This is a commandlinefu application to download a YouTube video and save as WebM (HTML 5 Streaming).

commandlinefu-youtube-to-webm.pl

use common::sense;
# zenbae: you need -vf expand osd trick
# iive	zenbae:  -vf expand=osd=1

package Command {
    use common::sense;

    use MooseX::App::Simple qw(Color);
    with 'MooseX::Role::Tempdir';
    
    use Sed;
    use FFmpeg::Stream::Helper;
    use WWW::YouTube::Download;
    use LWP::Simple;

    use feature 'say';
        
    option 'in' => (
        is => 'ro',
        isa => 'Str',
        required => 1,
        documentation => 'This argument is a string, accessible by the key titled id.  This is used to reference the media source selection.',
    );
    
    option 'out' => (
        is => 'ro',
        isa => 'Str',
        required => 1,
        documentation => 'This argument is a string, accessible by the key titled outfile.  This is used to reference the webm output filename.',
    );
    
    sub youtube_video_outfile {
        my ($self) = @_;
        return($self->tmpdir . "\\" . "commandlinefu-youtube-to-webm.download.mp4");
    }
    
    sub webm_outfile {
        my ($self) = @_;
        return($self->out);
    }

    sub run {
        my ($self) = @_;
        
        my $client1 = WWW::YouTube::Download->new;
        $client1->download($self->in, { filename => $self->youtube_video_outfile });
        
        my $commandlinefu1 = 'ffmpeg -i ' . $self->youtube_video_outfile . ' ' . $self->webm_outfile;
        my $buffer1 = `$commandlinefu1`;
    }        
}

my $cmd = Command->new_with_options->run unless caller;

1;