basic usage

Use output file as last argument.

ffmpeg output.mp4

File format (and its defaults) are derived from file ending.

Use -i to specify input files.

ffmpeg -i film.mp4 -i subtitles.srt

Several input files are possible.

Use -map to select streams.

ffmpeg -i film.mp4 -i subtitles.srt -map 0:0 -map 0:2 -map 1:0

i:j means take stream with index j in file with index i. File indices are given by order of -i uses in the command line.

Specify output codecs and options.

-c:v copy
-c:v mpeg4 -b:v 8000k
-c:v libx264 -crf 17 (lower numbers = higher quality)

-c:a copy
-c:a libmp3lame -b:a 320k
-c:a libfdk_aac -b:a 384k
-c:a aac -b:a 384k

-c:s mov_text

useful options

cutting off borders

centred:

-vf crop=in_w-20:in_h-100

positioned:

-vf crop=in_w-20:in_h-100:20:100

means cut off 10px off top, 10px off bottom, 50px off left, 50px off right.

starting and ending at a specific position

-ss 00:03:40 -t 00:01:12

or

-ss 220 -t 72

numbers in seconds (float)

concatenate same-codec files

Create file containing file names, e.g.:

file 'file1.mp4'
file 'file2.mp4'

Then:

ffmpeg -f concat -safe 0 -i .files -c copy output.mp4

extract d frames per second

ffmpeg -i input.mp4 -r d output-%03d.jpg

remove metadata

-map_metadata -1

dump metadata

ffmpeg -i input.mp3 -f ffmetadata metadata.txt