Get file name and extension in Ruby

I'm working on a program to download a video from YouTube, convert it to MP3 and create a directory structure for the files.

My code is:

FileUtils.cd("#{$musicdir}/#{$folder}") do
  YoutubeDlhelperLibs::Downloader.get($url)
  if File.exists?('*.mp4')
    puts 'Remove unneeded tempfile'
    Dir['*.mp4'].each do |waste|
      File.delete(waste)
    end
  else
    puts 'Temporary file already deleted'
  end

  Dir['*.m4a'].each do |rip|
    rip.to_s
    rip.split
    puts 'Inside the function'
    puts rip
  end

end

The first one goes to the already created music folder. Inside that I'm executing get. After that I have two files in the directory: "xyz.mp4" and "xyz.m4a".

I would like to fetch the filename without the extension so I can handle both files differently.

I'm using an array, but an array for just one match sounds crazy for me.

Has anyone another idea?