for i in *.mp4; do; ffmpeg -i $i -vf scale=-2:640 ${i%.*}_w640.mp4; done for i in *.mp4; do; ffmpeg -i $i -vf scale=-2:256 tt/${i%.*}_w256.mp4; done ffmpeg -i file.wmv -vcodec libx264 -acodec aac file_enc.mp4