2. Outline
•Introduction
•HD-History
•Architecture
•Characteristics of HD standard
•Difference b/w HD & Analog
•Future of HD
•Summary
•Conclusion
•Refrences
3. WHY HD
To Overcome Limitations
of Analog Television
• Noise free pictures
• Higher resolution images
Widescreen / HDTV
• No Ghosting
• Enhanced Sound Services
• Other Data services.
3
4. High Definition Television
DEFINITION: HDTV is generally recognized as a digital
video broadcast with a minimum resolution of 1280
pixels wide and 720 pixels high, a rate of 30 or more
frames/second and usually an aspect ratio of 16:9.
4
5. HDTV History
• Early 1980’s:
– Japan created analog HDTV
• Mid-1980s:
– US, trying to stay competitive, decided to go
digital
– Congress gave stations a separate channel for
transition to digital broadcast with the goal of all
stations using digital broadcasts by 2006.
6. Currently...
• Less than 15% of US homes have HDTV
capabilities
• Approximately 21% of stations have digital
broadcasts
7. High Definition Television
A standard definition analog television uses a
cathode ray tube with an electron gun to guide
the path of an electron beam to “paint” 480
vertical lines across the face of the screen. Each
time the beam strikes a dot of phosphor, light is
produced. For a color television set, each spot
consists of a group of three phosphor elements;
one for each primary color.
7
9. Implementation - Display technologies
• Plasma – Like LCD monitors, plasma HDTV sets are thin and are made up of cells
that correspond to pixels sandwiched between glass plates. Plasma cells contain three
separate gas-fill sub-cells, one for each color. When a current is applied to a sub-cell,
it ionizes the gas emitting ultraviolet light. The ultraviolet light in turn excites
fluorescent substances in the sub-cells that emit red, blue or green light.
• DLP – Digital light processing is a technology used in projection displays. In DLP
monitors, light is reflected off an array of microscopic hinged mirrors. Each tiny
mirror corresponds to a visible pixel. The light is channeled through a lens onto the
surface of the screen. Single chip DLP projectors can display 16.7 million colors. 3-
chip projectors can display 35 trillion colors.
• LCoS – Similar to DLP, LCoS projection systems use liquid crystals instead of mirrors
to block light. The liquid crystals are arranged in a grid in front of a highly reflective
surface.
11. HD TV Screen Refresh Rates
•A rate of 24 frames/second (progressive) has
been the movie film standard since the mid-20’s
•The television industry has used a rate of 60
frames/second (interlaced) since the 40’s
•Newer HDTV’s are being marketed as 120 Hz
and 240 Hz using circuitry to help reduce motion
blur
11
14. What is a format?
Formats are described by:
Number Number
Scanning Picture Frame rate
of active pixels of active lines
mode aspect ratio
per line per frame
Current main standards are:
SMPTE 274 M SMPTE 296 M
14
15. Archiving High definition
High definition video Standard definition video
1980 pixels 1080 lines 720 pixels 576 lines
1- hour programme file size : 1- hour programme file size :
from374 GB to 673 GB* 72 GB
To archive HD, Compression
could be required.
15
16. HDTV & SDTV Comparison
• Judging simply on pixel count, a 1080i HDTV
image is 6 - 9 times better than a standard, NTSC
image
• Audio is also improved.
18. Advantages
• By using lower-definition signals, one channel
can be split into several channels
• Extra channels used for:
– information services (datacasting)
– music
– Internet services
19. HDTV Features
• Provides up to 60 frames/sec screen writing
rate
• Uses MPEG-2 data compression
– source info data rate is 1.2Gbps
– broadcast data rate is 20Mbps
• Square pixels 1/4 the size of analog TV’s pixels
20. Type Of HDTV
Type Advantage Disadvantage
Heavy, max screen size limited,
Direct View (CRT) Cheap (if you can find one)
soon to be obsolete
Competitive price, suitable for rooms Motion blur more apparent than
LCD
with high ambient light Plasma
Brighter colors, less motion blur, wider More power consumption than
Plasma
viewing angle LCD, less competitive price
More bulky then flat panel, more
Rear Projection Larger screen size at lower cost
components to fail
Costly installation, not suitable for
Front Projection Best solution for screens over 60 inches
rooms with high ambient light
20
21. Connecting To Analog TV
Composite DVD
Or S-Video
Composite
or or S-Video
Composite or Composite From VCR
(if available) or S-Video
S-Video From VCR
COAX
VCR
22. Connecting To Digital TV
Digital Signal from Cable or Satellite
Component,
Composite DVD
Or S-Video
or Composite
or S-Video
Component From VCR
Or HDMI
Composite or
COAX S-Video
Cable or Satellite VCR
23. Impact of HDTV
• Broadcasters & consumers spend more $
• Increased visual clarity has forced designers to spend
considerably more money on sets, set dressings
• Blu-Ray vs HD-DVD
24. Future of HD
• DEC 2012: All commercial stations must begin
digital broadcasts
• Move will be cheaper, quicker, and easier as products
and services become more widespread and people
grow accustomed to the new technology.
• Super HD TV
25. Conclusion
• As NTSC retires, HDTV programming, products, and
production services will continue to grow exponentially.
• HDTV has brought a more cinematic experience into
viewer’s homes and with digital cinema, delivered the film
industry a few of the benefits of television. However,
HDTV still has much lower resolution than 70mm film.
It’s a matter of time before some will begin pressuring for
another increase in quality.
The average domestic TV in Australia has all sorts of distortions. Digital TV will remove those distortions. Just like a CD, you never hear a scratched CD. It’s either perfect or it’s nothing.
A Format is described by: The number of active pixels per line, the number of active lines per frame. Then, it is completed, by the scanning mode, the aspect ratio and the frame rate. Current main standards are: SMPTE 274 M SMPTE 296 M and finally, ITU R BT 709 5. 30’
Archiving uncompressed high definition requires far more storage capacity than SD. ( 5 to 10 times more ) . So , to archive HD, compression could be required
That would also work with satellite or cable set top boxes. Your provider will give, sell, or rent you the appropriate set top box that puts out an analog signal even though it is receiving a digital signal from their service. Your VCR and DVD player would still operate in analog. Older or cheaper analog TVs may not have enough Composite or S-Video connectors to connect all your accessories, but most newer or higher quality sets should have enough.
A digital TV should work fine with the appropriate cable or satellite set top box. Most digital TVs are expected to be able to display an analog signal, so your VCR and DVD player should still work as players. It may depend on the set top box (check with your provider) whether it will also be able to output an analog signal to the VCR for recording video. Future (HD or Blue Ray) DVD players (or recorders) will output a digital signal, so they will be connected to a digital TV via component or HDMI connectors. It’s unclear whether any STBs will be able to output an analog signal (for your VCR). So, VCRs may not be able to record in a digital world. Some DVDs are able to record, so it’s assumed, that they can record a digital signal, but that may only be true of the newer DVD recorders.
