audiolength

#!/usr/bin/env bash
#
# audiolength : duration of an audio file HH:MM:SS
#
# @Author  Chris Reid <spikeysnack@gmail.com>
# @Date    13 June 2017
# @License Free for non-commercial use. Nothing guaranteed
# @requires  soxi awk
#DEBUG=1
DEBUG=


# output to stderr only if debug is true
debug()
{
    [[ ${DEBUG} ]] && >&2 echo "${@}"
    return 0 # so it is true
}

SOXI=$(which soxi)

for A in "gawk" "nawk" "awk" "mawk"
do
    A=$(which $A)
    AWK=${AWK:-${A}} # find one
done

[[ ! $SOXI ]]  && echo "CAN NOT FIND soxi.  Install or fix path."  && exit 1
[[ ! $AWK  ]]  && echo "CAN NOT FIND any awk binaries."  && exit 1


AUDEXTS="flac mp3 ac3 pcm mp2 mpa mpc ogg oga ape  m4a aac aiff wma wav wv"
# these are partial matches but wrong
PROBLEMEXT="m4 c"              # these are anomalies
aext=("${AUDEXTS}")
problemext=("${PROBLEMEXT}")


# check good file return 0 for good
goodfile()
{
    [[ $# -eq 0 ]] && >&2 echo "goodfile: no argument" && exit 1

    ext="${1##*.}"

    debug "GOODFILE: ext = ${ext}"

    BAD=1   # bash 1 is false
    GOOD=0  # bash 0 is true


    for P in ${problemext[@]}
    do
    # file is on problematic filename list
        [[ "${P}" =~ "${ext}" ]] &&   debug "GOODFILE: PROBLEM FILE" && return ${BAD}
    done


    for E in ${aext[@]}
    do
    # file is in good filename list
        [[ "${E}" =~ "${ext}" ]] &&   debug "GOODFILE: GOOD" && return ${GOOD}
    done

    debug "NO MATCHES"

    return ${BAD}
}





clean_files()
{
    FileList=( "$@" ) # make an array from the args

    debug "OLD FILE LIST:  ( ${FileList[@]} )"

    n=${#FileList[@]} # number of elements

    # oops no files
    [ "${n}" -eq 0 ] && >&2 printf "no file(s) specified."   && exit 1

    #clean out non-files, files with no extension, non-audio files
    for (( i=0; i<n; i++ ))
    do
    M="${FileList[$i]}"
    ext="${M##*.}"

    # not a file name
    [ ! -f "${M}" ] &&  unset FileList[$i]  && continue

    # case of file name  with no extension
    test "${ext}" = "${M}" && unset FileList[$i]  && continue

    goodfile "${M}"

    let good=$?


    if [[ $((good)) -eq 0 ]] ; then

        debug echo "GOOD IS TRUE"

    else
            debug "GOOD IS FALSE"
        unset FileList[$i]
        continue
    fi

    done # for i

    debug "NEW FILE LIST:  ( ${FileList[@]} )"

    echo "${FileList[@]}"
}




duration()
{
    local DUR

    [[ $# -eq 0 ]] && >&2 echo "duration: no argument" && exit 1

    DUR=$(${SOXI}  -D "${1}" | $AWK '{SUM += $1} END { printf "%d:%d:%d\n",SUM/3600,SUM%3600/60,SUM%60}')

    echo "${DUR}"
}


main()
{
    # oops no files
    [[ ${#@} -eq 0 ]] && >&2 printf "main: no file(s) specified."   && exit 1

    files=( "$(clean_files "${@}")" )

    [[ ! ${files} ]] && exit

    for F in "${files[@]}"
    do
       dur=$(duration "${F}")

       echo "${F}: ${dur}"
    done
}



main "${@}"

# END