ffmpeg -i input.avi -c:v libx265 output.mp4
ffmpeg -i input.avi -c:v libx264 output.mp4
ffmpeg -i input.mp4 -c:v flv output.flv
Convert to H265 with smaller size and medium quality: ffmpeg -i input.mp4 -c:v libx265 -crf 28 -vf "scale=iw/2:ih/2" -c:a copy output.mp4
ffmpeg -i input.mp4 -c:v libx265 -crf 28 -vf "scale=720:-1" -c:a copy output.mp4
ffmpeg -i input.mp4 -c:v libx265 -crf 28 -vf "scale=720:trunc(ow/a/2)*2" -c:a copy output.mp4
ffmpeg -i input.mp4 -c:v libx265 -crf 28 -vf "scale=trunc(oh*a/2)*2:720" -c:a copy output.mp4
Trim Video without Re-Encoding ffmpeg -i input.mp4 -ss 3:45 -t 1:21 -c copy output.mp4
Convert Any Audio to MP3-128k ffmpeg -i input.wav -ab 128 output.mp3
Extract All frames of Video
Fast / Lossless / Space-hogger: ffmpeg -i input.mp4 -r 1/1 $filename%03d.bmp
Slow / Lossy / Space-efficient: ffmpeg -i input.mp4 -r 1/1 $filename%03d.jpg
SuperSlow / Lossless / Space-efficient: ffmpeg -i input.mp4 -r 1/1 $filename%03d.png
Extract Nth frame of Video
ffmpeg -i input.mp4 -vf "select=eq(n\,34)" -vframes 1 output.png
ffmpeg -i input.mp4 -vf "drawbox=x=iw-320:y=ih-240:w=320:h=240:color=black:t=fill" output.mp4
you need %%, instead of %03d
don't use the quotes around -vf option's value, e.g. select=....
for drawbox filter use t=max if you are on an older ffmpeg version
