multigif.pl

#!/usr/bin/perl
#
# multigif - convert a gif to webp and webm
#
# Requires imagemagick and ffmpeg on the PATH.
#

use strict;
use warnings;

my $numArgs = $#ARGV + 1;
if ($numArgs != 1) {
    die("need exactly one command line argument - the filename of the GIF to convert.\n")
}

my $filename = shift;
if ($filename !~ /\.gif$/) {
    die("invalid file extension: '$filename', expected .gif\n")
}
if (!-f $filename) {
    die("file not found: '$filename'\n")
}

my @outputFormats = ("webp", "webm");
foreach (@outputFormats) {
    convert($filename, $_)
}

sub convert {
    my $inputFilename = shift;
    my $outputFormat = shift;

    my $basename = $inputFilename =~ s/^(.*)\.gif/$1/r;
    my $outputFilename = sprintf("%s.%s", $basename, $outputFormat);

    my $cmd = "magick $inputFilename -coalesce $outputFilename";
    `$cmd`;
}