-codecs          # List codecs.
-c:v             # Video codec (-vcodec) - 'copy' to copy stream.
-c:a             # Audio codec (-acodec).
 
-fs SIZE         # Limit file size (bytes).

-b:v 1M          # Video bitrate (1M = 1Mbit/s).
-b:a 1M          # Audio bitrate.

-aspect RATIO    # Aspect ratio (4:3, 16:9, or 1.25).
-r RATE          # Frame rate per sec.
-s WIDTHxHEIGHT  # Frame size.
-vn              # No video.

-aq QUALITY      # Audio quality (codec-specific).
-ar 44100        # Audio sample rate (hz).
-ac 1            # Audio channels (1=mono, 2=stereo).
-an              # No audio.
-vol N           # Volume (256=normal).

ffmpeg -i input.mp3 -ac 1 -ab 128000 -f mp4 -acodec libfaac -y output.m4r

# no audio
ffmpeg -i input.mov -vcodec h264   -an output.mp4
ffmpeg -i input.mov -vcodec libvpx -an output.webm
 
ffmpeg -i input.mov -vcodec h264 -acodec aac output.mp4
ffmpeg -i input.mov -vcodec libvpx -acodec libvorbis output.webm

<video width="320" height="240" controls>
  <source src="movie.mp4" type='video/mp4'></source>
  <source src="movie.webm" type='video/ogg'></source>
</video>