Hi Nathan,

Nathan Dehnel 写道：
> bash-5.0$ youtube-dl -x 
> https://www.youtube.com/watch?v=7Ijd_iN9Blk
> [youtube] 7Ijd_iN9Blk: Downloading webpage
> [download] Deadmau5 - Hit Save-7Ijd_iN9Blk.webm has already been 
> downloaded
> [download] 100% of 15.45MiB
> ERROR: ffprobe/avprobe and ffmpeg/avconv not found. Please 
> install one.

It works fine without ‘-x’:

  λ youtube-dl https://www.youtube.com/watch?v=7Ijd_iN9Blk
  [youtube] 7Ijd_iN9Blk: Downloading webpage
  [download] Destination: Deadmau5 - Hit Save-7Ijd_iN9Blk.mp4
  [download] 100% of 37.09MiB in 00:02

This *is* functioning correctly in my view: that advanced options 
optionally require run-time dependencies is not a bug but a 
feature.  The programme clearly explains which package could be 
installed to continue, and the user can chose which one they 
prefer - including neither, which suffices for the majority of 
youtube-dling.

Matters would be different if the error message were less clear, 
or perhaps if ffmpeg weren't so insanely great:

  λ guix size youtube-dl | tail -n1
  total: 186.9 MiB
  λ guix size youtube-dl ffmpeg | tail -n1
  total: 811.2 MiB

(!)

Kind regards,

T G-R