1. Converting to some format

ffmpeg -i input.mp3 output.m4a

2. Merging audio and video

  • Can change final container (mkv is most versatile), ffmpeg automatically decides the decoders for the job.
ffmpeg -i audio.mp3 -i video.mp4 -c copy merged_video.mkv

3. Keeping Output quality same as Input quality (-sameq)

ffmpeg -i input.avi -sameq output.mkv

4. Convert only first 30 seconds (-t)

ffmpeg -i aadat.mp3 -t 30 aadatintro.mp3
  • -t also supports hh:mm:ss as time format
  • Variation of this can be used to cut a part of the video, -ss flag sets the start time. So set the start time with -ss and duration with -t
ffmpeg -i aadat.mp3 -ss 1:12 -t 1:00 solo.mp3

5. Strip audio or video

  • -an removes audio and -vn strips video
ffmpeg -i video.mp4 -vn audio.mp3

6. Bitrate

  • -ab sets the audio bitrate and -b sets the video bitrate explicitly
ffmpeg -i audio.mp3 -ab 128k audiocompressed.mp3

Notes

  • default bitrate for video is 200kbps and 64 kbps for audio
  • ffmpeg options are always applied to next file in argument list, can be input or ouput file.
  • RTFM for more