content: This is good, because it will always work and the title was about converting to mp3, but in your example I would use something like: ffmpeg -i video.mp4 -vn -codec copy audio.m4a or for mp3 audio ffmpeg -i video.avi -vn -codec copy audio.mp3 etc. Most players should be able to play aac audio and the loss in quality from transcoding can be avoided.