How to rotate videos on ubuntu!

Using mencoder:

• To rotate by 90 degree clockwise
• mencoder -vf rotate=1 -o output.mp4 -oac pcm -ovc lavc -fps 30 -ofps 30 input.mp4
• It is important to specify both input and output frame rate (with fps, ofps), else you will get the  error.
• To flip horizontally
• mencoder -vf flip -o output.mp4 -oac pcm -ovc lavc -fps 30 -ofps 30  input.mp

Using ffmpeg

• To rotate the video by 90 degrees, we can use the following command
• ffmpeg -i input.mp4 -vf "transpose=1" output.mp4
• "transpose=1" => 90 degree clockwise
• "transpose=2" => 90 degree anti-clockwise
• You may get the following error while running the command-"No such filter: 'transpose'". In this case, you should you need to install Libavfilter.
• To vertically flip the video 
• ffmpeg -i input.mp4 -vf  vflip output.mp4
• To horizontally flip the video
• ffmpeg -i input.mp4 -vf  hflip output.mp4