okay, linux script to wrangle files so I can dump them on m-crew

gen_mcrew_filealbum.sh

#!/usr/bin/env bash

#set -x

scratchfolder="$(mktemp -d)"
# initially, we created two passes for mono v stereo.
# this proved to be a pain in the ass to keep straight.
# so...everything on the disc is mono.
#mkdir -p "${scratchfolder}/stereo"
#mkdir -p "${scratchfolder}/mono"

# get the song time and truncate it
get_trktime () {
  local trktime
  trktime="$(ffprobe -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "${1}" 2>/dev/null)"
  printf '%s\n' "${trktime}"
}

# this is fed into bc...
DISCEXP='0'
get_disctime () {
  echo "${DISCEXP}+0" | bc
}
add_disctime () {
  local time="${1}"
  DISCEXP="${DISCEXP}+${time}"
}

# pick files in random order
sources=(${HOME}/Downloads/Season\ */*)

# okay, we *always* start with this track
songs=("${HOME}/Downloads/Nokia 3310 - Classic Monophonic RINGTONE (2017).mp4")
add_disctime "$(get_trktime "${songs[0]}")"

# now walk through our sources array and do something
selections=()
maxct="${#sources[@]}"
pad="${#maxct}"
while true ; do
  # are we out of time? 4200 is 70 minutes in seconds.
  dtime=$(get_disctime)
  dtime="${dtime%.*}"
  [[ "${dtime}" -gt 4200 ]] && break

  # have we chosen 254 tracks?
  [[ "${#songs[@]}" -ge 254 ]] && break

  # have we chosen all the possible songs?
  [[ ${#selections[@]} -ge ${#sources[@]} ]] && break

  # pick a random track we have not played before.
  select=false
  while [[ "${select}" == "false" ]] ; do
    chosen=$(($RANDOM % ${#sources[@]}))
    selected=$(printf "%0${pad}d" "${chosen}")
    case "${selections[*]}" in
      *" ${selected} "*) : ;;
      *) select=true ;;
    esac
  done
  selections=("${selections[@]}" "${selected}")

  # is the song between 4 and 23 seconds? (mcrew needs 6sec and we will _get_ there...)
  songtime=0
  songtime=$(get_trktime "${sources[${chosen}]}")
  [[ "${songtime%.*}" -le 23 ]] || continue
  [[ "${songtime%.*}" -ge 4 ]] || continue

  # does the song only differ in extension?
  case "${songs[*]}" in
    *" ${sources[${chosen}]%.*}"*) continue ;;
  esac

  # add to disc timing, add to song list.
  add_disctime "${songtime}"
  songs=("${songs[@]}" "${sources[${chosen}]}")
done

# process the selected songs...
titles=("BANGRS${1}") # add the disc title
songct="${#songs[@]}"
printf '#EXTM3U: TITLE=%s%s TRACKS=%s\n' 'BANGRS' "${1}" "${songct}" > "${scratchfolder}/BANGRS${1}.M3U"
destpad="${#songct}"
# note this is pulling out indexes
for index in "${!songs[@]}" ; do
  file="${songs[${index}]}"
  # first, figure out a workable title. we're limiting to 7 characters...
  title="$(basename "${file}")"
  # remove extension and the first word (prefix)
  title="${title%.*}"
  title="${title#* }"
  # uppercase everything
  title="${title^^}"
  # remove all spaces
  title="${title// /}"
  # remove years from the end
  title="${title%([0-9][0-9][0-9][0-9])}"
  # remove any dashes, parens et al.
  title="${title//[()-.]/}"
  # grab the last 7 characters...
  title="${title: -7}"
  titleidx=1
  while true ; do
    # handle pathological file titles
    [[ "${titleidx}" -gt 36 ]] && exit 1
    case "${titles[*]}" in
      *" ${title} "*) : ;;
      *) break ;;
    esac
    # grab the first 5 and do ~X appending
    title="${title:0:5}"
    # steal the _last_ character of bc output.
    idxb36="$(bc <<< "obase=36; ${titleidx}")"
    title="${title}~${idxb36: -1}"
    # up and again (if we run again)
    ((titleidx++))
  done
  # add title to pool of used title names, update playlist
  titles=("${titles[@]}" "${title}")
  printf '#EXTINF:0, original="%s" %s\n' "${file#${HOME}/}" "${title}"
  # decode the file.
  ffmpeg -y -i "${file}" "${scratchfolder}/dec.wav" < /dev/null
  # we're getting the length and channel config here.
  channels="$(soxi -c "${scratchfolder}/dec.wav")"
  case "${channels}" in
    1) chtext='mono'   ;;
    *) chtext='stereo' ;;
  esac
  rate="$(soxi -r "${scratchfolder}/dec.wav")"
  samples="$(soxi -s "${scratchfolder}/dec.wav")"
  runlength="$((rate * 6))"
  destfile="$(printf "%0${destpad}d_${chtext}" "$((index + 1))").WAV"
  # PCLK-MN10A manual, page 50.
  printf '%s\n' "${title}" >> "${scratchfolder}/TITLES.TXT"
  # pad to six seconds if needed
  if [[ "${samples}" -lt "${runlength}" ]] ; then
    padding="$((runlength - samples))"
    sox "${scratchfolder}/dec.wav" "${scratchfolder}/${destfile}" pad 0 "${padding}"s
    rm "${scratchfolder}/dec.wav"
  else
    mv "${scratchfolder}/dec.wav" "${scratchfolder}/${destfile}"
  fi
  printf '%s\n' "${destfile}"
done >> "${scratchfolder}/BANGRS${1}.M3U"

# convert the title files, m3u to windows/dos format.
for expdir in mono stereo '' ; do
  [[ -f "${scratchfolder}/${expdir}/TITLES.TXT" ]] && unix2dos "${scratchfolder}/${expdir}/TITLES.TXT"
done
unix2dos "${scratchfolder}/BANGRS${1}.M3U"

# copy the running file to the scratch folder too
cp "$0" "${scratchfolder}/$(basename "${0}")"

# compress scratch into a zip
here="$(pwd)"
( cd "${scratchfolder}" && zip -r "${here}/BANGRS${1}.ZIP" . )

# drop scratch
[[ "${scratchfolder}" != "/" ]] && {
  rm -rf "${scratchfolder}"
}