Crop Video temporary
FFMpeg might do what you need. It's pretty powerful commandline tool to convert video formats, sizes, etc.

Here is a clear and simple tutorial for installing FFMpeg and using basic functions

Here is a specific SuperUser thread about using it to cut small clips from a larger clip.


  So is their any video player or software by which i can crop/split
  video online so it don't affect my server space.


There are a couple of "online editors" such as WeView, I haven't used them.

FFMpeg can read files from a stream or ftp, see the documentation: https://www.ffmpeg.org/ffmpeg-protocols.html#ftp

But if I understand you correctly, you want the software to cut the clips and convert them totally on server. I do not think that is possible with normal protcols. FFMpeg may be able to download and cut the file in one script. But I suggest posing that as a separate question if you decide to use it.