Kindly tell me that why video clip dos't play even after successfully uploading.

why video clip does not play even after successfully uploading. is there a soft ware needed to be downloaded?

By "uploading" are you saying you successfully moved the video from your computer to a web site and it will not play through your browser? Try looking at it on a different machine. If it doesn't work there either, the problem is on the web site. If it does, make sure your machine is up to date and has the codec for that file format installed.