添加水印
./ffmpeg -i /mnt/hgfs/shared/resource/shenghua.avi -i /mnt/hgfs/shared/resource/my_logo.png -filter_complex overlay /mnt/hgfs/shared/resource/shenghua_die.mp4
轉碼，壓縮碼率
./ffmpeg -i /mnt/hgfs/shared/resource/shenghua.avi -f mp4 -acodec aac -vcodec mpeg4 -b 128k -ab 64k
/mnt/hgfs/shared/resource/shenghua_conv128.mp4