Television Standards
• B&W TV– EIA - (Electronic Industry Association) originally
defined the 525 line 30 frame per second, 1:2 interlace, two fields per video frame
– CCIR standards body that originally defined the 625 line 25 frames per second
• Color TV– NTSC - National Television Standards Committee – PAL - Phase Alternating Line– SECAM - Système Électronique pour Couleur avec
Mémoire
Television Standards
The Main Video Signal Standards
Name Frame/Field rate Aspect Ratio Scan Lines
TV standard Color System Sub carrier Freq
NTSC 29.97/59.94 4:3 525
EIA NTSC 3.58MHz
PAL 25/50 4:3 625
CCIR PAL 4.43MHz
SECAM 25/50 4:3 625
CCIR SECAM 4.25/4.40MHz
Pal/Secam – Better colors/Better picture/More Flicker
Television
• Brain– If you divide a still image into a collection of
small colored dots, your brain will reassemble the dots into a meaningful image,
– If you divide a moving scene into a sequence of still pictures and show the still images in rapid succession, the brain will reassemble the still images into a single moving scene.
Television
• The Cathode Ray Tube (CRT)– the "cathode" is a heated filament – The heated filament is in a vacuum created inside a
glass "tube." – The "ray" is a stream of electrons that naturally pour
off a heated cathode into the vacuum. – the stream of electrons is focused by a focusing
anode into a tight beam and then accelerated by an accelerating anode.
– hits the flat screen at the other end of the tube which is coated with phosphor, which glows when struck by the beam.
Television (B&W)
• In a black-and-white TV, the screen is coated with white phosphor and the electron beam "paints" an image onto the screen by moving the electron beam across the phosphor a line at a time.
• "raster scan" pattern • 480 lines visible from top to
bottom• Aspect ratio: 4:3 equivalent to
640 x 480 (VGA) interlaced, 320x240 non-interlaced.
525
lines
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itted
480
Line
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Television
• interlacing technique:– the screen is painted 60 times per second but only
half of the lines are painted per frame. The beam paints every other line as it moves down the screen -- for example, every odd-numbered line. Then, the next time it moves down the screen it paints the even-numbered lines, alternating back and forth between even-numbered and odd-numbered lines on each pass. The entire screen, in two passes, is painted 30 times every second.
• progressive scanning (digital video cameras):– paints every line on the screen 60 times per second.
Television (Color)
• A color TV screen differs from a B&W screen in three ways: – There are three electron
beams that move simultaneously across the screen. They are named the red, green and blue beams.
– the screen is coated with red, green and blue phosphors arranged in dots or stripes.
– very close to the phosphor coating, there is a thin metal screen called a shadow mask. This mask is perforated with very small holes that are aligned with the phosphor dots (or stripes) on the screen.
Television (HDTV, DTV)
• Supports:– 480p - 640x480 pixels progressive – 720p - 1280x720 pixels progressive – 1080i - 1920x1080 pixels interlaced – 1080p - 1920x1080 pixels progressive
• uses MPEG-2 encoding
Television (HDTV)
• 210,000 pixels vs. 2 million pixels
• 10 x more picture detail
• Better Sound (AC-3, Dolby Digital)
Monitors
• The CRT and electronics in a monitor are much more precise than is required in a TV
• a lot more pixels and has a much crisper display
Coaxial cable
• Coaxial cabling is the primary type of cabling used by the cable television industry,
• can carry information for a great distance,
• multiple signals,• includes one physical
channel - supplies both video and monaural audio signals on the same line,
• altered by modulation to higher frequency.
Audio/Video Cables (Composite)
• Provide better video picture quality and add stereo sound compatibility,
• combines the three basic elements of a video picture (color, brightness, and synchronization data) into a single combined ("composite") signal.
• video signal has not yet been altered by modulation
• Commonly used.
S-Video Cable
• Allows portions of the video signal to be processed separately, resulting in sharper images with finer detail,
• splits the video signal to two parts (luminance and color),
• need to connect an audio cable.
Component video Cable
• High-end DVD players, satellite receivers and HDTV’s utilize Component Video,
• need to connect an audio cable,
• splits the video signal up into three separate components (Y/Pb/Pr) for preserving high resolution and accurate color rendition.
• can provide the highest quality pictures available today, with bright crisp colors and excellent fine picture detail.
RGB
• RGBHV (15 pin High Density D-Type connector ) (VGA)
1: Red out 6: Red return 11: Monitor ID 0 in
2: Green out
7: Green return
12: Monitor ID 1 inor data from display
3: Blue out 8: Blue
return 13: Horizontal
Sync out
5: Ground 10: Sync
return 15: Monitor ID 3 in
or data clock
FireWire
• IEEE 1394, i.Link, Lynx• fast external bus standard,• data transfer rates of up to 400Mbps (in 1394a)
and 800Mbps (in 1394b),• can be used to connect up 63 external devices,• supports both Plug-and-Play and hot plugging,• provides power to peripheral devices,• FireWire cables can run as long as 4.5 meters, • ideal for devices that need to transfer high levels
of data in real-time, such as video devices.
USB (Universal Serial Bus )
• External bus standard,• maximum data rate of 12 Mbps,• connect up to 127 devices,• supports both Plug-and-Play and hot plugging,• provides power to peripheral devices• cables can run as long as 5 meters; with hubs,
devices can be up to 30 meters (six cables' worth),
• the USB 2.0 20x faster than USB 1.1
FireWire vs. USB
Feature USB FireWire 1.1 2 400 800Data transfer rate 12 Mbps 480 Mbps 400 Mbps 800 MbpsNumber of devices 127 127 63 63Cable type 4 wires 3 wires 6 wires 8 wiresNetwork topology Hub Hub
Daisy chain
Daisy chain
Camcorders(Analog)
• VHS– resolution of about 230 to 250 horizontal lines
• SVHS– resolution of about 380 to 400 horizontal lines
• 8mm– Compact– Resolution is about the same size as VHS
• Hi-8– Resolution is about 400 horizontal lines
Camcorders (Digital)
• MiniDV– resolution of 500 horizontal lines– lightweight and compact
• Digital 8– Similar to regular DV camcorders, but they
use standard Hi-8-mm tapes
Digital Video Formats
FORMAT Resolution
NTSCResolution
PALVideo
CompressionVideobitrate
VCD 352x240 352x288 MPEG1 1150kbps SVCD 480x480 480x576 MPEG2 ~2000kbps
DVD 720x480 720x576 MPEG2,
MPEG1~5000kbps
HDDVD HDTV (WMVHD)
1920x1080 1280x720 MPEG2 (WMX, MPEG4)
~20Mbps (~8Mbps)
AVI DivX XviD WMV 640x480 MPEG4 ~1000kbps
MOV Quick- Time
640x480 Sorenson, Cinepak, MPEG4 ...
~1000kbps
RM Real- Media 320x240 RM ~350kbps AVI DV 720x480 720x576 DV 25Mbps
http://www.videohelp.com/dvd
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