CHAPTER 6: VIDEO
ITBIS351 Multimedia Systems and Hypermedia
Yaqoob Al-Slaise
OUTLINE
Consider the
implications of using
digital video in
multimedia
Discuss video analog
and digital
technologies and
displays
Find and acquire video
clips
Work with digital video
containers and codecs
to select the best video
recording formats for
multimedia projects
Shoot and edit video
for use in multimedia
VIDEO
Of all the multimedia elements, video
places the highest performance demand on
your computer or device—and its memory
and storage.
HOW VIDEO WORKS
 When light reflected from an
object passes through a video
camera lens, that light is
converted into an electronic
signal by a special sensor called a
charge-coupled device (CCD)
ANALOG VIDEO
 Analog video has a resolution
measured in the number of
horizontal scan lines (due to the
nature of early cathode-tube
cameras).
VIDEO STANDARDS
(COMPONENT)
 Component: Separates the
Red, Green, Blue channels on
different CCDs as separate
signals on its own conductor.
 Component is used for
high quality video.
S-VIDEO
 S-Video: (Separate Video)
uses two channels:
• Luminance: sometimes
referred as Y (greyscale).
• Chrominance: sometimes
referred as C (color)
COMPOSITE
 Composite: when all the
signals are mixed together and
carried on a single cable as a
composite of the three color
channels and the sync signal.
The composite signal yields less-
precise color definition.
HELICAL SCAN
 A single video frame is made
up of two fields that are
interlaced.
 Tracking is the fine
adjustment of the tape during
playback so that the tracks are
properly aligned as the tape moves
across the playback head.
ANALOG BROADCAST
STANDARDS
 NTSC
 National Television Standards
Committee
 a single frame of video was made
up of 525 horizontal scan lines drawn
onto the inside face of a phosphorcoated picture tube every 1/30th of a
second by a fast-moving electron beam.
 Odd lines than even lines (60 lines
per second= 60Hz)
FLICKERING
ANALOG BROADCAST
STANDARDS
 PAL
 Phase Alternate Line
(PAL)
 increased the screen
resolution to 625 horizontal
lines, but slowed the scan rate to
25 frames per second.
 50 lines per second = 50Hz
ANALOG BROADCAST
STANDARDS
 SECAM
 Sequential Color and Memory
(SECAM)
 a 625-line, 50 Hz system.
 SECAM transmits only one color at
a time, it is free of the color artifacts
present in NTSC and PAL resulting
from the combined transmission of
both signals.
ANALOG BROADCAST
STANDARDS
DIGITAL VIDEO
HDTV
 HDTV provides high resolution in a 16:9 aspect ratio.
 The broadcast industry promulgated an ultra-high-resolution, 1920
× 1080 interlaced format (1080i).
 BUT the computer industry wanted a 1280 × 720 progressive-scan
system (720p) for HDTV.
 Both formats have been included in the HDTV standard by the
Advanced Television Systems Committee (ATSC).
DISPLAYS
DISPLAYS
 cathode ray tube (CRT): Colored phosphors screen glow red,
green, or blue when they are energized by an electron beam.
DEGAUSSING
FLAT SCREEN
 Liquid-crystal display (LCD) is a flat panel display, electronic visual
display, or video display that uses the light modulating properties of liquid
crystals. Liquid crystals do not emit light directly.
 Plasma: the technology utilizes small cells containing electrically
charged ionized gases, or what are in essence chambers more commonly
known as fluorescent lamps.
INTERLACING
COMPARISON
OVERSCAN/ UNDERSCAN
MPEG
MPEG-1
MPEG-2
• 1.2 Mbps of video • higher data rates
• 250 Kbps of two(3 to 15 Mbps).
channel stereo
• higher image
audio using CDresolution.
ROM technology. • multiresolution
scalability.
• Standard for
Digital TV and
DVDs.
MPEG-4
• It offers indexing,
hyperlinking,
querying,
browsing,
uploading,
downloading.
• Virtual Reality
SHOOTING AND EDITING
VIDEO
 Fast processor(s)
 Plenty of RAM
 Computer with FireWire (IEEE 1394 or i.Link) or USB connection
and cables
 Fast and big hard disk(s)
 A second display to allow for more real estate for your editing software
 External speakers
 Nonlinear editing (NLE) software
SHOOTING PLATFORM
STORYBOARD
CHROMA KEY
 Chroma keys allow you
to choose a color or range
of
colors
that
become
transparent, allowing the
video image to be seen
“through” the computer
image.
WHITE BALANCE
LINEAR EDITING
NON LINEAR EDITING