ffmpeg -i <input>.mp4 <output>.webm
ffmpeg -i MVI_0083.MP4 -s 960x540 20190322_out.webm ffmpeg -i MVI_0083.MP4 -s 960x540 20190322_out.mp4 ffmpeg.exe -i "test.avi" -c:v libx264 -crf 20 -c:a aac -strict -2 "test.mp4"