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Introduction to Multimedia Lecture #9 Intro to Video Instructors: Mohamed MAGANGA

A Vision of Students Today. Introduction to Multimedia Lecture #9 Intro to Video Instructors: Mohamed MAGANGA. Today’s Agenda. 3 Topics Left Video (pt.2) Sound (1) Review (1). Announcements Warm Up Today’s Lecture Lect 9: Intro to Video.

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Introduction to Multimedia Lecture #9 Intro to Video Instructors: Mohamed MAGANGA

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  1. A Vision of Students Today Introduction to Multimedia Lecture #9 Intro to Video Instructors: Mohamed MAGANGA

  2. Today’s Agenda 3 Topics Left • Video (pt.2) • Sound (1) • Review (1) • Announcements • Warm Up • Today’s Lecture • Lect 9: Intro to Video “A good film is when the price of the dinner, the theatre admission and the babysitter were worth it.”  Alfred Hitchcock

  3. Major Assignment - 10% • Marking Criteria: • Technical: file organization, file names (lower case) • Color creativity • Website Design: content, layout, style, links • Video – Word Overlay, transitions, music, style • Animation: creativeness and how it was incorporated in the website EVERYTHING MUST BE WORKING TEST IT ALL 3

  4. Warm Up Questions Which of the following terms means: “seeing two or three of the previous frames in order to predict where to put the next frame” Tweening: Process of ___________________________ to give the appearance that the first image evolves smoothly into the second image. Tweening Onion Skin Morphing Onion Skin: Creating animated cartoons and editing movies to see ____________________ Morphing: Process of blending together _______________ into a series of images 4

  5. Warm up Questions: • Question: How many frames per second should we have when building an animation for display on a computer? • Question: Which type of animation uses frames: • Cel Based • Path Based • Both • Neither • Question: If an animation is 40 frames long and the fps is 5, how long will the animation take to play?

  6. Today’s Agenda • Video – Part 1 • What is Video • Capturing Video • Firewirevs USB • Editing Video • How TV Works • Review 6

  7. What is Video? Video uses the power ofMotion and Sound A sequence of still images or frames that create the illusion of movement when played in succession. Movies Display at ______ fps Computer Displayed Video Display at ________ fps for smoothness 2 Types of Video: Analog: Smooth ___________ waves ex. Conventional TV Digital: Each frame is a _____________, stored as 0s and 1s

  8. Digital Video Digital Videois composed of a series of bitmap graphics, each one called a ____________. Characteristics: • Bits storecolor and brightness data for each video frame. • Retains image quality no matter how many times it is copied. • Easily manipulated on a pc because stored in digital format “Digital Technology is the same revolution as adding sound to pictures and the same revolution as adding color to pictures. Nothing more and nothing less.” - George Lucas, film maker of STAR Wars

  9. What kinds of Digital Videos? Classified by its platform or application (how it will be delivered) • Desktop video (DTV) • Videos constructed and displayed using a personal computer • Web-based video • Incorporated in Web pages and accessed with a browser • DVD-video • A DVD format used for commercial DVDs that contain feature-length films. • PDA video • Small-format video designed to be viewed on a PDA or cell phone screen

  10. How much planning goes into making a movie before the first scene is ever shot? http://www.youtube.com/watch?v=FvQV21hkMjI&feature=related (we will just watch the first 2 minutes) 10

  11. Creating Digital Video 11

  12. Ready to Make a Video –Assumption: you took the footage Let’s take a closer look! Edit Digital Video (using Computer, Digital Video softwareex. Adobe Premiere, Avid) • Edit it • Add all kinds of cool titles • Filters, transitions • Superimpose clips • Synchronize audio with video • Authoring software: create menus and interactivity Capture Video • Download video from camcorder to computer Output Video • Output to different file formats • Back out to tape, the Web, CD, DVD 12

  13. Capturing the Video with Camcorders • If we use an: • Analog Camcorder,: • Electronic impulses are recorded • Must convert it to digital BEFORE we can put it on our computer to edit. • To convert analog video to digital video we need a ___________ • Digital Video Camcorder: • Information is sent as _____________ • Thus no need to convert!

