The documentation for youtube-dl says I can run a post-process command with the --exec option.
Using Windows, here is an example I have tried:
youtube-dl --exec "ffmpeg -i {} -ac 2 -c:a libfdk_aac -cutoff 20000 -afterburner 1 -vbr 0 {}.m4a" https://www.youtube.com/watch?v=sw9DlMNnpPM
Note that {} passes the file name to the post-process command. For example filename.webm.
The problem is that {} includes the file extension.
How can I pass the file name to the post-process command without the file extension?
For example, if I were to convert the video, I would rather avoid getting an output name like filename.webm.m4a. Needless to say, I would rather want filename.m4a.