The document discusses video technology including analogue and digital video. It explains that analogue video uses continuously varying electrical signals to represent brightness and color, while digital video represents this information using discrete binary numbers. The document also covers video concepts such as frame rate, resolution, compression methods, and standards for analogue television like NTSC, PAL, and SECAM.

2. OVERVIEW
 Introduction to Video
 Analogue Video
 Digital Video
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3. INTRODUCTION TO VIDEO
 Moving pictures – film and video:
 a series of still images presented at a speed that gives
the illusion of motion
 Film uses a photo emulsion that reacts to the different
wavelengths that reproduces images
 Analog film records images on transparent medium
projected onto a screen
 Video uses electronic circuits to capture information
 Analog video records images as continuously varying
electrical voltages that produce images on a CRT or
projection screen
 Film and video rely on the trick of human eyes – 3
persistence of vision

4. INTRODUCTION TO VIDEO CONT…
 What is video?
 A series of electronically captured still images
display in rapid succession to achieve the illusion of
motion
 Two types of video:
 Analogue
 Digital
Video vs.
Animation?
Recall topic 1.1
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5. VIDEO SIGNAL
 Light = electromagnetic radiation
 The variation in light wavelength that represent
brightness and colour can be rendered accurately
by electronic circuit.
 Electronic waveforms signal = analogue signal
 Analogue video utilizes fluctuations in the electronic
waveform to represent brightness and colour.
 Analogue video signal – continuous signal
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6. VIDEO SIGNAL CONT…
 To capture the electronic waves form digitally, we
have to represent them as finite binary numbers.
 The transformation from waveforms to numbers is
never always 100% correct.
 Digital representation of analog signal has to be
balanced between accuracy and functionality.
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7. VIDEO – FRAMES AND FRAME RATE
 Frame rate (Scan rate) – how fast the frames are
displayed.
 Standard frame rate:
 film = 24 fps
 25 or 29.97 fps (depending on video standard)
 Lowering frame rate (e.g. 8 fps) can result in video with
jerky movements or flickers.
 Generally, frame rate of 15 fps = natural movement; use
for Internet.
What happens if we
raise the frame
rate? 7

8. VIDEO – RESOLUTION AND ASPECT RATIO
 Resolution = number of scan lines that fit on screen
 Aspect ratio = width divided by height
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9. VIDEO IMAGE
 Video image is created by an electron gun in the
CRT.
 The electronic signal illuminates lines of
phosphorus dots on the screen.
 Methods to illuminate or scan the image:
 Interlaced scan alternates the scanning between odd
numbered lines in the frame and even numbered lines in
the frame (NTSC).
 Progressive scan scans each line of the image
sequentially (computer monitor).
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10. VIDEO COLOUR SIGNALS
Composite Video Component Video
 Combines two signals:  Colors are represented
 Luminance or amount separately.
of brightness in the  Red, Green, Blue light
image. signals combine to
 Chrominance or color create color range.
hue in the image.  Better color quality.
 Inexpensive to create
and transmit.
Video captured in component color.
NTSC standard = composite color. 10
Computer monitors = component color.

11. ANALOGUE VIDEO
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12. ANALOGUE VIDEO
 Analogue video consist of series of images
produced by continuous analogue signals.
Ref: http://www.danalee.ca/ttt/analog_video.htm
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13. ANALOGUE VIDEO
 In an analogue video signal, each frame is
represented by a fluctuating voltage signal.
 This is known as analogue waveform.
 Composite analogue video has all its components
(brightness, colour, synchronisation information, etc.)
combined into one signal.
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14. ANALOGUE VIDEO – FORMATS & STANDARDS
 A broadcast television standard:
 NTSC - National Television Standards Committee
 Developed in the US and first used in 1954
 The oldest existing broadcast standard.
 Consists of 525 horizontal lines of display and 60 vertical lines.
 Scanning method (interlacing)
 Only one type exists - NTSC M.
 PAL - Phase Alternating Line
 Developed in Germany and first used in 1967.
 A variant of NTSC, PAL uses a 625/50-line display.
 Different types use different video bandwidth and audio carrier
specifications.
 Common types are B, G, and H. (Less common - D, I, K, N, & M)
 These different types are generally not compatible with one another.
 In England and much of Europe 14

15. ANALOGUE VIDEO – FORMATS & STANDARDS CONT
 SECAM - Système Électronique pour Couleur avec
Mèmoire.
 Developed in France and first used in 1967.
 Uses a 625/50 line display.
 Different types use different video bandwidth and audio carrier
specifications.
 Types B and D are usually used for VHF.
 Types G, H, and K are used for UHF.
 Types I, N, M, K1 and L are used for both VHF and UHF.
 These different types are generally not compatible with one
another.
What’s the TV
standard in
Malaysia?
15
 http://countrycode.org/tv-standards

