Audio

---audio from video----

ffmpeg -i input_video.mp4 -vn output_audio.mp3

ffmpeg -i video.flv -vn -ar 44100 -ac 2 -ab 192 -f mp3 audio.mp3


---audio and video together---

ffmpeg -i audio.mp3 -i video.avi video_audio_mix.mpg

---picture to audio---

ffmpeg -loop 1 -i image.jpg -i sound.mp3 -c:v libx264 -c:a aac -strict experimental -b:a 192k -shortest output.mp4