A list of useful commands for the FFmpeg command line tool.
Download FFmpeg: https://www.ffmpeg.org/download.html
Full documentation: https://www.ffmpeg.org/ffmpeg.html
ffmpeg -i in.mp4 out.avi
ffmpeg -i in.mkv -c:v copy -c:a copy out.mp4
Use the crf
(Constant Rate Factor) parameter to control the output quality. The lower crf, the higher the quality (range: 0-51). The default value is 23, and visually lossless compression corresponds to -crf 18
. Use the preset
parameter to control the speed of the compression process. Additional info: https://trac.ffmpeg.org/wiki/Encode/H.264
ffmpeg -i in.mp4 -preset slower -crf 18 out.mp4
Without re-encoding:
ffmpeg -ss [start] -i in.mp4 -t [duration] -c copy out.mp4
-ss
specifies the start time, e.g.00:01:23.000
or83
(in seconds)-t
specifies the duration of the clip (same format).- Recent
ffmpeg
also has a flag to supply the end time with-to
. -c
copy copies the first video, audio, and subtitle bitstream from the input to the output file without re-encoding them. This won't harm the quality and make the command run within seconds.
With re-encoding:
If you leave out the -c copy
option, ffmpeg
will automatically re-encode the output video and audio according to the format you chose. For high quality video and audio, read the x264 Encoding Guide and the AAC Encoding Guide, respectively.
For example:
ffmpeg -ss [start] -i in.mp4 -t [duration] -c:v libx264 -c:a aac -strict experimental -b:a 128k out.mp4
To copy the video from in0.mp4 and audio from in1.mp4:
ffmpeg -i in0.mp4 -i in1.mp4 -c copy -map 0:0 -map 1:1 -shortest out.mp4
- With -c copy the streams will be
stream copied
, not re-encoded, so there will be no quality loss. If you want to re-encode, see FFmpeg Wiki: H.264 Encoding Guide. - The
-shortest
option will cause the output duration to match the duration of the shortest input stream. - See the
-map
option documentation for more info.
First, make a text file.
file 'in1.mp4'
file 'in2.mp4'
file 'in3.mp4'
file 'in4.mp4'
Then, run ffmpeg
:
ffmpeg -f concat -i list.txt -c copy out.mp4
Delay video by 3.84 seconds:
ffmpeg -i in.mp4 -itsoffset 3.84 -i in.mp4 -map 1:v -map 0:a -vcodec copy -acodec copy out.mp4
Delay audio by 3.84 seconds:
ffmpeg -i in.mp4 -itsoffset 3.84 -i in.mp4 -map 0:v -map 1:a -vcodec copy -acodec copy out.mp4
Use the libass library (make sure your ffmpeg install has the library in the configuration --enable-libass
).
First convert the subtitles to .ass format:
ffmpeg -i sub.srt sub.ass
Then add them using a video filter:
ffmpeg -i in.mp4 -vf ass=sub.ass out.mp4
To extract all frames from between 1 and 5 seconds, and also between 11 and 15 seconds:
ffmpeg -i in.mp4 -vf select='between(t,1,5)+between(t,11,15)' -vsync 0 out%d.png
To extract one frame per second only:
ffmpeg -i in.mp4 -fps=1 -vsync 0 out%d.png
Rotate 90 clockwise:
ffmpeg -i in.mov -vf "transpose=1" out.mov
For the transpose parameter you can pass:
0 = 90CounterCLockwise and Vertical Flip (default)
1 = 90Clockwise
2 = 90CounterClockwise
3 = 90Clockwise and Vertical Flip
Use -vf "transpose=2,transpose=2"
for 180 degrees.
- Locate the playlist file, e.g. using Chrome > F12 > Network > Filter: m3u8
- Download and concatenate the video fragments:
ffmpeg -i "path_to_playlist.m3u8" -c copy -bsf:a aac_adtstoasc out.mp4
If you get a "Protocol 'https not on whitelist 'file,crypto'!" error, add the protocol_whitelist
option:
ffmpeg -protocol_whitelist "file,http,https,tcp,tls" -i "path_to_playlist.m3u8" -c copy -bsf:a aac_adtstoasc out.mp4
To replace the first 90 seconds of audio with silence:
ffmpeg -i in.mp4 -vcodec copy -af "volume=enable='lte(t,90)':volume=0" out.mp4
To replace all audio between 1'20" and 1'30" with silence:
ffmpeg -i in.mp4 -vcodec copy -af "volume=enable='between(t,80,90)':volume=0" out.mp4
Deinterlacing using "yet another deinterlacing filter".
ffmpeg -i in.mp4 -vf yadif out.mp4
Parameters: -r
marks the image framerate (inverse time of each image); -vf fps=25
marks the true framerate of the output.
ffmpeg -r 1/5 -i img%03d.png -c:v libx264 -vf fps=25 -pix_fmt yuv420p out.mp4
- Extract all frames:
ffmpeg -i input.mp4 thumb%04d.jpg -hide_banner
- Extract a frame each second:
ffmpeg -i input.mp4 -vf fps=1 thumb%04d.jpg -hide_banner
- Extract only one frame:
ffmpeg -i input.mp4 -ss 00:00:10.000 -vframes 1 thumb.jpg
ffmpeg -i in.mov -vf "drawtext=fontfile=arial.ttf: text=%{n}: x=(w-tw)/2: y=h-(2*lh): fontcolor=white: box=1: boxcolor=0x00000099: fontsize=72" -y out.mov
ffmpeg -i in.mp4 -map_metadata -1 -metadata title="My Title" -c:v copy -c:a copy out.mp4
https://ffmpeg.lav.io/ is an interactive resource to compose FFmpeg actions.
One issue I've had on Plex is videos with closed captioning. I use this little snippet to remove them:
If you want to extract those captions first, you can run: