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 (see image above).
NB/ I used these one-liner scripts to convert Roy’s Rocket Radio to YouTube-able vids. That was the easy part. The agonisingly slow part was uploading to YouTube.
For One File
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 All Files in a Directory
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"
The command should be run in the directory containing the files you want to convert.
Sources and More Examples