The document is a seminar presentation by Anirudh Kannan focusing on HDTV technology and scanning techniques, covering topics like A/V transmission, audio and video formats, and pixel resolution. It explains key concepts such as luminance, chrominance, frame rates, and the benefits of progressive vs. interlaced video. The conclusion recommends 1080p as the preferable option for high-definition video due to its better clarity and detail.

1. Seminar
HDTV Technology
&
Scanning Techniques

2. Presented by :
Anirudh Kannan

3. Topics to be Covered
• A/V Reception & Transmission
• Video & Audio formats
• Luminance, Chrominance & Loudness
• Pixels and Resolution
• Aspect Ratio
• Frames
• Scanning techniques
• 1080i or 720p or 1080p?

4. A/V Transmission and Reception
(Broadcasting)

5. A/V Transmission or Broadcasting is the distribution
of audio and video content to a dispersed audience via
any audio or visual mass communications medium, but
usually one using electromagnetic radiation (radio waves).
The receiving parties may include the general public or a
relatively large subset thereof.
Broadcasting has been used for purposes of private
recreation, non-commercial exchange of messages,
experimentation, self-training, and emergency
communication in addition to commercial purposes like
popular radio or TV stations with advertisements.

6. A/V Transmission & Reception System

7. Video & Audio Formats

8. Audio Formats
• An audio file format is a file format for storing digital
audio data on a computer system. This data can be stored
uncompressed, or compressed to reduce the file size. It can
be a raw bit stream, but it is usually a container format or an
audio data format with defined storage layer.
• Some of the major Audio Formats used for broadcasting and
transmission are WAV, MP3, AAC, FLAC, m4a, wma

9. Video formats
• Uncompressed video delivers maximum quality, but with a very
high data rate. A variety of methods are used to compress video
streams, with the most effective ones using a Group Of
Pictures (GOP) to reduce spatial and temporal redundancy.
• Broadly speaking, spatial redundancy is reduced by registering
differences between parts of a single frame; this task is known
as intra-frame compression and is closely related to image
compression. Likewise, temporal redundancy can be reduced by
registering differences between frames; this task is known as inter-
frame compression, including motion compensation and other
techniques.
• The most common modern standards are MPEG-2, used
for DVD, Blu-ray and satellite television, and MPEG-4, used for
Mobile phones (3GP) and Internet.

10. Luminance, Chrominance & Loudness

11. In scientific terms, the brightness of light is measured in
terms of Luminance or Luma. The word ‘Luminance’ is
directly defined by CIE in relation to human vision. It is
represented by the letter Y as far as video is concerned.
Chrominance or chroma represented by C is the signal used
in video systems to convey the color information of the
picture, separately from the accompanying luma signal (or Y
for short).
Loudness is the characteristic of a sound that is primarily a
psychological correlate of physical strength (amplitude).

12. Luminance only, Chrominance only & Full Color Image

13. Frames, Pixels & Resolution
The quality of a display system depends on it’s resolution,
how many pixels it could display and how many bits are
used to display each pixel!

14. Frame
• In filmmaking, video production, animation, and
related fields, a film frame or video frame is one
of the many still images which compose the
complete moving picture.
• When the moving picture is displayed, each
frame is flashed on a screen for a short time
(nowadays, usually 1/24, 1/25 or 1/30 of a
second) and then immediately replaced by the
next one. This is called Frame Rate. Persistence of
vision blends the frames together, producing
the illusion of a moving image.