  14. Capturing Video –Download video from camcorder to computer To use video in a multimedia application, it must be in digital form (0s and 1s) So how do you get a camcorder video into digitized form? Video card Analog Video camera Software: Capturing, Editing, Outputting Connecting Leads: Firewire or USB cable Digital camera 14

  15. Digital Video Camcorders • Most Digital Video Camcorders (DV Camcorders), do a little bit of compression right inside the camera. • common DV compression used by today’s camcorders: DV25 is the most • DV25 Format Specs: • Pixel Dimension is 720 X 480 (note this is 3:2 ratio) • Frame Aspect Ratio either 4:3 or 16:9 • Data Rate: 25 mega bits per second (that’s why it is DV25) • Frame Rate: 29.97 fps • Colour Sampling: YUV 4:1:1

  16. Colour Compression In The Camera • For still images RGB is commonly used • For video the model is YUV (YIQ) or YCbCr (for MPEG compression) • Y  luminanace (brightness) • UV (CbCr)  chrominance (color/hue) • Question: Black and White TV only used the _____ signal (fill in the blank with Y, U or V)Answer: ______________________ • Question:Which one will the human eye detect changes in more easily? How does this help us with compression? Answer:________________

  17. Color Sampling Method for Video-compression technique Color Sampling:Refers to technique in digital video –compression technique BACKGROUND:in Video we do not store record all color in an image • Color SamplingallowsAverages out pixelsto cut down on bandwidth (faster transfer rates) • Eye senstivity: • Rods – light vs. dark, black vs. white -- not color • Cones – see color • We can detect brightness better than color (more rods) • You may see that the compression used 4:1:1 4:2:0 4:4:4 • What does this mean? • Assume we have 4 pixels 

  18. Color Sampling Method for Video http://dvxuser.com/articles/colorspace/ Red, Orange, Blue, Purple red + blue= Purple • 4:1:1 • Blocks of 4 pixels averaged out • 4 x 1 block Result: So all four pixels get forced to become purple (shades of brightness) Blocks of 4 pixels averaged out • 4:2:0 • Blocks of 4 pixels averaged out • 2x2 grid block • You may see that the compression used 4:1:1 Color Sampling Method, What does this mean? • Assume we have 4 pixels

  19. Color Sampling Method for Video http://dvxuser.com/articles/colorspace/

  20. Connection Types: Digital Analog Video • S video (better quality) • Yellow RCA Audio Firewire connection Sony Hi-8 TRV-80 20

  21. To get the video off of your camera onto a computer you must use either: Analog USB cables Firewire Video Capture Card Plugs directly Firewire (4 pin) • Converts video from ANALOG TO DIGITAL USB 21

  22. Capturing Video –Video Capture DeviceDownloadvideo from camcorder to computer Firewire ( ________, _________) • A means by which information could be sent from the camcorder directly to the computer • A high-speed digital serial_________that allows the output of the camera to be fed directly into a computer in digitized form • Digital Video footage requires 13GB of storage per hour of video. • All major manufacturers agreed to use a common digital tape format and a method -- Firewire (universal standard) • 4-pin to 4-pin plugs • 4-pin to 6-pin plugs • 6-pin to 6-pin plugs 22

  23. Summarizing Analog vs Digital 1983 1994 DIGITAL(Newer Technology) • Records a binary code (string of 1s and 0s) compressed on magnetic tape or other media • Adv: No image degradation • Plug your video camera directly into your computer via a Firewire (aka i.Link) or USB connection. • These are digital connections and allow you to "dump" footage straight from the camera to hard drive. ANALOG(Older Technology ) • Records electrical signals/pulses directly onto a medium (like a tape) with a magnetic encoding. • Disadv: Picture loses quality • Video capture card needed to convert video from analog to digital for your computer Solid State Media Card - Memory Sticks 23

  24. A little history on TVs Digital video often adheres to standards for TV broadcasting – 2 standards • NTSC Standard: • Regular Analog TV broadcasting began in the United States in 1939 and carried through to today • Frame rate was originally 30fps but when color was introduced, needed to go down to _______ fps to accommodate for colour information. • PAL Standard: • Britain, Europe and other countries • Frame rate is set for _________ fps

  25. A little history on TVs Experiments with High Definition TV began in the late 40s and 50s but it wasn’t adopted by a single station till 1996. Before 1996 ALL TV was broadcast using _________________(see next slide) The original ANALOG video choices made about TV display (frames per second, frame size, etc..) affect the standards that were picked for DIGITAL video and applied today!

  26. How did the original TV display work? • The scan only draws every OTHER line (1,3, 5, …479) then starts back at the top and draws the even lines (2,4,…480). • Thus two passes • Each pass is called a field • The process is called Interlaced display • This way it can cheat the eye, while the phosphor dots are disappearing, it is drawing the line underneath. Our eyes see phosphor dots on the screen. An electron beam (gun) activates the dots. The gun scans through the dots horizontally A complete scan is when the gun starts at the top left and scans several times horizontally till it gets to the bottom right

  27. How did the original TV display work? Increasing the frame rate in the old days required a lot more bandwidth, so they “cheated” and used interlacing to trick the eye Interlacing effect (old TVs) Line 1,3,5,7, Line 2,4,6,8.. Progressive effect(not interlaced)(now used by Flat Screens because of the panel) Line 1,2,3,4,5,6,7.. http://www.crutchfield.com/Learn/learningcenter/home/understanding-resolution.html

