flac_to_mp3.sh

#!/bin/bash
# flac2mp3.sh: Transcode FLAC audio files to MP3 audio files
# James A. Hillyerd
# $Revision: 24 $, $Date: 2006-10-04 19:10:00 -0700 (Wed, 04 Oct 2006) $
# Release: 1.1
#
# Usage: flac2mp3 <input-dir> <output-dir>

### Begin Configuration
# The values below will be overridden by those in ~/.flac2mp3.conf if it
# exists

# Copy artwork (*.jpg) files? Set to "true" or "false"
COPY_ARTWORK="true"

# Where we store working data (including the decoded wav file)
TMPDIR="/tmp"

# Path to flac binary
FLAC="$(which flac)"

# Path to metaflac binary (part of flac distribution)
METAFLAC="$(which metaflac)"

# Path to lame binary
LAME="$(which lame)"

# Options to pass to lame during encoding
LAME_OPTS="--vbr-new -V 1 --nohist -b 192"

# Multiple instances of this running on the same output-dir will be more
# reliable with locking available.
DOTLOCKFILE="$(which dotlockfile)"

# Note that INND's shlock isn't reliable, but we don't have a good way
# to tell whether this is that shlock or Erik Fair's shlock(1) which
# comes with several BSDs because both use the same command args.
SHLOCK="$(which shlock)"

# Maximum number of times we allow flac decode to fail per file
# before aborting
MAXFAILS=5

### End Configuration

### Read User Configuration
[[ -f ~/.flac2mp3.conf ]] && source ~/.flac2mp3.conf

# Check that we have all the required binaries
if [ ! -x "$FLAC" ]; then
  echo "ERROR: flac not installed" >&2
  exit 1
fi

if [ ! -x "$METAFLAC" ]; then
  echo "ERROR: metaflac not installed" >&2
  exit 1
fi

if [ ! -x "$LAME" ]; then
  echo "ERROR: lame not installed" >&2
  exit 1
fi

# Were we called correctly?
if [ -z "$1" -o -z "$2" ]; then
  ME=$(basename "$0")
  echo "Usage: $ME <input-dir> <output-dir>" >&2
  exit 1
fi

WORK="$TMPDIR/flac2mp3.$$"
ERR="$WORK/stderr.txt"
WAV="$WORK/track.wav"
TAGS="$WORK/track.tags"

# Get absolute directory paths
INPUTDIR="$1"
OUTPUTDIR="$2"
cd "$INPUTDIR"
INPUTDIR="$PWD"
cd "$OLDPWD"
cd "$OUTPUTDIR"
OUTPUTDIR="$PWD"

# Setup work directory
rm -rf "$WORK"
if [ -e "$WORK" ]; then
  echo "Couldn't delete $WORK"
  exit 1
fi
mkdir "$WORK"
if [ ! -d "$WORK" ]; then
  echo "Couldn't create $WORK"
  exit 1
fi

# Get input file list
cd "$INPUTDIR"
OLDIFS="$IFS"
IFS=$'\n'
for filepath in $(find . -type f -name '*.flac' -print \
    | sort | sed -e 's/^\.\///' -e 's/\.flac$//'); do
  IFS="$OLDIFS"
  filedir="$(dirname "$filepath")"
  filename="$(basename "$filepath")"
  if [ ! -d "$OUTPUTDIR/$filedir" ]; then
    mkdir -p "$OUTPUTDIR/$filedir"
  fi

  if [ ! -f "$OUTPUTDIR/$filepath.mp3" ]; then
    # Lock the working file
    if [ -x "$DOTLOCKFILE" ]; then
      if ! "$DOTLOCKFILE" -p -r 0 -l "$OUTPUTDIR/$filepath".lock; then
        # Could not get a lock, so skip to next file
        continue
      fi
    elif [ -x "$SHLOCK" ]; then
      if ! "$SHLOCK" -f "$OUTPUTDIR/$filepath".lock -p $$; then
        # Could not get a lock, so skip to next file
        continue
      fi
    fi

