ffmpeg | shira.at


ffmpeg is a commandline tool to convert media (audio, video) into different formats, manipulate or compress them, put filters on, etc. .

This is a list of ffmpeg flags and commands I commonly use.
This is neither a complete list nor a guide on how to use ffmpeg.
If the code doesn’t start with ffmpeg then it’s only the middle part.
This middle part needs to be inserted ffmpeg -i input.mp4 <here> output.mp4.

Common flags

Compress video

Should be between 20 and 28 for good quality.
The lower the bigger the filesize.
51 is max compression and looks very bad.
A good value is 25 for compression/filesize balance.

ffmpeg -i input.mp4 -crf 25 output.mp4

Remove Audio / Video


Example: Convert video to audio

ffmpeg -i input_video.mp4 -vn output_audio.mp3

Change Codecs

vcodec changes the video’s codec and acodec the audio one.
copy means it takes the input straight to the output. This makes it way faster.

-vcodec h264
-vcodec libvpx
-vcodec copy

-acodec aac
-acodec mp3
-acodec copy

Copy all input codecs to output

With this you take the input video and audio and copy it to output.
This makes cutting videos (e.g. by time) very quick as no converting takes place.

ffmpeg -i input.mp4 -c copy output.mp4

Convert Music to lower bitrate

-map 0:a:0 -b:a 96k

Aspect ratio

-aspect 16:9

Double Speed of video (0.5 = x2)

-vf "setpts=0.5*PTS"

Double audio speed

ffmpeg -i input.mp4 -filter:a "atempo=2.0" -vn output.mp3

Set bitrate

-b:v 1M
-b:a 96k

Volume of audio

ffmpeg -i input.mp3 -af 'volume=1.5' output.mp3

Change scale of video

iw = width, ih = height, -1 means auto
The first example command halfs the width (and height automatically)
The second one sets the width and height (and thus the aspect ratio) explicitly

-vf scale="iw/2:-1"
-vf scale="1280:720"

Crop (Cut) Video

w = width of output video
x = left top startpoint for the rectangle

ffmpeg -i input.mp4 -filter:v "crop=w:h:x:y" output.mp4

Video to images

Names are image-001.png, image-002.png, …
-r = framerete in which screenshots are taken, default=25
%3d = name, 001 - 999

ffmpeg -i input.mp4 -r 1 -f image2 image-%3d.png

Add Text to the video

-vf drawtext="text='MyTextHere': fontcolor=white: fontsize=24: x=(w-text_w)/2: y=(h-text_h)/2"

Combine 2 videos

ffmpeg -i in_one.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts _1.ts
ffmpeg -i in_two.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts _2.ts
ffmpeg -i "concat:_1.ts|_2.ts" -c copy -bsf:a aac_adtstoasc together.mp4

Convert a video from 30 to 60 FPS

ffmpeg -i Input.mp4 -filter:v "minterpolate='fps=60'" Out60.mp4

Make 2 input files side by side

ffmpeg -i 30.mp4 -i 60.mp4 -filter_complex hstack comparison.mp4

Cut Video

The time either in 00:01:23.000 or in seconds format, here seconds are used
This example would cut the video, so that only seconds 3 to 8 plays
aka. 5 seconds long output video -t = duration, -ss = starttime

ffmpeg -i input.mp4 -ss 3 -t 5 output.mp4

Burn in subtitles

ffmpeg -i in.mkv -vf subtitles=in.mkv out.mp4

Convert a folder from mp4 to mp3

for i in *.mp4; do ffmpeg -i "$i" "$(basename "$i" .mp4)".mp3  ; done

Compress a folder with only 2 threads (2 cpu cores)

for i in *.mp4; do ffmpeg -i "$i" "_$(basename "$i" .mp4)".mp4 ; done

Complex Example Commands

Convert gif to mp4 file

Source: https://web.dev/replace-gifs-with-videos/

ffmpeg -i my-animation.gif -vf "crop=trunc(iw/2)*2:trunc(ih/2)*2" -b:v 0 -crf 25 -f mp4 -vcodec libx264 -pix_fmt yuv420p my-animation.mp4

Create a meme video with white bar and text ontop of a video

ffmpeg -i inputfile.mp4 -filter_complex \
"[0:v]pad=iw:ih+100:0:(oh-ih)/2+50:color=white, \
 drawtext=text='Me coming to my wife's funeral':fontsize=42:x=(w-tw)/2:y=(100-th)/2" \

Meme video with top and bottom white bars and text

ffmpeg -i input.mp4 -filter_complex \
"[0:v]pad=iw:ih+100:0:(oh-ih)/2:color=white, \
 drawtext=text='ONE DOES NOT SIMPLY':fontsize=24:x=(w-tw)/2:y=(50-th)/2, \
 drawtext=text='STOP ME FROM FILTERING':fontsize=24:x=(w-tw)/2:y=h-25-(th/2)" \

Convert 15fps mkv with subtitles to mp4

The input file is a 15fps and full HD .mkv video with external subtitles and unoptimized, weird encodings.
This command makes it into a 30fps normal HD .mp4 video with the subtitles burned into the video and encodings that are optimized and widely acknowledged (h264/aac).

ffmpeg -i input.mkv -vf "subtitles=input.mkv,scale=1280:720" -crf 25 -vcodec h264 -acodec aac -r 30 output.mp4