delay input
read -p "Delay for subtitles in ms [1000ms]: " delay
delay=${delay:-1000}

for i in ${!source_files[@]}; do
  # Options for mkvmerge later
  inputs=()

  printf "\e[1m\e[38;5;14m=>\e[0m\e[1m Copying subtitles from \e[0m\e[38;5;2m${source_files[$i]}\e[0m\e[1m to \e[0m\e[38;5;10m${target_files[$i]}\e[0m\e[1m...\e[0m\n"

  # Extract subtitles
  printf "  \e[1m\e[38;5;14m==>\e[0m\e[1m Extracting subtitles...\e[0m\n"

  subs=$(mkvmerge -i "from/${source_files[$i]}" | awk '$4=="subtitles"')
  while read sub; do
    track=$(awk -F '[ :]' '{print $3}' <<< "$sub")
    properties=$(mkvmerge -J "from/${source_files[$i]}" | jq ".tracks[$track].properties")
    name=$(echo $properties | jq ".track_name" | sed -e 's/^"//' -e 's/"$//')
    language=$(echo $properties | jq ".language" | sed -e 's/^"//' -e 's/"$//')

    mkvextract -q tracks "from/${source_files[$i]}" "${track}:tmp/${source_files[$i]}-${track}.ass"

    inputs+=("-y" "-1:${delay}" "--track-name" "-1:${name}" "--language" "-1:${language}" "tmp/${source_files[$i]}-${track}.ass")
  done < <(echo "$subs")
  
  # Extract attachments
  printf "  \e[1m\e[38;5;14m==>\e[0m\e[1m Extracting attachments...\e[0m\n"

  attachments=$(mkvmerge -i "from/${source_files[$i]}" | awk '$1=="Attachment"')
  while read attachment; do
    track=$(awk -F '[ :]' '{print $3}' <<< "$attachment")
    filename=$(awk -F "'" '{print $4}' <<< "$attachment")
    type=$(awk -F "'" '{print $2}' <<< "$attachment")

    mkvextract -q attachments "from/${source_files[$i]}" "${track}:tmp/attachments/${filename}"

    inputs+=("--attachment-mime-type" ${type} "--attach-file" "tmp/attachments/${filename}")
  done < <(echo "$attachments")
  
  # Merge
  printf "  \e[1m\e[38;5;14m==>\e[0m\e[1m Merging to new file...\e[0m\n"
  mkvmerge -q -o "out/${target_files[$i]}" "to/${target_files[$i]}" "${inputs[@]}"
  
  # Clean tmp files
  rm -r tmp
done

printf "\e[1m\e[38;5;14m=>\e[0m\e[1m Done!\e[0m\n"