===== How To Make A Yealink Ringtone =====
Hopefully this would have some use outside of Yealink ringtones of course.

Yealink phones require a u-law, 8k, mono WAV file for ringtones. If you do not already have an MP3 file, start by going to any Invidious instance and download the whole video as an MP4, then convert it quickly to an MP3 [[https://www.freeconvert.com/mp4-to-mp3|here]].  Then make sure you have the MP3 codec for sox:

  sudo apt-get install libsox-fmt-mp3

Convert the MP3 to WAV like so:

  sox file1.mp3 file2.wav

Cut the WAV file to the desired length (30 seconds or so oughtta do it for a ringtone):

  ffmpeg -i file2.wav -ss 00:00:41 -to 00:01:11 -c copy file3.wav

Now convert it to the correct format:

  sox -r 8000 -c 1 -e u-law file3.wav file4.wav

Adjust the volume if necessary:

  sox -v 0.9 file4.wav file5.wav

Log in to the web interface for your phone, go to the Settings tab, and upload the WAV file about half way down the list of options. Then switch to the Account tab, click Basic in the left menu, select the account you wish to configure at the top, and choose the ringtone from the dropdown list.