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Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
Lecture 8 Video
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Lecture 8 Video

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  • 1. SFDV2001 – Web Development Lecture 8: Video
  • 2. History <ul><li>Magic Lantern, Athanasius Kircher in 1671 </li></ul><ul><li>Zoetrope, William George Horner 1834 </li></ul><ul><li>Celluloid, invented in 1856 </li></ul><ul><li>Zoopraxiscope, Muybridge 1878 </li></ul><ul><li>Cinématographe, Lumière brothers 1894 </li></ul><ul><li>Nickelodean 1905 </li></ul><ul><ul><li>Costs a nickel to watch a 15 minute movie </li></ul></ul><ul><ul><li>First actual movie theatre </li></ul></ul>11/09/07 SFDV2001:21 - Video
  • 3. Moving Pictures <ul><li>Flip book </li></ul><ul><li>Animation – GIF </li></ul><ul><li>Persistence of vision </li></ul><ul><li>Phi </li></ul><ul><li>Wagon wheel illusion </li></ul><ul><li>Movement detectors </li></ul>11/09/07 SFDV2001:21 - Video
  • 4. Video Basics <ul><li>Length </li></ul><ul><ul><li>seconds </li></ul></ul><ul><li>Frame size </li></ul><ul><ul><li>width and height </li></ul></ul><ul><ul><li>160 x 120 </li></ul></ul><ul><ul><li>320 x 240 </li></ul></ul><ul><ul><li>640 x 480 NTSC </li></ul></ul><ul><ul><li>768 x 576 PAL </li></ul></ul><ul><li>Frame rate </li></ul><ul><ul><li>frames per second </li></ul></ul><ul><ul><li>10 -15 fps, web </li></ul></ul><ul><ul><li>24 fps, Movies </li></ul></ul>11/09/07 SFDV2001:21 - Video
  • 5. Video Basics <ul><li>Quality </li></ul><ul><ul><li>compression </li></ul></ul><ul><ul><li>noise </li></ul></ul><ul><ul><li>colour </li></ul></ul><ul><li>Colour Depth </li></ul><ul><ul><li>bits per pixel. </li></ul></ul><ul><li>Data rate </li></ul><ul><ul><li>kbps. </li></ul></ul><ul><ul><li>how fast you have to transfer data to let the movie play without interruption. </li></ul></ul><ul><li>Audio. </li></ul><ul><ul><li>Soundtrack. </li></ul></ul>11/09/07 SFDV2001:21 - Video
  • 6. Video and the internet <ul><li>Initially just treat like another file </li></ul><ul><li>Download the data and let the user sort it out. </li></ul><ul><li>Video players </li></ul><ul><ul><li>Quicktime </li></ul></ul><ul><ul><li>MS break the law and steal Quicktime from Apple </li></ul></ul><ul><li>Embed the player in a browser program </li></ul><ul><li>What about a plug-in rather than download </li></ul><ul><li>Now two types </li></ul><ul><ul><li>Download </li></ul></ul><ul><ul><li>Streaming </li></ul></ul>11/09/07 SFDV2001:21 - Video
  • 7. YouTube <ul><li>Egalitarian access to video posting </li></ul><ul><li>Like blogs but with Video </li></ul><ul><li>OkGo – was a hit on YouTube first. </li></ul><ul><li>Lonelygirl15 – Viral marketing </li></ul><ul><li>Competition </li></ul><ul><ul><li>Google Video </li></ul></ul><ul><ul><li>MS – SoapBox </li></ul></ul><ul><li>Escape from the “mainstream media” </li></ul>11/09/07 SFDV2001:21 - Video
  • 8. Download <ul><li>Just treat like any other file type. </li></ul><ul><li>A link to download </li></ul><ul><li>Using a plug-in </li></ul><ul><li>Advantages </li></ul><ul><ul><li>No special plug-in for a normal link. </li></ul></ul><ul><ul><li>Download in the users own time. </li></ul></ul><ul><ul><li>Disadvantages </li></ul></ul><ul><li>File copied to the users computer. </li></ul><ul><ul><li>No fast forwarding. </li></ul></ul><ul><ul><li>No control over redistribution. </li></ul></ul><ul><ul><li>Whole file download. </li></ul></ul>11/09/07 SFDV2001:21 - Video
  • 9. Streaming <ul><li>Only send the next bit in the movie. </li></ul><ul><ul><li>Throw away older stuff. </li></ul></ul><ul><li>Advantages </li></ul><ul><ul><li>Control of data. </li></ul></ul><ul><ul><li>Allows fast-forward and other control. </li></ul></ul><ul><ul><li>Constant communication allows flexible download. </li></ul></ul><ul><ul><li>Allows real-time web-casts. </li></ul></ul><ul><li>Disadvantages </li></ul><ul><ul><li>Must have special server and client software. </li></ul></ul><ul><ul><li>Users do not have a cached version and so have to access the site to view again. </li></ul></ul><ul><ul><li>Higher server load. </li></ul></ul>11/09/07 SFDV2001:21 - Video
