1. ffmpeg -i video1.mp4 -r 30 -s 960x540 -vcodec libx264 -vpre medium video2.mp4

giving error File for preset 'medium' not found  while executing on aws-server

2. ffmpeg -i video1.mp4 -r 30 -s 960x540 -vcodec libx264  video2.mp4   << this code works fine but taking alot of time to execute/convert

3. ffmpeg -i video1.mp4 -r 30 -s 960x540 -vcodec libx264 -vpre medium video2.mp4   it is working fine on my localpc but not with aws-server