  28. NTSC Standards • High Definition for NTSC: • 1440 X 1080 • 1280 X 720 • Frame Aspect Ratio is 16:9 • 1440:1080  ratio is 1.333 (pixels are not square) • 1280:720  ratio is 16:9 (pixel are square ) Frame aspect ratio is the ratio of width to height of the image frame. 16:9 Frame aspect ratio 4:3 Frame aspect ratio NTSC Standard DV Frame: • For NTSC  720 X 480 pixels For Pal  720 X 576 pixels • Pixels are distorted (not square) because 720:480 is actually 3:2 ratio

  29. How do we see images on a CRT Display TV vs Flat Screen http://www.crutchfield.com/Learn/learningcenter/home/understanding-resolution.html 29

  30. OLDER TECHNOLOGY • Screen resolution __________ • Electron gun beam activates the dots PLASMA or LCD Screen resoluiton sof _________ _________ Flat grid of pixels http://www.crutchfield.com/learn/learningcenter/home/tv_flatpanel.html?page=2 http://www.crutchfield.com/S-EMMmc3InSom/learn/learningcenter/home/tv_flatpanel.html http://www.crutchfield.com/Learn/learningcenter/home/understanding-resolution.html?page=2 Older TVs 480 Scan Lines New Plasma, Flat Screen  720 or 1080 lines  progressive not interlaced

  31. How do we see images on a Flat Panel TV Don’t need to know more detail for the exam Most flat-panel TVs are progressive displays • Illuminating a fixed grid of tiny pixels. • Every pixel has three sub-pixels: (RGB) • Color and brightness information controlled at the sub-pixel level • Uses progressive display • Screen resolutions of 1080p (progressive)1080i (interlacing)

  32. Capturing Video –Download video from camcorder to computer Resolution Comparison Digital Advantage:higher resolution(# of horizontal lines) Depending on features of individual unit, you may be able to achieve: 32

  33. Newer TVs http://www.crutchfield.com/Learn/learningcenter/home/understanding-resolution.html Question: On a newer HD TV, what does the circled area mean?

  34. Firewire vs. USB It used to take A LONG time to move video from your camcorder to your computer (Hours and Hours) • USB • USB 1.1. could transmit at 12Mbps • Used for mice, keyboards, printers, _____________ • USB 2.0 came along, backward compatible, transmitted at 480Mbps (could beat with Firewire400 and do video) • Firewire • Firewire initiated by Apple and the IEEE in the late 80s. • It is a high speed data transfer technology. • Transmitted originally at 400Mbps • Apple wanted to charge 1 dollar for every machine that was going to use it, this caused most PC manufacturers to decide against it, in favour of USB 1.1. • Currently, we have Firewire 800, transmits at 800 Mbps, at some point in the future, they expect new Firewire will transmit at 3.2 Gbps! 34 Apple IPODS no longer have firewire ports

  35. Capturing Video Download video from camcorder to computer Benefits of Digital • No Loss of Quality – Digital Videotape can be copied almost indefinitly. Important consideration in Postproduction sessions that require numerous generations of video effects. • No need of analog-to-digital conversionDigital material can be directly uploaded to digital editing systems • Reduces or eliminates problems such as dropouts due to error-correction circuitry associated with digital electronics • Archival (long-term) storage. Digital videotapes are better suited forlonger periods • Quality of digital recordings is significantly betterthan analog recordings 35

  36. Capturing Video Download video from camcorder to computer Controlling the Transfer Process • Video Capture software:Doesn’t matter if you are using an analog or digital camera Software Should have Features: • Start and stop the transfer • Select a file format for storing your video footage • Specify file name for each video clip • Video capture software is supplied with video editing software and with video capture devices TIP: Videos are easier to edit if you divide them into several files, each containing a one or two minute video clip. 36

  37. In Lab – MovieMaker Learning to edit your video Capture Video (using video capture card) from camcorder to computer Edit Digital Video (using Computer, Digital Video softwareex. Adobe Premiere, Avid) • Edit it • Add all kinds of cool titles • Filters, transitions and FX • Superimpose clips • Synchronize audio with video • Output in different file formats Output Video (back out to tape, the Web, CD, DVD) In Lab – MovieMaker Movie on Adobe Premier 37

  38. Let’s Review • When would you use Firewire? • If you have a digital camcorder • If you have an analog camcorder • Which of the following is a benefit of using a digital video recorder? • No loss of data • Can edit digital footage on a computer, you can NOT edit analog footage on a computer. • You don’t need a video capture card • All of the above are benefits of going digital. 38

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