Changing Playback rate with Gstreamer?

Hi All,


I'm wondering if there is a way to change the playback display period 
rate of an input stream.


For example, I'd like to convert:

   file1.mp4  with 1000 frames, plays back @10 fps = 100 seconds long

Into

   file1_fast.mp4  with 1000 frames, plays back @20 fps = 50 seconds long


I can do it with ffmpeg in various ways as detailed here:

https://trac.ffmpeg.org/wiki/How%20to%20speed%20up%20/%20slow%20down%20a%20video

Are there any simple pipelines elements that can do that?


(NB: I believe the videorate plugin does not do what I want. Please flag 
if you know otherwise!)


Thanks!


Will.