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Hdtv technology
HDTV provides higher quality digital video broadcasts compared to analog television. It offers improved resolution, reduced noise and ghosting, and additional audio/data services. HDTV transitioned from analog to digital broadcasts and its adoption is growing. Key aspects include higher pixel counts, different display technologies like plasma and DLP, and higher frame rates that reduce motion blur compared to standard definition. HDTV connectivity requires components that support digital signals and higher resolutions. Its impact includes increased spending on equipment and production quality.
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Hdtv technology
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- 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 OvercomeLimitations 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 • Early1980’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 than15% of US homes have HDTV capabilities • Approximately 21% of stations have digital broadcasts
- 7. High Definition Television Astandard 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
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- 9. Implementation - Displaytechnologies • 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.
- 10. Motion Blur A sequenceof images such of a movie or animation
- 11. HD TV ScreenRefresh 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
- 12. Technical Aspects Interlaced display
- 13. Frame rate conversion- 3-2 pulldown
- 14. What is aformat? 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 Highdefinition 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 & SDTVComparison • Judging simply on pixel count, a 1080i HDTV image is 6 - 9 times better than a standard, NTSC image • Audio is also improved.
- 17. HDTV & SDTVComparison
- 18. Advantages • By usinglower-definition signals, one channel can be split into several channels • Extra channels used for: – information services (datacasting) – music – Internet services
- 19. HDTV Features • Providesup 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 AnalogTV 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 DigitalTV 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.
- 26. Questions 26
Editor's Notes
- #4 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.
- #15 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’
- #16 Archiving uncompressed high definition requires far more storage capacity than SD. ( 5 to 10 times more ) . So , to archive HD, compression could be required
- #22 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.
- #23 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.