By Roy Mathur 2017-03-26 1217 GMT Boldly Voyaging the Multiverse: Probably the Best Nerd Blog in the Multiverse
Here are some examples of how to convert audio podcasts in mp3 format to YouTube videos in mp4 format adding nice black and white wave form visualisations. They require the ffmpeg command-line tool, and are one-liners that must be run from the Windows command prompt. NB/ I used these one-liner scripts to convert Roy's Rocket Radio to YouTube-able vids. That was the easy part. The agonizingly slow part was uploading to YouTube.
ffmpeg -i YOURFILE.mp3 -filter_complex "[0:a]showwaves=s=640x480:mode=line:rate=25,format=yuv420p[v]" -map "[v]" -map 0:a YOURFILE.mp4
Replace YOURFILE with the file you want to convert.
FOR /F "tokens=*" %G IN ('dir /b *.mp3') DO ffmpeg -i "%G" -filter_complex "[0:a]showwaves=s=640x480:mode=line:rate=25,format=yuv420p[v]" -map "[v]" -map 0:a "%~nG.mp4"