16. DIGITAL VIDEO
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17. DIGITAL VIDEO
 Digital video uses binary numbers to represent
image data
 Two sources of digital video:
 Convert existing analog video to digital.
 Create or purchase digital footage.
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18. ANALOGUE VS. DIGITAL
Analogue Video Digital Video
 Continuous signal –  Digital or discrete-time
fluctuating voltage signal – in binary
signal number
 Reduces in quality over  Stable/enduring quality
the time or when  Random access
duplicates
 Linear access
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19. DIGITAL VIDEO QUALITY
 Factors contribute to quality
 Screen resolution
 Number of horizontal and vertical pixels used to present the
video image.
 Colour resolution
 the number of colours displayed on the screen at one time.
 Frame rate - Number of individual video frames
displayed per second.
 The higher the frame rate, the smoother the video
 Compression method
 Algorithm used to compress and decompress the video.
Developers can adjust these factors to optimize delivery of digital video. 19

20. SCREEN RESOLUTION
 Screen resolution (or output resolution) - number of
horizontal and vertical pixels used to present the
video image.
 impacts processing, storage, and transmission
requirements.
 High quality digital video (DV) format is 720 X 480 (or
350,000 pixels at rates of 30fps).
 CD-Rom and Internet are too slow to deliver that much
data.
 Solution: reduce the display size, which reduces the
number of pixels/second to output. Why does the
video degrade
Why is YouTube when viewed at full
videos are best at screen? 20
smaller size?

21. DIGITAL VIDEO - COMPRESSION
 Compression is key to successful delivery of digital
video.
 Three strategies for compressing video:
 Intra-frame: re-encodes within the frame.
 Inter-frame: eliminates intervening frames saving only
changes between the frames.
 Variable bit rate (VBR)
 CBR (constant bit rate) assigns same number of bits per
second to all parts of the video.
 VBR assigns more bits to complex scenes and fewer bits to
simpler scenes.
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22. DIGITAL VIDEO COMPRESSION
 Choosing compression depends on:
 Output destination
 DVD
 Internet
 Editing capability
 Detailed editing tasks
 Limited editing tasks
 Type of images in video
 Complex scenes
 Similar scenes
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23. INTRA-FRAME
 Lossless strategy could be Run-length encoding
(RLE).
 Result: smaller more efficient file with all the original
data.
 Lossy strategy commonly used is M-JPEG.
 Individual images are compressed and linked together
as motion sequences.
 Best for video editing as every frame is preserved
despite data being lost from each separate frame.
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24. INTER-FRAME
 MPEG compression identifies:
 I-frames: "intra-frame" or complete compressed
frames
 P-frames: predictive frames record more
significant changes.
 B-frames: bidirectional frames record smaller
changes between the I and P frame.
 Good choice for distributing video.
 Not appropriate for recording and editing video
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25. VARIABLE BIT RATE
 Constant Bit Rate encoding uses same number of
bits per second for simple and complex video.
 Variable Bit Rate assigns more bits to complex
scenes and fewer bits to simpler scenes.
 Common option in video editing software.
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26. COMMON VIDEO CODECS
 MPEG
 MPEG-1 (short videos on Video CD—optical disc
format).
 MPEG-2 (transmission of video for television).
 MPEG-4 (video over the web).
 M-JPEG (less-compressed higher quality files
without inter-frame loss)
 RealVideo (proprietary codec for streaming video
on web)
 DV (uses M-JPEG, suitable for authoring or
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archiving)

27. DIGITAL VIDEO - FORMATS & STANDARDS
 Developers use these  Common video file
formats to render the final formats
project in a form suitable for  Windows Video file (.avi)
delivery
 D1
 Movie file (.mpg or .mpeg)
 D2 and D3  Windows Media Video file
(.mwv)
 DV
 CD Video  MPEG-4 file (.mp4)
 DVD video  QuickTime Movie file
 Quicktime (.mov, .qt)
 Video for Windows  Any others?
 Real Video.
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28. DIGITAL VIDEO CHALLENGES
 Large file sizes
 Every second of uncompressed digital video requires
30MB of storage.
 Hardware performance
 Computer processors, memory and bus size must deliver
digital video to the screen at full motion frame rates.
 Distribution methods
 DVD players.
 High speed network bandwidth Digital video made possible by:
 Compression algorithms
 Fast computer hardware
 DVD storage
 Gigabit bandwidth.
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29. DIGITAL VIDEO
 Quality is long lasting
 Quality for duplicates is almost the same as the
original
 Allow random search/access of content
 Can be compressed for better and easier storage and
distribution
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30. MORE ON VIDEO..
Things to consider:
 When to use
 When video can say something that would be
impossible or difficult to say with medium such as
graphics, photos, or text.
 Where to place
 In the page
 In a separate context
 User Interaction with Video
 No control – video play immediately
 User control – play/stop buttons 30

31. USES OF VIDEO
 Consumer use  Corporate Use
 Television  Corporate video
 Home entertainment  Live video / video on
 Etc.. ? demand
 Video surveillance
system
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32. SUMMARY
 Introduced video – definition and concept
 Two categories of video
 Ref and Readings:
 https://learningnetwork.cisco.com/docs/DOC-6492
 http://www.danalee.ca/ttt/analog_video.htm
 Barfield, L. (2004). Design for New Media: Interaction
design for multimedia and the web. Essex, England:
PearsonAddison Wesley.
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