By Roy Mathur, on 2017-03-26, at 1217 GMT, for 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 a waveform visualisation. They require the ffmpeg command line tool, and are one-liners that must be run from the Windows command prompt.
I used these one-liner scripts to convert Roy's Rocket Radio episodes to YouTube-able vids. That was the easy bit. 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"