I dont want to use player like vlc to speedup the playback. I want to actually speedup playback in the original file.
Its like I want video to be played 2 times faster.
mencoder has a
slowmoVideo is able to speed up and slow down video
First download and install the program. When it is loaded go to File > New and select your video file.
With your video loaded draw you curves (by clicking on an empty area) to describe how the video should speed up and slow down.
When you have finished go to File > Render (Ctrl + R) and choose a directory to save your video