  • 10. Video File Formats <ul><li>AVI: .avi MS 1992. </li></ul><ul><li>Quicktime: .mov files. </li></ul><ul><li>RealMedia: .rm files (.ram and .rpm for streaming versions). </li></ul><ul><li>Windows Media: .wmv files (.asx for streaming version). </li></ul><ul><li>MPEG 1,2 4: .mpg .mpeg. </li></ul><ul><li>Sorenson – low bandwidth. </li></ul><ul><li>H.264 – MPEG4 OSX high compression rate. </li></ul>11/09/07 SFDV2001:21 - Video
  • 11. MPEG <ul><li>Moving Pictures Experts Group </li></ul><ul><li>First met in 1988 </li></ul><ul><li>Digital storage finally getting big enough for video </li></ul><ul><li>Goal to develop encoding for digital video </li></ul><ul><li>Two levels suggested </li></ul><ul><ul><li>MPEG-1 – Low quality </li></ul></ul><ul><ul><li>MPEG-2 – better quality </li></ul></ul>11/09/07 SFDV2001:21 - Video
  • 12. MPEG-1 <ul><li>Multiple codecs - Co ding dec oding </li></ul><ul><li>Different Frames </li></ul><ul><ul><li>I Key frame I </li></ul></ul><ul><ul><li>B Small changes with reference to I's and P's </li></ul></ul><ul><ul><li>P Reference frame </li></ul></ul><ul><li>I's compressed like JPEG </li></ul><ul><li>B's and P's are differences </li></ul><ul><li>Lossy compression </li></ul>11/09/07 SFDV2001:21 - Video
  • 13. Quicktime <ul><li>1991 File format </li></ul><ul><ul><li>*.mov </li></ul></ul><ul><ul><li>multimedia container file </li></ul></ul><ul><ul><li>Contains one or more tracks </li></ul></ul><ul><ul><ul><li>audio </li></ul></ul></ul><ul><ul><ul><li>video </li></ul></ul></ul><ul><ul><ul><li>effects </li></ul></ul></ul><ul><ul><ul><li>text </li></ul></ul></ul><ul><ul><li>Apple Video codec, Animation codec, Graphics codec </li></ul></ul><ul><li>1999 – added streaming support </li></ul>11/09/07 SFDV2001:21 - Video
  • 14. Video Compression <ul><li>Spatial compression: </li></ul><ul><ul><li>Compress each frame separately. </li></ul></ul><ul><ul><li>Done by MJPEG codec in digital video cameras. </li></ul></ul><ul><li>Temporal compression: </li></ul><ul><ul><li>Encode changes from frame to frame. </li></ul></ul><ul><ul><li>Uses keyframes to synchronise. </li></ul></ul><ul><ul><li>MPEG Sorenson use both. </li></ul></ul><ul><ul><li>Also utilise DCT: </li></ul></ul><ul><ul><ul><li>convert to frequency. </li></ul></ul></ul><ul><ul><ul><li>quantise. </li></ul></ul></ul><ul><ul><ul><li>entropy-code. </li></ul></ul></ul>11/09/07 SFDV2001:21 - Video
  • 15. Flash <ul><li>Adobe flash plug-in </li></ul><ul><ul><li>Includes video content. </li></ul></ul><ul><ul><li>Allows full interaction with movie. </li></ul></ul><ul><ul><li>Open standard </li></ul></ul><ul><ul><li>Streaming format </li></ul></ul><ul><ul><li>Vector based movies very small compressed size. </li></ul></ul><ul><ul><li>Presentation completely under control.. </li></ul></ul>11/09/07 SFDV2001:21 - Video
  • 16. Examples Worth Looking At <ul><li>BBC’s interview clips using RealMedia: </li></ul><ul><ul><li>Notice the picture quality </li></ul></ul><ul><ul><li>obvious temporal compression. </li></ul></ul><ul><ul><li>Notice the use of buffering to allow for data rate issues. </li></ul></ul><ul><li>Apple’s movie trailers site: </li></ul><ul><ul><li>Notice use of different frame sizes. </li></ul></ul><ul><ul><li>Designed to show off Quicktime. </li></ul></ul><ul><li>GDC TV </li></ul><ul><ul><li>Intergration of video and presentation. </li></ul></ul><ul><li>YouTube, Google Video </li></ul>11/09/07 SFDV2001:21 - Video
  • 17. Digital Format <ul><li>Blu-ray vs HD-DVD </li></ul><ul><li>The digital format battle of the future </li></ul><ul><li>Blu-ray </li></ul><ul><ul><li>The digital format battle of the future </li></ul></ul><ul><ul><li>Sony Playstation Blu-ray </li></ul></ul><ul><ul><li>25 GB single layer, 50 GB double layer </li></ul></ul><ul><ul><li>Many companies </li></ul></ul><ul><li>HD-DVD </li></ul><ul><ul><li>Toshiba, NEC, Sanyo, and, most recently, Microsoft, HP </li></ul></ul><ul><ul><li>15 GB single, 30 GB double </li></ul></ul><ul><li>Both use MPEG2 </li></ul>11/09/07 SFDV2001:21 - Video
  • 18. Summary <ul><li>Video files are Huge </li></ul><ul><li>The future of the web includes video </li></ul><ul><li>Broadband required before video makes sense </li></ul><ul><li>Various Codec compress video </li></ul><ul><li>Steaming vs Download formats </li></ul><ul><ul><li>When to use and the advantages/disadvantages </li></ul></ul><ul><li>Temporal vs Spatial compression </li></ul><ul><ul><li>How do they work </li></ul></ul>11/09/07 SFDV2001:21 - Video

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