rotate video with ffmpeg or avconv

Rotate 90 clockwise:

ffmpeg -i in.mp4 -vf "transpose=1" out.mp4 

rotation parameters as follows:

0 = 90CounterCLockwise and Vertical Flip (default)

1 = 90Clockwise

2 = 90CounterClockwise

3 = 90Clockwise and Vertical Flip

https://askubuntu.com/questions/83711/how-can-i-rotate-a-video