I want code to right click context menu on a file and if it is a .mp4, then convert that to a .mp3 of the same name
also include an option to play faster by +25 +33 +50 or slower by -25 -33 -50 (in a sub menu)
I understand this is different depending on your system, so answer how to do it for the people who use the same system as you
Looks like Thunar has a “Custom Actions” feature under the Edit menu where you can get the same result.