Convert files in a directory to mp3

dir_to_mp3.pl

# Convert files in a directory to mp3

use strict;
use warnings;
use feature "say";
use Data::Dumper;
use File::Basename;
use File::Path;
use File::Spec::Functions;

sub convert_dir_to_mp3 {
    my $dir = shift @_;
    my $outdir = File::Spec::Functions::catfile($dir, shift @_);
    my $bitrate = shift @_;
    
    die "$outdir already exists" if -d $outdir;
    File::Path::make_path($outdir) or die "Failed to create path: $outdir";
    
    opendir(DIR, $dir) or die "Could not open $dir\n";
    
    while (my $file = readdir(DIR)) {
        next if !($file =~ /\.(?:wav|mp3|flac)$/i);
    
        $file = File::Spec::Functions::catfile($dir, basename($file));
        my $outfile = File::Spec::Functions::catfile($outdir, basename($file));
        $outfile =~ s/\.[^.]+$/\.mp3/g;
    
        # use  -ac 1  for stereo to mono
        my $cmd = "ffmpeg -i \"$file\" -hide_banner -loglevel warning -vn ".
                  "-write_id3v1 1 -id3v2_version 3 ".
                  "-b:a ${bitrate}k \"$outfile\"";
        
        system($cmd) == 0 or die "$0: [$cmd] failed: $?\n";
    }
    
    closedir(DIR);
}

if (!caller) {
    if (@ARGV) {
        for my $dir (@ARGV) {
            convert_dir_to_mp3($dir, "encoded", 128);
        }
    }
    else {
        while (<STDIN>) {
            chomp $_;

            if ($_ =~ /^(\d+)/ && $1 > 160) {
                $_ =~ s/\d+\t//g;
                convert_dir_to_mp3($_, "encoded", 128);
            }
        }
    }
}

dir_to_mp3.py

import os
import re
import sys
from subprocess import run

path = "." if len(sys.argv) < 2 else sys.argv[1]

for root, dirs, files in os.walk(path):
    for f in files:
        f = os.path.join(path, root, f)
        
        if m := re.match(r"(.+)\.(?:m4a|mp4|wav|aiff|flac)$", f):
            print(f)
            outfile = m.group(1) + ".mp3"
            result = run([
                "ffmpeg",
                "-n", # -n never overwrite (and exit), -y always overwrite
                "-hide_banner",
                "-loglevel", "warning",
                "-i", f,
                "-b:a", "192k",
                "-vn",
                outfile
            ])
            
            if result.returncode != 0:
                print(f"error encoding `{f}`")
                sys.exit(1)
            
            os.remove(f)