Video technology

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  • Video technology

    1. 1. Understanding Video Technology Unit 21- Understanding Video Technology
    2. 2. Still / Moving Image • Moving image has it’s root in still photography… Still image… Moving image…
    3. 3. The Beginnings • The 1880s was a time of advancement, invention and enterprise in the world of moving images • Several factions from around the globe were working on new and innovative type of technology which attempted to capture and project moving images • Until this time, photography had been the sole method of recording actual ‘real life’ ‘View from the window at Le Gras’ circa 1828 ‘Boulevard du Temple’ 1839
    4. 4. Thomas Edison • Thomas Edison patented the caveat for the Kinetoscope in 1888 stating that it would ‘do for the eye what the phonograph does for the ear’ • He charged on of his assistants, photography expert William Kennedy Laurie Dickson, with the task of inventing the Kinetoscope • By 1891, after a couple of prototypes had been made and tested, the Kinetograph (the camera) and the Kinetoscope had been patented • The 1891 patent used 35mm film which, until recently was still widely used today
    5. 5. The Kinetoscope • 18 in. x 27 in. x 4 ft. high • peephole with magnifying lenses in the top • Inside the box the film, in a continuous band of approximately 50 feet, was arranged around a series of spools. • A large, electrically driven sprocket wheel at the top of the box engaged corresponding sprocket holes punched in the edges of the film, which was thus drawn under the lens at a continuous rate. • Beneath the film was an electric lamp, and between the lamp and the film a revolving shutter with a narrow slit. • As each frame passed under the lens, the shutter permitted a flash of light so brief that the frame appeared to be frozen. • This rapid series of apparently still frames appeared, thanks to the persistence of vision phenomenon, as a moving image.
    6. 6. The Lumiere Brothers • Father, Antoine was a photographer and successful businessman • In 1984, Antione was invited to a demonstration of Edison’s Peephole Kinetoscope in Paris • He presented his son Louis with a piece of Kinetoscope film, given to him by one of Edison’s concessionaires and said, "This is what you have to make, because Edison sells this at crazy prices and the concessionaires are trying to make films here in France to have them cheaper”. Augustine and Louis Lumiere
    7. 7. The Lumiere Brothers cont… Augustine and Louis Lumiere • Through 1894, attempts were made to replicate and improve Edison’s Kinetoscope design • They considered Edison’s Kinetograph flawed because it was too bulky and was resigned to the studio • And they thought Kinetoscope was limited as only one person could view the moving images at any one point • In1895, the Lumiere Brothers painted the lighter (5kg) and quieter Cinematograph
    8. 8. In England… • The first single lens motion picture camera was patented in Leeds, by French-born Louis Aime Augustin Le Prince in 1888 • The first films were made on a sensitised paper roll a little over 2 inches wide • Prince started commercial development of his motion picture camera in early 1890 with an updated version • He arranged for a demonstration to M. Mobisson, the Secretary of the Paris Opera Lous Aime Augustin Le Prince
    9. 9. In England… • On September 16 1890, Prince boarded a train at Dijon bound for Paris with his motion picture camera and films • He never arrived in Paris. No trace of Prince or his motion picture camera were ever found. The mystery was never solved… • However, the first moving pictures developed on celluloid film were made in Hyde Park in 1889 by William Friese Greene, a British inventor, who patented the process in 1890 William Friese Greene
    10. 10. In England… • In 1895, a pair of Greek showmen, George Georgiades and his partner George Tragides, were at the centre of a row with the already powerful American Edison company • The pair originally purchased six Kinetoscopes from Edison, forming the American Kinetoscope Company and opened Kinetoscopes at several locations in London, amongst them The Strand and Old Broad Street • They wanted to expand but machinery was rare and expensive • The Greek pair decided to make their own version with the help of R. W. Paul who owned an optical instrument works • Edison did not have a patented for his Kinetoscope in the UK…
    11. 11. In England… • Once the pirate Kinetoscopes were made, Edison refused to sell films for Paul’s machines, so Paul approached Birt Acres to help construct a camera to shoot their own films • They obtained film from the American Celluloid Co. of Newark, N.J. and started filming their own with American born cinema pioneer Birt Acres as the cameraman • Over the next few years, William Friese-Green, undertook extensive research and advanced the creation of British cameras • Unfortunately his technology was not successfully incorporated into any practical application • Friese-Green's most bitter opponent was ex-hypnotist, mind reader and showman George Albert Smith
    12. 12. In England… • Smith is thought by many to be the real driving force behind the early cinema industry • In 1892, Smith acquired the lease to St Ann's Well Garden in Hove, Brighton and turned it into a pleasure garden • The garden became his ‘film factory' and is the scene of many early films • In 1897 Smith turned the garden's pump house into a space for developing and printing and in the grounds, probably in 1899, he built a 'glasshouse' film studio George Albert Smith
    13. 13. Lower-class Entertainment • Once a reliable form of projection was discovered, establishments began showing early films, such as The Great Train Robbery (1903) • These were mostly converted shop fronts called Nickelodeons • So called because admission was 5c (a nickel) • In its inaugural years, film was seen as a entertainment for the lower classes, for those who couldn’t afford to watch stage plays • Only failed stage actors would star in film and they remained anonymous
