Video Compression and the Internet

Need for Compression Important to advancement of internet Video prevalent all over the net Compression has improved greatly over the past 10 years Helped revolutionize the way internet delivers content

How it works Exploits flaw in human perception Algorithms written to do this Areas of similar color averaged out Image is the same over period of time All works to make files smaller, with better quality Allowing faster transmission online Able to fit onto ipods, phones, etc

What is a codec? Allows for the compression (co), and decompression (dec) of a video file Represents analog information in a digital way Bitrate – amount of data per second required – Lower is better

List of codecs through the years MPEG1 MPEG2 Sorenson Realplayer Quicktime DivX XviD H.264/x264 VC-1

Importance of flash Allowed sites like Youtube to flourish Unified the standard of how to deliver video Prior to flash video, different standards, confusing Including Windows Media player, Quicktime, Realplayer and more Everybody already has flash, so no ambiguity

The flash video format Flv files embedded in websites – Contain video files H.264, VP6, Sorenson H.263 Previous flash versions starting at 6 supported different formats

Why encode video Too large to upload to YouTube – 1gb file limit Most digital cameras use poor codecs with little to no compression, wasting hard drive space, also making sending over internet unfeasible Rip your dvds to your computer Digitalize old home movies on analog sources for preservation and sharing online To put on your portable media player (ipod) Use of filters to improve video quality from bad sources

What does it take to encode video? Choose a codec – h.264/x264 and xvid are common A video file An encoder – FFMpeg, MeGUI, Handbrake

What’s next GPU based encoding Badaboom – Uses Nvidia graphics cards Faster than CPU Quality an issue currently

Further Information

Sources o4_2.htm#Interesting o4_2.htm#Interesting mat_spec_v10.pdf mat_spec_v10.pdf happened-to-video-on-web_20.html happened-to-video-on-web_20.html pubased_computing_really_upon_us pubased_computing_really_upon_us 39&p=2 39&p=2