downloading music from youtube (part 1)

When I am gymming I use the youtube app on my phone to play videos of songs I like when and occasionally via youtube recommendations a song I have not heard before will play. Sometimes it just so happens I like the recommendation and I will want to download the audio of the videos. Thus far for youtube video perusing and playing I used yeetube. The very basic workflow I have is calling yeetube-search, entering my search term, finding the video I want to play in the yeetube buffer (shown below) and playing the video. The thing is yeetube does not seem to have a built-in command for downloading just the audio of a video. And so my quest for writing such a command begins…

The first thing I needed to see how yeetube downloads audio so I looked at the body of yeetube-play (shown below). The main thing I needed to know from the command is the function yeetube-get-url¹ which is what gets the url from an entry in the yeetube buffer.

(defun yeetube-play ()
  "Play video at point in *yeetube* buffer."
  (interactive)
  (let* ((video-url (yeetube-get-url))
	     (video-title (yeetube-get :title))
         (proc (apply yeetube-play-function video-url
                      (when yeetube-mpv-modeline-mode (list video-title)))))
    (when (processp proc)
      (process-put proc :now-playing video-title))
    (push (list :url video-url :title video-title) yeetube-history)
    (message "Playing: %s" video-title)))

For now, the following function, oo-yeetube-download-audio does the job albeit in a coarse way. It sets the default directory to my music directory, ~/Music, gets the url from the youtube entry and invokes the ytl-dlp shell command on it which downloads the audio. Later, I want to make it download the audio asynchronously–right now it synchronous and in practice that means my Emacs freezes, becoming completely unusable to me, while the audio is downloaded. It usually taking less than 10 seconds for the songs I download so it is not catastrophic. Also, I want to view youtube entries in the minibuffer as opposed to the yeetube buffer–at least sometimes.

For the details of what defun! does check out my configuration as well as my article on progn!. But the TLDR is that it let-binds the variables url, command and default-directory by using set! as an indicator.

(defun! oo-yeetube-download-audio ()
  "Download audio of video at point to the ~/Music directory.
This also downloads the thumbnail."
  (interactive)
  (set! default-directory (expand-file-name "~/Music"))
  (set! url (shell-quote-argument (yeetube-get-url)))
  (set! command (format "yt-dlp -x --audio-format wav --embed-thumbnail %s" url))
  (call-process-shell-command command))

Lastly, I did want to mention the function oo-yeetube-video-link which I wrote to help me copy youtube links for this article. I did not end up using them above–I removed the sentence with the links in them–but two of the songs I downloaded were shameless and tattoo which I plan to listen to while gyming.

(defun! oo-yeetube-video-link ()
  "Copy the video link at point into the `kill-ring'."
  (interactive)
  (set! default-directory (expand-file-name "~/Music"))
  (set! url (yeetube-get-url))
  (awhen (kill-new url)
    (message "Copied %s!" url)))