    14. 14. D.W. Griffith • Kentucky born DW Griffith was a failed stage actor who start acting in Edison Film Company films in 1907 • Started directing in 1908 after a member of staff called in sick • He made 60 films in 1908 • In 1909, he made over 100 • Who do you think was the most important person on a set at this time?D.W. Griffith
    15. 15. Edison’s Cartel • In 1908 Edison attempted to exploit his filmic invention by charging companies per foot of film • Anyone suspected of exhibiting a non-Edison production had their equipment smashed • Biograph Pictures, started by William Dickson, who actually invented the Kineoscope paid Edison for the right to make films William Dickson
    16. 16. From NY To Hollywood • Many of the smaller companies suffered at the hands of Edison’s financial demands • They were also having equipment broke by Edison’s ‘trust member’ for not forwarding him any funds • So, en mass, several directors headed a safe distance away, pitching up in South California • DW Griffith was one of the first directors to head over to Hollywood
    17. 17. How TV images are created? • Video images are made up of hundreds of lines • The process is so quick however, that the human eye simple sees a unified picture • Think of picture being put through a shredder – the result would be a picture, in lots of lines
    18. 18. Television Standards Q: How many lines are scanned for UK standard definition? A: 625 Q: And many time is this process repeated every second? A: 15 Q: So, how many lines are scanned in one second? A: 9375 • This is called the Phase Alternating Line system
    19. 19. Phase Alternating Line (PAL) • System developed in the 1950s and unveiled the European Broadcasting Union in 1963 • Transmits colour images • Generally refers to the 625 line / 25 frames per second system • Used in several European countries such as the UK, Portugal, Spain, Israel and Eastern Europe
    20. 20. National Television Standards Committee (NTSC) • NTSC is the television standard for The Americas • There a 525 lines on a NTSC standard transmission • The frame rate is 30 frames per second • This is also what an iPhone records in • The system was created in 1941
    21. 21. Sequential Colour Avec Memoire (SECAM) • The first colour transmission system in Europe • Used in the Middle East, parts of Africa and Russia • Same amount of lines as PAL (625) and same frame rate (25 fps) • However, the colour is transmitted differently to PAL and NTSC – SECAM transmits colours separately on alternate lines (red on one, blue on another), therefore the colour resolution is halved in comparison to PAL and NTSC
    22. 22. PAL PRO • Has more scan lines so the pictures have higher picture detail, higher levels of contrast and better colour reproduction than NTSC CON • Lower frame rate means the picture motion can appear to flicker more than 30 frames and colour saturation can vary from frame to frame
    23. 23. SECAM PRO • The high number of scan lines means a good quality picture, the colour hues are in constant saturation and it has stable colour reproduction CON • Like PAL there is more motion flicker and Pattern effects seem to crop up on the picture from time to time, there are also many many variants of SECAM from country to country a lot of which are incompatible with one another
    24. 24. NTSC PRO • There is less flicker and smoother motion in the video output because of higher frame rates and it produces less noise CON • The lower number of scan lines means the picture isn’t as clear as PAL and the contrast level poor. Colour levels can fluctuate from frame to frame
    25. 25. Standards conversion • The process of turning one system to another, usually PAL to NTSC (625 lines / 25fps to 525 lines / 30 fps • Several complex ways of converting standards Simplified • PAL – NTSC: repeat every fifth frame and creating five additional frames per second • Reduce the number of lines by 100 lines
    26. 26. Film – TV / video • Film is shot at 24fps • This means when it is played on PAL systems (25fps) it will be 4% quicker • 25fps is 4% quicker than 24 fps • Check out the running time of Back the Future on IMDB • Now check the running time on the DVD on Amazon • What do you notice? • What problems do you think this might cause?
    27. 27. Film – TV / video • Film – NTSC poses for of a problem because of the 24fps – 30fps difference (that’s 20%) • Several complex methods are used to ready film for NTSC • The most common way to convert was called the 3:2 pull down technique • This is when one frame in every six is repeated • This however causes judder and view anomolies
    28. 28. 3:2 Pulldown Technique
    29. 29. Film formats • 35mm – Created by Edison in the late 1800s, still in use today • 16mm – Created in the 1920s, grainy and less sharp • 8mm – 1932, half the price of 16mm • 65 / 70mm – Used for Imax etc • Rule of thumb: The larger the film format, the better the quality, the more expensive the technology, the bigger and heavier the equipment
    30. 30. Aspect Ratios • The width and height of an image
    31. 31. 4:3 / 1.33:1 • Seen on early TV
    32. 32. 16:9 – Widescreen • Letterboxing occurs with this aspect ratio
    33. 33. 2.35:1 – Anamorphic • Letterboxing occurs with this aspect ratio • Distortion / oval flaring may occur
    34. 34. Considerations of a filmmaker?
    35. 35. Word match task…
    36. 36. Broadcast systems • Five main types of broadcast systems • Terrestrial TV • Satellite TV • Cable TV • Digital TV • Internet TV • In groups, create a presentation on ONE of the above broadcast systems
    37. 37. Broadcast systems • What you need to think about: • The history of the broadcast system • How it works • What are the pros and cons of each broadcast system • Examples (visual / video examples) • Each presentation must be at least 10 minutes long • Prepare for questioning after the presentation

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