Audiovisualiser not visible
ffmpeg -i music.mp3 -loop 1 -i image.jpg -filter_complex "[0:a]showwaves=s=1280x175:colors=Red:mode=p2p[v];[1:v][v]overlay=(W-w)/2:(H-h)/2:format=auto,format=yuv420p[outv]" -map "[outv]" -map 0:a -c:v libx264 -c:a copy -shortest -movflags +faststart output.mp4



Remove the format filter after showwaves.
Use format=auto in the overlay filter.
Do all of the filtering within the filtergraph, so remove -pix_fmt and replace it with the format filter.


If you want image.jpg to fit within a specific size such as 1280x720:

ffmpeg -i music.mp3 -loop 1 -i image.jpg -filter_complex "[0:a]showwaves=s=1280x175:colors=Red:mode=p2p[fg];[1:v]scale=1280:720:force_original_aspect_ratio=increase,crop=1280:720,setsar=1[bg];[bg][fg]overlay=(W-w)/2:(H-h)/2:format=auto,format=yuv420p[outv]" -map "[outv]" -map 0:a -c:v libx264 -c:a copy -shortest -movflags +faststart output.mp4