15. Pixels
• Pixel or picture element is a physical point in a bitmap image
or the smallest addressable element in all points addressable
display device, like TV/computer screen. Hence, it is the
smallest controllable element of the picture represented on
the screen.
• Monitors/Screens display pictures by dividing the display
screen into thousands or millions of pixels, arranged in rows
and columns. The pixels are so close together that they
appear connected.
• The number of bits used to display each pixel determines how
many colours or shades of grey can be displayed. Eg. In 8-bit
color mode, the color monitor uses 8 bits for each pixel,
displaying 2^8 or 256 different colours

16. Rough Idea of Pixels!

17. Resolution
• The display resolution of a digital television, computer monitor or display device is
the number of distinct pixels in each dimension that can be displayed. It can be an
ambiguous term especially as the displayed resolution is controlled by different
factors in cathode ray tube (CRT), flat-panel display which includes liquid-crystal
displays, or projection displays using fixed picture-element (pixel) arrays.
• It is usually quoted as width × height, with the units in pixels: for example, "1024 ×
768" means the width is 1024 pixels and the height is 768 pixels. This example
would normally be spoken as "ten twenty-four by seven sixty-eight" or "ten
twenty-four by seven six eight".
• High-definition television (HDTV):
– 720p (1280 × 720 progressive scan)
– 1080i (1920 × 1080 split into two interlaced fields of 540 lines)
– 1080p (1920 × 1080 progressive scan)
• CRT television:
– 480i (Analog system of 486i split into two interlaced fields of 240 lines)
– 576i (720 × 576 split into two interlaced fields of 288 lines)

18. Aspect Ratio

19. Aspect ratio describes the dimensions of video screens and video
picture elements. All popular video formats are rectilinear, and so
can be described by a ratio between width and height. The screen
aspect ratio of a traditional television screen is 4:3. High definition
televisions use an aspect ratio of 16:9.
The aspect ratio of an image describes the proportional
relationship between its width and its height.
It is commonly expressed as two numbers separated by a colon, as
in 16:9. For an x:y aspect ratio, no matter how big or small the
image is, if the width is divided into x units of equal length and the
height is measured using this same length unit, the height will be
measured to be y units.

20. Lets See How The HDTV looks like
as compared to standard
definition TV!

21. 4:3 Aspect Ratio in CRT TV 16:9 Aspect Ratio in HDTV
4 units
3units
16 units
9units

23. Scan Video Signals

24. Video signals are of two types
1. Progressive Scan Video
Video sources that are listed with the letter p are called
progressive scan signals. Examples of this would be 480p, 720p
or 1080p. Progressive scan video content displays both the even
and odd scan lines at the same time
2. Interlaced Scan Video
Video sources that are listed with the letter i are called
interlaced scan video. An example of this would be 480i or 1080i.
Interlaced video displays even and odd scan lines as separate
fields. The even scan lines are drawn on the screen, then the odd
scan lines are drawn on the screen. Two of these even and odd
scan line fields make up one video frame.

25. Interlaced Scan

28. Progressive Scan

30. Interlaced & Progressive Scan

31. Progressive or Interlaced!
• The advantage of progressive
scan is clearer picture with more
detail, contrast and crisper lines.
This is achieved because the
entire picture is on the screen at
once.
• The primary drawback to
progressive video, at least until
very recently, was the higher
bandwidth requirement. It
requires double the bandwidth
required by interlaced Scan.
Higher the bandwidth higher will
be the cost.
• The main benefit of interlaced
video is that it allows more
detailed images to be created
than would otherwise be possible
within a given amount of
bandwidth
• interlaced video comes with real-
world downside, including image
softening that occurs during fast-
motion sequences as well as
strobing effects that sometimes
appear when striped shirts, plaid
jackets, bricks in a building, or
similar types of objects are shown

32. Conclusion: 1080i or 720p or 1080p?

33. 1080p!
• Using progressive 1080p with 60 full frames per second in the future has a
potential to eventually solve the problems of interlaced scan or 1080i but
it will require a whole new range of studio equipment including cameras,
storage and editing systems which are coming up soon.
• Currently the only way to have a fluid motion with progressive scanning in
most countries is 720p that has a frame rate that is two times faster than
1080p but the resolution of only 1280 × 720 pixels (instead of 1920 × 1080
pixels) which may be a problem for some applications and you will have to
compromise with the screen resolution!
• In fact, all digital, non-CRT displays are natively progressive, and any
interlaced video signals they receive must be converted, or "de-
interlaced", to the progressive format before they can be displayed.
If your are going to buy a new HDTV in near future, go for a
1080p!!