You probably only downloaded the DASH video, this should work: $ youtube-dl -f 18 http://newsoffice.mit.edu/2014/algorithm-recovers-speech-from-vibrations-0804

You probably only downloaded the DASH video, this should work: $ youtube-dl -f 18 http://newsoffice.mit.edu/2014/algorithm-recovers-speech-from-vibrations-0804 http://newsoffice.mit.edu/2014/algorithm-recovers-speech-fro... You can use the -F option to list the available formats.