This is the command that I run:
ffmpeg -y -i source_file.wav -loop 1 -i image.jpg -filter_complex "[0:a]showwaves=s=1920x175:colors=White:mode=line,format=yuv420p[v];[1:v][v]overlay=0:1000[outv]" -map "[outv]" -pix_fmt yuv420p -map 0:a -c:v libx264 -c:a aac -shortest output9.mp4
The output video looks like this:
As you can see behind the visualization of the amplitude is a black box. Is it possible to make this box transparent so that the visualization is overlayed directly on the video?