of the digital media file to the front, this move of the meta data gave the media player all the information it required to begin playback as the file was still being downloaded. Prior to that change, the meta data summary was located at the end of a media file and the entire file would need to be downloaded in order for the meta data to be read and the player begin playback. HTTP Pseudo-streaming (or progressive download), similar to streaming media or HTTP Live Streaming, also supports adaptive bitrate streaming. The disadvantage of HTTP Pseudo-streaming over streaming media is reduced security, since HTTP is easier to sniff compared to RTMP, along with long loading times when seeking larger videos. Optimization for HTTP Pseudo-streaming The MP4 files consist of chunks of data, called atoms. These atoms stores information like subtitles, etc. The special atom, called moov atom is responsible for storing information regarding how to play the video like dimensions, frames per second and such which is important to begin playing a video on HTML5 Video player. But atoms can appear in any order, so web servers like Nginx spends some CPU, memory and disk I/O to find the moov atom so that HTML5 Video based clients can start playing the video. To optimize for HTTP Pseudo-streaming, it's important to move the moov atom to the beginning, so that web servers like Nginx optimize for faster pseudo-streaming resulting in playing of playbacks without having to wait for the entire file to be arrived or scanned. ffmpeg -i sample_input.mp4 -movflags faststart -acodec copy -vcodec copy sample_output.mp4 -movflags faststart does the optimization by moving the index (moov atom) to the beginning of the file. -acodec copy extracts the audio from the input file unaltered. -vcodec copy extracts the video from the input file unaltered. By doing this optimization, we effectively prevent web servers, like nginx, from spending relative amount of computation in finding the moov atom hence increasing the playback performance on HTML5 Video based client. Seeking Initially, the file is played from the beginning. A user may wish to point to a part of the file which haven't been downloaded yet. This capability is called seeking and it makes possible to download and start playing any part of the media file. That is often referred to as pseudo-streaming. For Flash video seeking requires a list of seek points in the media