Extracting audio from a video, save it as Mp3

Command: ffmpeg -i video.avi -vn -ar 44100 -ac 2 -ab 192 -f mp3 sound.mp3

Source video : video.avi
Audio Frequency: (-ar) Set the audio sampling frequency
Audio bitrate :  (-ab) 192kb/s
Output format : mp3
Output file : sound.mp3