ffmpeg cheatsheet

gistfile1.txt

# https://support.twitter.com/articles/20172128?lang=en#video-formats
# https://trac.ffmpeg.org/wiki/Encode/H.264

# gif to mp4 for twitter
ffmpeg -i in.gif -pix_fmt yuv420p -vf crop="floor(in_w/2)*2:floor(in_h/2)*2" out.mp4

# extract part of video (-t duration)
ffmpeg -i in.mp4 -ss 00:00:00.000 -to 00:00:15.000 -vcodec copy -acodec copy part.mp4

# convert to mp4 for twitter
ffmpeg -i in.mp4 -vcodec libx264 -acodec aac -strict experimental out.mp4
# H.264 profile: -profile:v baseline/main/high/high10/high422/high444
# preset: -preset ultrafast/superfast/veryfast/faster/fast/[medium]/slow/slower/veryslow
# bitrate = file size / duration: -b:v 555k -b:a 128k
# minrate/maxrate: -minrate 1024k -maxrate 1024k
# -vf scale=-1:480

# to gif (two steps)
ffmpeg -i part.mp4 -vf fps=15,scale=640:-1:flags=lanczos,palettegen -y /tmp/palette.png
ffmpeg -i part.mp4 -i /tmp/palette.png -lavfi 'fps=15,scale=640:-1:flags=lanczos [x]; [x][1:v] paletteuse' -y part.gif

# add empty voice track and limit the frame rate
ffmpeg -f lavfi -i anullsrc -i in.mov -r 40 -preset slower -shortest -c:a aac -strict experimental out.mov