any2mp3.sf

#!/usr/bin/ruby

# Daniel "Trizen" Șuteu
# Date: 17 June 2014
# Edit: 21 March 2020
# Website: https://github.com/trizen

# Convert any media file to MP3, using `n` parallel processes of ffmpeg.

func usage(code=0) {
    var name = File(__FILE__).basename

    print <<"USAGE"
usage:
      #{name} [options] [input files]

options:
       -b  --bitrate=i   : MP3 bitrate (default: 192K)
       -t  --threads=i   : use this many threads (default: 2)
       -o  --outdir=s    : output directory (default: .)

example:
      #{name} -t 4 *.mp4    # convert MP4 to MP3
USAGE

    Sys.exit(code)
}

func executeCmd(cmd, arg) {
    Sys.run(cmd, arg...)
}

func wait_th(forks) {
    say ":: Running threads: #{forks.len}"
    say ":: FFmpeg exit-code: #{forks.pop_rand.wait}"
}

func main() {
    const extensionRe = %r/\.\w{1,5}\z/
    const outputFormat = "mp3"

    const ffmpegCmd = "ffmpeg"

    var bitrate    = 192
    var maxThreads = 2
    var outputDir  = Dir.cwd

    ARGV.getopt!(
        'b|bitrate=i' => \bitrate,
        'o|outdir=s'  => \outputDir,
        't|threads=i' => \maxThreads,
        'h|help'      => usage,
    )

    var ffmpegArg = ["-loglevel", "fatal", "-y", "-vn", "-ac", "2", "-ab", "#{bitrate}K", "-ar", "48000", "-f", outputFormat]

    if (ARGV.len == 0) {
        Sys.warn("\n[!] No input file has been provided!\n")
        usage(2)
    }

    if (!outputDir.exists) {
        outputDir.create || die "Can't create dir `#{outputDir}': #{$!}"
    }

    var forks = []
    var counter = 0

    ARGV.each { |entry|

        var file = File(entry)

        if (!file.exists) {
            Sys.warn("File `#{file}' does not exists! Skipping file...\n")
            next
        }

        if (!file.is_file) {
            Sys.warn("File `#{file}' is not a plain file! Skipping it...\n")
            next
        }

        var outputFile = file.basename.sub(extensionRe)

        outputFile = File(outputDir, outputFile + '.' + outputFormat)
        printf("[%2d] %s -> %s\n", counter++, file, outputFile)

        var args = ['-i', file.to_s, ffmpegArg..., outputFile]
        forks.append(executeCmd.ffork(ffmpegCmd, args))

        if (forks.len >= maxThreads) {
            wait_th(forks)
        }
    }

    while (forks.len > 0) {
        wait_th(forks)
    }

    if (counter > 0) {
        say ":: All done!"
    }
}

main()