remove-mkv-subtitles.sh

#!/bin/bash

# usage: ./remove-mkv-subtitles.sh [--no-dry] [path(s)]

# Script to find MKV files in the given paths and remove subtitle tracks from them. Dry run by default.

# (usually) non-default dependencies: mkvtoolnix, dc

remvsub(){
  set -e
  orig="$1"
  temp="$2"

  # Copy from $orig path to $temp path, excluding subtitles (-S)
  # This requires no transcoding by mkvmerge, so it is relatively
  # quick, bottlenecked on disk io.
  mkvmerge -q -o "$temp" -S "$orig"
  mv "$temp" "$orig"
}

scanmkv(){

  mkv="$1"
  dryrun="$2"
  nicepath="$(basename "$mkv")"
  echo -en "[\e[0;34mSCAN\e[m] $nicepath"

  # Check if we need to bother
  mkvinfo "$mkv" | grep -q 'Track type: subtitles'
  ret=$?
  if [ $ret -ne 0 ]; then
    echo -e "\e[0K\r[\e[0;33mSKIP\e[m] $nicepath"
    exit
  fi

  if $dryrun; then
    echo -e "\e[0K\r[\e[0;32mNOOP\e[m] $nicepath"
    exit
  fi

  of="$mkv"
  nf="$mkv.nosubs"
  ofs=$(stat -c%s "$of")

  touch "$nf" > /dev/null 2>&1
  if [ $? -ne 0 ]; then
    echo -e "\e[0K\r[\e[0;31mPERM\e[m] $nicepath"
    exit
  fi

  # Execute the removal in the background, so we can
  # display a nice progress meter inline
  remvsub "$of" "$nf" > /dev/null 2>&1 &

  # progress counter, will advance after background
  # remvsub function finishes running
  while ps -p $! > /dev/null 2>&1; do
    sleep 0.5
    if [ -e "$nf" ]; then
      nfs=$(stat -c%s "$nf")
      pc=$(echo "2k $nfs $ofs / 100 * p" | dc)
      pad_pc=$(printf "%03.f" $pc)
      echo -en "\e[0K\r[\e[0;32m$pad_pc%\e[m] $nicepath"
    fi
  done

  # If the new (temporary) file still exists after our
  # background job exited we know the process failed.
  if [ -e "$nf" ]; then
    echo -e "\e[0K\r[\e[0;31mFAIL\e[m] $nicepath"
  else
    echo -e "\e[0K\r[\e[0;32mDONE\e[m] $nicepath"
  fi

}


if [ "$1" = '--no-dry' ]; then
  shift
  dryrun=false
else
  dryrun=true
  echo "Dry-run mode. 'NOOP' means this file would have its subtitles removed"
  echo "To act on these files run: $0 --no-dry $@"
fi


defpath=.
if [ ! -z "$@" ]; then
  defpath="$@"
fi

export -f scanmkv remvsub
find $path "$defpath" -name '*.mkv' -type f -print0 | xargs -0 -IARG bash -c "scanmkv \"ARG\" $dryrun"