    # Clear tags
    rm -f "$TAGS"
    ARTIST=
    ALBUM=
    TITLE=
    DATE=
    GENRE=
    TRACKNUMBER=

    # Get tags
    $METAFLAC --export-tags-to="$TAGS" "$filepath.flac"
    sed -i -e 'h
        s/^[^=]*=//
        s/"/\\"/g
        s/\$/\\$/g
        s/^.*$/"&"/
        x
        s/=.*$//
        y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/
        G
        s/\n/=/' "$TAGS"
    source "$TAGS"
    echo "$ARTIST / $ALBUM ($DATE) / $TRACKNUMBER - $TITLE"

    # Decode FLAC (loop until success or MAXFAILS reached)
    attempt=0
    success=0
    while (( ! $success  )) && (( $attempt < $MAXFAILS )); do
      let attempt++
      rm -f "$ERR" "$WAV"
      echo -n "Decoding attempt $attempt: "
      $FLAC -sd -o "$WAV" "$filepath.flac" 2> "$ERR"
      if (( ! $? )) && [ ! -s "$ERR" ]; then
        success=1
        echo "OK"
      else
        echo "FAILED"
        # Waiting seems to help
        sleep 2
      fi
    done
    if (( $attempt > $MAXFAILS )); then
      echo "$MAXFAILS decode attempts failed, aborting"
      cat "$ERR"
      exit 1
    fi

    # Encode MP3
    $LAME $LAME_OPTS --tt "$TITLE" --ta "$ARTIST" --tl "$ALBUM" \
        --tn "$TRACKNUMBER" --tg "$GENRE" --ty "$DATE" \
        "$WAV" "$OUTPUTDIR/$filepath.mp3"
    if (( $? )); then
      echo ""
      echo "Encode failed, retrying sans genre"
      $LAME $LAME_OPTS --tt "$TITLE" --ta "$ARTIST" --tl "$ALBUM" \
          --tn "$TRACKNUMBER" --ty "$DATE" \
          "$WAV" "$OUTPUTDIR/$filepath.mp3"
      if (( $? )); then
        echo ""
        echo "Encode failed, aborting"
        exit 1
      fi
    fi
    echo ""
    echo ""

    # Remove the lock file
    if [ -x "$DOTLOCKFILE" ]; then
      "$DOTLOCKFILE" -u "$OUTPUTDIR/$filepath".lock
    elif [ -x "$SHLOCK" ]; then
      rm -f "$OUTPUTDIR/$filepath".lock
    fi
  fi
done

# Copy artwork
if [ "$COPY_ARTWORK" == "true" ]; then
  echo -n "Copying artwork: "
  OLDIFS="$IFS"
  IFS=$'\n'
  for filepath in $(find . -type f -name '*.jpg' -print \
      | sort | sed -e 's/^\.\///'); do
    IFS="$OLDIFS"
    filedir="$(dirname "$filepath")"
    filename="$(basename "$filepath")"
    if [ ! -d "$OUTPUTDIR/$filedir" ]; then
      mkdir -p "$OUTPUTDIR/$filedir"
    fi

    # If the input is newer than the output, or the output does not exist
    if [ "$filepath" -nt "$OUTPUTDIR/$filepath" ]; then
      # Lock the working file
      if [ -x "$DOTLOCKFILE" ]; then
        if ! "$DOTLOCKFILE" -p -r 0 -l "$OUTPUTDIR/$filepath".lock; then
          # Could not get a lock, so skip to next file
          continue
        fi
      elif [ -x "$SHLOCK" ]; then
        if ! "$SHLOCK" -f "$OUTPUTDIR/$filepath".lock -p $$; then
          # Could not get a lock, so skip to next file
          continue
        fi
      fi
          
      cp -f "$filepath" "$OUTPUTDIR/$filepath"
      echo -n "."

      # Remove the lock file
      if [ -x "$DOTLOCKFILE" ]; then
        "$DOTLOCKFILE" -u "$OUTPUTDIR/$filepath".lock
      elif [ -x "$SHLOCK" ]; then
        rm -f "$OUTPUTDIR/$filepath".lock
      fi
    fi
  done

  echo " Done!"
fi

# Clean up
rm -rf "$WORK"
exit