...However, none of these tools support PARALLEL computing easily.
After some research, I found amazing solution designed & developed by 'Dustin Kirkland' based on Ubuntu JUJU and avconv. But our requirement was little bit diffrent from Dustins's solution. Our requirement was to convert single video in Multi-bitrate and in formats like 3gp, flv and upload them to single or multiple CDN(like Akamai or tata). Also we want to build this solution on top of CentOS and ffmpeg. So I decided to design and develop "Simple Scalable, Parallel, Multi-bitrate Video Transcoding System" by myself.