Small bash script to extract audio from video files.

extract_audio.sh

#!/bin/bash

# Some consts
OUT_CODEC="libvorbis"
OUT_EXTENSION=".ogg"

pids=""

# Kick off the conversions
for file in *
do
  mime_type=$(file --brief --mime-type ${file})
  # Discard the subtype:
  mime_type=${mime_type%/*}

  if [ "${mime_type}" = "video" ]
  then
    # Build the outfile
    outfile="${file%.*}${OUT_EXTENSION}"

    # Consider existence to mean that it's been done before
    if [ -e "${outfile}" ]
    then
      echo "Skipping ${file} (destination exists)..."
      continue
    fi

    # Announce it:
    echo -n "${file} TO ${outfile}..."

    # Do the conversion
    avconv -i "${file}" -vn -acodec ${OUT_CODEC} ${outfile} &> /dev/null &
    pid=$!
    echo "${pid}"

    pids="$pids $pid"
  fi
done

failed=""

# Waiting...
for pid in ${pids}
do
  echo "${pid} is pending..."
  wait ${pid} || failed="${failed} ${pid}"
done

if [ -z "${FAIL}" ]
then
  echo "Done."
else
  echo "Process(es) failed (${FAIL}), check state manually."
fi