Common switches
-codecs # list codecs
-c:v # video codec (-vcodec) - 'copy' to copy stream
-c:a # audio codec (-acodec)
-fs SIZE # limit file size (bytes)
Bitrate
-b:v 1M # video bitrate (1M = 1Mbit/s)
-b:a 1M # audio bitrate
Video
-aspect RATIO # aspect ratio (4:3, 16:9, or 1.25)
-r RATE # frame rate per sec
-s WIDTHxHEIGHT # frame size
-vn # no video
Audio
-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)
Example
Ringtone conversion using ffmpeg
ffmpeg -i foo.mp3 -ac 1 -ab 128000 -f mp4 -acodec libfaac -y target.m4r
To web
# no audio
ffmpeg -i input.mov -vcodec h264 -an -strict -2 output.mp4
ffmpeg -i input.mov -vcodec libvpx -an output.webm
ffmpeg -i input.mov -vcodec h264 -acodec aac -strict -2 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>