ffmpeg commands

ffmpeg

//png sequence with alpha from video
ffmpeg -c:v libvpx -i myvideo.webm  %02d.png

//video from png sequence
ffmpeg -framerate 30 -i image%d.png -c:v libx264 -crf 10 -b:v 1M output.mp4
ffmpeg -framerate 30 -i image%d.png -c:v libvpx -crf 10 -b:v 1M output.webm
//video from png sequence with alpha
ffmpeg -framerate 30 -i image%d.png -c:v libvpx-vp9 -pix_fmt yuva420p output.webm

//gif to webm (quality 0 to 60, lower is better)
ffmpeg -i inputfilename.gif -c vp9 -b:v 0 -crf 10 outputfilename.webm

//convert video with same parameters
ffmpeg -i inputfilename.mkv -c:v copy -c:a copy outputfilename.mp4

//remove sound
ffmpeg -i inputfilename.mp4 -c copy -an outputfilename.mp4

//convert video with alpha to hevc (note: adjust 2000k with your bitrate target)
ffmpeg -i myvideo.mov -c:v hevc_videotoolbox -allow_sw 1 -alpha_quality 0.75 -b:v 2000k -vtag hvc1/ output.mov

//convert mp4 with alpha to hevc mov
ffmpeg -i myvideo.mp4 -acodec copy -vcodec copy -f mov output.mov

//mp4 to webm
ffmpeg -i myvideo.mp4 -c:v libvpx-vp9 -crf 15 -b:v 0 -b:a 128k -c:a libopus myvideo.webm

//extract poster from first frame (note: adjust 0.0 to frame needed, here it's the first frame)
ffmpeg -ss 0.0 -i myvideo.webm -frames:v 1 myposter.jpg

//batch loudness normalization of multiple files
// target loudness (I), loudness range (LRA), and true peak level (tp). For speech use speechnorm instead.
@echo off
for %%A in (*.wav) do (
    ffmpeg -i "%%A" -af loudnorm=I=-16:LRA=11:tp=-1.5 -ar 44100 "normalized_%%A"
)
//batch convert to mp3
@echo off
for %%A in (*.wav) do (
    ffmpeg -i "%%A" -codec:a libmp3lame -qscale:a 2 "%%A.mp3"
)

//extract only a portion of video (-ss start, -t duration)
ffmpeg -ss 5 -t 3 -i source.webm -vf scale=553:-1 -filter:v "setpts=0.5*PTS" output.webm

//accelerate 2x speed
ffmpeg -i source.webm -filter:v "setpts=0.5*PTS" output.webm

//rescale (-1 means keep proportion)
ffmpeg -i source.webm -vf scale=400:-1 -filter:v output.webm

//cut video in 2 parts (-t 00:05:00.000 duration of first video, -ss 00:05:00 start time of second video) not very precise in the duration...
ffmpeg -i input.mp4 -t 00:05:00 -c copy part1.mp4 -ss 00:05:00 -c copy part2.mp4

//convert to apng format (-r fps, -plays 0 means loop, compression [0,100] with 100 most compression)
ffmpeg -i source.webm -f apng -compression_level 100 -r 12 -plays 0 output.png

//convert to gif (-r fps)
ffmpeg -i source.webm -f gif -r 12 output.gif