how do I run ffmpeg so that it creates a video - an mp4 that runs in a loop and an mp3 that runs in the background?

I have been trying to do something I thought relatively simple with ffmpeg. I have two files: an MP4 and an MP3. The MP4 is short, the MP3 is long. The MP4 is silent. I want to create a video that runs the MP4 in a loop while playing in the background the MP3 (just once). So the length of the new video is the length of the MP3. I tried multiple things with ffmpeg, but nothing works. I generate a short video always without sound. This is the latest command I tried that was the closest I could understand to "should work": ffmpeg -stream_loop 1 -i silent-video.mp4 -i audiofile.mp3 -c:v copy -c:a aac -b:a 192k -preset:v fast output_video_with_multiple_video_loops.mp4